JPH0890363A - Screw tightening device - Google Patents

Abstract

PURPOSE: To prevent the generation of the axial deviation of a driver by forming the driver of a driver shaft of approximate triangular section and a tip part which is arranged on the tip of the driver shall and engaged with a head part of a screw to be rotated. CONSTITUTION: A driver 41 is provided with three flat surfaces 412 which are straightly cut in an outer circumferential wall by 120 deg. and a driver shaft 410 forming approximately triangular section where three sliding parts 413 of small area to slide on an inner circumferential surface of an absorbing tube are formed between the flat surfaces, and three crescent-shaped passages 414 are formed between the inner circumferential surface of the absorbing tube and the outer circumferential wall. At the tip part 411 of the driver 41, the angle to be formed by the outer walls is formed to a head part of a screw N, and the angle is formed smaller than that formed by the inner wall surface of a recessed part NC with which the tip part 411 of the driver 41 is engaged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw tightening device capable of optimally tightening a vacuum sucked screw.

[0002]

2. Description of the Related Art In a conventional first screw tightening device, a vacuum suction passage P between the driver shaft S of a driver D for tightening a screw and an inner wall of a suction pipe K is provided as shown in FIG. In order to form the parallel surface T, the circumferential side walls facing each other are formed to form the parallel surface T.

In the second conventional screw tightening device, as shown in FIG. 11, the tightening device F has the same tightening operation by a driver D driven by a motor M through a gear G in accordance with a drive input from a controller C. Accordingly, the screw N is rotationally driven and tightened.

In the conventional third screw tightening device, as shown in FIG. 12, the outer peripheral end NG of the screw N sucked and sucked into the suction pipe K and the inner peripheral wall KI of the suction pipe K are brought into point contact with each other. It was sealed.

[0005]

The above-mentioned first conventional screw tightening device forms the parallel surfaces T on the circumferential side walls of the driver D facing the driver shaft S, and therefore the parallel surface T is formed. Due to deformation due to processing heat for forming the surface T and thermal deformation due to induction hardening, misalignment occurs, which causes misalignment of the driver, so that the screw N cannot be stably fastened and abnormal heating occurs. There was a problem that it might occur.

In the above-mentioned second conventional screw tightening device, the tightening device F follows the drive input from the controller C, and the screw D follows the same tightening operation by the driver D.
Since the screw N is rotationally driven for tightening, there is a problem that the screw N may be insufficiently tightened or excessively tightened due to the initial height and posture of the screw N, and the quality may be deteriorated. It was.

In the above-mentioned third conventional screw tightening device, since the outer peripheral end of the screw N and the inner peripheral wall of the suction pipe K are sealed by point-like contact, the inside of the suction pipe is sufficiently sealed. However, there is a problem in that a sufficient vacuum cannot be obtained, a screw N suction error occurs, and a screw-out product is generated at a predetermined portion of the work.

[0008] Therefore, the present inventors have made the driver shaft of the driver into a substantially triangular cross-section, and the driver shaft of the driver has three sections on the circumference.
Focusing on the first technical idea of the present invention of sliding on the inner peripheral wall of the suction pipe at a point, it is fastened by detecting the position of the vertically moving member that vertically moves according to the vertical movement of the driver. The second aspect of the present invention for checking the height of screws
The third technical idea of the present invention is to check the degree of vacuum based on the sealing state when the screw is set in the setting portion at the tip of the suction pipe before tightening the screw. As a result of further research and development while paying attention to it, as a result, it is possible to prevent misalignment of the driver, prevent the screw N from being insufficiently tightened or excessively tightened, and prevent the screw N from being sucked incorrectly and the work piece from missing. The present invention has been achieved to achieve the object.

[0009]

A screw tightening device of the present invention (the first invention according to claim 1) sets a suction pipe for sucking a conveyed screw and a screw conveyed in the suction pipe by suction. A vacuum suction device that vacuum-sucks the inside of the suction pipe through the suction path, and a tightening device that tightens the screw set in the suction pipe by a driver that moves up and down and rotates. In the above, the driver comprises a driver shaft having a substantially triangular cross section, and a tip end portion that is disposed at a tip end of the driver shaft and engages with a head portion of the screw to be driven to rotate.

The screw tightening device of the present invention (the second invention according to claim 2) has a suction pipe for sucking the conveyed screw and a suction path for sucking and setting the screw conveyed in the suction pipe. A vacuum suction device that vacuum-sucks the inside of the suction pipe, and a tightening device that tightens the screw set in the suction pipe by a screwdriver that moves up and down and rotates. The height detection mechanism detects the height of the tightened screw by detecting the position of the vertically moving member that moves up and down according to the movement.

The screw tightening device of the present invention (the third invention according to claim 3) has a suction pipe for sucking the conveyed screw and a suction path for sucking and setting the screw conveyed in the suction pipe. In the screw tightening device, a vacuum suction device that vacuum-sucks the inside of the suction pipe and a tightening device that tightens the screw set in the suction pipe by a screwdriver that moves up and down and rotates. The vacuum monitoring device for detecting the vacuum pressure based on the sealing state when the screw is set in the setting part is provided.

[0012]

The screw tightening device of the first invention having the above structure is
The screw suctioned by the vacuum suction device via the suction path to the inside of the suction pipe to suck and set the screw conveyed into the suction pipe, and the tightening device includes the driver shaft and the driver shaft having a substantially triangular cross section. And a tip portion that is disposed at the tip of the screw and is driven to rotate by engaging with the head of the screw, and tightens the screw set in the suction pipe by the driver that rotates and moves up and down. is there.

In the screw tightening device of the second invention having the above structure, the vacuum suction device vacuum sucks the inside of the suction pipe through the suction path, and the screw conveyed in the suction pipe is suction set and tightened. A mounting device tightens the screw set in the suction pipe by the driver that rotates and moves up and down, and at this time, the height detection mechanism moves up and down according to the up and down movement of the driver. By detecting the position of the member, the height of the tightened screw is detected, and the abnormal height is dealt with accordingly.

In the screw tightening device of the third invention having the above structure, the vacuum suction device vacuum-sucks the inside of the suction pipe through the suction path, and the screw conveyed in the suction pipe is suction-set and tightened. An attachment device tightens the screw set in the suction pipe by the driver that rotates and moves up and down, and the vacuum monitoring device sets the screw in the setting portion at the tip of the suction pipe. The vacuum pressure is detected based on the sealed state at the time, and if the vacuum pressure is abnormal, a corresponding action is taken.

[0015]

According to the screw tightening device of the first invention having the above-mentioned operation, the screw set in the suction pipe is tightened by the driver having the driver shaft having a substantially triangular cross section. It is possible to prevent the occurrence of core wobbling, to enable stable tightening of screws, and to prevent the occurrence of abnormal heating.

In the screw tightening device of the second aspect of the present invention, the height detecting mechanism is tightened by detecting the position of the vertically moving member which moves up and down according to the vertical movement of the driver. Since the height of the screw is detected and the abnormal height is dealt with accordingly, insufficient tightening and excessive tightening of the screw can be prevented, and the quality can be improved.

In the screw tightening device of the third aspect of the present invention, the vacuum monitoring device detects the vacuum pressure based on the sealing state when the screw is set in the setting portion at the tip of the suction pipe. When the vacuum pressure is abnormal, a corresponding action is taken, so that it is possible to prevent the suction failure of the screw N and the occurrence of a screw-out item in the work and to improve the quality.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) As shown in FIGS. 1 to 9, the screw tightening device of the first embodiment is an embodiment of the first to third inventions, and includes a screw carrying device 1 for carrying screws. A suction pipe 2 for sucking the conveyed screw N, a vacuum suction device 3 for sucking the inside of the suction pipe 2, and the suction pipe 2
A fastening device 4 having a driver 41 including a driver shaft 410 having a substantially triangular cross-section coaxially inserted therein and a tip portion 411 engaging with the head of the screw N, and a vacuum suction path 3
1, a vacuum monitoring device 5 including a vacuum sensor 51 and a discrimination circuit 52 for monitoring the vacuum pressure, a sensor 61 provided on a vertically moving member 60 integrally fixed to the drive motor, and The height detection mechanism 6 is composed of a facing member 62 integrally fixed to the suction pipe 2 and arranged to face the sensor 61, and an XY robot 70 that holds the fastening device 4. Moving mechanism 7 and the discrimination circuit 5
A control circuit 8 that outputs a control signal to the moving mechanism 7 based on a signal from the motor 2 and a torque monitoring device 9 that detects the tightening torque of the screw by the driver 41 and monitors the torque.
It consists of and.

As shown in FIGS. 1 and 2, the transfer device 1 comprises a hopper 14 for accommodating a large number of screws, a chute rail 15R supported by a rail support 15C, and a holding plate 15P. It is composed of a chute 15 for supplying screws obliquely, and sequentially conveys the screws to a catcher 2C that constitutes the suction pipe 2.

As shown in FIGS. 1 and 2, the fastening device 4 has a drive motor 44 arranged to be vertically movable by a catcher lifter 46 with respect to a base 4B fixed to the side of the robot 70, and a drive motor. The drive motor 44 is inserted in the lower part of the case main body 43 that is integrally arranged in the lower part of the 44.
A driver 41 that is rotationally driven by a drive shaft,
The driver 4 is disposed below the case body 43.
A tube 4 that constitutes the adsorption pipe 2 in which 1 is inserted.
It consists of 5 and.

As shown in FIGS. 3 and 4, the driver 41 has three flat surfaces 412 whose outer peripheral wall is linearly bored at intervals of 120 degrees, and the suction pipe 2 is interposed between the flat surfaces 412. It has a driver shaft 410 having a substantially triangular cross section in which three small-area sliding portions 413 that slide on the inner peripheral surface are formed, and three crescent-shaped ones are formed between the driver shaft 410 and the inner peripheral surface of the adsorption pipe 2. Passage 4
14 is formed.

The tip portion 411 of the driver 41 is
As shown in FIG. 3, the angle formed by the outer wall is smaller than the angle formed by the inner wall surface of the recess NC formed on the head portion of the screw N and engaged with the tip portion 411 of the driver 41.

The suction pipe 2 is composed of the case body 43.
1 and a catcher 2C disposed at the lower end of the tube 45, which is constituted by a thin tube 45 supported by the base 4B similarly to the chute rail 15R. 2C
And an L-shaped receiving portion 2R for receiving the screw supplied from the chute rail 15R through the opening 2O.

As shown in FIG. 5, an annular shoulder portion 451 forming a set portion is formed on the inner peripheral wall of the tip of the tube 45 constituting the suction pipe 2, and the head portion and the shoulder portion of the sucked screw are formed. And 451 are configured to form an annular face seal.

As shown in FIG. 1, the height detecting mechanism 6 is fixed between the drive motor 44 and the case body 43, which are supported by the catcher lifter 46 so as to be vertically movable with respect to the base 4B. The micro switch constituting the sensor 61 fixed to the first bar member constituting the vertical movement member 60 fixed to the flange, and the tube 45 constituting the suction pipe 2 fixed to the base 4B. A facing member 62 which is formed on a disk portion provided at the tip of the second bar member 620 fixed by the arm member fixed to the above and engages with the micro switch.
The position of the lower end of the driver 41, which is defined by the positional relationship among the drive motor 44, the case body 43, and the tube 45, is determined by the engagement of the microswitch and the circular recess. ,
The driver 41 descends at a low speed and rotates at a high speed to detect the height of the tightened screw.

The torque monitoring device 9 is shown in FIGS.
The gear 4 that reduces the rotation speed of the drive motor 44 as shown in FIG.
The torque sensor 91 arranged between the output shaft and the driver 41 in 4G detects the tightening torque of the screw N by the driver 41, and the detected tightening torque is set as shown in FIG. When the tightening torque is reached, the controller 92 outputs a tightening stop signal to the driver 41.
The configuration is such that the screw tightening operation of the screw N can be completed.

In the vacuum suction device 3, as shown in FIG. 6, the suction pump is rotated by the compressed air from the compressed air source 30A controlled by the control valve on the basis of the signal from the source pressure control sensor so that the vacuum suction is performed. The generator 30, the filter 32 that separates the central portion 32C and the outer peripheral portion 32P, which are connected to the vacuum generator 30, with an annular filter element 32E, and the outer peripheral portion 3 of the filter 32 has one end.
The suction path 3 formed by the hose 31H that communicates with the 2P and the other end communicates with the lower part of the case body 43.
It consists of 1.

As shown in FIG. 6, the vacuum monitoring device 5 for detecting the vacuum pressure based on the sealing state when the screw is set in the setting portion at the tip of the suction pipe is the suction path 31 formed by the hose 31H. It is composed of a vacuum sensor 51 for detecting the internal vacuum state and a determination circuit 52 for determining the level of the vacuum state detected by the vacuum sensor 51.

The vacuum sensor 51 is a digital type pressure sensor as shown in FIG.
It is arranged at an appropriate place inside and can detect the vacuum level.

As shown in FIGS. 6 and 7, the discriminating circuit 52 is a first circuit for discriminating whether or not the vacuum level detected by the vacuum sensor 51 has the screw N attracted to the setting portion. It is determined whether or not the value is equal to or more than a reference value, and it is determined whether the value is equal to or more than a second reference value for determining whether the face seal is set in the setting portion of the suction pipe 2 in a normal posture, When it is less than the first reference value, an alarm signal is output by the output device 53 to turn on the lamp, and a stop signal is output to the control circuit 8. It is configured to output a movement signal for moving to the work position.

The control circuit 8 is composed of a robot controller as shown in FIG. 7, and is capable of outputting coordinate signals corresponding to the work position and the stop / retract position in accordance with the signal output from the discrimination circuit 52. Become.

The moving mechanism 7 is an XY robot 70.
And a vacuum level detected by the vacuum sensor 51, based on a coordinate signal from the control circuit 8,
The fastening device 4 can be moved to a work position for performing work on a work and a retracted position.

In the screw tightening device of the first embodiment having the above-mentioned structure, the carrying device 1 presses a large number of screws housed in the hopper 14 and the chute rail 15R supported by the rail support 15C. Screws are obliquely supplied from the hopper 14 by the chute 15 composed of a plate 15P, and the screws are sequentially conveyed to the catcher 2C constituting the suction pipe 2.

The fastening device 4 is driven by the drive motor 44 which is arranged so as to be vertically movable by the catcher lifter 46 with respect to the base 4B fixed to the side portion of the robot 70.
The driver 41, which is disposed below the case body 43, is driven by a driver 41 that is rotationally driven through a drive shaft that is inserted into the lower portion of the case body 43 that is integrally disposed below the drive motor 44. The screw conveyed to the catcher 2C arranged at the lower end of the tube 45 constituting the suction pipe 2 is engaged and rotated.

As shown in FIGS. 3 and 4, the driver 41 has three crescent-shaped passages formed between the outer peripheral wall of the driver pipe 41 and the inner peripheral surface of the suction pipe 2 in a straight line. The sliding portions 413 having a small area, which are formed in three places at intervals of 120 degrees between the three flat surfaces 412 forming the slide surface slide on the inner peripheral surface of the adsorption pipe 2, so that the three places are slid. Moving part 4
Since the sliding reaction force from 13 toward the driver shaft center acts at the same time, the three sliding reaction forces are canceled and balanced, so that an unbalanced acting force is not generated on the driver shaft 410.

The tip portion 411 of the driver 41 is
As shown in FIG. 3, since the angle formed by the outer wall is formed smaller than the angle formed by the inner wall surface of the recess NC formed in the head of the screw N, the tip of the tip portion is formed by the screw N.
The bottom portion of the concave portion NC formed in the head portion of the head reliably contacts the bottom portion.

The suction pipe 2 is supported by the base 4B, is arranged at the lower part of the case body 43, and is arranged at the lower end of the thin tube 45.
The L-shaped receiving portion 2R of C receives the screw supplied from the chute rail 15R through the opening 20 as shown in FIG.

A tube 45 constituting the adsorption pipe 2
The annular shoulder portion 451 forming a set portion formed on the inner peripheral wall of the tip of the head forms an annular face seal with the head of the screw sucked as shown in FIG.

The height detection mechanism 6 includes the drive motor 4
4, the position of the lower end of the driver 41, which is determined by the positional relationship among the case body 43 and the tube 45, is determined by the engagement of the micro switch and the circular recess.
The height of the screw fastened by the driver 41 descending at a low speed and rotating at a high speed is detected by a microswitch constituting the sensor 61, and the detected height is, for example, 1 mm which is a reference height. If it is significantly lower or higher than that, it is detected as an abnormal height.

When the height of the screw detected by the height detecting mechanism 6 is within the tolerance of the reference value of 1 mm, the torque monitoring device 9 rotates the driver 41 at a medium speed and lowers it. When the screw is seated, the rotation of the driver 41 is once stopped, and then the screw 41 is rotated again by the driver 41, and the torque sensor 91 causes the screw 41 to rotate the screw N as shown in FIGS. 7 and 9. When the tightening torque is detected and the detected tightening torque reaches the tightening torque set as shown in FIG. 8, the screw tightening operation of the screw N by the driver 41 is completed.

In the vacuum suction device 3, as shown in FIGS. 6 and 7, the suction pump is rotated by the compressed air from the compressed air source 30A controlled by the control valve based on the signal from the source pressure control sensor. The central part 32C in which the vacuum generator 30 communicates with the vacuum generator 30.
And the one end that separates the outer peripheral portion 32P from the outer peripheral portion 32P communicates with the outer peripheral portion 32P of the filter 32,
The inside of the case body 43 is vacuum-sucked through the hose 31H that constitutes the suction path 31 and has the other end connected to the lower portion of the case body 43.

The vacuum sensor 51 constituting the vacuum monitoring device 5 is a digital type pressure sensor arranged at an appropriate position in the suction path 31, and the suction path 3 is provided.
The vacuum state in 1 is detected to detect the state (presence / absence, posture) of the screw set in the setting section.

The discriminating circuit 52 which constitutes the vacuum monitoring device 5 is a first reference for discriminating whether or not the vacuum state detected by the vacuum sensor 51 is sucked by the screw N on the set portion. It is determined whether or not the value is equal to or more than a value, and it is determined whether the value is equal to or more than a second reference value for determining whether or not a face seal is set in the setting portion of the suction pipe 2 in a normal posture, When it is less than the reference value of 1, an alarm signal is output by the output device 53 to turn on the lamp, and a stop signal is output to the control circuit 8. When it is more than the second reference value, the work of the work is performed. A movement signal for moving to the position is output.

The control circuit 8 is composed of a robot controller and outputs coordinate signals corresponding to the work position and the stop / retract position in accordance with the signal output from the discrimination circuit 61.

The moving mechanism 7 is an XY robot 70.
And a vacuum level detected by the vacuum sensor 51, based on a coordinate signal from the control circuit 8,
The fastening device 4 is moved to the work position for performing work on the work and the stop and retract position.

In the screw tightening device of the first embodiment having the above-described action, the screw set in the suction pipe 2 is tightened by the driver 41 having the driver shaft 410 having a substantially triangular cross section. The small-area sliding portions 413 formed at three positions at 120 ° intervals are used for the adsorption pipe 2
Since it slides on the inner peripheral surface of, the sliding reaction force from the three sliding portions 413 toward the driver axis acts at the same time.
Since the three sliding reaction forces are offset and balanced, the driver shaft 41
Since no unbalanced acting force is generated in 0, the occurrence of core deviation of the driver is prevented, stable fastening of screws is possible, and abnormal heating is prevented. Further, in the first embodiment apparatus, 12
Since the three surfaces are formed at 0 degree intervals, it is possible to prevent deformation due to processing heat caused by processing from both surfaces in the same direction for forming parallel surfaces facing each other in the conventional apparatus and accompanying misalignment of the driver. Play.

Further, in the screw tightening device of the first embodiment, the height detecting mechanism 6 detects the position of the vertically moving member which moves up and down in response to the vertical movement of the driver by the micro switch, thereby tightening the screw. Accurately detect the height of the attached screw, and adjust the height for abnormal heights or replace the screws accordingly, so it is possible to prevent insufficient or excessive tightening of screws. It has the effect of preventing it and improving the quality.

Further, in the screw tightening device of the first embodiment, the vacuum monitoring device 5 detects the vacuum pressure based on the sealing state when the screw is set in the setting part at the tip of the suction pipe 2. When the vacuum pressure is abnormal, the tightening is stopped and the screw is replenished. Therefore, it is possible to prevent the suction error of the screw N and the screw shortage in the work, and to improve the quality. Play.

Further, in the screw tightening device of the first embodiment, the tip portion 411 of the driver 41 forms the angle formed by the outer wall as shown in FIG. 3 with the concave portion NC formed in the head portion of the screw N.
Since it is formed smaller than the angle formed by the inner wall surface of, the tip of the tip portion 411 surely abuts the lowest portion of the bottom portion of the recess NC formed in the head of the screw N,
There is an effect that the height of the screw can be accurately detected by the height detection mechanism 6.

Further, in the screw tightening device of the first embodiment, when the torque monitoring device 9 detects that the height of the screw detected by the height detecting mechanism 6 is within the allowable range of the reference value of 1 mm, the driver 41 is rotated at a medium speed and is lowered, and once the screw is seated, the driver 4
1 is stopped, and then the driver 41 is turned on again.
When the screw 41 is rotated by and reaches the set tightening torque, the screw tightening operation of the screw N by the driver 41 is completed, so that the screw tightening with the set tightening torque is realized and the quality is improved. Has the effect.

Further, in the screw tightening device of the first embodiment, an annular shoulder portion 451 which constitutes a set portion is formed on the inner peripheral wall of the tip of the tube 45 which constitutes the suction pipe 2, so that the sucked screw Since the head portion and the shoulder portion 451 are configured to form an annular face seal, the face seal state changes depending on the state (presence or absence, posture) of the screw set in the setting portion. Therefore, there is an effect that the state of the screw can be accurately detected.

Further, in the screw tightening device of the first embodiment, when the value is less than the first reference value, the output device 53 outputs an alarm signal to turn on the lamp, and the control circuit 8
And outputs a stop signal to the moving mechanism 7 to move the work to the work position when the work amount is equal to or larger than the second reference value.

The embodiments described above are merely examples for the purpose of explanation, and the present invention is not limited to them. Those skilled in the art will recognize from the claims, the detailed description of the invention and the description of the drawings. Modifications and additions can be made without departing from the technical idea of the present invention.

In the above embodiment, the XY type robot is explained as an example of the moving mechanism, but the present invention can also be applied to the scalar type and the joint type robots, and the movements other than the robot are possible. Special purpose machines are also available.

[Brief description of drawings]

FIG. 1 is a side view showing a fastening device and a screw conveying device of a first embodiment device of the present invention.

FIG. 2 is a perspective view showing the device of the first embodiment.

FIG. 3 is a partially enlarged side view showing a driver and screws of the device of the first embodiment.

FIG. 4 is a cross-sectional view showing a driver and a tube of the device of the first embodiment.

FIG. 5 is a vertical sectional view showing a driver and a tube of the device of the first embodiment.

FIG. 6 is an air circuit diagram showing the vacuum suction device and other components of the first embodiment device.

FIG. 7 is a block diagram showing the overall system of the first embodiment device.

FIG. 8 is an explanatory diagram showing torque control of a driver of the first embodiment device.

FIG. 9 is a block diagram showing a torque monitoring device of the first embodiment device.

FIG. 10 is a transverse cross-sectional view showing a first conventional screw tightening device.

FIG. 11 is a block diagram showing a second conventional screw tightening device.

FIG. 12 is a vertical cross-sectional view showing a third conventional screw tightening device.

[Explanation of symbols]

 1 Screw Conveying Device 2 Suction Pipe 3 Vacuum Suction Device 4 Tightening Device 5 Vacuum Monitoring Device 6 Height Detecting Mechanism 7 Moving Mechanism 8 Control Circuit 9 Torque Monitoring Device 31 Vacuum Suction Path 41 Driver 410 Driver Shaft 411 Tip 51 Vacuum Sensor 52 Discrimination circuit 60 Vertical movement member 61 Sensor 62 Opposing member 70 XY robot

Claims (7)

[Claims] 1. A suction pipe for sucking a conveyed screw, a vacuum suction device for vacuum-sucking the suction pipe through a suction path to suck and set the screw conveyed in the suction pipe, and a suction pipe inside the suction pipe. A tightening device for tightening a set screw by a screwdriver that moves up and down and rotates, wherein the screwdriver is provided at a driver shaft having a substantially triangular cross section and at the tip of the driver shaft. A screw tightening device, comprising: a tip portion that is engaged with a head portion of the screw and is rotationally driven. 2. A suction pipe for sucking the conveyed screw, a vacuum suction device for vacuum suction inside the suction pipe through a suction path for suction setting the screw conveyed in the suction pipe, and a suction pipe inside the suction pipe. A tightening device for tightening a set screw by a screwdriver that moves up and down and rotates, and by detecting the position of a vertically moving member that moves up and down according to the up and down motion of the driver. A screw tightening device comprising a height detection mechanism for detecting the height of the tightened screw. 3. A suction pipe for sucking the conveyed screw, a vacuum suction device for vacuum sucking the suction pipe through a suction path to suck and set the screw conveyed in the suction pipe, and a suction pipe inside the suction pipe. In a screw tightening device consisting of a tightening device that tightens the set screw with a screwdriver that moves up and down and rotates, the vacuum pressure based on the seal state when the screw is set in the setting part at the tip of the suction pipe. A screw tightening device comprising a vacuum monitoring device for detecting 4. The angle formed by the outer wall of the tip portion of the driver is smaller than the angle formed by the inner wall surface of a recess formed in the head of the screw and engaged with the tip portion of the driver. A screw tightening device characterized in that 5. The screw according to claim 3, wherein a shoulder portion is formed on a tip inner peripheral wall of the suction pipe, and the head portion of the screw and the shoulder portion form a face seal. Fastening device. 6. The tightening torque of the screw by the driver according to claim 2,
A screw tightening device comprising a torque monitoring device for checking whether or not a set torque has been reached. 7. The vacuum sensor according to claim 5, wherein the vacuum detection device is arranged in the suction path and detects a vacuum level in the suction path, and the vacuum sensor in the shoulder portion based on the vacuum level detected by the vacuum sensor. A discriminating circuit for discriminating the presence or absence of a screw and a seating state, an output device for issuing an alarm or display based on an output signal from the discriminating circuit, and a movement signal from the discriminating circuit for moving the fastening device to a stop position. A screw tightening device comprising a moving mechanism.