JPH10329051A - Screw tightening machine and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw tightening machine which can conduct loosening work with a screw tightening machine and restrain a clutch part from being worn by decreasing the sheel diameter of the screw tightening machine. SOLUTION: This screw tightening machine is provided with the first motor 1, the second motor 4, a driver bit 7 connected to the rotating shaft 40 of the second motor 4, and an electromagnetic clutch 6 disposed between the first motor 1 and the driver bit 7, whereas the first motor 1 and the second motor 4 are disposed in series coaxially, and the electromagnetic clutch 6 is disposed between the rotating shaft 10 of the first motor 1 and the rotating shaft 40 of the second motor 4. Therefore, the shell diameter of a screw tightening machine body can be decreased, so it is possible for a worker to hold the screw tightening machine easily, thereby improving workability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small and lightweight screwdriver used for assembling home appliances, automobiles, houses and buildings.

[0002]

2. Description of the Related Art Conventionally, screw tightening machines have been automated using electric power or pneumatic pressure in order to reduce assembly work time. If desired, a high-speed rotation function and a high torque generation function are required. In order to satisfy this demand, as a first conventional example, for example, a screw tightening machine having a configuration as shown in FIG. 4 has been disclosed (for example, JP-A-59-69273). That is, 1X
Is a high torque driver that generates low speed and high torque, 2X is a low torque driver that generates high speed and low torque, 3X is a belt, 5X is a pulley, 6X is a one-way clutch, 7 is a driver bit, 81X and 82X are high torque drivers 1X, respectively. A signal circuit for transmitting a signal indicating that the tightening has been completed from the low torque driver 2X to the control device 8X, 83X and 84X are signal circuits for transmitting drive signals from the control device 8X to 1X and 2X, respectively, and S represents a screw. In this conventional screw tightener, when the low torque driver 2X is rotated, the clutch 6X becomes free with respect to the high torque driver 1X, and the tribbit 7 directly connected to the low torque driver 2X generates the low torque driver 2X. The transmitted torque is transmitted to the screw S as it is. For this reason, the screw S is to be tightened at a low torque with respect to the workpiece (not shown). Here, when the screw S is seated, a seating completion signal is output, and the control device 8X further outputs a drive signal to the high torque driver 1X. Since the screw S is tightened with a low torque and the driver bit 7 is not rotating, the torque of the high torque driver 1X is transmitted to the driver bit 7 through the clutch 6X, and the screw S is tightened. That is, high-speed operation is realized by the low-torque driver 2X, and high-torque tightening is realized by the high-torque driver 1X.

As a second conventional example, a screw tightening machine having a structure as shown in FIG. 5, for example, is disclosed (for example, Japanese Patent Application Laid-Open No. 3-32531). That is, 1X is a motor, 6X is a one-way clutch, 7 is a driver bit, 10
X is a rotating shaft, 11X is a high-speed rotating shaft 13X and a low-speed rotating shaft 1
Split gear that outputs different rotation speed and torque to 4X,
2X is a clutch, 15X is a main shaft, 16X is a sensor for detecting a change in the current of the motor 1X, 17X is a differential detection circuit of a detection signal, 18X is a control circuit for comparing and discriminating the signal and turning off the switch 19X, and 20X is a motor. 1X power input terminal. According to this prior art, as an example,
The motor 1X rotates at 6000 rpm, and the split gear 11X
The rotation of the rotation shaft 10X is divided and decelerated into a high-speed rotation shaft 13X having a rotation speed of 200 rpm and a low-speed rotation shaft 14X having a rotation speed of 60 rpm.
The rotation speed of 4X is finally 6 rpm by the speed reducer 111X.
m. When the screw is actually tightened, the clutch 12X provided on the high-speed rotating shaft 13X is connected and rotates at 200 rpm until the screw is seated. When the torque increases, the clutch 12X slips and the rotation speed decreases. When the rotation speed of the main shaft 15X becomes 6 rpm or less, the clutch 6X is tightened by the torque of the low-speed rotation shaft 14X. In this way, the screw is tightened by seating by high-speed rotation of the high-speed rotating shaft 13X, and tightening after seating is performed with high torque by the operation of the one-way clutch 6X.

Further, as a third conventional example, for example, FIG.
(See, for example, Japanese Patent Application Laid-Open No. Hei 7-164340). That is, the first stage sun gear 31 of the planetary gear mechanism 3 is connected to the rotating shaft 10X of the motor 1X. The rotational force of the sun gear 31 is transmitted to the high-speed rotating shaft 13X via the planetary gear 32 and the carrier 33. The rotational force transmitted to the high-speed rotation shaft 13X is transmitted to the second-stage sun gear 34, the second-stage planetary gear 35, and the carrier 36 that rotatably holds the planetary gear 35 provided on the high-speed rotation shaft 13X. Is transmitted to the drive side meshing portion 61X of the meshing clutch 60X. The high-speed rotating shaft 13X extends downward and is rotatably supported on the main shaft 15X via a bearing. A sliding member 30X is spline-connected to the high-speed rotating shaft 13X so as to be slidable in the axial direction. A roller-like cam follower 31aX, which constitutes one side of the cam device 31X, is vertically supported on the high-speed rotation shaft 13X below the sliding member 30X. On the upper part of the main shaft 15X, a climbing cam 31bX constituting the other side of the cam device 31X is provided with a cam follower 31a.
It is connected via a shaft coupling 32X so as to face X. Note that a stopper mechanism is provided on the shaft coupling 32X so as not to rotate beyond the operating range of the cam device 31X in the rotation direction.

[0005] A compression coil spring 33X is interposed between the sun gear 34 and the sliding member 30X along the high-speed rotating shaft 13X, and an enlarged view of the cam device 31X is shown in FIG.
, The compression coil spring 33X is connected to the cam follower 31.
aX is pressed against the first cam position p of the V-shaped groove formed on the riding cam 31bX or the flat second cam position q located on the sun gear side therefrom. Further, a driving side meshing portion 61X that constitutes one side of the meshing clutch 60X is connected to the lower end of the carrier 36 so as to be slidable in the axial direction, and between the carrier 36 and the driving side meshing portion 61X, A compression spring 35X is interposed as an elastic member. A cylindrical transmission member 36X is spline-connected to the main shaft 15X so as to be interlockable in the axial direction, and is also interlockable in the axial direction with the sliding member 30X, and is not interlockable in the rotation direction via a ball bearing 37X. Is engaged. At the upper end of the transmission member 36X, a driving side meshing portion 61X is provided.
, A driven side meshing portion 62X that constitutes the other side of the meshing clutch 60X is provided. Further, an annular groove 38X is formed at a predetermined position on the outer peripheral portion of the transmission member 36X, and the housing 21X is provided with a position detector 39X for detecting the annular groove 38X with a proximity sensor.

In the above configuration, when the main shaft 15X is screwed with a small torque, as shown in FIG. 7, the cam follower 31aX of the cam device 31X moves to the lower first cam position p.
Is pressed against the cam 31bX, so that the sliding member 30
X can be linked with the rotation of the main shaft 15X via the cam device 31X. At this time, since the sliding member 30X is held at the lower position together with the transmission member 36X, the driven-side meshing portion 62X of the meshing clutch 60X is not meshed with the driving-side meshing portion 61X. Therefore, the rotation of the motor 1X is performed by the rotation shaft 10X, the planetary gear mechanism 3 and its high-speed rotation shaft 13X,
The power is transmitted to the output shaft 15X via the sliding member 30X, the cam device 31X, and the shaft coupling 32X in order. As the next step,
When the torque applied to the main shaft 15X shifts to the screw tightening state, the cam device 31X generates a thrust in the axial direction,
The cam follower 31aX is pushed from the first cam position p to the upper second cam position q against the compression coil spring 33X in accordance with the load torque, and cannot be interlocked with the cam 31bX in the rotation direction. By this operation, the sliding member 30X is displaced upward integrally with the transmission member 36X via the ball bearing 37X, and the driven side engaging portion 62X moves upward,
The drive side meshing portion 61X meshes, and the meshing clutch 60X is connected. Therefore, the rotation of the motor 1X is controlled by the rotation shaft 10X, the planetary gear mechanism 3 and its carrier 3X.
6. The power is transmitted to the main shaft 15X via the dog clutch 60X and the transmission member 36X sequentially. In this way, high-speed rotation screwing and high-torque tightening can be realized by a mechanical method.

[0007]

However, in the first conventional example, the two motors serving as the rotary driving sources are arranged in parallel, so that the diameter of the body of the screw tightening machine becomes large. However, it was difficult to work while holding the screwing machine. Further, in the screw tightening work, not only the work of tightening the screw but also the work of loosening the screw once tightened frequently. However, the conventional screw tightening machine has a drawback that the screw cannot be loosened because the one-way clutch is used. In the second conventional example, two rotation shafts, a high-speed rotation shaft and a low-speed rotation shaft, must be installed in parallel in the body of the screw tightening machine, and many stepped gears must be formed. Because of this, the body diameter of the screw tightening machine increases,
As in the prior art, it is difficult for an operator to hold the screwing machine and perform the screwing operation. In addition, this prior art screw tightening machine also has a disadvantage that the screw loosening operation cannot be performed because the one-way clutch is used. Further, in the third conventional example, when shifting from low torque to high torque screw tightening, the cam follower and the cam of the cam device and the engagement portions 34a and 34b of the engagement clutch suddenly shift from high speed rotation to low speed rotation. However, since high torque is applied and friction is high, these parts are worn out when the screw tightening machine is used for a long time, and there is a disadvantage that the torque cannot be transferred. An object of the present invention is to provide a screw tightening machine that reduces the body diameter of the screw tightening machine while maintaining high-speed rotation, enables loosening work using the screw tightening machine, and suppresses wear of the clutch unit. And

[0008]

Means for Solving the Problems In order to solve the above problems, a first means comprises a first motor, a second motor,
A screw tightening machine including a driver bit connected to a rotation shaft of the second motor and a clutch provided between the first motor and the driver bit, wherein the first motor and the The second motor is arranged in series on the same axis, and the clutch is arranged between the rotation axis of the first motor and the rotation axis of the second motor. The second means is that a speed reducer is arranged between the first motor and the clutch. The third means includes a sun gear connected to a rotation shaft of the first motor, a plurality of planetary gears meshing with the sun gear, a carrier rotatably supporting the planetary gears,
A planetary gear mechanism having an internal gear meshed with the planetary gear, wherein the clutch is a drive shaft side clutch plate connected to the carrier, and a driven side connected to a rotation shaft of the second motor. And a clutch plate.

The fourth means is provided with a torque sensor between the rotation shaft of the second motor and the driver bit. Fifth means is that the torque sensor is configured to control the second
The torque sensor is provided between the rotation axis of the motor and the driver bit, and the rotation axis of the torque sensor is partially or entirely made of a magnetostrictive material. Excitation detected as a change in
The detection coil is formed in a non-contact manner on the outer periphery of the rotation shaft of the torque sensor. A sixth means is that the torque sensor is constituted by a strain gauge for detecting a reaction force of the driver bit transmitted to the speed reducer when the screw is tightened. Seventh means is that the strain gauge fixes a strain tube having a double structure to a housing of the second motor, affixes a strain gauge to an outer wall of an inner tube of the strain tube, and grips a lower portion of the strain tube. It is connected to the section. According to an eighth aspect, the first motor and the second motor are each configured by an electric motor or an air motor. A ninth means is that the clutch is constituted by any one of a meshing clutch, a friction clutch, a fluid clutch and an electromagnetic clutch. The tenth means includes a first encoder connected to a rotation shaft of the first motor, and a second encoder connected to a rotation shaft of the second motor.

The eleventh means receives the output of the first encoder, the output of the second encoder, and the output of the torque sensor as inputs, and outputs the first motor, the second motor,
And a control circuit for outputting operation commands of the electromagnetic clutch and the electromagnetic clutch. In a twelfth aspect, the control circuit unit includes a current detection circuit that detects a load current of the first motor, and a torque calculation processing circuit that calculates a torque value from an output of the current detection circuit. is there. A thirteenth means is a sensor, wherein the control circuit section selects an arbitrary output signal among the output signals of the first encoder, the second encoder, and the torque sensor, and displays an output value of the signal. It is provided with output display means. The fourteenth means arranges the first motor and the second motor on the same axis, detects the first encoder for detecting the rotation angle of the first motor, and detects the rotation angle of the second motor. A second encoder that connects a driver bit to the rotation axis of the second motor, and has a clutch between the rotation axis of the first motor and the rotation axis of the second motor. In the method for controlling a tightening machine, the first motor is operated when the second motor is not operating and the clutch is in a connected state, and the first motor is operated when the clutch is in a non-connected state. 2
This is a method of operating the motor. The fifteenth means is configured such that, at the time of tightening the screw, when the first motor reaches a predetermined rotation angle by an output signal from the first encoder starting from when the clutch is engaged,
This is a method of stopping the first motor and completing screw tightening. Sixteenth means is provided with a torque sensor for detecting a torque applied to the driver bit, and when tightening a screw, starting from the time when the clutch is engaged, the signal of the first encoder and the torque sensor In this method, a torque value is differentiated by a rotation angle from both signals, and when the differentiated value reaches a predetermined value, the first motor is stopped to complete screw tightening.
A seventeenth means is a method of transmitting the signal of the torque sensor, the operation command signal of the first motor and the second motor by one of wired and wireless communication means.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a first embodiment of the present invention. In the figure, reference numeral 100 denotes a shaft unit, a first motor 1 having a rotating shaft 10, a first encoder 2 for detecting a rotating speed and a rotating angle of the first motor 1, and a rotating shaft of the first motor 1. A speed reducer 3 composed of a planetary gear mechanism connected to a first motor 1;
0, a second encoder 5 for detecting a rotation speed and a rotation angle of the second motor 4, one of which is connected to the output side of the speed reducer 3, and the other of which is connected to the second encoder 5. Clutch 6 composed of an electromagnetic clutch and rotating shaft 4
It comprises a driver bit 7 connected to 0.

The first motor 1 includes a rotor 11 made of a permanent magnet and a stator 13 on which an armature coil 12 is mounted, and is connected to a rotation shaft 21 of the first encoder 2 by a coupling 14. The first encoder 2 is provided with a metal thin film slit on a glass substrate and includes a disk 22 fixed to a rotating shaft 21 and an optical sensor head 23 having a light receiving element and a light emitting element. This is to detect the angle. The other end of the rotating shaft 10 of the first motor 1 is connected to a sun gear 31 of the speed reducer 3 via a coupling 15. Reducer 3
A first stage planetary gear 32 meshing with the sun gear 31 and a first stage carrier 33 rotatably supporting the planetary gear 32
And the second stage sun gear 34 connected to the carrier 33
A second stage planetary gear 35 meshing with the sun gear 34;
And a second stage carrier 36 connected to the planetary gear 35. The planetary gears 32 and 35 are respectively meshed with internal gears 38 </ b> A and 38 </ b> B provided inside the cylindrical housing 37. Rotating shaft 36A of carrier 36
Is further connected to a drive shaft 61 of the clutch 6 via a coupling 39.

The clutch 6 is provided with a drive shaft 61 provided with a disc-shaped connection plate 62, a drive shaft-side clutch plate 63A provided opposite to the connection plate 62, and opposed to the clutch plate 63A. The clutch plate 63B on the driven shaft side, a permanent magnet 64 provided at an axial end of the clutch plate 63A, and a spring 65 provided between the permanent magnet 64 and the connection plate 62.
And an electromagnetic coil 66 fixed inside the housing 37 and repelling the permanent magnet 64 when excited. When the clutch 6 is in the disconnected state, the connection plate 62 is pressed against the clutch plate 63 on the drive shaft side by the spring 65. On the other hand, when the clutch 6 is in the connected state, the repulsive force from the electromagnetic coil 67 together with the permanent magnet 64
The clutch plate 63A on the drive shaft side is pushed down.
Therefore, the clutch plate 63A separates from the connecting plate 62 and engages with the clutch plate 63B on the driven shaft side. The clutch plate 63B on the driven shaft side is coupled to one end of the rotating shaft 51 of the second encoder 5 via a coupling 67. The second encoder 5 has the same configuration as the first encoder 2, and the other end of the rotating shaft 51 is coupled to one end of the rotating shaft 40 of the second motor 4 via a coupling 68. I have. The second motor 4 has substantially the same configuration as the first motor 1, and the other end of the rotating shaft 40 is connected to the driver bit 7.

A control circuit section 8 for controlling the operation of the shaft unit section 100 outputs drive signals 81A and 81B of the first motor 1 and the second motor 4, output signals of the first encoder 2 and the second encoder 5, Encoder signal processing circuits 82A and 82B for processing, an electromagnetic clutch drive circuit 83 for driving the clutch 6, a current detection circuit 84A for detecting a drive current supplied to the first motor 1 and the second motor 4, and a current value A torque calculation processing circuit 84B for converting the torque is provided. CPU, ROM, R
A control unit 85 composed of an AM and having an arithmetic circuit that receives various input signals and generates a control signal; a data transmission circuit 86A and a data reception circuit 86B that perform data transmission with an external host computer;
C, an input circuit 86D for inputting data from the setting unit 86C to the control unit 85, and a photocoupler 86E. The control unit 85 sends drive signals to the motor drive circuits 81A and 82B and the electromagnetic clutch drive circuit 83 via the photocoupler 86E, and transmits control signals to and from the control unit 85. The control unit 85 includes a display unit 87
Thus, data such as screw tightening torque is displayed.

The operation of the above configuration will now be described. Screw S
In the process of screwing to the workpiece W, first, the setting unit 8
6C or an external host computer, input initial setting values such as a fastening torque, a screwing speed, and a seating torque, and send them to the control unit 85. In this embodiment, wire transmission is performed using a wire cable. However, the transmission method may be wire transmission using an optical fiber, or wireless transmission using radio waves or infrared rays. Subsequently, the driver bit 7 is inserted into the head of the screw S, and a drive signal is sent from the control unit 85 via the electromagnetic clutch drive circuit 83 to bring the clutch 6 into a disconnected state. In this state, the control unit 85 sends the photocoupler 8
A command to start the second motor 4 is sent to the motor drive circuit 81B through 6E. When the second motor 4 starts to start, a signal from the second encoder 5 is signal-processed by the encoder signal processing circuit 82B so that the screwing speed becomes a predetermined screwing speed, and a digital signal as an output thereof is fed back to the control unit 85. Then, the control unit 85 controls the rotation speed of the second motor 4. For example, the second motor 4 is driven at a rated rotation speed of 3000 rpm, and the screw S is screwed into the workpiece W by the driver bit 7.

When the control unit 85 detects that the screw S has reached the seating point and the torque of the rotating shaft 40 has increased and the control unit 85 has reached the predetermined torque via the current detection circuit 84A and the torque calculation processing circuit 84B, the control is performed. A command to stop the second motor 4 is sent from the unit 85 to the motor drive circuit 81B. At the moment when the second encoder 5 detects the stop of the rotation of the second motor 4, the control unit 85 sends an electromagnetic clutch drive circuit 83.
A command to connect the clutch 6 is transmitted to the clutch plate 63A on the drive shaft side of the clutch 6 and the clutch plate 63 on the driven shaft side.
B is connected. Subsequently, a command to operate the first motor 1 is sent from the control unit 85 to the motor drive circuit 81A through the photocoupler 86E. When the first motor 1 starts rotating, its rotational force is reduced by the speed reducer 3, the clutch 6, the second
The driver bit 7 via the rotary shaft 40 of the motor 4
Conveyed to. When the screw S is tightened and the control unit 85 detects that the predetermined torque has been reached via the current detection circuit 84A and the torque calculation processing circuit 84B, the control unit 85 issues a motor stop command to the first motor 1. It is sent to the drive circuit 81A, and the screw tightening is completed in the above process.

In this embodiment, the first and second stages of the speed reducer 3
Assuming that the speed reduction ratio of each stage is 10: 1, the rated rotation speed of the rotating shaft 10 of the first motor 1 is 3000 rpm, and the rated torque is 0.02 kgfm, the rotational performance is finally rated after the speed reducer 3. Rotation speed 30 rpm, rated torque 1.
It was 41 kgf · m. Therefore, the screwing rotation speed is 3000 rpm, the seating torque is 0.2 kgfm, the tightening rotation speed is 50 rpm, and the fastening torque is 1.5 k.
As a result of a screw tightening test of a 5M-10L screw set to gf · m, screw tightening can be completed in an average of 1.2 seconds, and the variation in the tightening torque is kept within ± 1% from the set value. I was able to. As described above, the screw tightening machine of the present invention can perform accurate and quick screw tightening. In the above screw tightening test, the screws are tightened by the torque method, but screws can be tightened by the rotation angle method or the torque gradient method. In the rotation angle method, a signal from the first encoder 2 is sent to the control unit 85 starting from the time when the clutch 6 is engaged when the screw is tightened, and the screw tightening is completed when a predetermined rotation angle is reached. It is. In the torque gradient method, both the signal of the first encoder 2 and the signal of the torque calculation processing circuit 84B are sent to the control unit 85 starting from the time when the clutch 6 is engaged when the screw is tightened. The torque value is differentiated by the rotation angle, and screw tightening is completed when the differentiated value reaches a predetermined value.

As described above, in the screw tightening machine of the present invention,
Since the first motor 1 for generating high torque and the second motor 4 for realizing high-speed rotation are arranged in series so that the rotation axes are on the same axis, and the clutch 6 is provided between them, The body diameter does not increase as in the prior art screw tightening machine. Accordingly, the workability is improved because the operator can easily hold the screw tightening machine with one hand. Further, since the one-way clutch is not used, a screw loosening operation using a screw tightening machine can be performed. In addition, when shifting from high-speed rotation screwing to low-speed rotation tightening, the electromagnetic clutch is connected after the rotation of the shaft is completely stopped, so there is no wear on the clutch plate unlike a conventional screw tightening machine. In this embodiment, the electromagnetic clutch is used as the clutch. However, the clutch can be engaged or disengaged manually or by using an electromagnetic valve or the like using a meshing clutch, a friction clutch or a fluid clutch. The same effect as that of the embodiment can be obtained. Further, in the present embodiment, although the speed reducer including the planetary gear mechanism is used on the output side of the first motor 1, the first motor 1 does not use the speed reducer, and the first motor 1 has a lower rated output than the second motor 4 at a lower speed.
If the motor 1 is used, the same effect as in the present embodiment can be expected. In this embodiment, the electric motor is used as the rotary drive source, but an air motor may be used instead of the electric motor.

FIG. 2 is a block diagram showing a second embodiment of the present invention. The screw tightener according to the present invention includes a second motor 4 of the screw tightener shown in the first embodiment instead of the current detection circuit 84A and the torque calculation processing circuit 84B of the first embodiment.
Magnetostrictive torque sensor 9A between the motor and driver bit 7
Is installed to detect the torque applied to the driver bit 7. Rotary shaft 9 of torque sensor 9A
0 is the rotation axis 40 of the second motor 4 and the driver bit 7
Couplings 91 and 92 with the rotating shaft 70 of
Are respectively connected. On the surface of the rotating shaft 90, a slit-shaped magnetostrictive thin film 93 is formed. Magnetostrictive thin film 93
Is formed by a sputtering method, and Ni
It is a material having a magnetostrictive effect, such as Fe and Ni. further,
An exciting / detection coil 94 is wound around the rotating shaft 90 facing the magnetostrictive thin film 93 in a non-contact manner, so that the torsional distortion of the rotating shaft 90 during screw tightening is detected as a change in the magnetic permeability of the magnetostrictive material. is there.

The control circuit section 8 includes an excitation coil drive circuit 88 for driving an excitation / detection coil 94 of the torque sensor 9A.
And a torque sensor signal processing circuit 89A that receives a detection signal from the excitation / detection coil 94 as an input, and an A / D converter 89B that converts an analog signal into a digital signal. Is input to the control unit 85. As described above, by installing the torque sensor 9A in the screw tightening machine, it is possible to detect the torque of the seating point or to accurately detect the final tightening torque, and to stop the first motor 4 when the screwing is completed, 6 and the start and stop of the first motor 1 at the start and completion of screw tightening can be performed at high speed while detecting the signal of the torque sensor 9A. In the present embodiment, a striped magnetostrictive thin film 93 having a magnetostrictive effect, such as NiFe or Ni, formed by sputtering for torque detection is used, but a foil having a magnetostrictive effect may be attached to the rotating shaft 90 with an adhesive. Good. Further, even if the rotating shaft 90 itself is made of, for example, maraging steel or the like having a magnetostrictive effect, the same effect as in the present embodiment can be obtained.

FIG. 3 is a schematic sectional view of a screw tightening machine showing a third embodiment of the present invention. In this case, a strain gauge type torque sensor 9B is provided instead of the torque sensor 9A using the magnetostrictive thin film 93 in the second embodiment. That is, in FIG. 3, reference numeral 9B denotes a torque sensor.
5 and a strain gauge 96 is attached to the outer wall of the inner pipe of the strain pipe 95.
Is attached. Further, a lower portion of the strain tube 95 is connected to the grip portion 97. When tightening the screw,
That is, when the first motor 1 is operating with the clutch 6 connected, the gripper 97 is fixed,
Due to the rotational reaction force applied to the internal gears 38A and 38B of the speed reducer 3 and the rotation reaction force applied to the stator 13 of the first motor 1, a distortion tube 95 having a double structure causes torsional distortion. By detecting the torsional strain with the strain gauge 96, the torque applied to the rotating shaft 40 is obtained. Further, when the second motor 4 is driven when the second motor 4 is driven when the screw 6 is screwed, that is, when the clutch 6 is disconnected, the double-structured strain tube 95 generates torsional distortion due to the reaction force applied to the stator 42 of the second motor 4. Occurs. This torsional strain is detected by the strain gauge 96, and the torque applied to the rotating shaft 40 is obtained. By installing the torque sensor 9B in the screw tightening machine, it is possible to detect the torque at the seating point or to accurately detect the final tightening torque, stop the second motor 4 when screwing is completed, connect the clutch 6, In addition, the start and stop of the first motor 1 at the start and completion of screw tightening can be performed at high speed while detecting the signal of the torque sensor 9B.

[0022]

As described above, according to the present invention, the motor 1C for generating high torque and the motor 1D for realizing high-speed rotation are arranged in series, and the clutch is installed between them. The body diameter can be smaller than that of the conventional screw tightening machine. Therefore, the workability is improved because the operator can easily grip the screw tightening machine. On the other hand, since a clutch is not used, a screw loosening operation using a screw tightening machine becomes possible. In addition, when shifting from high-speed screwing to low-speed tightening, the electromagnetic clutch is connected after the drive shaft rotation has completely stopped, so there is little wear on the clutch plate as with conventional screw tightening machines, and the life is short. This has the effect of providing a long screw tightening machine.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of the present invention.

FIG. 3 is a configuration diagram showing a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing a first conventional example.

FIG. 5 is a configuration diagram showing a second conventional example.

FIG. 6 is a side sectional view showing a third conventional example.

FIG. 7 is a side sectional view showing a main part of a third conventional example.

[Explanation of symbols]

1: first motor, 10: rotating shaft, 11: rotor, 1
2: armature coil, 13: stator, 14, 15, 3
9, 67, 68, 91, 92: coupling: 2: first
Encoder, 21: rotating shaft, 22: disk, 23:
Light sensor head, 3: speed reducer, 31, 34: sun gear,
32, 35: planetary gear, 33, 36: carrier, 37:
Housing, 38A, 38B: internal gear, 4: second motor, 40: rotary shaft, 41: housing, 42: stator, 5: second encoder, 51: rotary shaft, 6: clutch, 61: drive shaft, 62: connecting plate, 63A, 63B: clutch plate, 64: permanent magnet, 65: spring, 66: electromagnetic coil, 7: driver bit, 8: control circuit section, 81A,
81B: motor drive circuit, 82A, 82B: encoder signal processing circuit, 83: electromagnetic clutch drive circuit, 84A:
Current detection circuit, 84B: torque calculation processing circuit, 85: control unit, 86A: data transmission circuit, 86B: data reception circuit, 86C: setting unit, 86D: input circuit, 86E: photocoupler, 87: display unit, 88: Excitation coil drive circuit,
89A: torque sensor signal processing circuit, 89B: A / D converter, 9A, 9B: torque sensor, 93: magnetostrictive thin film, 9
4: Excitation / detection coil, 95: strain tube, 96: strain gauge, 97: gripper

Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16D 15/00 F16D 15/00 // F16H 3/44 F16H 3/44 Z

Claims (17)

[Claims] A first motor, a second motor, and a driver bit connected to a rotation shaft of the second motor;
In a screw tightening machine including a clutch provided between the first motor and the driver bit, the first motor and the second motor are arranged in series on the same axis, and the clutch A screw tightening machine is disposed between a rotation axis of the first motor and a rotation axis of the second motor. 2. The screw tightening machine according to claim 1, wherein a speed reducer is arranged between the first motor and the clutch. 3. The speed reducer includes: a sun gear connected to a rotation shaft of the first motor; a plurality of planetary gears meshing with the sun gear; a carrier rotatably supporting the planetary gears; A planetary gear mechanism having an internal gear meshed with a planetary gear, wherein the clutch is provided on a drive shaft side clutch plate connected to the carrier, and on a driven side connected to a rotation shaft of the second motor. 3. The screw tightening machine according to claim 2, further comprising a clutch plate. 4. The screw tightening machine according to claim 1, wherein a torque sensor is provided between a rotation shaft of the second motor and the driver bit. 5. An exciting / detecting coil for detecting a change in torque of a rotating shaft of the torque sensor as a change in magnetic permeability of the magnetostrictive material, wherein a part or the whole of a rotating shaft of the torque sensor is formed of a magnetostrictive material. 5. The screw tightening machine according to claim 4, wherein the screw is formed in a non-contact manner on an outer periphery of a rotation shaft of the torque sensor. 6. The screw tightening machine according to claim 4, wherein said torque sensor comprises a strain gauge for detecting a reaction force of said driver bit transmitted to said speed reducer during screw tightening. 7. The torque sensor has a double structure strain tube fixed to a housing of the second motor, a strain gauge is attached to an outer wall of an inner tube of the strain tube, and a lower portion of the strain tube is gripped. 7. The screw tightening machine according to claim 6, wherein the screw tightening machine is connected to the screwdriver. 8. The screw tightening machine according to claim 1, wherein the first motor and the second motor are configured by one of an electric motor and an air motor. 9. The screw tightening machine according to claim 1, wherein the clutch comprises one of a meshing clutch, a friction clutch, a fluid clutch, and an electromagnetic clutch. 10. The apparatus according to claim 1, further comprising: a first encoder connected to a rotation shaft of said first motor; and a second encoder connected to a rotation shaft of said second motor. 10. The screw tightening machine according to any one of 1 to 9. 11. The operation of the first motor, the second motor, and the clutch, using the output of the first encoder, the output of the second encoder, and the output of the torque sensor as inputs. The screwdriver according to claim 10, further comprising a control circuit that outputs a command. 12. The control circuit section includes a current detection circuit for detecting a load current of the first motor, and a torque calculation processing circuit for calculating a torque value from an output of the current detection circuit. The screw tightening machine according to claim 11, wherein 13. A display for displaying an output value of the output signal by selecting an arbitrary output signal from output signals of the first encoder, the second encoder, and the torque sensor. The screw tightening machine according to claim 11, further comprising a part. 14. A first motor and a second motor are arranged on the same axis, and a first encoder for detecting a rotation angle of the first motor and a rotation angle of the second motor are detected. A second encoder, wherein a driver bit is connected to a rotation shaft of the second motor, and a screw tightener having a clutch between the rotation shaft of the first motor and the rotation shaft of the second motor. The first motor is operated when the second motor is not operating and the clutch is connected, and the second motor is operated when the clutch is not connected. A method for controlling a screw tightening machine, characterized by operating a motor. 15. When the first motor reaches a predetermined rotation angle by an output signal from the first encoder starting from the time when the clutch is engaged when the screw is tightened, 15. The method according to claim 14, wherein the first motor is stopped to complete the screw tightening. 16. A torque sensor for detecting a torque applied to the driver bit, wherein a signal from the first encoder and a signal from the torque sensor start when the clutch is engaged when tightening a screw. A torque value is differentiated by a rotation angle from both of the signals, and when the differentiated value reaches a predetermined value, the first motor is stopped to complete screw tightening. 1
16. The method for controlling a screw tightening machine according to 4 or 15. 17. The apparatus according to claim 14, wherein a signal of said torque sensor, an operation command signal of said first motor and said second motor are transmitted by one of wired and wireless communication means. A control method for a screw tightening machine according to any one of the sixteenth aspects.