JP6529959B2 - Screw tightening device and screw tightening system - Google Patents

Description

  Embodiments disclosed herein relate to a screw tightening device and a screw tightening system.

  2. Description of the Related Art Conventionally, among screw tightening devices that automatically tighten a screw, there is a screw tightening device that enables the bit holding portion to be replaced depending on the type and size of the screw.

  Such a screwing device rotationally drives the bit engaged with the screw and tightens or loosens the screw, but linearly drives the bit to follow the axial movement of the screw to be loosened (air cylinder etc. Is generally provided.

  In addition, in such a screw tightening device, a transmission mechanism for transmitting a linear drive force from the drive source to the bit is provided between the drive source for the linear drive and the bit holding unit for holding the bit (for example, Patent Reference 1).

Unexamined-Japanese-Patent No. 2006-95624

  However, since the conventional screw tightening apparatus as described above has a linear drive power source and a transmission mechanism of a linear driving force leading to the bit holding section, the diameter of the bit holding section becomes large, and the entire apparatus is also The structure was complex and large.

  In addition, when such a screw fastening device is used in a narrow place or the like, there may be a problem of interference with the surroundings. Therefore, the conventional screw fastening device has limited available places.

  One aspect of an embodiment is made in view of the above, and it aims at providing a screw fastening device and a screw fastening system which can make a diameter of a bit holding part small.

The screw fastening device according to one aspect of the embodiment includes a bit holding portion, a pressing portion, a main body portion, and an attaching / detaching portion. The bit holding portion has a rotating portion that is rotated by a driving force around an axis and a linear moving portion that linearly moves according to the external force in the axial direction, and the bit is closer to the tip than the linear moving portion. And coaxially hold. The pressing portion is provided in the bit holding portion coaxially with the bit, and the bit is elastically deformed and compressed by pressing the bit against the screw, and the linear moving portion is fixed until the loosening of the screw is completed. The spring is a spring that is linearly driven so as to always press the bit against the screw to be loosened and always follow the movement of the screw while always pressing the tip side. The main body portion supports the bit holding portion. The attaching / detaching portion is provided in the main body portion, and the distal end side of the bit holding portion is detachably attachable to the main body portion.

  According to one aspect of the embodiment, the bit holder can be reduced in diameter.

FIG. 1 is a schematic partial cross-sectional view of the screw fastening device according to the first embodiment. FIG. 2A is a front view of a screw fastening device. FIG. 2B is a right side view of the screw tightening device. FIG. 2C is a cross-sectional view taken along line B-B shown in FIG. 2B. FIG. 2D is an enlarged view of the housing shown in FIG. 2C. FIG. 3A is a cross-sectional view showing the attachment / detachment mechanism. FIG. 3B is a cross-sectional view showing the attaching / detaching mechanism. FIG. 4 is a perspective view showing the alignment mechanism. FIG. 5 is an explanatory view of the operation of each part when gripping a screw. FIG. 6 is a cross-sectional view of the bit holding portion when gripping a screw. FIG. 7 is a perspective view of the screw fastening device according to the second embodiment. FIG. 8A is a cross-sectional view showing the attachment / detachment mechanism. FIG. 8B is a cross-sectional view showing the attaching / detaching mechanism. FIG. 9 is a schematic view showing a screw tightening system. FIG. 10 is a functional block diagram of a screw tightening system. FIG. 11A is a flowchart showing the timing of opening and closing the chuck. FIG. 11B is a flowchart showing the timing of opening and closing the chuck.

  Hereinafter, embodiments of the disclosed screwing device and screwing system will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited by the embodiments described below.

First Embodiment
FIG. 1 is a schematic partial cross-sectional view of the screw fastening device according to the first embodiment. Specifically, FIG. 1 shows the internal configuration of the bit holding unit by making the bit holding unit a cross section. In addition, the screwing apparatus described below can loosen not only the screw but also the screw.

  Further, the screws to be loosened by such a screw tightening device include bolts and the like. Here, the term "screw" is used as a generic term for a fastening member provided with a spiral groove such as a bolt.

  As shown in FIG. 1, the screw tightening device 10 includes a main body portion 11, an attaching / detaching portion 17, a bit holding portion 18, and a pressing portion 27. The main body portion 11 supports a bit holding portion 18 engaged with a screw to be loosened, and outputs a driving force around the axis AX toward the bit holding portion 18. The main body 11 is provided with an output shaft described later on the tip side in the direction of the axis AX.

  Further, the attaching / detaching portion 17 is provided on the front end side of the main body portion 11, and the distal end side of the bit holding portion 18 is detachably attached to the main body portion 11 so that the main body portion 11 and the bit holding portion 18 are coaxial. In addition, although the attaching / detaching part 17 is provided with the attaching / detaching mechanism for making the bit holding | maintenance part 18 detachable with respect to the main-body part 11, this point is mentioned later.

  Further, the bit holding portion 18 includes a housing 19, and coaxially holds a bit 20 engaged with a screw loosened by the screw tightening device 10 on the distal end side of the housing 19.

  Specifically, the bit holding unit 18 further includes a socket 21 and a joint 24. The socket 21 is coaxially disposed inside the housing 19. A joint 24 coaxially disposed inside the housing 19 is connected to the distal end side of the socket 21. A bit 20 is coaxially connected to the tip end of the joint 24.

  In the bit holding portion 18, the housing 19, the socket 21 and the joint 24 disposed inside the housing 19, and the bit 20 connected to the joint 24 are coaxially arranged in series.

  That is, the respective portions (housing 19, socket 21, joint 24, and bit 20) of the main body 11, the bit holding portion 18, and the bit holding portion 18 are coaxial. The axes AX shown in FIG. 1 are these common axes.

  In the following description, the upper side (upper end side of the main body 11) in the figure may be referred to as the end side, and the lower side (lower end side of the bit 20) may be referred to as the tip side.

  The socket 21 will be described in more detail below. As shown in FIG. 1, the socket 21 includes a rotating portion 22 and a linear moving portion 23. The rotating portion 22 is provided between the outer peripheral surface of the cylindrical main body in the socket 21 and the inner peripheral surface of the housing 19. The rotating portion 22 supports the socket 21 rotatably around an axis AX.

  The linear movement portion 23 is provided on the inner peripheral surface of the socket 21 main body. The linear movement portion 23 allows the socket 21 to be linearly moved in the direction of the axis AX with respect to a torque transmission shaft described later, and can not rotate around the axis AX.

  The bit holding portion 18 has the socket 21 (the rotating portion 22 and the linear moving portion 23) to hold the bit 20 so as to be rotated by the driving force around the axis AX and to linearly move according to the external force in the axis AX direction. Do.

  By the way, in the screwing device 10, when the screw is tightened or loosened, it is necessary to make the bit 20 follow the movement of the screw to be loosened in the direction of the axis AX to maintain the engagement between the bit 20 and the screw.

  Conventionally, a linear motion drive source such as an air cylinder for linearly driving the bit is provided on the main body side, and such a linear motion drive source precisely controls the drive so that the bit follows the axial movement of the screw Configuration.

  Further, in the conventional screw tightening device, a transmission mechanism for transmitting the driving force from the drive source to the bit is provided between the linear drive source and the bit.

  Therefore, in the conventional screw tightening device, the transmission mechanism is disposed from the main body side to the bit holding portion side, and the diameter of the bit holding portion is large. In addition to the transmission mechanism, there is a linear drive source, and the entire apparatus is also complicated in structure and large in size.

  Therefore, in the screw tightening device 10 according to the first embodiment, the pressing portion 27 for pressing the bit 20 to the tip side is provided instead of the linear drive source. Further, as shown in FIG. 1, the pressing portion 27 is provided in the bit holding portion 18.

  By providing the pressing portion 27 in the bit holding portion 18 instead of the linear drive source, the bit 20 can follow the movement of the screw in the direction of the axis AX. Moreover, since the pressing portion 27 presses the socket 21 coaxially connected to the end side of the bit 20, the pressing portion 27 can be provided on the end side of the bit holding portion 18. That is, it is not necessary to provide the pressing portion 27 on the outer peripheral side of the socket 21.

  As a result, the bit holding portion 18 can be reduced in diameter. Furthermore, the linear drive source and the transmission mechanism are not required, and the screw tightening device 10 can be miniaturized with a simple structure.

  In the screw tightening device 10 according to the first embodiment, the pressing portion 27 is provided inside the housing 19, and the pressing portion 27 is a spring. Furthermore, a drive source for driving the mounting and demounting unit 17 is provided on the main body unit 11 side. Such a configuration will be described later with reference to FIG. 2A and the like.

  Hereinafter, the screw fastening device according to the first embodiment will be described in more detail with reference to FIGS. 2A to 2D. FIG. 2A is a front view of a screw fastening device. FIG. 2B is a right side view of the screw tightening device. FIG. 2C is a cross-sectional view taken along line B-B shown in FIG. 2B. FIG. 2D is an enlarged view of the housing shown in FIG. 2C. In addition, the hatching part shown to FIG. 2B is an AA line cross section shown to FIG. 2A.

  Further, an axis AX shown in FIGS. 2A to 2D is an axis common to the respective parts of the screw tightening device 10. As in the description of FIG. 1, the main body 11 side is referred to as the distal side, and the bit 20 side is referred to as the distal side. These are the same in the description with reference to FIG.

  As shown in FIGS. 2A and 2B, the screw tightening device 10 includes a main body 11, a mounting and demounting unit 17, a bit holding unit 18, and a pressing unit 27. The screw tightening device 10 is a so-called nut runner that automatically tightens (or loosens and removes) a screw.

  As shown in FIGS. 2A and 2B, the main body portion 11 includes a flat base 12 and a cylindrical housing 13 provided on the upper surface of the base 12 and elongated in the axis AX direction. In the upper surface of the base 12, in addition to the housing 13, a first drive source 28 for driving the attaching / detaching portion 17 and a block 14 gripped by a hand 97 (see FIG. 9) of a robot 90 described later are disposed.

  Also, a servomotor M (see FIG. 10), a reduction gear (not shown), etc. are arranged in series inside the housing 13 from the end of the main body 11 to the end of the base 12. Be done.

  As shown in FIG. 2C, the main body 11 further includes an output shaft 15 that extends coaxially with the axis AX from the tip end surface, that is, the lower surface of the base 12. The output shaft 15 outputs the driving force around the axis AX output from the servomotor M (see FIG. 10) to the bit holding unit 18. The tip end side of the output shaft 15 is formed into a rectangular axis, and the torque transmission shaft 16 is coaxially connected to the tip side which is a rectangular axis.

  Thus, the main unit 11 outputs the driving force around the axis AX from the servomotor M (see FIG. 10) to the bit holding unit 18 via the output shaft 15 (torque transmission shaft 16), and the bit holding unit The bit 20 held at 18 is rotationally driven. That is, the main body unit 11 is a drive unit that drives the bit 20.

  In the main body portion 11, by outputting the driving force from the servomotor M to the bit holding portion 18 via the reduction gear, torque necessary for tightening and loosening of the screw can be obtained. The main body 11 also includes a torque detector (not shown) that detects the torque of the screw to be loosened.

  As shown in FIGS. 2A and 2B, the main body portion 11 is provided with a detachable portion 17 on the lower surface of the base 12. The attaching / detaching portion 17 attaches the bit holding portion 18 to the lower surface of the base 12 so as to be coaxial with the main body portion 11. The attaching / detaching unit 17 includes an attaching / detaching mechanism that makes the bit holding unit 18 attachable / detachable. Details of the attachment / detachment mechanism will be described later with reference to FIGS. 3A, 3B, and 4.

  As shown in FIGS. 2A and 2B, the bit holding portion 18 includes a cylindrical housing 19 and holds the bit 20 on the distal end side of the housing 19.

  The bit 20 engages the head of the screw to rotate the screw around the axis AX (clockwise or counterclockwise). The bit 20 is replaceable, and may be replaced according to the type and size of screw, or may be replaced with a new one due to wear or deterioration.

  As shown in FIGS. 2C and 2D, the bit holding unit 18 further includes a socket 21 and a joint 24. The bit holding portion 18 holds the bit 20 via a socket 21 and a joint 24 disposed inside the housing 19.

  As shown in FIG. 2C, the socket 21 is formed in a tubular shape and disposed coaxially with the housing 19 inside the housing 19. The distal end side of the socket 21 is connected to a joint 24 coaxially disposed inside the housing 19 similarly to the socket 21.

  As shown in FIG. 2D, the inner circumferential surface of the housing 19 is provided with a protrusion 19a that protrudes toward the axis AX. The protrusion 19 a is provided to be slightly larger in diameter than the outer peripheral surface of the socket 21. The socket 21 is disposed inside the housing 19 in a state of being regulated along the axis AX direction by the projecting portion 19 a.

  The socket 21 includes a rotating unit 22 and a linear moving unit 23. The rotating portion 22 is provided between the outer peripheral surface of the cylindrical main body of the socket 21 and the inner peripheral surface of the housing 19 at the distal end side. The rotating portion 22 is a bearing, and rotatably supports the socket 21 main body around the axis AX. For example, a needle bearing can be used as the rotating portion 22.

  The linear movement portion 23 is provided on the inner peripheral surface of the socket 21 main body. The linear movement portion 23 allows the socket 21 to be linearly moved in the axis AX direction with respect to the torque transmission shaft 16 inserted in the axis AX direction from the distal end side of the socket 21 and can not rotate around the axis AX. Do.

  The torque transmission shaft 16 transmits the driving force around the axis AX output from the output shaft 15 of the main body 11 to the bit holder 18. The upper surface (end side end surface) of the torque transmission shaft 16 is provided with a rectangular recess which can be fitted with the rectangular shaft of the output shaft 15.

  The outer peripheral surface of the torque transmission shaft 16 is provided with a groove extending in the direction of the axis AX, a so-called spline. On the other hand, the linear movement portion 23 is formed in a cylindrical shape, and a spline that fits with the spline of the torque transmission shaft 16 is provided on the inner peripheral surface of the cylindrical body.

  The socket 21 is linearly moved in the direction of the axis AX following the external force in the direction of the axis AX by the linear moving portion 23 having such a spline structure. The socket 21 rests in a state where no external force is applied. In addition, the socket 21 is motively separated from the main body 11 side in the direction of the axis AX.

  As a configuration having a linear motion function other than the spline structure, for example, there is a configuration in which the torque transmission shaft 16 has a prismatic shape and the linear motion portion 23 has an inner circumferential shape into which the torque transmission shaft 16 can be fitted.

  As shown in FIG. 2C, the joint 24 connected to the front end side of the socket 21 follows the rotation of the socket 21 and rotates, and follows the linear movement of the socket 21 and linearly moves. A bit 20 is detachably connected to the tip end of the joint 24.

  As shown in FIGS. 2C and 2D, centering taper members 25 and 25 are provided between the inner peripheral surface of the housing 19 and the outer peripheral surface of the socket 21 when extending the bit 20 in the direction of the axis AX. Be The taper members 25, 25 are annularly formed along the inner peripheral surface of the housing 19 and the outer peripheral surface of the socket 21, and are arranged with their inclined surfaces facing each other.

  As shown in FIG. 2C, centering taper portions 26 and 26 are provided on the inner peripheral surface of the housing 19 and the outer peripheral edge on the distal end side of the joint 24 when the bit 20 is contracted in the direction of the axis AX. The tapered portions 26, 26 are provided along the inner peripheral surface of the housing 19 and the outer peripheral edge of the joint 24 with their inclined surfaces facing each other.

  As shown in FIG. 2C, inside the housing 19, a pressing portion 27 that presses the socket 21 to the tip end side is provided. The pressing portion 27 is, for example, a compression coil spring and coaxially disposed on the distal side of the socket 21.

  The socket 21 is always urged toward the tip side via the linear movement portion 23 by a spring which is the pressing portion 27. That is, the bit 20 integrally connected with the socket 21 and the joint 24 in the direction of the axis AX is pressed toward the tip side by the biasing force of the pressing portion 27 via the socket 21 and the joint 24.

  From here, the attaching / detaching mechanism of the attaching / detaching portion will be described with reference to FIGS. 3A and 3B. FIG. 3A is a cross-sectional view showing the attaching / detaching mechanism of the attaching / detaching portion (before mounting of the bit holding portion). FIG. 3B is a cross-sectional view showing the attaching / detaching mechanism of the attaching / detaching portion (after the mounting of the bit holding portion).

  As shown in FIG. 3A, the attaching / detaching portion 17 includes a pair of air cylinders 28, 28 as a first driving source. The pair of air cylinders 28, 28 is disposed concentrically with the axis AX at a phase difference of 180 degrees on the upper surface of the base 12 on the side of the main body 11.

  The telescopic rods 28 a, 28 a of the pair of air cylinders 28, 28 pass through the base 12 and the tip end side is disposed on the bit holding portion 18 side. The telescopic rods 28a, 28a are connected at their tip ends to the floating joints 29, 29 at the bit holding portion 18 side.

  The floating joints 29, 29 are connected to a flange portion 31 provided on the outer peripheral surface of the short cylindrical circular receiving portion 30. The circular receiving portion 30 is provided so as to be able to expand and contract in the direction of the axis AX, and expands and contracts in the direction of the axis AX following the expansion and contraction of the expansion rods 28a and 28a.

  The circular receiving portion 30 is provided with a circular recess 32 on the end surface on the tip side. The inner peripheral surface of the circular recess 32 is a tapered surface 33 provided to be inclined so as to expand in diameter. Further, the circular receiving portion 30 is provided with a communication hole 34 communicating from the main body portion 11 side to the bit holding portion 18 side.

  The cylindrical portion 35 is inserted into the communication hole 34. The output shaft 15 of the main body portion 11 is inserted into the cylindrical portion 35 in the mounting state of the bit holding portion 18. A tapered surface 36 is provided on the tip side inner peripheral edge of the cylindrical portion 35 so as to expand in diameter.

  A through hole 37 penetrating in the thickness direction is provided on the inner peripheral surface of the cylindrical portion 35. A steel ball 38 is disposed in the through hole 37. The opening diameter on the inner peripheral surface side of the through hole 37 is smaller than the diameter of the steel ball 38. The steel balls 38 are retracted into the space formed by the tapered surfaces 36 when the telescopic rods 28a, 28a of the air cylinders 28, 28 are contracted.

  On the other hand, a flange portion 39 is provided on the end side end surface of the bit holding portion 18 on the bit holding portion 18 side. At the end side end face of the flange portion 39, a circular convex portion 40 which can be fitted into the circular concave portion 32 on the side of the main body portion 11 is provided.

  A cylindrical portion 41 which can be fitted into the cylindrical portion 35 on the side of the main body portion 11 is provided at the end side end surface of the circular convex portion 40. A V-shaped groove 42 is provided on the end side of the outer peripheral surface of the cylindrical portion 41. The side circumferential surface of the circular convex portion 40 is provided with a tapered surface 43 which is inclined so as to decrease in diameter toward the distal end surface.

  As shown in FIG. 3B, when the bit holding portion 18 is attached to the main body portion 11, the cylindrical portion 41 on the bit holding portion 18 side is fitted into the cylindrical portion 35 on the main body portion 11 side. The output shaft 15 is inserted into the cylindrical portion 41. The output shaft 15 passes through the inner circumferential surface of the cylindrical portion 41 and enters the inside of the housing 19, and the distal end side is connected to the distal end side of the torque transmission shaft 16.

  At this time, when the cylindrical portion 41 on the bit holding portion 18 side reaches the position of the steel ball 38, the telescopic rods 28a, 28a are extended toward the bit holding portion 18 by the driving of the air cylinders 28, 28.

  In the state in which the telescopic rods 28 a and 28 a are extended, the steel balls 38 disposed in the through holes 37 are pushed out to the inner peripheral surface side of the cylindrical portion 35 by the inner peripheral surface of the communication hole 34 by a predetermined dimension. In addition, since the diameter of the inner peripheral surface side of the through hole 37 is smaller than the diameter of the steel ball 38, the steel ball 38 is restricted from protruding beyond a predetermined size.

  The steel ball 38 protruding by a predetermined dimension is fitted into the V-shaped groove 42 provided in the cylindrical portion 41 on the bit holding portion 18 side. When the steel ball 38 is fitted into the V-shaped groove 42, the tapered surface 36 of the cylindrical portion 35 on the main body portion 11 and the tapered surface 43 of the cylindrical portion 41 on the bit holding portion 18 abut.

  Thereby, the bit holding is performed by the force of the steel ball 38 pushing the V-shaped groove 42 and the force pushing the tapered surface 36 of the cylindrical portion 35 on the main body 11 side pushing the tapered surface 43 of the cylindrical portion 41 on the bit holding portion 18 side. The part 18 is locked to the main body part 11. The bit holding portion 18 is detachably attached to the main body portion 11 by the attachment / detachment mechanism of the so-called coupler structure. In addition, the simple operation makes it possible to easily attach and detach.

  FIG. 4 is a perspective view showing a positioning mechanism of the detachable portion. As shown in FIG. 4, the attaching / detaching portion 17 includes a positioning mechanism for preventing relative rotation of the main body portion 11 and the bit holding portion 18 around the axis AX when or after the bit holding portion 18 is attached.

  As shown in FIG. 4, the attaching / detaching portion 17 includes a positioning pin 44 and a bush 47 as a positioning mechanism. The positioning pin 44 includes a base 45 that protrudes from the lower surface of the base 12 of the main body 11 to the tip end, and a pin 46 that protrudes from the tip end of the base 45 to the tip.

  The bush 47 is attached to a through hole provided in the flange portion 39 of the bit holding portion 18 and is provided so as to be able to insert the pin portion 46 of the positioning pin 44. The position where the bush 47 is provided is a position corresponding to the position of the positioning pin 44 after the bit holding portion 18 is attached.

  When the bit holding portion 18 is attached, the phases of the tip end side (rectangular axis) of the output shaft 15 and the rectangular concave portion of the torque transmission shaft 16 need to coincide with each other. Although not shown, the attaching / detaching portion 17 includes, for example, a phasing mechanism using a dog or a sensor.

  From here, it returns to Drawing 2A-Drawing 2C, and the grasping mechanism of a screw is explained with reference to these figures. As shown in FIGS. 2A and 2B, the screw fastening device 10 further includes a second drive source 50, an arm 52, and a chuck 54 as a screw gripping mechanism.

  As shown to FIG. 2B, the air cylinder 50 as a 2nd drive source is provided with the expansion-contraction rod 50a expanded-contracted to an axial AX direction from a cylinder. The spring portion 51 is connected to the distal end side of the telescopic rod 50a. The spring portion 51 includes a spring 51a and a rod 51b inside the cylinder. For example, a compression coil spring can be used as the spring 51a.

  Further, the air cylinder 50 and the spring portion 51 are coaxially arranged in parallel with the axis AX direction. The rod 51b biased by the spring 51a is connected to the arm 52 on the tip end side of the spring portion 51.

  As shown in FIGS. 2A and 2B, the arm 52 is formed in a rectangular plate shape. The arm 52 is provided with a bend so as to be close to the housing 19 side of the bit holding portion 18. A linear guide 53 is provided between the arm 52 and the housing 19 to guide the linear movement of the arm 52 in the direction parallel to the axis AX.

  As shown in FIG. 2C, the arm 52 is connected to the link of the chuck 54 on the tip side. The chuck 54 includes a pair of arms 54a and 54a and claws 54b and 54b. Each of the arms 54a and 54a has a plurality of (three) axes. The arm 54a, the claw 54b and the shaft form a link.

  As shown in FIG. 2B, in the air cylinder 50, the chuck 54 is opened and closed via the arm 52 by the expansion and contraction of the expansion rod 50a. The spring portion 51 always biases the chuck 54 to be opened by the elastic deformation of the spring 51a. As a result, an appropriate gripping force can be obtained when the chuck 54 is gripping a screw.

  The chuck 54 is provided rotatably around the axis AX. Therefore, in FIG. 2B, the chuck 54 opens and closes in a direction orthogonal to the thickness direction of the arm 52, but in the same figure, for example, the chuck 54 can also be opened and closed in a direction parallel to the thickness direction of the arm 52 .

  Here, each part operation | movement at the time of screw holding is demonstrated with reference to FIG. FIG. 5 is an explanatory view of the operation of each part when gripping a screw. In FIG. 5, the upper half of the figure shows a state in which the bit is engaged with the screw, and the lower half shows a state in which the chuck is closed from there and the screw is gripped.

  As shown in FIG. 5 (upper half), when the screw tightening device 10 is moved to the tip side along the direction of the axis AX and is brought closer to the screw 60 installed on the screw base 61 (in FIG. Then, the tip end of the bit 20 is engaged with the head (upper end surface) of the screw 60. At this time, the chuck 54 is in an open state. That is, one and the other of the pair of facing arms 54a and 54a and the claws 54b and 54b are separated from each other. There is a screw hole (not shown) at the tip of the screw 60 installed on the screw base 61.

  Then, as shown in FIG. 5 (lower half), when the screw fastening device 10 is further moved to the distal end side, the bit 20 is moved to the distal end side by a distance corresponding to the length of the screw 60. At this time, the chuck 54 is in a closed state. That is, the pair of facing claws 54b and 54b approaches each other, and the head (a part of the side peripheral surface side and the lower surface) of the screw 60 is gripped by the claws 54b and 54b.

  When the chuck 54 tightens the screw 60 by the screw tightening device 10, the bit 20 engaged with the screw 60 resists the pressure of the spring 27 (see FIG. 2C etc.) as the pressing portion and the end of the bit holding portion 18 Close after moving to the side by the length of the screw 60. Also, the closed chuck 54 opens by the time the bit 20 begins to rotate to tighten the screw 60.

  In the chuck 54, when the screw 60 is loosened by the screw tightening device 10, when the loosening of the screw 60 is completed, the bit 20 resists the pressure of the spring 27 (see FIG. 2C etc.) It is closed in the state moved to the end side by the length of the screw 60 and in the state in which the rotation of the bit 20 is stopped.

  As described above, by controlling the opening / closing timing of the chuck 54, when the screw 60 is tightened or loosened by the screw fastening device 10, it is possible to reliably prevent the screw 60 from popping out due to the pressing by the bit 20.

  The timing at which the chuck 54 is opened and closed may be controlled by a control device 300 (see FIGS. 9 and 10) described later. Also, the screw fastening device 10 itself may be provided with a controller alone and configured to be controlled by such a controller. In addition, the screwing device 10 is provided with a mechanical opening / closing operation unit, and there are various methods of realizing timing control such as, for example, manually operating this operation unit.

  Next, with reference to FIG. 6, the operation of each part of the bit holding portion at the time of screw gripping will be described. FIG. 6 is a cross-sectional view of the bit holding portion when gripping a screw.

  As shown in FIG. 6, when the screw 60 is gripped, in the bit holding unit 18, the bit 20 moves (translates) distally along the direction of the axis AX inside the housing 19. As a result, the socket 21 integrally connected to the bit 20 in the direction of the axis AX via the joint 24 moves to the end side.

  At this time, the socket 21 linearly moves while being guided by the linear movement portion 23 of the spline structure. By the distal movement of the socket 21 (the linear moving portion 23), the spring 27 as a pressing portion is compressed, and the elastically deformed spring 27 presses the bit 20 on the front end side via the socket 21 and the joint 24. Thus, the bit 20 is always pressed against the screw 60.

  According to the screw fastening device 10 according to the first embodiment, the pressing portion 27 for always pressing the bit 20 toward the tip end side of the bit holding portion 18 is provided to the bit holding portion 18 so that the screw 60 can be loosened. The bit 20 can follow the movement in the direction of the axis AX. As a result, the drive source and the transmission mechanism, which have been required to follow the movement of the screw 60 in the direction of the axis AX, are not necessary, and the diameter of the bit holding portion 18 can be reduced. In addition, the entire screw tightening device 10 is simple and compact in size.

  By providing such a pressing portion 27 inside the bit holding portion 18 (housing 19), the diameter of the bit holding portion 18 can be further reduced. In addition, by using a simple member such as a spring for the pressing portion 27, the screw tightening device 10 can be configured to be simple, small, and inexpensive.

  Further, in the screw tightening device 10, since the first driving source (air cylinder) 28 for driving the mounting and demounting portion 17 is provided on the main body portion 11 side, the diameter of the bit holding portion 18 is further reduced. Simple and compact.

Second Embodiment
FIG. 7 is a perspective view of the screw fastening device according to the second embodiment. Note that the second embodiment to be described below is different from the first embodiment described above in that the first drive source is provided on the gantry side. The same or corresponding parts as in the first embodiment appearing in the description of the second embodiment are designated by the same reference numerals, and the description thereof will be omitted.

  As shown in FIG. 7, the screw tightening device 70 includes a mount 72 that supports the device main body 71 of the screw tightening device 70. In addition, the screw fastening device main body 71 is the structure equivalent to the screw fastening device 10 (refer FIG. 2A etc.) which concerns on 1st Embodiment except the point demonstrated below. In addition, in FIG. 7, the main-body part 11 (refer FIG. 8A etc.) to which the bit holding part 18 is attached is abbreviate | omitted.

  As shown in FIG. 7, the gantry 72 includes a base portion 73 and a support portion 74 erected in parallel to the axis AX direction from the base portion 73. In the screw tightening device 70, a pair of air cylinders 28, 28 as a first drive source is provided on the mount 72 side.

  A rectangular plate-like mounting portion 75 is provided on the upper portion of the support portion 74, and the pair of air cylinders 28 and 28 are mounted on the mounting portion 75. The pair of air cylinders 28, 28 extend and retract parallel to the direction of the axis AX with the telescopic rods 28a, 28a directed distally. A horizontal plate 76 is connected to the telescopic rods 28a, 28a. The telescopic rods 28a, 28a move (translate) the horizontal plate 76 in a direction parallel to the axis AX direction.

  The horizontal plate 76 is formed in the shape of a rectangular plate, and one end thereof is disposed on the side of the gantry 72 by being connected to the telescopic rods 28a and 28a, and the other end is disposed on the screwing device main body 71 side. A notch 76a is provided on the other end side of the horizontal plate 76, and the distal end of the bit holding portion 18 is disposed inside the notch 76a.

  Further, a substantially U-shaped plate 79 having a substantially rectangular notch is provided at the middle position of the support portion 74 so as to extend to the bit holding portion 18 side and having a substantially rectangular notch on the bit holding portion 18 side. Although not shown, at the lower part of the outer peripheral surface of the bit holding portion 18, a flange which is subjected to a two-faced width process so as to be fitted into the notch is provided. For this reason, the bit holding portion 18 is inserted into the notch at a constant angle around the axis. The bit holding portion 18 is attached to the mount 72 in an aligned state by being inserted into the notch of the plate 79.

  Here, with reference to FIG. 8A and FIG. 8B, the attachment / detachment mechanism of the attachment / detachment part provided in the screw fastening device according to the second embodiment will be described. 8A and 8B are cross-sectional views showing the attaching / detaching mechanism of the attaching / detaching portion.

  As shown in FIG. 8A, in the detachable portion 77, a spring (for example, a compression coil spring) 78 is provided in the space between the inner peripheral surface of the circular receiving portion 30 and the outer peripheral surface of the cylindrical portion 35 on the body portion 11 side. It is arranged. The circular receiving portion 30 linearly moves in the direction of the axis AX, and is biased by the spring 78 toward the distal end.

  In the attaching / detaching mechanism of the attaching / detaching portion 77, when attaching the bit holding portion 18 to the main body portion 11, first, as shown in FIG. 8A, the main body portion 11 is coaxially disposed with the bit holding portion 18 held by the gantry 72. . Thereafter, when the main body portion 11 is moved to the tip end side, that is, the bit holding portion 18 side, the cylindrical portion 41 on the bit holding portion 18 side is inserted into the cylindrical portion 35 on the main body portion 11 side.

  When the cylindrical portion 41 on the bit holding portion 18 side is inserted into the cylindrical portion 35 on the main body portion 11 side, the horizontal plate 76 is moved to the end side by the telescopic rods 28a and 28a of the pair of air cylinders 28 and 28 on the gantry 72 side. And move (rise). Further, the circular receiving portion 30 on the main body portion 11 side is pushed up to the end side against the biasing force of the spring 78 by the elevation of the horizontal plate 76.

  At this time, as long as the circular receiving portion 30 is pushed up, the steel ball 38 retracts into the space formed on the tapered surface 36 as in the first embodiment described above, so the cylinder on the bit holding portion 18 side Insertion of the part 41 is possible.

  As shown in FIG. 8B, when the cylindrical portion 41 is inserted until the steel ball 38 on the main body 11 side reaches the position of the V-shaped groove 42, the horizontal plate 76 is moved to the leading end side by the pair of air cylinders 28, 28. When moved (lowered), the circular receiving portion 30 is pushed downward by the biasing force of the spring 78.

  When the circular receiving portion 30 is pushed to the tip side, the steel ball 38 fits into the V-shaped groove 42. At the same time, the tapered surface 33 on the side of the main body portion 11 abuts on the tapered surface 43 on the side of the bit holding portion 18. Thereby, the main body unit 11 and the bit holding unit 18 are locked. The bit holding portion 18 is detachably attached to the main body portion 11 by the attachment / detachment mechanism of the so-called coupler structure. In addition, the simple operation makes it possible to easily attach and detach.

  According to the screw tightening device 70 of the second embodiment, the bit holding portion 18 is provided with the pressing portion 27 which always presses the bit 20 toward the tip end of the bit holding portion 18 as in the first embodiment described above. Thus, the bit 20 can follow the movement of the screw to be loosened in the direction of the axis AX. As a result, the diameter of the bit holding portion 18 can be reduced, and the screwing device main body 71 can be simplified and downsized.

  Also in the screw tightening device 70, the bit holding portion 18 can be further reduced in diameter by providing the pressing portion 27 inside the bit holding portion 18 (housing 19). Further, by using a simple member such as a spring for the pressing portion 27, the screw tightening device main body 71 can be made simple, small in size, and inexpensive.

  Further, in the screw tightening device 70, the first driving source (a pair of air cylinders 28, 28) for driving the mounting and demounting portion 77 is provided on the gantry 72 side, so the diameter of the bit holding portion 18 becomes smaller. The 71 is simpler and smaller.

(Screw tightening system)
Here, a screw tightening system provided with the screw tightening device according to the first or second embodiment described above with reference to FIG. 9 will be described. FIG. 9 is a schematic view showing a screw tightening system. In addition, below, a screw fastening apparatus is demonstrated as the screw fastening apparatus 10 (refer FIG. 2A etc.) which concerns on 1st Embodiment.

  As shown in FIG. 9, the screw tightening system 80 includes a screw tightening device 10, a robot 90, and a control device 300. The screwing system 80 also includes a work table 62 for tightening or loosening the screws. In the work table 62, the screw 60 is installed on the screw base 61 (see FIG. 5). The description of the screw tightening device 10 is omitted.

  As shown in FIG. 9, the robot 90 is, for example, a single arm type articulated robot. Specifically, the robot 90 includes a first arm 91, a second arm 92, a third arm 93, a fourth arm 94, a fifth arm 95, and a base 96. Prepare. The robot 90 may be a double arm type or the like.

  The first arm 91 is supported at its proximal end by the second arm 92. The second arm 92 is supported at its proximal end by the third arm 93 and supports the first arm 91 at its distal end.

  The third arm 93 is supported at its proximal end by the fourth arm 94 and supports the second arm 92 at its distal end. The fourth arm 94 is supported at its proximal end by the fifth arm 95 and supports the third arm 93 at its distal end.

  The fifth arm 95 is supported at its base end by a base 96 fixed to a floor or the like, and supports the fourth arm 94 at its tip. In addition, actuators such as servomotors are mounted on joint portions (not shown) which are connection portions of the first arm portion 91 to the fifth arm portion 95, respectively. The robot 90 can perform multi-axis operation by driving an actuator.

  Specifically, the actuator of the joint that connects the first arm 91 and the second arm 92 rotates the first arm 91 around the B axis. The actuator of the joint that connects the second arm 92 and the third arm 93 rotates the second arm 92 around the U axis.

  Further, an actuator of a joint that connects the third arm 93 and the fourth arm 94 rotates the third arm 93 around the L axis. The actuator of the joint that connects the fourth arm 94 and the fifth arm 95 rotates the fourth arm 94 around the S axis.

  The robot 90 further includes individual actuators that rotate the first arm 91 around the T axis, the second arm 92 around the R axis, and the third arm 93 around the E axis.

  That is, the robot 90 has seven axes. Then, the robot 90 can perform various multi-axis operations combining seven axes based on an operation instruction from a control unit 301 (see FIG. 10) of the control device 300 described later.

  The tip of the first arm 91 is the tip movable part of the robot 90, and the hand 97 is attached to the tip movable part. The hand 97 grips the block 14 (see FIG. 2A and the like) of the screw tightening device 10 at the tip of the robot 90.

  The control device 300 is a so-called robot controller, and drives and controls an actuator of each joint including the arms 91 to 95 of the robot 90 and the hand 97. The control device 300 and the robot 90 are connected by a cable 98 or the like.

  Further, the control device (robot controller) 300 controls driving of the first drive source 28 (see FIG. 3A and the like) and the second drive source 50 (see FIG. 2B and the like) of the screw tightening device 10. The controller 300 and the first drive source 28 and the second drive source 50 are connected by a cable 99 or the like.

  Here, an internal configuration of a robot, a screw tightening device and a control device included in the screw tightening system will be described with reference to FIG. FIG. 10 is a functional block diagram of a screw tightening system. Note that FIG. 10 shows components necessary for screw tightening / removal, attachment / detachment, and driving of the chuck.

  As shown in FIG. 10, a robot controller 300 as a control device includes a control unit 301. The control unit 301 generates a signal for operating the robot 90 based on the teaching information and the like, and outputs the signal to the robot 90.

  Further, the control unit 301 generates and outputs a signal for operating the servomotor M toward the screw tightening device 10. Further, the control unit 301 outputs a signal for operating the first drive source 28 and the second drive source 50 included in the screw tightening device 10 to the drive sources 28 and 50.

  For example, in the case of the robot 90, the operation signal output from the control unit 301 is generated as a pulse signal to a servomotor (not shown) mounted on each of the arm units 91 to 95 of the robot 90 and each joint of the hand 97. Ru. The “arm” refers to the above-described first to fifth arm portions 91 to 95.

  In addition, if the operation signal output from the control unit 301 is the screw tightening device 10, the servo motor M provided in the screw tightening device 10, the first drive source 28 driven in the attaching / detaching mechanism, and the screw gripping mechanism 2 as a signal to the driving source 50.

  Note that, between the control unit 301 and the servomotor M of the screw tightening device 10, a programmable controller, a screw tightening device controller, or the like for strict control of torque by screw tightening may be disposed.

  Also, as described above, the screw tightening device 10 includes a torque detector (not shown). The torque detected by the torque detector is output to the control unit 301. When the detected torque reaches a prescribed torque that indicates screw tightening completion, a signal is output to the control unit 301. Then, the control unit 301 outputs a signal to stop the operation toward the screw tightening device 10.

  Next, the procedure of the screw tightening operation and the screw loosening operation by the screw tightening system will be described. In addition, drive control of a robot and a screw fastening device is performed by the control part 301 (refer FIG. 10) of the control apparatus (robot controller) 300. FIG. Note that a programmable controller may be separately provided as the screw fastening device.

  First, the procedure of screwing will be described. In the screwing operation, the robot places the screwing device gripped by the hand coaxially with the screw. Here, it is assumed that the screw is at a place different from the working position (screw hole) and the work is started from there.

  The robot moves the screwing device axially to the screw side to engage the bit at the tip with the screw. The chuck then closes and grips the head of the screw. Then, the robot moves the screw tightening device to the screw hole and places the screw gripped by the chuck in the screw hole.

  Once the screw is installed in the screw hole, open the chuck and release the screw grip. The bit starts to rotate when the gripping of the screw by the chuck is released. Here, the bit is set to rotate clockwise, but when the screw to be tightened is a reverse screw or the like, the bit is set to rotate counterclockwise.

  During rotation of the bit, torque is detected by the torque detector of the screwing device. It is further determined by the control unit 301 (see FIG. 10) whether or not the detected torque has reached a specified value. When it is determined that the torque has reached the specified value, the rotation of the bit is stopped by an instruction from the control unit 301. This completes the tightening of the screw.

  Here, with reference to FIG. 11A, the timing at which the chuck opens and closes while each part operates in the screw tightening operation will be extracted and described. FIG. 11A is a flowchart showing the timing of opening and closing the chuck in the screw tightening operation. The control of opening and closing the chuck at a predetermined timing is performed by the control unit 301 (see FIG. 10) of the control device (robot controller) 300 as described above.

  As shown in FIG. 11A, when the bit engages with the screw (step S101) and the screw tightening device is further moved to the screw side, the bit resists the pressure of the pressing portion and moves to the end of the bit holding portion. The movement is started (step S102). The chuck is closed (step S104) when the bit is moved distally by a predetermined distance, that is, by the length of the screw (step S103). As a result, the chuck holds the screw.

  Thereafter, when the screw gripped by the chuck is installed in the screw hole (step S105), the chuck opens (step S106), and the chuck releases the grip of the screw. When gripping of the screw is released, the bit starts to rotate clockwise (step S107).

  Next, the procedure of the screw loosening operation will be described. In the unscrewing operation, the robot places the hand-clamped screwing device coaxially with the tightened screw. The robot then moves the screwing device to the screw side to engage the bit at the tip with the tightened screw.

  When the bit is engaged with the screw, the bit starts to rotate. Here, the bit is set to rotate counterclockwise, but when the loosening screw is a reverse screw or the like, the bit is set to rotate clockwise.

  Here, it is determined by the control unit 301 (see FIG. 10) of the control device (robot controller) 300 whether or not the rotation time of the bit has passed a predetermined time. This time is preset according to the length of the screw to be loosened. When it is determined that the predetermined time has elapsed, the rotation of the bit is stopped by an instruction from the control unit 301. If it is determined that the predetermined time has not elapsed, the rotation of the bit continues until the predetermined time elapses.

  When the bit stops rotating, close the chuck and grasp the screw. When the screw holds the screw, the robot moves the screw tightening device holding the screw to a predetermined position. This completes the removal of the tightened screw.

  Here, with reference to FIG. 11B, the timing at which the chuck opens and closes while each part operates in the screw loosening operation will be extracted and described. FIG. 11B is a flowchart showing the timing of opening and closing the chuck in the screw loosening operation.

  As shown in FIG. 11B, the bit engaged with and rotated by the screw to loosen the screw is pushed as the screw retracts in the axial direction, and the distal end of the bit holder against the pressure of the pusher It moves to (step S201). When the bit is moved by a predetermined distance, that is, the screw length (step S202), the control unit 301 (see FIG. 10) determines whether the bit has stopped rotating (step S203).

  If it is determined that the bit has stopped rotating (step S203, Yes), the chuck is closed (step S204). As a result, the chuck holds the screw. If it is determined in the process of step S203 that the bit has not stopped rotating (step S203, No), the bit continues rotating, and the chuck remains open during that time.

  According to the above-described screwing system, the robot 90 performs a screwing operation and a screwing operation to widen the working range. In addition, by the cooperation of the screw tightening device 10 and the robot 90, each operation of engaging the bit 20 with the screw 60, arranging the screw 60 in the screw hole, and moving the screw 60 from the screw hole can be performed automatically.

  Then, when the screw is tightened, by closing the chuck 54 in a state where the bit 20 moves to the end side of the bit holding portion 18, it is possible to prevent the screw 60 from jumping out due to the pressing of the bit 20.

  In addition, when tightening the screw, the chuck closed in a state in which the screw 60 is gripped is opened before the bit 20 starts to rotate, whereby the screw 20 can be installed in the screw hole. The pressing can prevent the screw 60 from jumping out.

  In addition, when the screw is loosened, the screw 60 is released by closing the chuck 54 in a state in which the bit 20 has moved to the end side of the bit holding portion 18 and a state in which the bit 20 stops rotating. Besides, it is possible to avoid the risk of gripping the screw 60 during rotation.

  Further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the invention are not limited to the specific details and representative embodiments represented and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

Reference Signs List 10 screw tightening device 11 main body 15 output shaft 16 torque transmission shaft 17 detachable portion 18 bit holding portion 19 housing 20 bit 21 socket 22 rotary portion 23 linear motion portion 24 joint 27 pressing portion (spring)
28 1st drive source (air cylinder)
50 Second drive source (air cylinder)
Reference Signs List 60 screw 70 screw tightening device 72 base 80 screw tightening system 90 robot 91 first arm 92 second arm 93 second arm 94 fourth arm 95 fifth arm 97 hand 300 control device (robot controller)
301 Control unit AX axis

Claims (7)

A bit that has a rotating part that is rotated by a driving force about an axis and a linear moving part that linearly moves according to an external force in the axial direction, and holds the bit coaxially with the axis on the tip side of the linear moving part A holding unit,
Provided on the bit holding portion coaxially with the bit, the bit is elastically deformed and compressed by pressing the bit against the screw, and the linear moving portion is always pressed to the distal end side until the tightening and loosening of the screw is completed A pressing portion, which is a spring that linearly drives the screw to follow the movement of the screw while always pressing the bit to the screw being loosened ;
A main body portion supporting the bit holding portion;
A screw-fastening device comprising: an attaching / detaching portion provided in the main body portion and capable of attaching / detaching the distal end side of the bit holding portion to the main body portion. The pressing unit is
It is provided in the inside of the said bit holding part. The screw-fastening apparatus of Claim 1 characterized by these. The screw source according to claim 1, wherein a drive source for driving the attaching / detaching portion is provided on the main body portion side. A chuck for holding a screw engaged with the bit;
The chuck is
In the case where the screw is tightened, the bit engaged with the screw is closed in a state of being moved to the terminal side of the bit holding portion against pressure by the pressing portion. Screwing device described. The chuck is
The screw tightening device according to claim 4 , wherein after closing, the bit is opened before it starts to rotate. A chuck for holding a screw engaged with the bit;
The chuck is
When loosening the screw, the bit is closed in a state in which the bit is moved to the terminal side of the bit holding portion against pressure by the pressing portion, and rotation is stopped. The screw tightening device according to any one of ~ 5 . A bit that has a rotating part that is rotated by a driving force about an axis and a linear moving part that linearly moves according to an external force in the axial direction, and holds the bit coaxially with the axis on the tip side of the linear moving part The holding portion and the bit holding portion are provided coaxially with the bit, and the bit is elastically deformed and compressed by being pressed against the screw, and the linear moving portion is moved to the tip until the tightening and loosening of the screw is completed. A pressing portion which is a spring that linearly drives the screw so as to always press the bit against the screw to be loosened while always pressing the side, a main portion for supporting the bit holding portion, and A screw-fastening device comprising: a main body portion; and an attaching / detaching portion that detachably mounts the distal end side of the bit holding portion to the main body portion;
A screwing system characterized in that the screwing device comprises an articulated robot attached to a tip.

Images