JP4984301B2 - Bolt tightening method and apparatus - Google Patents

Description

  The present invention relates to a bolt fastening method for fastening a plurality of bolts to a workpiece, and a bolt fastening device used for carrying out this method.

  Conventionally, when tightening multiple bolts to a workpiece using a tightening head equipped with a single nut runner, move the tightening head to the bolt supply location and hold the bolt at the tip of the socket connected to the output shaft of the nut runner The process of supplying the bolt to the part and the process of moving the fastening head to the work side and fastening the bolt held by the bolt holding part to the work are repeated. In this case, every time one bolt is tightened, the tightening head has to be reciprocated from the workpiece side to the bolt supply place, and the efficiency becomes worse. Although it is possible to improve efficiency by mounting a plurality of nut runners on the tightening head, this increases the equipment cost.

  Conventionally, a tightening head on which a nut runner is mounted so as to be able to advance and retract in the work direction is provided with a slider that moves forward in the work direction together with the nut runner and stops when it advances to a predetermined position, and a bolt catcher that is rotatably supported by the slider. A provided bolt fastening device is known (for example, see Patent Document 1). In this case, the bolt is dropped into the bolt catcher through the pipe from above, and then the bolt catcher is rotated so that the bolt is concentric with the socket of the nut runner, and in this state, the nut runner is advanced in the work direction. The socket is inserted into the bolt catcher and the bolt is transferred to the socket.

If such a bolt tightening device is used, it is not necessary to move the nut runner to the bolt supply place away from the work after the bolt tightening, and the efficiency can be improved. However, in this case, an auxiliary facility for supplying bolts including a slider and a bolt catcher is arranged near the tip of the socket of the nut runner, so that the auxiliary facility may interfere with the work and cannot be bolted.
JP-A 64-78730

  In view of the above points, the present invention provides a bolt tightening method and an efficient bolt tightening method that can perform an efficient bolt tightening operation without arranging auxiliary equipment for supplying bolts in the vicinity of the tip of the nut runner socket. It is an object of the present invention to provide a bolt fastening device used for implementation.

  In order to solve the above-described problems, the present invention provides a bolt tightening method for tightening a plurality of bolts to a workpiece using a tightening head equipped with a nut runner, and the output of the socket and nut runner connected to the output shaft of the nut runner. One of a plurality of bolts held in a bolt magazine mounted on the tightening head, and a bolt supply preparation step for releasing the connection with the shaft and changing the socket to an upward posture in which the bolt holding portion at the tip of the socket faces upward After the completion of the bolt supply preparation process, the bolt supply process for inserting the bolt into the socket's bolt holding section from above with the bolt gripping means, and the completion of the bolt supply process, the socket is connected to the nutrunner. Change the tightening posture along the axis of the output shaft of the nutrunner to the output shaft of the nutrunner. A bolt tightening preparation step for connecting the brackets, and a bolt tightening step for rotating the socket by the nut runner after completion of the bolt tightening preparation step and tightening the bolt held by the bolt holding portion of the socket to the workpiece. To do.

  According to the above-described method of the present invention, a plurality of bolts to be fastened to a workpiece are held in a bolt magazine mounted on a tightening head, and the bolts are supplied from the bolt magazine to the socket. It is not necessary to supply bolts to the socket. Accordingly, the tightening operation can be continued with the tightening head positioned on the workpiece side, and a plurality of bolts can be efficiently tightened to the workpiece.

  Also, even if the tightening posture is a horizontal or downward posture where it is difficult to stably supply the bolt to the bolt holding portion at the tip of the socket, by changing the posture of the socket to an upward posture, Thus, the bolt can be stably inserted, and time loss due to a mistake in supplying the bolt can be reduced. Furthermore, it is not necessary to arrange an auxiliary facility for supplying bolts in the vicinity of the tip of the socket connected to the output shaft of the nut runner, so that it is possible to prevent the bolt tightening from being impossible due to the interference of the auxiliary facility with the workpiece.

Further, the bolt tightening apparatus of the present invention, the clamping head mounted nut runner, and detaching mechanism for detachably connecting wearing socket on the output shaft of the nut runner to perform tightening of being rotated bolt by the nut runner, an output shaft of the nut runner A socket changer that changes the posture of the socket to the upward posture in which the bolt holding portion at the tip of the socket faces upward, and the tightening posture along the axis of the nut runner output shaft, and the bolt magazine that holds a plurality of bolts And a bolt supply mechanism for holding one of the bolts held by the bolt magazine and inserting the bolt from above into the bolt holding part of the socket in the upward posture. .

  According to the apparatus of the present invention, the bolt supply preparation process and the bolt tightening preparation process of the method of the present invention can be performed by the attaching / detaching mechanism and the posture changing mechanism, and the bolt supply process of the present invention can be performed by the bolt supply mechanism. . Therefore, the method of the present invention can be reliably performed.

In the bolt tightening method of the present invention, the tightening head is provided with at least two sockets that are interchangeably connected to the output shaft of the nut runner, and the bolt supply preparatory step , the bolt supply step, the bolt tightening preparatory step, and the bolt tightening. One cycle work process consisting of a process is sequentially executed for each socket, and in the bolt supply preparation process for each socket, each socket is moved to a standby position separated from the axis of the output shaft of the nutrunner, while facing upward At the bolt tightening preparation step for each socket, the posture is changed to the tightening posture while moving each socket from the standby position to the use position that matches the axis of the output shaft of the nut runner, and the bolt supply preparation step for one socket And the bolt tightening preparation process for the other socket It is desirable to run at.

  According to this, during the bolt tightening process of tightening the bolt held by the socket connected to the output shaft of the nut runner to the workpiece, the bolt can be supplied to another socket in the standby position, and the bolt tightening process is completed. Later, the socket connected to the output shaft of the nutrunner is moved from the use position to the standby position, and at the same time, the other socket is moved from the standby position to the use position, so that the socket replacement work can be performed efficiently. As a result, the tightening cycle time per bolt can be shortened, and a plurality of bolts can be tightened to the workpiece with higher efficiency.

  In order to carry out this method, the device of the present invention comprises at least two sockets that are interchangeably connected to the output shaft of the nut runner, a use position that matches each socket with the axis of the output shaft of the nut runner, and the socket. A movement mechanism that moves to a standby position separated from the axis, and the posture change mechanism, and the posture change mechanism changes the posture of each socket to the upward posture when moving to the standby position, and when moving to the use position, A socket exchanging mechanism for changing the posture to a tightening posture is provided, and the attaching / detaching mechanism is configured to detachably connect the socket in the use position and the output shaft of the nut runner, and the bolt gripping means is in the standby position. The socket is configured to insert a bolt from above into the bolt holding part of the socket, and the socket replacement mechanism places one socket in the standby position. It is configured to simultaneously move the other one socket for use position as to dynamic desirable.

  Further, when at least two sockets are provided as described above and the standby position is different for each socket, the bolt head is provided with a separate bolt magazine and bolt gripping means for each socket in the tightening head. A bolt grip preparation step of moving each bolt magazine corresponding to each socket to a bolt delivery position where one of a plurality of bolts held in the magazine can be gripped by each bolt gripping means corresponding to each socket; A bolt gripping process for gripping the bolts by each bolt gripping means, a magazine retracting process for moving each bolt magazine to a retracted position deviating from the downward movement trajectory of each bolt gripping means, and moving each bolt gripping means downward And a bolt insertion step of inserting a bolt into the bolt holding portion of each socket at each standby position. There.

  According to this, it is possible to insert the bolts into the bolt holding portions of the respective sockets without causing any interference with the respective bolt magazines simply by linearly moving the respective bolt gripping means in the vertical direction. Therefore, it is easier to ensure the positional accuracy of the bolt gripping means than when moving the bolt gripping means in directions other than the vertical direction so as to avoid the bolt magazine, and the bolt can be supplied stably and reliably to the socket. .

  In order to carry out this method, in the device according to the present invention, when the socket replacement mechanism is configured to move each socket to a different standby position for each socket, a separate bolt magazine and bolt gripping means are provided for each socket. Each bolt gripping means is linearly movable in the vertical direction on the same line as the axis of the socket when the corresponding socket is in the standby position, and each bolt magazine has a plurality of bolts held in the magazine. It is desirable to be able to move between a bolt delivery position where one of the bolts can be gripped by the corresponding bolt gripping means and a retracted position deviated from the downward movement trajectory of the corresponding bolt gripping means.

  Further, in this method, the bolt holding preparation step of the bolt supply step for one socket and the magazine retracting step of the bolt supply step for the other socket are executed at the same time, and further, the bolt supply step for one socket It is desirable that the bolt gripping step and the bolt inserting step of the bolt supply step for the other one socket are performed simultaneously. According to this, the cycle time of the tightening operation can be further shortened.

  In the apparatus of the present invention, when each bolt magazine is provided for each socket as described above, the bolt magazines are connected to each other, and when one bolt magazine is moved to the bolt delivery position, the other one bolt magazine is retracted. If it is configured to move to the position, the bolt holding preparation process of the bolt supply process for one socket and the magazine retracting process of the bolt supply process for the other socket can be executed simultaneously with a simple structure.

  FIG. 1 shows a work station for fastening a plurality of bolts B (see FIGS. 2 and 4) such as check bolts to a work W such as a transmission case. A robot R is disposed on the side of the station. A tightening head 1 serving as a main body of the bolt tightening device is mounted on the operating end of the robot R, that is, the wrist Rb at the tip of the robot arm Ra.

With reference to FIGS. 2 to 4, the tightening head 1 includes a vertically long base 2 fixed to the wrist Rb of the robot R, and a nut runner 3 is attached to the back surface of the base 2. The nut runner 3 includes an output shaft 3a in a horizontal posture at the lower end (see FIG. 5). Further, the tightening head 1 includes a first and second two sockets 4 _1, 4 _2, detachably connected to the output shaft 3a of the socket 4 _1, 4 ₂ and the nut runner 3 existing in the use position, which will be described later An attaching / detaching mechanism 5, a socket exchanging mechanism 6, and a bolt supply mechanism 7 for supplying the bolt B to the sockets 4 ₁ and 4 ₂ are provided.

As shown in FIG. 5, each socket 4 ₁ , 4 ₂ has a sleeve 41, a rotating shaft 42 pivotally supported in the sleeve 41, and a distal end portion of the rotating shaft 42 protruding from the sleeve 41 so as not to be relatively rotatable by a cross pin 43 a. And a connected socket body 43. At the front end of the socket main body 43, a bolt holding portion 44 formed of a rectangular concave hole that receives the head Ba of the bolt B is formed. A magnet 44 a that attracts the bolt B is embedded in the bottom of the bolt holding portion 44. Further, the rotating shaft 42 is an expansion / contraction composed of a shaft portion 42a on the base end side and a shaft portion 42c on the distal end side that is fitted to the shaft portion 42a so as not to be relatively rotatable while being biased axially forward by a spring 42b. Consists of a flexible shaft. Further, a ball plunger that engages with a recess 41 a formed on the inner periphery of the base end portion of the sleeve 41 at a circumferential interval at the base end portion of the rotating shaft 42 and applies a light restraining force to the rotating shaft 42. 45 is attached.

As shown in FIG. 5, the attachment / detachment mechanism 5 has a dog clutch 51 that is fitted to the output shaft 3 a of the nut runner 3 so as not to rotate relative to the output shaft 3 a so as to be slidable in the axial direction. I have. The dog clutch 51 is pivotally supported by a clutch holder 53 supported so as to be movable in the axial direction of the output shaft 3 a by a guide pin 52 (see FIGS. 3 and 4) projecting from the lower end of the base 2. The clutch holder 53 is provided with a cam groove 54 that is inclined rearward toward the upper side. The cam groove 54 is attached to the lower end of a rod 55a that is vertically moved by a cylinder 55 attached to the back surface of the base 2. The roller 56 is engaged. Thus, when the roller 56 is moved upward, the clutch holder 53 moves forward through the cam groove 54, and the dog clutch 51 engages with the rotating shaft 42 of the sockets 4 ₁ and 4 ₂ (in the upper half of FIG. 5). State), the sockets 4 ₁ and 4 ₂ and the output shaft 3a of the nut runner 3 are connected, and when the roller 56 is moved downward, the clutch holder 53 is retracted, and the dog clutch 51 is rotated about the rotating shaft of the sockets 4 ₁ and 4 ₂ . The connection between the sockets 4 ₁ , 4 ₂ and the output shaft 3 a of the nut runner 3 is released by separating from 42 (state shown in the lower half of FIG. 5). When the clutch holder 53 is advanced, the output shaft 3a of the nut runner 3 is rotated at a low speed. As a result, the dog clutch 51 is rotated relative to the rotation shaft 42 stopped by the ball plunger 45 and phase-adjusted, and the dog clutch 51 is engaged with the rotation shaft 42 when a predetermined engagement phase is reached.

Socket replacing mechanism 6, a moving mechanism for moving each socket 4 _1, 4 ₂ in a standby position separated from the position and said axis used that matches the axis of the output shaft 3a of the nut runner 3, the socket 4 _1, 4 ₂ And a posture changing mechanism for changing the posture to an upward posture in which the bolt holding portion 44 faces upward when moving to the standby position and changing the posture to a tightening posture along the axis of the output shaft 3a of the nut runner 3 when moving to the use position. Is done. In this embodiment, a moving table 61, which is a component of the moving mechanism, can be reciprocated in the lateral direction perpendicular to the axis of the output shaft 3a of the nut runner 3 along the guide rail 61a fixed to the front surface of the base 2. To support. Then, the moving table 61, each socket 4 _1, 4 ₂ respective sockets _41, 42 swingably supported on the attitude tightening upward posture at the hinge shaft 46 provided in the proximal end of the _second sleeve 41 is doing.

As shown in FIG. 3, a cam groove 61 b that is inclined in the horizontal direction and extends in the vertical direction is formed on the back surface of the moving table 61. Further, a slider 62 that is movable in the vertical direction along a guide rail 62 a fixed to the base 2 and a cylinder 63 that moves the slider 62 up and down are provided on the back surface of the base 2. A pin 62b that engages with the cam groove 61b is fixed to the slider 62 through a long hole 2a formed in the base 2 in the vertical direction. Thus, when the slider 62 is moved downward, the moving table 61 is moved forward one side (leftward in FIG. 2) via the pin 62b and the cam groove 61b, and when the slider 62 is moved upward, the moving table 61 is moved. Move backward in the other side (right side in FIG. 2). By forward movement of the moving table 61, together with the first socket 4 ₁ moves to the spaced standby position from the axis of the output shaft 3a of the nut runner 3 to one side (left side), the second socket 4 ₂ use position Go to, the backward movement of the moving table 61, the first socket 4 ₁ with moves to the use position, the second socket 4 ₂ spaced from the axis of the output shaft 3a of the nut runner 3 to the other side (right side) Move to the standby position (position shown in FIG. 2). In this embodiment, the moving table 61, the slider 62, and the cylinder 63 constitute a moving mechanism.

The posture changing mechanism includes a first and second pair of cams 65 ₁ , 65 ₂ corresponding to the first and _second sockets 4 ₁ , 4 ₂ fixed to the lower front portion of the base 2, and each socket 4. _{1, 4} linked to the base end portion of the _second sleeve 41, and a cam mechanism 64 consisting of the cam ₆₅ 1, 65 ₂ engages the cam follower 66.. Each of the cams 65 ₁ and 65 ₂ has a rail 65a that spirals in the lateral direction along a virtual cylindrical surface centering on the hinge shaft 46 of each of the sockets 4 ₁ and 4 ₂ . The rail 65a projects downward from the virtual cylindrical surface at the laterally inner end, and projects forward from the virtual cylindrical surface at the laterally outward end. The cam follower 66 includes a pair of rollers that engage with the cam 65 so as to sandwich the rail 65a. When the sandwiched portion of the rail 65a protruding downward from the virtual cylindrical face cam follower 66 becomes the each socket 4 _1, 4 ₂ tightening posture, the portion of the rail 65a protruding forward from the virtual cylindrical face cam followers 66 The sockets 4 ₁ and 4 ₂ are in the upward posture when the is sandwiched. Thus, the forward movement is to the left of the moving table 61 in FIG. 2, while moving from the first socket 4 ₁ use position to the standby position of the left, the posture change upward posture from the tightening posture by the first cam 65 ₁ while, the second socket 4 ₂ while moving in the use position from the standby position of the right and changes the posture of the posture tightening from the upward posture by the second cam 65 _2. Also, moving to the right the moving table 61 in FIG. 2, the first socket 4 ₁ while moving in the use position from the standby position of the left and posture changes posture tightening from the upward posture by the first cam 65 ₁ together, the second socket 4 ₂ while moving from the use position to the standby position of the right and changes the posture upward posture from the tightening posture by the second cam 65 _2.

The bolt supply mechanism 7 includes a first and second pair of bolt magazines 8 ₁ and 8 ₂ corresponding to the first and _second sockets 4 ₁ and 4 ₂ , and a first and second pair of bolt gripping means. 9 ₁ and 9 ₂ . On the front surface of the moving table 61, there is provided a slide plate 81 that is reciprocated in the lateral direction by a cylinder 81b along a guide rail 81a fixed thereto. Both the bolt magazines 8 ₁ and 8 ₂ are attached to the slide plate 81 at a predetermined interval in the lateral direction at a higher position than the bolt holding portions 44 of the sockets 4 ₁ and 4 _{2 in} the upward orientation. .

As shown in FIG. 6, each of the bolt magazines 8 ₁ and 8 ₂ is configured to hold a plurality (three in the illustrated example) of bolts B in a horizontal row. Each bolt magazine 8 ₁ , 8 ₂ is provided with a laterally inner cut-out claw 82 and a laterally outward push-in claw 83. The cut-out claw 82 and the push-in claw 83 are swingable in the lateral direction with the shafts 82a and 83a as fulcrums, respectively. Further, a tension spring 84 is stretched on both bolt magazine ₈ 1, ₈ between the _second cut-out claws 82, 82. Then, the pulling claw 82 is biased and held by the tension spring 84 in the closed position regulated by the stopper pin 86, and the cutting claw 82 indicates that the bolt B is dropped from the respective bolt magazines 8 ₁ and 8 ₂ inward in the lateral direction. Is preventing. When each of the bolt magazines 8 ₁ and 8 ₂ is moved outward in the lateral direction in a state where the innermost bolt B in contact with the cutting claw 82 is gripped by the bolt gripping means 9 ₁ and 9 _{2 as} will be described later, The bolt B is pulled out from the respective bolt magazines 8 ₁ and 8 _{2 in the} lateral direction while pushing the claw 82 inward in the lateral direction.

Pushing pawl 83, with swinging laterally inward by tensile spring 85 is stretched between the pin 85a and the pin 85b provided upright on the upper plate portion of each bolt magazine 8 _1, 8 ₂ erected to It is energized. When the innermost bolt B in the lateral direction of each of the bolt magazines 8 ₁ and 8 ₂ is pulled out, the bolt B on each of the bolt magazines 8 ₁ and 8 ₂ is pushed to a position where it comes into contact with the cutting claw 82 that swings back to the closed position. It is pushed laterally inward by the claw 83. In addition, an operation pin 83 b is erected on the pushing claw 83. Then, after the plurality of bolts B are tightened on the workpiece W, when the tightening head 1 is moved to a predetermined bolt supply place by the operation of the robot R, the pushing claws 83 are opened laterally outwardly via the operation pins 83b. In this state, a plurality of bolts B are supplied from a parts feeder (not shown) to the bolt magazines 8 ₁ and 8 ₂ .

2, 4 and 7, the first and each bolt gripping means ₉ 1, _{9 2} in the second includes a shaft portion Bb of the pair capable of gripping the gripping claws 91, 91 of the bolt B, the gripping An actuator 92 that opens and closes the claws 91 and 91 and rotates at low speed is provided. In addition, a pair of elevating frames 93 and 93 that are moved up and down by each cylinder 93b along each guide rail 93a fixed to the left and right sides of the front upper part of the moving table 61 are provided, and each bolt holding means 9 is provided in each elevating frame 93. and _{1, 9 2} mounting. The first bolt gripping means 9 ₁ moves up and down by the first socket 4 ₁ and the transverse same position with respect to the moving table 61, the second bolt grasping the second socket 4 ₂ and transverse same position with respect to the moving table 61 It means 9 ₂ is to be moved up and down. Thus, the forward movement to the left in Figure 2 of the moving table 61, when the upward posture by moving the first socket 4 ₁ to the standby position of the left, the first bolt grasping means 9 _1, the gripping claws so that the linear movement center between 91 and 91 (the gripping center) in a vertical direction in a state of being positioned in the first socket 4 on the _first axis and co-linear. Further, the backward movement to the right in Figure 2 of the moving table 61, when the upward posture by moving the second socket 4 ₂ in the standby position of the right, the second bolt grasping means 9 _2, the gripping claws center between 91 and 91 (the gripping center) will be linearly moved in the vertical direction in a state of being positioned on the second socket 4 _second axis collinear.

Next, a procedure for tightening the bolt B to the work W by the bolt tightening device of the present embodiment will be described starting from the state shown in FIG. Figure 2 is a during tightening process of a single bolt B by the first socket 4 ₁ resides in a standby position of the second socket 4 ₂ rightward in an upward position, the second bolt grasping means 9 _Paragraph 2 the bolt holding portion 44 of the socket 4 ₂ bolts B shows the inserted state.

When tightening process of bolts B by the first socket 4 ₁ is completed, the bolt supplying preparing step for the first socket 4 _1, at the same time performing a bolt tightening preparing step for the second socket 4 _2. In this step, first, the dog clutch 51 is retracted the clutch holder 53 is disengaged from the first socket 4 ₁ of the rotary shaft 42, to release the connection between the first output shaft 3a of the socket 4 ₁ and the nut runner 3. Next, the moving table 61 is moved leftward in FIG. According to this, the first socket 4 ₁ posture changes upward posture while moving to the standby position of the left, at the same time, changes its position to the attitude tightening while moving to the second socket 4 ₂ use position. Then, upon reaching the use position in the second socket 4 ₂ tightening posture, to advance the clutch holder 53 is engaged with the dog clutch 51 to the second rotating shaft 42 of the socket 4 _2, second sockets 4 ₂ and the nut runner 3 Are connected to the output shaft 3a.

This way, the second socket 4 ₂ bolt tightening for preparing process is completed, the second socket 4 ₂ is rotated by the nut runner 3, the bolt B held by the second bolt retaining portion 44 of the socket 4 ₂ workpiece W The bolt tightening process is performed.

Also performs a bolt supplying step for the first socket 4 ₁ In parallel with the above process. The bolt supplying step, the slide plate 81 is moved to the right with respect to the moving table 61, the first bolt magazine 8 _1, the lateral innermost bolt B on the magazine 8 ₁ first bolt grasping means 9 ₁ and the bolt grasping preparing step of moving the graspable bolt passing position, a bolt for gripping the lateral innermost bolt B on the first bolt magazine 8 ₁ by the first bolt grasping means 9 _first gripping claws 91 and 91 a grasping step, the slide plate 81 with respect to the moving table 61 is moved to the left, laterally outside the first bolt magazine 8 ₁ from moving track to below the first bolt gripping means 9 _first gripping claws 91 and 91 square and magazine evacuation step of moving to the retracted position out of the (left) to move the first bolt grasping means 9 ₁ below, the first socket 4 ₁ of the bolt holding portion of the upward orientation existing in the standby position A bolt insertion step of inserting the head Ba of bolt B from above 4, open first bolt gripping means 9 ₁ of the gripping claws 91, 91, a return step of returning the first bolt grasping means 9 ₁ in the upper position Consists of. Note that in the magazine evacuation step, lateral innermost bolt B of the first bolt magazine 8 on ₁ gripped by the first bolt grasping means 9 _first gripping claws 91 and 91 is pulled out from the magazine _81. Further, the bolt insertion step, the first bolt grasping means 9 _first gripping claws 91 and 91 rotating at low speed, to insert in registration phase the bolt head Ba of the bolt holding portion 44.

Here, the bolt grasping preparing step, the bolt grasping step and the magazine retracting step is performed between the in the first socket 4 ₁ bolt tightening by step until volt supply preparation process completed for the first socket 4 _1. Then, the bolt insertion process is executed immediately after the bolt supply preparation process is completed. Accordingly, prior to completion of the second socket 4 ₂ bolt tightening by step, it can be supplied reliably bolt B into the first socket 4 _1.

When the second socket 4 ₂ bolt tightening due process is completed, the bolt supplying preparing step for the second socket 4 ₂ simultaneously executes a bolt tightening sequence step for the first socket 4 _1. In this step, first, the dog clutch 51 is retracted the clutch holder 53 is disengaged from the second socket 4 ₂ of the rotary shaft 42, to release the connection between the second output shaft 3a of the socket 4 ₂ and the nut runner 3. Next, the moving table 61 is moved back to the right in FIG. According to this, the second socket 4 ₂ position changes upward posture while moving to the standby position of the right, at the same time, changes its position to the clamping position while moving the first socket 4 ₁ position of use. Then, upon reaching the use position in the first socket 4 ₁ tightening posture, to advance the clutch holder 53 is engaged with the dog clutch 51 to the first rotation axis 42 of the socket 4 _1, first socket 4 ₁ and the nut runner 3 Are connected to the output shaft 3a.

This way, the first socket 4 ₁ bolt tightening sequential steps for the completion, by rotating the first socket 4 ₁ by the nut runner 3, the bolt B held by the first bolt retaining portion 44 of the socket 4 ₁ workpiece W The bolt tightening process is performed.

Also performs a bolt supplying step for the second socket 4 ₂ In parallel with the above process. The bolt supplying step, the slide plate 81 with respect to the moving table 61 is moved to the left, the second bolt magazine 8 _2, the lateral innermost bolt B on the magazine 8 ₂ second bolt gripping means 9 the bolt grasping preparing step of moving the graspable bolt passing position _2, a bolt for gripping the lateral innermost bolt B on the second bolt magazine 8 ₂ second bolt gripping means 9 _second gripping claws 91 and 91 a grasping step, the slide plate 81 is moved to the right with respect to the moving table 61, laterally outer second bolt magazine 8 ₂ from moving track to below the second bolt grasping means 9 _second gripping claws 91 and 91 square and magazine evacuation step of moving to the retracted position out of the (right), by moving the second bolt grasping means 9 ₂ downward, the second socket 4 ₂ bolts holding portion of the upward orientation existing in the standby position A bolt insertion step of inserting the head Ba of bolt B from above 4, by opening the second bolt grasping means 9 _second gripping claws 91 and 91, a return step of returning the second bolt grasping means 9 ₂ upward position Consists of.

Here, the bolt grasping preparing step, the bolt grasping step and the magazine retracting step is performed between the second socket 4 ₂ bolt tightening in step with up volt supply preparation process completed for the second socket 4 _2, volt supply preparing step The bolt insertion process is performed immediately after completion. Accordingly, prior to completion of the first socket 4 ₁ by bolt tightening process, it is possible to supply a reliable bolt B to the second socket 4 _2. Then, the series of steps described above is repeated, and a plurality of bolts B are fastened to the workpiece W.

According to the tightening method of the present embodiment, the bolt magazines 8 ₁ and 8 ₂ mounted on the tightening head 1 hold the plurality of bolts B to be fastened to the workpiece W, and the sockets 4 _{1 are connected} to the bolt magazines 8 ₁ and 8 _2. , 4 ₂ for supplying a bolt B, the move one head 1 tightening after the step tightening the bolt B until the volt supply location, socket 4 _1, 4 ₂ is not necessary to provide a bolt B to. Accordingly, the tightening operation can be continued while the tightening head 1 is positioned on the workpiece W side, and the plurality of bolts B can be efficiently tightened to the workpiece W.

Further, during the bolt tightening process by one of the first and second sockets 4 ₁ and 4 ₂ , the bolt B can be supplied to the other socket, and after the bolt tightening process is completed, the nut runner 3 Since one socket connected to the output shaft 3a is moved from the use position to the standby position and at the same time the other socket is moved from the standby position to the use position, the socket replacement operation can be performed efficiently. As a result, the tightening cycle time per bolt can be shortened, and the plurality of bolts B can be fastened to the workpiece W with higher efficiency.

Further, even if the tightening posture is a horizontal or downward posture in which it is difficult to stably supply the bolt B to the bolt holding portion 44 at the tip of the socket, the socket 4 ₁ , 4 ₂ is changed to the upward posture so that the socket The bolt B can be stably inserted from above into the bolt holding portion 44 at the tip, and time loss due to a mistake in bolt supply can be reduced. Furthermore, it is not necessary to arrange an auxiliary facility for supplying a bolt near the tip of the socket connected to the output shaft 3a of the nut runner 3, and the bolt tightening becomes impossible due to the interference of the auxiliary facility with the work W. Can be avoided.

In addition, by making each bolt magazine 8 ₁ , 8 ₂ freely movable between the bolt delivery position and the retracted position, each bolt magazine 8 ₁ can be moved simply by linearly moving each bolt gripping means 9 ₁ , 9 ₂ in the vertical direction. , without causing interference with the _{8 2,} it can be inserted a bolt B into the socket ₄ 1, _{4 2} of the bolt holding portion 44. Therefore, compared to a case where even moving the bolt gripping means 9 _1, 9 ₂ in a direction other than the vertical direction so as to avoid the bolt magazine 8 _1, 8 _2, ensuring the positional accuracy of the bolt grasping means 9 _1, 9 ₂ Therefore, the bolt B can be supplied to the sockets 4 ₁ and 4 ₂ stably and surely.

The first and second bolt magazines 8 ₁ and 8 ₂ are connected to each other via the slide plate 81, and at the same time one of the bolt magazines 8 ₁ and 8 ₂ moves to the bolt delivery position, the other Move to the retreat position. That is, the bolt holding preparation process of the bolt supply process for one of the first and second sockets 4 ₁ and 4 ₂ and the magazine retracting process of the bolt supply process for the other socket are performed simultaneously. Then, these steps are executed before the completion of the bolt fastening preparation step for one socket and the bolt supply preparation step for the other socket, and immediately after the completion of the bolt fastening preparation step and the bolt supply preparation step, the bolt supply step for one socket. The bolt gripping step and the bolt inserting step of the bolt supply step for the other socket can be executed simultaneously. Thereby, the cycle time of the tightening operation can be further shortened.

As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to this. For example, in the above embodiment, in the bolt supply preparation step, the sockets 4 ₁ and 4 ₂ are set in the upward posture in which the bolt holding portion 44 faces directly above in the vertical direction, and the bolt gripping means 9 ₁ and 9 ₂ are set in the vertical vertical direction. Although the linear movement is possible, the upward attitude of each of the sockets 4 ₁ and 4 ₂ in the present invention may be an attitude in which the bolt holding portion 44 is substantially directed upward and inclined with respect to the vertical direction. Similarly, each bolt gripping means ₉ 1, _{9 2} in the linear movement direction serving vertical direction, the bolts gripping means ₉ 1, _{9 2} in the socket linear movement ₄ 1, ₄ bolts B into the _second bolt retaining portion 44 It is sufficient if it can be inserted, and it is not limited to the vertical direction. Further, the tightening posture of each of the sockets 4 ₁ and 4 ₂ is not limited to the horizontal posture as in the above embodiment, and may be a downward posture, for example.

In the above embodiment, the two sockets 4 ₁ and 4 ₂ are used. However, the number of sockets may be one or three or more. When there is one socket, it is not necessary to move the socket to a standby position separated from the axis of the output shaft 3 a of the nut runner 3. Accordingly, it is only necessary to change the posture of the socket between the tightening posture and the upward posture at a position matching the axis of the output shaft 3a of the nut runner 3.

In the above embodiment, the posture changing mechanism for the socket is configured by the cam mechanism 64. However, the posture changing mechanism may be configured by a mechanism that rotationally drives the hinge shaft 46 of each of the sockets 4 ₁ and 4 _2. . However, in this case, it is necessary to provide a drive source for the posture changing mechanism in addition to the cylinder 63 as a drive source for the moving mechanism (moving table 61). On the other hand, if the posture changing mechanism is composed of the cam mechanism 64, a driving source for the posture changing mechanism becomes unnecessary, which is advantageous in reducing the cost.

In the above embodiment, it is provided to both the first and second bolt grasping means ₉ 1, _{9 2} moving table 61, the base 2, first and second respective socket ₄ 1, _{4 2} wait The first and second bolt gripping means 9 ₁ and 9 ₂ may be provided so as to linearly move in the vertical direction at the same position as the position. In this case, the first and second each bolt magazine 8 _1, 8 ₂ are fixed to the moving table 61, in the forward movement to the left of the moving table 61, the first bolt magazine 8 ₁ retracted position, the second bolt magazine 8 ₂ moves the bolt delivery position, at the backward movement to the right of the moving table 61 can be configured such that the first bolt magazine 8 ₁ volt delivery position, the second bolt magazine 8 ₂ is moved to the retracted position .

  It is also possible to integrate the moving mechanism of the socket exchanging mechanism 6 and the attitude changing mechanism. For example, the tightening head 1 is provided with a rotary table that rotates about an equiangular bisector between an axis of the output shaft 3a of the nut runner 3 and a vertical line intersecting the output shaft 3a, and the rotary table has a plurality of sockets. Are attached so that the axis of each socket is inclined with respect to the equiangular bisector by half the angle formed by the axis of the output shaft 3a of the nut runner 3 and the vertical line. The socket that is in the use position that matches the axis in the tightening posture along the axis can be moved in the upward posture to the standby position away from the axis of the output shaft 3a by rotating the rotary table 180 °. According to this, the moving mechanism of the socket exchanging mechanism 6 and the posture changing mechanism are integrally configured by the rotary table. In this case, the standby positions of the sockets are the same, and the bolts can be supplied to the plurality of sockets by one bolt magazine and bolt gripping means.

  Moreover, although the transmission case is illustrated as the workpiece W, when a plurality of bolts are tightened on other workpieces, for example, when a starter or other auxiliary device is bolted to the engine block at a plurality of locations, The present invention can be similarly applied to a case in which suspension parts such as a damper and a suspension arm are bolted at a plurality of locations. There are few empty spaces near the bolt tightening positions of these workpieces. Therefore, the present invention that does not require an auxiliary facility for supplying bolts in the vicinity of the tip of the socket connected to the output shaft of the nut runner is suitable for the bolt tightening operation of these workpieces.

The side view which shows the work station which comprises the bolt fastening apparatus of embodiment of this invention. The front view of the bolt fastening device of an embodiment. The rear view of the bolt fastening device of an embodiment. FIG. 4 is a cut side view taken along line IV-IV in FIG. 2. The cut side view cut | disconnected by the VV line | wire of FIG. The cutting top view cut | disconnected by the VI-VI line of FIG. The top view of the arrangement | positioning part of the bolt holding means of the bolt fastening apparatus of embodiment.

Explanation of symbols

W ... Workpiece, B ... Bolt, 1 ... Clamping head, 3 ... Nutrunner, 3a ... Output shaft, 4 ₁ , 4 ₂ ... Socket, 44 ... Bolt holding part, 5 ... Removal mechanism, 6 ... Socket exchange mechanism, 61 ... Movement Table (moving mechanism), 64 ... cam mechanism (posture changing mechanism), 7 ... bolt supply mechanism, 8 ₁ , 8 ₂ ... bolt magazine, 9 ₁ , 9 ₂ ... bolt gripping means.

Claims (9)

A bolt tightening method for tightening a plurality of bolts on a workpiece using a tightening head equipped with a nut runner,
A bolt supply preparation step of releasing the connection between the socket connected to the output shaft of the nut runner and the output shaft of the nut runner and changing the posture of the socket to an upward posture in which the bolt holding portion at the tip of the socket faces upward,
One of a plurality of bolts held in the bolt magazine mounted on the tightening head is gripped by the bolt gripping means mounted on the tightening head, and after completion of the bolt supply preparation process, the bolt holding part of the socket is bolted from above by the bolt gripping means. A bolt supply process for inserting
After completing the bolt supply process, the socket is changed to a tightening attitude along the axis of the output shaft of the nut runner, and the bolt tightening preparation process for connecting the socket to the output shaft of the nut runner;
A bolt tightening method comprising: a bolt tightening step of rotating a socket by a nut runner after completion of a bolt tightening preparation step and tightening a bolt held by a bolt holding portion of the socket to a workpiece. The bolt tightening method according to claim 1, wherein at least two sockets are provided in the tightening head to be exchangeably connected to an output shaft of the nut runner,
An operation process of one cycle including the bolt supply preparation process , the bolt supply process, the bolt tightening preparation process, and the bolt tightening process is sequentially performed on each socket,
In the bolt supply preparation process for each socket, each socket is moved to the standby position separated from the axis of the output shaft of the nutrunner, and the posture is changed to the upward posture. In the bolt tightening preparation process for each socket, each socket is set in the standby position. From the nut runner to the use position that matches the axis of the output shaft of the nutrunner while changing the posture to the tightening posture,
A bolt tightening method comprising: simultaneously performing a bolt supply preparation step for one socket and a bolt tightening preparation step for another socket. The bolt tightening method according to claim 2, wherein the standby position is different for each socket, and each of the bolt magazine and the bolt gripping means is provided in the tightening head for each socket.
In the bolt supply process for each socket, each bolt magazine corresponding to each socket is moved to a bolt delivery position where one of a plurality of bolts held in the magazine can be gripped by each bolt gripping means corresponding to each socket. Bolt grip preparation step, bolt grip step for gripping bolts by each bolt gripping means, magazine retracting step for moving each bolt magazine to a retracted position that deviates from the downward movement trajectory of each bolt gripping means, and each bolt gripping A bolt tightening method comprising: a bolt inserting step of inserting a bolt into a bolt holding portion of each socket at each standby position by moving the means downward.   4. The bolt tightening method according to claim 3, wherein the bolt holding preparation step of the bolt supply step for one socket and the magazine retracting step of the bolt supply step for another socket are executed simultaneously. .   5. The bolt tightening method according to claim 4, wherein the bolt holding step of the bolt supply step with respect to one socket and the bolt insertion step of the bolt supply step with respect to another socket are simultaneously performed. To a tightening head equipped with a nutrunner,
And detaching mechanism for detachably connecting wearing socket on the output shaft of the nut runner to perform tightening of being rotated bolt by the nut runner,
A posture changing mechanism that changes the posture of the socket, which has been disconnected from the output shaft of the nut runner, between an upward posture in which the bolt holding portion of the socket tip faces upward and a tightening posture along the axis of the output shaft of the nut runner;
A bolt supply mechanism comprising: a bolt magazine that holds a plurality of bolts; and a bolt holding means that holds one of the bolts held by the bolt magazine and inserts the bolt from above into a bolt holding portion of a socket in an upward posture. A bolt fastening device characterized in that a bolt fastening device is provided. In the tightening head,
At least two sockets interchangeably connected to the output shaft of the nutrunner;
A movement mechanism that moves each socket to a use position that matches the axis of the output shaft of the nut runner and a standby position that is separated from the axis, and the attitude change mechanism, and each socket is moved to the standby position by the attitude change mechanism. A socket exchange mechanism is sometimes provided that changes the posture to the upward posture and changes the posture to the tightening posture when moving to the use position.
The attachment / detachment mechanism is configured to detachably connect a socket existing in a use position and an output shaft of the nutrunner,
The bolt gripping means is configured to insert a bolt from above into a bolt holding part of a socket existing in a standby position,
The bolt tightening device according to claim 6, wherein the socket exchanging mechanism is configured to move one socket to a standby position and simultaneously move another socket to a use position. The bolt tightening device according to claim 7,
The socket exchange mechanism is configured to move each socket to a different standby position for each socket;
Each of the bolt magazines and the bolt gripping means are provided for each socket,
Each bolt gripping means is linearly movable in the vertical direction on the same line as the axis of the socket when the corresponding socket is in the standby position.
Each bolt magazine has a bolt delivery position at which one of a plurality of bolts held in the magazine can be gripped by the corresponding bolt gripping means, and a retracted position deviated from the downward movement trajectory of the corresponding bolt gripping means. Bolt tightening device characterized by being movable. The bolt tightening device according to claim 8,
The bolt tightening device, wherein the bolt magazines are connected to each other, and when one bolt magazine is moved to a bolt delivery position, the other one bolt magazine is moved to a retracted position.

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