JP3569619B2 - Screw fastening method and device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a screw tightening method and apparatus, and more particularly to a screw tightening method and apparatus for tightening a plurality of screws substantially simultaneously.
[0002]
[Prior art]
In the assembly work in various industries such as electronic devices and precision machines, screw tightening work is the most basic.
A conventional screw tightening method will be described with reference to FIG. 6 taking as an example an assembling operation of a hard disk drive (HDD) device. FIG. 6 is a perspective view showing the HDD device.
[0003]
As shown in FIG. 6, a spindle motor 112 for rotating a disk 114 is mounted on the back side of an HD (Hard Disk) control board 110 on which a control IC (Integrated Circuit) 109 and the like are mounted. On the other hand, a plurality of disks 114 are provided on the front side of the HD control board 110. Spacers (not shown) are sandwiched between the disks 114, and the disks 114 are separated from each other by a predetermined distance.
[0004]
A disk clamp 116 is mounted on the uppermost disk 114. Four screw holes 118a to 118d are formed in the disk clamp 116, and all the disks 114 are fixed to the rotating shaft (not shown) of the spindle motor 112 by tightening with four screws. Since the disc clamp 116 has four screw holes 118a to 118d, in the screw tightening operation, in order to prevent the disc 114 from being distorted, while selecting a diagonal screw, the torque is changed from a small torque to a large torque. All the screws were tightened several times.
[0005]
Then, a head drive device 120 to which a plurality of arms 124 provided with a magnetic head 122 are mounted is mounted on the HD control board 110, and the HDD device is completed.
[0006]
[Problems to be solved by the invention]
However, when the screw is tightened to the disk clamp 116 as described above, the disk clamp 116 is tightened while being distorted, so that the disk 114 may be distorted. In the HDD device, since the magnetic head 122 is provided close to the disk 114, distortion of the disk 114 is a fatal obstacle. Therefore, it is required to perform screw tightening without causing distortion in the disk clamp 116.
[0007]
Therefore, it is conceivable to use a screw fastening device that can simultaneously tighten a plurality of screws and simultaneously tighten a plurality of screws. However, even when simply tightening a plurality of screws at the same time, various factors such as variations in screws, variations in a tightened body such as a disk clamp, variations in the number of rotations of a bit of a screw tightening device, and variations in a generated torque, etc. It is very difficult to tighten the screws without causing distortion of the tightened body.
[0008]
In addition, when a screw is tightened, a rotational torque is generated in a tightened body such as a disk clamp. However, when a plurality of screws are tightened simultaneously, the rotational torque of the tightened body is multiplied by the number of screws. For this reason, there is also a problem that in order to prevent the rotation of the tightened body, the tightened body must be pressed with a force corresponding to the rotation torque.
[0009]
An object of the present invention is to provide a screw tightening method and apparatus capable of tightening a screw without causing distortion of a tightened body.
It is another object of the present invention to provide a screw tightening method and apparatus capable of suppressing a rotational torque generated in a tightened body even when a plurality of screws are tightened simultaneously.
[0010]
[Means for Solving the Problems]
[0011]
The above object is a screw tightening device for tightening a plurality of screws to be simultaneously tightened at a plurality of locations at a preset tightening torque,Each is driven by a motor equipped with an encoder that generates a pulse signal corresponding to the rotation,A plurality of screw tightening means for screwing the plurality of screws, and a synchronous control means for controlling the plurality of screw tightening means in synchronization with each other, wherein a target set torque until the set tightening torque is reached is adjusted in a plurality of stages. The synchronous control means, at each stage, until the tightening torque of all of the plurality of screws reaches the target set torque, while maintaining the tightening torque at the target set torque,Based on the pulse signal from the encoder,The plurality of screw tightening means are made to stand by, and after all the tightening torques of the plurality of screws reach the target set torque, screw tightening by the plurality of screw tightening means is restarted.When the plurality of steps are completed and all the tightening torques of the plurality of screws reach the set tightening torque, all the screws of the plurality of screws are further maintained at the set tightening torque for a predetermined hold time. Finish tighteningThis is achieved by a screw tightening device characterized in that: Thereby, the tightening torque of the plurality of screws can be increased substantially the same, so that the screws can be tightened without causing distortion in the tightened body.
[0012]
Further, the above object is achieved by setting a plurality of screws at a plurality of locations at a preset tightening torque.AtSometimesTo tightenA method of tightening a screw, comprising:Is, ClockwiseJust, Counterclockwise screwConsists of, The clockwise screw and the counterclockwise screwTo reduce the rotational torque generated in the tightened bodyThis is achieved by a screw tightening method characterized by screwing. Accordingly, the clockwise rotation torque and the counterclockwise rotation torque generated in the tightened body cancel each other, so that even when a plurality of screws are simultaneously tightened, the rotation torque generated in the tightened body can be suppressed. .
In the above screw tightening method, it is preferable that the number of the clockwise screws and the number of the counterclockwise screws are the same among the plurality of screws.
[0013]
Further, the above object is achieved by setting a plurality of screws at a plurality of locations at a preset tightening torque.AtSometimesTo tightenA screw tightening device for tightening, wherein the plurality of screws areIs, ClockwiseJust, Counterclockwise screwConsists ofA clockwise screw tightening means for tightening the clockwise screw, a counterclockwise screw tightening means for tightening the counterclockwise screw, the clockwise screw tightening means and the counterclockwise screw tightening means,To reduce the rotational torque generated in the tightened bodyScrew tighteningSystemControl means for controlling the screw tightening device. Accordingly, the clockwise rotation torque and the counterclockwise rotation torque generated in the tightened body cancel each other, so that even when a plurality of screws are simultaneously tightened, the rotation torque generated in the tightened body can be suppressed. .
In the above screw tightening device, it is preferable that the number of the clockwise screws and the number of the counterclockwise screws are the same among the plurality of screws.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
[First Embodiment]
A screw fastening method and apparatus according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram illustrating the screw fastening device according to the present embodiment. Note that the driver units 14a to 14d in FIG. 1 are viewed from below the driver units 14a to 14d, that is, from the side of the bits 16a to 16d. FIG. 2 is a side view showing the driver unit of the screw fastening device according to the present embodiment. FIG. 3 is a block diagram showing a screw tightening control unit and a driver unit of the screw tightening device according to the present embodiment. FIG. 4 is a time chart showing the operation of the screw fastening method and device according to the present embodiment. In the present embodiment, a description will be given by taking as an example the screwing of the disk clamp of the HDD device as shown in FIG.
[0015]
(overall structure)
First, the overall configuration of the screw fastening device according to the present embodiment will be described with reference to FIG.
The screw tightening device according to the present embodiment includes a synchronous control unit 10, four screw tightening control units 12a to 12d, and four driver units 14a to 14d.
[0016]
The screw tightening device according to the present embodiment synchronously controls the four screw tightening control means 12a to 12d by the synchronous control means 10 so that the screw tightening torques of the four driver units 14a to 14d increase substantially the same. is there. The target set torque until the set tightening torque is reached is finely set, for example, in eight stages, and in each stage, all four screw tightening control means 12a to 12d wait as necessary until the target set torque is reached, and as a result, The main feature is that synchronous control is performed so that the tightening torques of the four screws increase in the same manner.
[0017]
As shown in FIG. 1, the screw tightening device according to the present embodiment is connected to a sequencer 15 that controls the entire screw tightening operation in a factory or the like. The sequencer 15 gives a command to start and end the screw tightening operation to the screw tightening device, and the screw tightening device performs a predetermined screw tightening operation based on the command.
(Driver unit)
Next, the driver unit of the screw fastening device according to the present embodiment will be described with reference to FIGS.
[0018]
As shown in FIG. 1, the bits 16a to 16d of the driver units 14a to 14d are aligned so as to correspond to the positions of the screw holes 118a to 118d of the disk clamp 116 of the HDD device shown in FIG.
FIG. 2 is a side view of the driver unit 14. As can be seen from FIG. 2, the driver unit 14 of the screw tightening device according to the present embodiment is obtained by offsetting the position of the rotation axis by offsetting the driver head 18 provided with the bit 16 and the servomotor 20. With such a structure, the positions of the bits 16a to 16d of the plurality of driver units 14a to 14d can be made closer to the screw holes 118a to 118d of the disk clamp 116 shown in FIG. I have.
[0019]
An encoder 22 that generates a pulse signal in accordance with the rotation of the servomotor 20 is attached to a rotation shaft of the servomotor 20.
The encoder 22 and the servomotor 20 are connected to the screw tightening control means 12 via the connector 23, and the driver unit 14 is controlled by the screw tightening control means 12 (see FIG. 3).
[0020]
A sleeve 24 slidable in the rotation axis direction is provided at the tip of the driver head 18 of the driver unit 14. The sleeve 24 is provided so as to cover the bit 16. When air is sucked from an intake pipe 26 provided in the sleeve 24, the head of the screw is attracted to the bit 16.
(Screw tightening control means)
Next, the screw tightening control means of the screw tightening device according to the present embodiment will be described with reference to FIGS.
[0021]
As shown in FIG. 1, one screw tightening control means 12a to 12d is provided for each of the driver units 14a to 14d, and controls the driver units 14a to 14d in accordance with commands from the sequencer 15 and the synchronization control means 10. is there.
As shown in FIG. 3, an operation / display unit 28 is provided in the screw tightening control unit 12. In the operation / display unit 28, the setting of the tightening torque and the setting of the rotation direction of the screw are performed using a setting switch (not shown). The set tightening torque value and rotation direction are displayed by an LED or the like provided on the operation / display unit 28.
[0022]
The operation / display unit 28 is connected to the control unit 30, and the control unit 30 appropriately reads setting contents, and displays display information and the like from the control unit 30 by the operation / display unit 28.
An external control interface unit 32 is connected to the control unit 30. The control unit 30 inputs and outputs signals to and from the synchronization control unit 10 and the sequencer 15 via the external control interface unit 32.
[0023]
For example, information indicating that screw tightening is performed in eight stages is input from the synchronization control unit 10 to the control unit 30 via the external control interface unit 32 in advance. The control unit 30 obtains the target set torque in each stage from the information indicating that the screw is to be tightened in eight stages and the set screw tightening torque value, for example, so as to reach the target set torque in each stage of the screw tightening. Screws will be tightened.
[0024]
The control unit 30 controls the servo circuit 34 to rotate the servomotor 20 of the driver unit 14 according to a command from the sequencer 15 or the synchronization control unit 10. Then, while checking the pulse signal from the encoder 22 attached to the servomotor 20 of the driver unit 14, the screw tightening control is performed at an appropriate rotation speed. When the tightening torque of the screw reaches the target set torque in each stage, a signal is output to the synchronous control means 10 and the apparatus stands by until there is a command from the synchronous control means 10. When there is a command again from the synchronization control means 10, the screw tightening control means 12 starts screw tightening again. Then, in the same manner, the screws are tightened step by step. The overall operation of the screw tightening control means 12 will be described later.
[0025]
(Synchronous control means)
Next, the synchronization control means of the screw fastening device according to the present embodiment will be described with reference to FIGS.
The synchronization control means 10 is for synchronously controlling the four screw tightening control means 12a to 12d so that the tightening torques of the four driver units 14a to 14d increase substantially the same.
[0026]
As described above, information indicating that the screw is to be tightened in, for example, eight steps is stored in the synchronization control means 10 in advance. As described above, this information is output to the screw tightening control units 12a to 12d.
In the screw tightening operation, the synchronization control unit 10 monitors the SYNC signal output from the screw tightening control units 12a to 12d, and when all the screw tightening control units 12a to 12d output the SYNC signals, The tightening control means 12a to 12d determine that the tightening torque of the screw has reached the target set torque, and output an ACK signal to the screw tightening control means 12a to 12d.
[0027]
When the ACK signal is output, the screw tightening control means 12a to 12d restart the screw tightening again, and perform the screw tightening until the next set target torque is reached. Similarly, the four screw tightening control means 12a to 12d are synchronously controlled so that the tightening torques of the four screws increase in the same manner, and the four screws are tightened with substantially equal tightening torques. The overall operation of the synchronization control means 10 will be described later.
[0028]
Further, the synchronization control means 10 is provided with a hold time setting switch (not shown) for setting the hold time. The hold time is a time during which the screw is tightened for a certain time with the set tightening torque in order to stabilize the final tightening torque of the screw. By switching the hold time setting switch, the hold time is set to, for example, 50 ms or 200 ms.
[0029]
(Sequencer)
Next, the sequencer 15 for controlling the entire screw tightening operation in a factory or the like will be described with reference to FIGS.
As shown in FIG. 1, the sequencer 15 is connected to the synchronization control means 10 and the screw tightening control means 12a to 12d of the screw tightening device according to the present embodiment, and controls a screw tightening operation by giving a predetermined command.
[0030]
As shown in FIG. 4, the sequencer 15 outputs a START signal indicating the start of the screw tightening operation. When the START signal is input, the screw tightening control means 12a to 12d immediately control the driver units 14a to 14d to start screw tightening.
Then, the sequencer 15 monitors the MTDV (a) signal to the MTDV (d) signal output from the screw tightening control means 12a to 12d, and upon completion of the output of the MTDV (a) signal to the MTDV (d) signal, tightens the screw. Is completed, and the output of the START signal is terminated. Thus, a series of screw tightening operations is completed. The MTDV (a) signal to the MTDV (d) signal are signals indicating that the screw tightening control units 12a to 12d are operating. The overall operation of the sequencer 15 will be described later.
[0031]
(Screwing operation)
Next, a screw tightening method using the screw tightening device of the present embodiment will be described with reference to FIGS.
First, the initial setting of the screw fastening device according to the present embodiment will be described with reference to FIG.
[0032]
In the initial setting of the screw tightening operation, first, the power switches (not shown) of the synchronous control means 10 and the screw tightening control means 12 are turned on.
The synchronization control means 10 outputs to the screw tightening control means 12 information indicating that screw tightening is performed in eight stages. On the other hand, the control unit 30 of the screw tightening control unit 12 stores information indicating that screw tightening is performed in eight stages.
[0033]
Then, the operation setting of the synchronization control means 10 and the screw tightening control means 12 is performed. The synchronization control means 10 operates a hold time setting switch to set a desired hold time, for example, 200 ms. The screw tightening control unit 12 operates the operation buttons and the like of the operation / display unit 28 to set the tightening torque and the rotation direction of the screw tightening.
[0034]
Thus, the initial setting of the screw fastening device according to the present embodiment is completed.
Next, a screw tightening method using the screw tightening device according to the present embodiment will be described with reference to FIGS. 1, 3, and 4. FIG.
First, as shown in FIG. 4, the sequencer 15 outputs a START signal to start screw tightening.
[0035]
When the START signal is input, the screw tightening control units 12a to 12d enter a preparation stage for screw tightening, and start rotating the servomotors 20 of the driver units 14a to 14d, respectively. As a result, the servo motors 20 of the driver units 14a to 14d enter an idling state in which the servo motors 20 rotate with a small torque. Driver (a), Driver (b), Driver (c), and Driver (d) in the term chart of FIG. 4 indicate the operation states of the driver units 14a, 14b, 14c, and 14d, respectively. When air is sucked from the intake pipe 26 of the sleeve 24 of each of the driver units 14a to 14d, the heads of the screws are attracted to the tips of the respective bits 16a to 16d. Since the servomotor 20 is rotating in the idling state, the groove at the head of the screw is securely engaged with the bits 16a to 16d, thereby completing the preparation for screw tightening.
[0036]
When the preparation for screw tightening is completed, the screw tightening control means 12a to 12d output the SYNC (a) signal to SYNC (d) signal, respectively, and enter a standby state (Wait). In the term chart of FIG. 4, the SYNC (a) signal, the SYNC (b) signal, the SYNC (c) signal, and the SYNC (d) signal are the SYNC signals output from the screw tightening control means 12a, 12b, 12c, 12d, respectively. It is shown.
[0037]
On the other hand, the synchronization control means 10 monitors the SYNC (a) to SYNC (d) signals, confirms that all the SYNC signals have been output, determines that the preparation for screw tightening is completed, and performs the first time. An ACK signal (ACK1 in FIG. 4) is output.
When the first ACK signal is input, each of the screw tightening control units 12a to 12d controls the driver units 14a to 14d and starts screw tightening. When the screw tightening is started, the torque gradually increases as shown in FIG. Then, the screw tightening control units 12a to 12d perform screw tightening until the screw tightening torque reaches the target set torque of the first stage. Then, when the screw tightening torque reaches the target set torque of the first stage, the screw tightening control means 12a to 12d respectively control the servo motors 20a of the driver units 14a to 14d.Stops, SYNC (a) to SYNC (d) signals are output and the apparatus enters a standby state (Wait).
[0038]
On the other hand, the synchronization control means 10 monitors the SYNC (a) to SYNC (d) signals, and confirms that all the SYNC signals have been output, and when the screw tightening torque reaches the first-stage target set torque. Then, the second ACK signal (ACK2 in FIG. 4) is output.
On the other hand, when the second ACK signal is input, each of the screw tightening control means 12a to 12d restarts the screw tightening, and controls the driver units 14a to 14d to tighten the screws to the second-stage target set torque. Control.
[0039]
After that, when the screws are tightened in the same manner, the screws are tightened so that the tightening torque of the four screws increases as a result.
Then, by the seventh-stage screw tightening, the screw tightening torque reaches a preset tightening torque set from the operation / display unit of the screw tightening control unit.
When the screw tightening torque reaches the set tightening torque, the screw tightening control means 12a to 12d output the SYNC (a) signal to the SYNC (d) signal, respectively, while maintaining the set tightening torque. When all the SYNC signals are output, the synchronization control means 10 outputs the eighth ACK signal (ACK8 in FIG. 4). This ACK signal is output for a time corresponding to the hold time, for example, for 200 ms.
[0040]
The screw tightening control means 12a to 12d keep the screw tightening torque at the set tightening torque and stabilize the screw tightening torque while the eighth ACK signal is output.
When the output of the eighth ACK signal ends, the screw tightening control means 12a to 12d ends the screw tightening.
[0041]
On the other hand, the sequencer 15 monitors the MTDV (a) signal to the MTDV (d) signal output from the screw tightening control means 12a to 12d, and upon ending the output of the MTDV (a) signal to the MTDV (d) signal. It is determined that the screw tightening has ended, and the output of the START signal ends. Thereby, the screw tightening operation is completed.
[0042]
As described above, according to the present embodiment, the target set torque until the set tightening torque is reached is finely set, and in each stage of the screw tightening, it is necessary to wait until the screw tightening torque reaches the target set torque. As a result, synchronous control can be performed so that the tightening torques of all the screws are increased in the same manner, so that the screws can be tightened without causing distortion of the tightened body.
[0043]
[Second embodiment]
A screw tightening method and apparatus according to a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram illustrating the screw fastening device according to the present embodiment. Note that the driver units 14a to 14d in FIG. 5 are viewed from below the driver units 14a to 14d, that is, from the side of the bits 16a to 16d. The same components as those of the screw fastening method and device according to the first embodiment shown in FIGS. 1 to 4 are denoted by the same reference numerals, and description thereof will be omitted or simplified. In the present embodiment, an example will be described in which a disk clamp of an HDD device fixed by four screws as shown in FIG. 6 is screwed.
[0044]
When a plurality of screws are simultaneously tightened on the disk clamp 116 of the HDD device as shown in FIG. 6, the rotational torque of the disk clamp 116 is usually multiplied by the number of screws. Therefore, in the present embodiment, the number of clockwise screws and the number of counterclockwise screws are set to the same number, and these screws are screwed almost simultaneously, so that the clockwise rotation torque and the counterclockwise The main feature is that the rotational torques of the two cancel each other. Accordingly, even when a plurality of screws are simultaneously tightened, the rotational torque generated in the disk clamp 116 can be suppressed. The screw tightening method and device according to the present embodiment are the same as the first embodiment except that the screw rotation direction is different from that of the first embodiment.
[0045]
For the reasons described above, in the present embodiment, the number of clockwise screws and the number of counterclockwise screws are the same. Therefore, clockwise screws are used for the screw holes 118a and 118c of the disk clamp 116 of the HDD device shown in FIG. 6, and counterclockwise screws are used for the screw holes 118b and 118d.
In the initial setting of the screw tightening device, the screw tightening control means 12a and 12c set the rotation direction of the screw clockwise by operating the respective operation / display unit 28. On the other hand, with respect to the screw tightening control means 12b and 12d, the rotation direction of the screw is set counterclockwise by operating the respective operation / display unit 28.
[0046]
As a result, when the screw is tightened to the disk clamp 116, the bits 16a and 16c of the driver units 14a and 14c rotate clockwise as indicated by arrows in FIG. 5, and the screw is tightened clockwise. On the other hand, the bits 16b and 16d of the driver units 14b and 14d rotate counterclockwise, and the screws are tightened counterclockwise.
[0047]
The clockwise screw tightening generates a clockwise rotational torque of two screws in the disk clamp 116, and the clockwise screw tightening generates a clockwise rotational torque of two screws in the disk clamp 116. However, since the number of clockwise screws and the number of counterclockwise screws are the same, the clockwise rotation torque and counterclockwise rotation torque of the disc clamp 116 cancel each other. Thereby, the rotational torque generated in the disk clamp 116 is suppressed. Since strong rotational torque is not generated in the disk clamp 116, there is no need to press the disk clamp 116 with a strong force.
[0048]
Further, in the screw tightening, as shown in FIG. 4, similarly to the first embodiment, the target set torque until the set tightening torque is reached is finely set, and the screw tightening torque is set at each stage of the screw tightening. It waits as necessary until the set torque is reached, and as a result, synchronous control is performed so that the tightening torque of all screws increases the same.
[0049]
As described above, according to the present embodiment, the number of clockwise screws and the number of counterclockwise screws are set to the same number, and these screws are screwed almost simultaneously. The counterclockwise rotation torque cancels out each other, so that even when a plurality of screws are simultaneously tightened, the rotation torque generated in the tightened body can be suppressed.
[0050]
[Modified embodiment]
The present invention is not limited to the above embodiment, and various modifications are possible.
For example, in the first and second embodiments, four driver units are provided to simultaneously tighten four screws. However, the number of screw units is not limited to four, and may be appropriately adjusted according to the number of screws to be tightened to the tightened body. What is necessary is just to provide a driver unit and a screw tightening control means.
[0051]
Further, in the first and second embodiments, the screw tightening of the disk clamp of the HDD device has been described as an example. However, the present invention is not limited to the screw tightening of the disk clamp of the HDD device. The present invention can be applied to screw tightening of any tightened body as long as the tightened body has a plurality of screw holes, such as screw tightening.
[0052]
Further, in the first and second embodiments, the synchronization control means, the screw tightening control means, and the driver unit are separately provided, but may be integrally formed as appropriate.
Further, in the first and second embodiments, the case of performing the screw tightening in eight steps has been described as an example. However, the present invention is not limited to the eight steps, and the types and lengths of the body to be tightened and the screws are not limited. What is necessary is just to set suitably according to conditions.
[0053]
In the first and second embodiments, the START signal, the MTDV signal, the SYNC signal, and the ACK signal are output in a time chart as shown in FIG. 4, but the signal format and timing are not limited to these. Instead, if the screw can be tightened as described above, the format and timing of the signal may be appropriately set.
[0054]
【The invention's effect】
As described above, according to the present invention, the target set torque until the set tightening torque is reached is finely set, and in each stage of the screw tightening, it is necessary to wait until the screw tightening torque reaches the target set torque. As a result, synchronous control can be performed so that the tightening torques of all the screws are increased in the same manner, so that the screws can be tightened without causing distortion of the tightened body.
[0055]
According to the present invention, the number of clockwise screws and the number of counterclockwise screws are the same, and these screws are screwed almost simultaneously. The rotational torques cancel each other, whereby even when a plurality of screws are simultaneously tightened, the rotational torque generated in the tightened body can be suppressed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a screw fastening device according to a first embodiment of the present invention.
FIG. 2 is a side view showing a driver unit of the screw fastening device according to the first embodiment of the present invention.
FIG. 3 is a block diagram showing a screw tightening control unit and a driver unit of the screw tightening device according to the first embodiment of the present invention.
FIG. 4 is a time chart showing the operation of the screw fastening method and device according to the first embodiment of the present invention.
FIG. 5 is a block diagram showing a screw fastening device according to a second embodiment of the present invention.
FIG. 6 is a perspective view showing an HDD device.
[Explanation of symbols]
10. Synchronous control means
12, 12a, 12b, 12c, 12d ... screw tightening control means
14, 14a, 14b, 14c, 14d ... driver unit
15 ... sequencer
16, 16a, 16b, 16c, 16d ... bits
18 ... Driver head
20: Servo motor
22 ... Encoder
23… Connector
24 ... Sleeve
26 ... Intake pipe
28 Operation / display section
30 ... Control unit
32 ... External control interface
34 ... servo circuit
109 ... IC
110 ... HD control board
112 ... Spindle motor
114 ... Disk
116… Disc clamp
118a, 118b, 118c, 118d ... screw holes
120 head drive device
122 ... magnetic head
124 ... arm

Claims (5)

A screw tightening device for tightening a plurality of screws to be simultaneously tightened at a plurality of locations at a preset tightening torque,
A plurality of screw tightening means, each driven by a motor attached with an encoder that generates a pulse signal corresponding to the rotation, and screwing the plurality of screws,
Synchronous control means for controlling the plurality of screw tightening means while synchronizing,
Set the target set torque until reaching the set tightening torque in multiple stages,
The synchronous control means, at each stage, until all the tightening torques of the plurality of screws reach the target set torque, while maintaining the tightening torque at the target set torque , based on a pulse signal from the encoder, The plurality of screw tightening means are made to stand by, and after all the tightening torques of the plurality of screws reach the target set torque, screw tightening by the plurality of screw tightening means is restarted, and the plurality of steps are completed. When all the tightening torques of the plurality of screws reach the set tightening torque, the screw tightening of all the plurality of screws is terminated after maintaining the set tightening torque for a predetermined hold time. A screw tightening device. A screw tightening method in which a plurality of screws are simultaneously tightened to a plurality of locations with a preset set tightening torque,
The plurality of screws includes a right-handed screw and a left-handed screw,
A screw tightening method, wherein the clockwise screw and the counterclockwise screw are tightened so as to suppress a rotational torque generated in a tightened body. The screw tightening method according to claim 2 ,
A screw tightening method, wherein the number of the clockwise screws and the number of the counterclockwise screws are the same among the plurality of screws. A screw tightening device for tightening a plurality of screws to be simultaneously tightened at a plurality of locations at a preset tightening torque,
The plurality of screws includes a right-handed screw and a left-handed screw,
Clockwise screw tightening means for tightening the clockwise screw,
Anticlockwise screw tightening means for tightening the anticlockwise screw,
A screw tightening device comprising: a control unit that controls the clockwise screw tightening unit and the counterclockwise screw tightening unit so as to suppress a rotational torque generated in a tightened body. The screw fastening device according to claim 4,
The screw fastening device, wherein the number of the clockwise screws and the number of the counterclockwise screws among the plurality of screws are the same.

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