JP3265805B2 - Torque wrench and rail fastening robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque wrench for rotating a socket fitted to a bolt or a nut by a driving source and fastening or loosening the bolt or the nut, and a railroad rail provided with the torque wrench on a sleeper. The present invention relates to a fixed rail fastening robot.

[0002]

2. Description of the Related Art As is well known, in a conventional general impact wrench or torque wrench having a driving source driven by electric power, air pressure, or the like, a socket is fitted to a bolt or a nut and the socket is driven by the driving source. The drive source is stopped when it is determined that the bolt or the like has been fastened with a predetermined fastening force, and the fastening operation is completed.

When a large number of bolts or nuts are fastened continuously using a conventional impact wrench or torque wrench having the above-described structure, the bolts or the like are naturally connected to the bolts or the like from the viewpoint of working efficiency. It is desired to set the rotational speed of the fitted socket as high as possible.

[0004]

The conventional impact wrench has a mechanism that rotates at high speed at low load and slips at low load to rotate at low speed. But the work efficiency is good. However, since the bolt or nut fastening torque is generated by the impact torque, it cannot be measured by a motor current measurement, a separately installed torque sensor measurement, or the like, so that the torque value cannot be controlled.

[0005] In the conventional torque wrench, torque control is possible, but a large motor is required in order to increase the working speed, and a portable power supply device is not used in track maintenance work sites because the power source becomes too large. That is, there is no torque wrench of small horsepower capable of switching from high-speed and low-torque of several revolutions to low-speed and high-torque of a small angle, so that the mechanization of the track maintenance work site has not progressed.

[0006] In track maintenance work such as rail replacement and the like, a large number of bolts are fastened. However, the female screw portions, mounting brackets, and bolts formed on the respective sleepers are all in the same state, and the respective bolts are in the same condition. When the fastening operation is started at the position where the bolts are fastened, if the relative positions of the female threads of these sleepers, the mounting bracket, and the bolts are all the same, the bolts can be bolted using an impact wrench as in the past. Even if the fastening operation is performed, it should be possible to make the fastening force of a large number of bolts uniform by controlling the fastening time to be constant, that is, to keep the dispersion of the fastening force within a predetermined range so that the work can be performed efficiently.

However, in practice, any one of the female screw portion, the mounting bracket, and the bolt formed on the sleeper is deteriorated or damaged by the time of the fastening operation, and the precision when manufactured is lost. Alternatively, since the fastening work may be performed in a state where each member is displaced from the predetermined positional relationship, in an impact wrench where the change in the number of rotations due to the change in load is large, the fastening force of each bolt is uniform. Could not be. For this reason, the torque management work was separately performed after the fastening work.

[0008] The present invention has been made in view of the above-mentioned circumstances, and exhibits high working efficiency when continuously performing the fastening work of a large number of bolts or nuts, and
An object of the present invention is to provide a torque wrench that can make the fastening force of each bolt and the like uniform, and a rail fastening robot including the torque wrench.

[0009]

In the torque wrench according to the first aspect, a socket is fitted to a bolt or a nut.
A torque wrench for fastening or loosening the bolt or nut by rotating the socket by a drive source, wherein a planetary gear unit is interposed between an output shaft of the drive source and a fixed drive shaft of the socket. A sun gear in the planetary gear device is connected to rotate integrally with the output shaft, and a planet carrier is connected to rotate in conjunction with the drive shaft; A clutch mechanism is interposed between a shaft and the internal gear of the planetary gear device, and a brake mechanism for fixing the internal gear at a fixed position is provided.

According to a second aspect of the present invention, there is provided the torque wrench according to the first aspect, wherein the drive source is constituted by a servomotor, and a specific control amount of the servomotor reaches a reference value. A control unit is provided for controlling the operation of the clutch mechanism and the brake mechanism based on a signal transmitted upon detection.

The rail fastening robot according to a third aspect of the present invention is a rail fastening robot which mounts a bolt fastening mechanism on a bogie having traveling wheels and fastens a bolt for fixing the rail to a sleeper while traveling on the rail. The bolt fastening mechanism comprises a torque wrench according to claim 1 or 2 as a fastening device for fastening a rail fastening bolt.

[0012]

In the torque wrench according to the first aspect, a planetary gear device is disposed between the output shaft of the drive source and the drive shaft fixed to the socket, and the clutch mechanism and the brake mechanism are operated according to the situation. By doing so, the planetary gear device transmits the rotation of the output shaft without changing the rotation speed or at a reduced speed.

According to a second aspect of the present invention, there is provided a torque wrench according to the first aspect, wherein the drive source is a servomotor, and a signal transmitted when a specific control amount of the servomotor reaches a reference value. Based on the above, since a control unit that controls the operation of the clutch mechanism and the brake mechanism is provided, when fastening a bolt or a nut by the planetary gear device, in the initial stage of a fastening operation that does not require a large torque. Transmits the rotation of the output shaft without changing the number of rotations, with a small torque and high speed rotation,
At the end of the fastening operation requiring a large torque, the rotation of the output shaft is reduced and transmitted to achieve a large torque / low speed rotation, and a large torque is required when the bolt or nut is loosened. In the early stage of the loosening operation, the rotation of the output shaft is reduced and transmitted to reduce
At the end of the loosening operation that does not require a large torque at a low speed, the rotation of the output shaft is transmitted without changing the number of rotations, thereby obtaining a small torque and a high speed.

According to a third aspect of the present invention, there is provided a rail fastening robot having a bolt fastening mechanism mounted on a bogie having traveling wheels, and the bolt fastening mechanism includes the torque wrench according to the first or second aspect. And this rail fastening robot runs on the rail, stops at the position of the bolt to be fastened or loosened, and fastens the bolt when fixing the rail to the sleeper by the torque wrench,
When removing rails from sleepers, loosen bolts.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a torque wrench of the present invention and a rail fastening robot provided with the torque wrench will be described below with reference to FIGS. First, the configuration of the rail fastening robot 1 will be described with reference to FIGS. FIG.
Or the rail fastening robot 1 shown in FIG.
, A control panel 6 for controlling the operation of the rail fastening robot 1, a generator 7, and a traveling motor 8
And a bolt fastening mechanism 9. And
The bolt fastening mechanism 9 includes a bolt position detection sensor 15
, A torque wrench 16 and a wrench elevating motor 17, and are housed in the casing 18 together with the traveling motor 8. In FIG. 7, reference numerals 19 and 19 are fluorescent lamps. The rail fastening robot 1 fastens the bolts 23, 23 while traveling on rails 22, 22, which are placed on sleepers 21 arranged at predetermined intervals,
The rail 22 is fixed to the sleeper 21 via the mounting bracket 24.

Next, the structure of the torque wrench 16 will be described with reference to FIGS. The torque wrench 16 shown in FIG. 1 includes an AC servomotor (drive source) 31, an electromagnetic clutch (clutch mechanism) 32, and a planetary gear device 33.
, An electromagnetic brake (brake mechanism) 34 and a reduction gear 3
5 and 36, socket 37, and AC servomotor 31
And a control unit 38 for controlling the electromagnetic clutch 32 and the electromagnetic brake 34 based on a signal transmitted from the controller 38. Then, the electromagnetic clutch 32, the planetary gear unit 33, the electromagnetic brake 34, the reduction gears 35 and 3
6 is housed in a casing 39. The torque wrench 16 has a socket 3 attached to the head of a bolt 23 for fixing the rail 22 to the sleeper 21 via a mounting bracket 24.
7 and the socket 37 is connected to the AC servomotor 3.
The bolt 23 is fastened by being rotated by 1.

As shown in FIGS. 1 and 2, the electromagnetic clutch 32 includes a coil 42, a field core 43,
It is roughly composed of a rotor 44, an armature 45, and a leaf spring 46. The field core 43 containing the coil 42 is fixed to the casing 39, and the rotor 44 is connected to the output shaft 31a of the AC servomotor 31 and attached to a power transmission shaft 47 that rotates integrally with the output shaft 31a. Have been. The leaf spring 46 is fixed to a connecting member 52 attached to an internal gear 51 (see FIG. 3) constituting the planetary gear device 33 with a screw 46a #, and further fixed to the armature 45 with a pin 46b #. .

With the above configuration, the armature 45
It is urged by the leaf spring 46 in the direction of the planetary gear unit 33 and is normally separated from the rotor 44,
When the electromagnetic force that draws the armature 45 in the direction of the rotor 44 exceeds the biasing force of the leaf spring 46, the armature 45 abuts on the rotor 44 and the generated frictional force causes the rotor 4 to rotate.
4 and rotate together.

Next, as shown in FIG. 3, the planetary gear unit 33 includes an internal gear 51, a sun gear 53, planetary carriers 54A and 54B rotating coaxially with the internal gear 51, a sun gear 53 and an internal gear. Four planetary gears 55 meshing with 51
... Each planetary gear 55 includes a pair of support plates 55a, 55a and one pin 55b.
Are supported by the planet carriers 54A and 54B. Then, as shown in FIG. 1, the sun gear 53 is connected to a power transmission shaft 47 connected to the output shaft 31a of the AC servomotor 31, and the planet carrier 54B is connected to the reduction gear 3
5 is connected to a power transmission shaft 57 that transmits power.

As shown in FIGS. 1 and 4, the electromagnetic brake 34 includes a coil 61 and a field core 62.
, A rotor 63, an armature 64, a spline adapter 65, and compression springs 66. Then, the field core 62 including the coil 61 is fixed to a support portion 39 a protruding from the casing 39, and the rotor 63 is mounted on the field core 62. The spline adapter 65 is fixed to a connecting member 58 attached to the internal gear 51 constituting the planetary gear device 33.

With the above configuration, the armature 64
The spline adapter 6 is compressed by the compression spring 66.
5, the spline adapter 65, the connecting member 58, and the internal gear 51 are normally separated from the rotor 63 as shown in FIG. Are energized, and an electromagnetic force that draws the armature 64 in the direction of the rotor 63 generates a compression spring 66.
Above, the gear portion 64a formed on the armature 64 meshes with the gear portion 63a formed on the rotor 63, and the rotation of the spline adapter 65, the connecting member 58, and the internal gear 51 Stop.

Further, below the electromagnetic brake 34, as shown in FIG. 1, a reduction gear 35 and a reduction gear 36 each composed of a planetary gear unit are arranged.
5 is fixed to a support portion 39 b projecting from the casing 39, and the reduction gear 36 is fixed to the casing 39. The rotation of the power transmission shaft 57 connected to the planet carrier 54B constituting the planetary gear device 33 is reduced to a predetermined rotation speed by the reduction gear 35 and the reduction gear 36, and transmitted to the drive shaft 69. Rotate.

The torque wrench 16 constructed as described above
The operation of the rail fastening robot 1 including the torque wrench 16 in the bolt fastening mechanism 9 will be described. The rail fastening robot 1 is mounted on rails 22 and 22 temporarily stopped on sleepers 21 arranged on a railroad laying site after the leveling, and thereafter, the generator 7 is controlled by the control panel 6, the traveling motor 8, Power is supplied to the bolt fastening mechanism 9 and the fluorescent lamps 19, 19.
Then, the rail fastening robot 1 travels on the rails 22 and 22 by the travel motor 8 and stops at the position where the bolt 23 to be fastened is detected by the bolt position detection sensor 15.
Then, the wrench elevating motor 17 lowers the torque wrench 16 (indicated by a two-dot chain line in FIGS. 5 and 7),
Is fitted with the socket 37 of the torque wrench 16.

At this time, the coil 42 constituting the electromagnetic clutch 32 of the torque wrench 16 is energized, and the armature 45 is in contact with the rotor 44. On the other hand, the current of the coil 61 constituting the electromagnetic brake 34 is cut off, and the armature 64 is separated from the rotor 63.

Therefore, the internal gear 51 constituting the planetary gear unit 33 is, together with the sun gear 53,
1 and the power transmission shaft 47 connected to the first output shaft 31a, and the relative positions of the planetary gears 55..., The internal gear 51 and the sun gear 53 do not change, and the planetary carriers 54A and 54B. Also rotates integrally with the internal gear 51 and the sun gear 53, so that the rotation of the power transmission shaft 47 is not reduced in the planetary gear device 33 and the power transmission shaft 57
Is transmitted to The rotation of the power transmission shaft 57 is reduced to a predetermined rotation speed by the reduction gears 35 and 36, and the drive shaft 69, that is, the socket 37 fitted to the bolt 23.
To screw the bolt 23 into the female screw portion formed on the rail 22.

When the AC servomotor 31 detects that the torque required to rotate the bolt 23 has become larger than a predetermined value, it sends a signal to the control unit 38 and receives this signal. The control unit 38 controls the electromagnetic clutch 32
Of the coil 42 constituting the armature 45
Is separated from the rotor 44. On the other hand, the coil 61 constituting the electromagnetic brake 34 is energized to cause the gear portion 64 a of the armature 64 to mesh with the gear portion 63 a of the rotor 63.

Therefore, the internal gear 51 constituting the planetary gear device 33 is fixed to the casing 39, and the planetary gears 55 are rotated by the rotation of the sun gear 53.
The planetary carriers 54A and 54B supporting the planetary gears 55 ... also rotate around the sun gear 53, so that the rotation of the power transmission shaft 47 is maintained at a predetermined speed in the planetary gear device 33. Decelerated power transmission shaft 57
Is transmitted to This rotation of the power transmission shaft 57 is performed in the same manner as in the initial stage of the fastening operation of the bolt 23, as in the case of the speed reduction gears 35 and 36.
By rotating the drive shaft 69, that is, the socket 37 fitted to the bolt 23,
Further, the bolt 23 is screwed into a female screw portion formed on the rail 22.

The torque required to rotate the bolt 23 further increases, and the AC servomotor 31 detects the end of the fastening operation and detects the specified torque, so that the output shaft 31
The rotation of a is stopped. And the wrench lifting motor 17
Raises the torque wrench 16, the rail fastening robot 1 is moved by the traveling motor 8 to the position of the next bolt 23 to be fastened, and the above operation is repeated.

The work of loosening the bolts 23 performed by the rail fastening robot 1 to remove the rails 22 already fixed to the sleepers 21 is performed by the bolts 23 described above.
Is performed in substantially the same manner as the fastening operation of However, in this case, when the socket 37 is fitted to the bolt 23 to be loosened, the current of the coil 42 constituting the electromagnetic clutch 32 is cut off, and the armature 45 is separated from the rotor 44. On the other hand, the coil 61 constituting the electromagnetic brake 34 is energized, the gear 64a of the armature 64 meshes with the gear 63a of the rotor 63, and the rotation of the output shaft 31a of the AC servomotor 31 Gear device 33
Is transmitted to the reduction gears 35 and 36.

When the AC servomotor 31 detects that the torque required to rotate the bolt 23 has become smaller than a predetermined value, it transmits a signal to the control unit 38. Upon receiving this signal, the controller 38 controls the electromagnetic brake 3
4, the current of the coil 61 constituting the electromagnetic clutch 3 is cut off.
The rotation of the output shaft 31 a of the AC servomotor 31 is transmitted to the reduction gears 35 and 36 without being reduced in the planetary gear unit 33 by energizing the coil 42 constituting the second motor 2.

Thereafter, when the torque required to rotate the bolt 23 is further reduced, and the AC servomotor 31 detects the specified torque indicating the end of the loosening operation, the rotation of the output shaft 31a is stopped.

According to the torque wrench 16 and the rail fastening robot 1 provided with the torque wrench 16 in the bolt fastening mechanism 9, the following effects can be obtained.
That is, in the torque wrench 16, the planetary gear device 33 is disposed between the output shaft 31 a of the AC servomotor 31 and the drive shaft 69 to which the socket 37 is fixed. Brake 3
By operating 4, the planetary gear device 33 transmits the rotation of the output shaft 31a without changing its rotation speed or at a reduced speed.

Therefore, the AC servomotor 31 can always be used at the maximum rotation speed and the maximum torque, so that high work efficiency can be obtained even when a large number of bolts 23 are continuously tightened and loosened. Particularly, in the fastening operation, the fastening force of each bolt 23 can be made uniform. In addition, a small-sized and light-weight AC servomotor 31 having a small capacity can be employed, and the power consumption can be reduced.

The AC servomotor 31 transmits a signal when it detects that the torque required to rotate the bolt 23 to be fastened or loosened is larger or smaller than a predetermined value. Since the control unit 38 controls the electromagnetic clutch 32 and the electromagnetic brake 34 based on the above, when the bolt 23 is fastened by the planetary gear device 33, the rotation of the output shaft 31a in the early stage of the fastening operation that does not require a large torque. Is transmitted without changing its rotation speed to obtain a small torque and high speed rotation. At the end of the fastening operation in which the torque exceeds a predetermined value, the rotation of the output shaft 31a is reduced and transmitted to obtain a large torque and low speed. Rotation, and
When the bolts 23 are loosened, in the initial stage of the loosening work requiring a large torque, the rotation of the output shaft 31a is transmitted at a reduced speed to achieve a large torque / low speed rotation, and the torque becomes smaller than a predetermined value. At the end of the loosening operation, the rotation of the output shaft 31a is transmitted without changing the rotation speed, so that a small torque and high speed rotation can be achieved. In addition, since no other torque detecting device is required, the torque wrench 16
And the control of the electromagnetic clutch 32 and the electromagnetic brake 34 becomes easy.

The rail fastening robot 1 having the torque wrench 16 in the bolt fastening mechanism 9 mounts the generator 7, the traveling motor 8, the bolt fastening mechanism 9 and the like on the bogie 4 having the traveling wheels 3. 8 by rail 22,
22 and stops at a position where the bolt position detection sensor 15 constituting the bolt fastening mechanism 9 detects the bolt 23 to be fastened, the wrench elevating motor 17 lowers the torque wrench 16, and the torque wrench 16 When the rail 22 is fixed to the sleeper 21, the bolt 23 is fastened, and when the rail 22 is removed from the sleeper 21,
Loosen bolt 23. Therefore, the railroad ties 21
The fastening or loosening work of a large number of bolts 23 for fixing the bolts can be performed efficiently.

In the above-described embodiment, the AC servo motor 31 constituting the torque wrench 16 is
The torque required to rotate the motor is defined as a control amount, and when it is detected that this value is larger or smaller than a predetermined value, a signal is transmitted to the control unit 38 to control the electromagnetic clutch 32 and the electromagnetic brake 34. Although the case has been described as an example, an appropriate value may be adopted as the control amount depending on the situation.

For example, when the rotation speed of the drive shaft 69 is set as a control amount, the AC servo motor 31 outputs a signal when detecting that the rotation speed of the drive shaft 69 is larger or smaller than a predetermined value. Is transmitted, and based on this signal, the control unit 38
Controls the electromagnetic clutch 32 and the electromagnetic brake 34.
When the bolt 23 is fastened by the planetary gear device 33, in the initial stage of the fastening operation that does not require a large torque, the rotation of the output shaft 31a is transmitted without changing the rotation speed to drive the drive shaft 69, that is, the socket. In the last stage of the fastening operation in which the rotation speed of the drive shaft 69 is increased and the rotation speed of the drive shaft 69 is reduced, the rotation of the output shaft 31a is transmitted at a reduced speed, and when the bolt 23 is loosened, a large torque is applied. In the initial stage of the required loosening operation, at the end of the loosening operation in which the rotation of the output shaft 31a is decelerated and transmitted, the torque is reduced and the rotation speed of the drive shaft 69 is increased.
The rotation of the output shaft 31a is transmitted without changing the rotation speed.

As the drive source, other than the AC servomotor 31, other types of appropriate motors such as a DC motor and an air motor may be used according to the situation, and the clutch mechanism and the brake mechanism are similarly used. It is not limited to the electromagnetic clutch 32 and the electromagnetic brake 34. However, at this time, it is needless to say that power corresponding to the drive source to be used should be prepared, and when a drive source without a servo mechanism is used, it is detected that the control amount has reached a predetermined value separately. A means to do this is needed. Also, the control of the clutch mechanism and the brake mechanism may be a signal other than the electric signal corresponding to the adopted device.

Further, the case where the reduction gears 35 and 36 composed of planetary gears are arranged between the power transmission shaft 57 and the drive shaft 69 has been described as an example.
5 and 36 are not limited to the planetary gear set,
The number of the power transmission shafts 57 and the drive shaft 69 may be directly connected to each other, or may be integrated with each other.

[0040]

According to the torque wrench and the rail fastening robot of the present invention, the following effects can be obtained. That is, in the torque wrench according to the first aspect, the planetary gear device is disposed between the output shaft of the drive source and the drive shaft fixed to the socket, and operates the clutch mechanism and the brake mechanism according to the situation. Thus, the planetary gear device transmits the rotation of the output shaft without changing the rotation speed or at a reduced speed. Therefore, since the drive source can always be used at the maximum rotation speed and the maximum torque, even when performing the fastening and loosening work of a large number of bolts or nuts continuously, high working efficiency can be obtained.
In the fastening operation, the fastening force of each bolt or nut can be made uniform. In addition, a small-sized and lightweight drive source having a small capacity can be adopted, so that energy consumption can be reduced.

A torque wrench according to a second aspect of the present invention is the torque wrench according to the first aspect, wherein the drive source is a servomotor, and a signal transmitted when a specific control amount of the servomotor reaches a reference value. Based on the above, since a control unit that controls the operation of the clutch mechanism and the brake mechanism is provided, when fastening a bolt or a nut by the planetary gear device, in the initial stage of a fastening operation that does not require a large torque. Transmits the rotation of the output shaft without changing the number of rotations, with a small torque and high speed rotation,
At the end of the fastening operation requiring a large torque, the rotation of the output shaft is reduced and transmitted to achieve a large torque / low speed rotation, and a large torque is required when the bolt or nut is loosened. In the early stage of the loosening operation, the rotation of the output shaft is reduced and transmitted to reduce
At the end of the loosening operation, in which the rotation speed is low and a large torque is not required, the rotation of the output shaft can be transmitted without changing the rotation speed, thereby achieving a low torque and high speed rotation.
Moreover, no other torque detecting device is required, the size of the torque wrench can be reduced, and the control of the clutch mechanism and the brake mechanism is facilitated.

According to a third aspect of the present invention, there is provided a rail fastening robot having a bolt fastening mechanism mounted on a truck having traveling wheels, and the bolt fastening mechanism includes the torque wrench according to the first or second aspect. Then, it travels on the rail and stops at the position of the bolt to be fastened. When the rail is fixed to the sleeper by the torque wrench, the bolt is fastened, and when the rail is removed from the sleeper, the bolt is loosened. . Therefore, fastening or loosening of a large number of bolts for fixing the rail to the sleeper can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a torque wrench according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an electromagnetic clutch provided in the torque wrench.

FIG. 3 is an exploded perspective view showing the planetary gear device provided in the torque wrench.

FIG. 4 is a perspective view showing an electromagnetic brake provided in the torque wrench.

FIG. 5 is a front view showing a rail fastening robot according to one embodiment of the present invention.

FIG. 6 is a plan view showing the rail fastening robot.

FIG. 7 is a side view showing the rail fastening robot.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 rail fastening robot 3 running wheel 4 carriage 9 bolt fastening mechanism 16 torque wrench 21 sleeper 22 rail 23 bolt 31 AC servomotor (drive source) 31a output shaft 32 electromagnetic clutch (clutch mechanism) 33 planetary gear unit 34 electromagnetic brake (brake mechanism) 37) socket 38 control unit 51 internal gear 53 sun gear 54A planet carrier 54B planet carrier 55 planet gear 69 drive shaft

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-121879 (JP, A) JP-A-61-293735 (JP, A) JP-A-53-121298 (JP, A) JP-A-1- 171777 (JP, A) Japanese Utility Model Showa 49-40097 (JP, U) Japanese Utility Model Hei 5-63735 (JP, U) Japanese Utility Model Utility Model 4-32870 (JP, U) Japanese Utility Model Utility Model 5-5367 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23P 19/06 B25B 23/147 B25B 23/157

Claims (3)

(57) [Claims] 1. A torque wrench for fitting a socket to a bolt or a nut and rotating the socket by a drive source to fasten or loosen the bolt or the nut, wherein the output shaft of the drive source and the socket A planetary gear device is interposed between the fixed drive shaft and a sun gear in the planetary gear device is connected so as to rotate integrally with the output shaft. A clutch mechanism interposed between the output shaft and an internal gear of the planetary gear device, and a brake mechanism for fixing the internal gear at a fixed position; A torque wrench characterized by being provided with: 2. The torque wrench according to claim 1, wherein the drive source is constituted by a servomotor, and based on a signal transmitted when detecting that a specific control amount of the servomotor has reached a reference value. And a control unit for controlling the operation of the clutch mechanism and the brake mechanism. 3. A rail fastening robot which mounts a bolt fastening mechanism on a bogie having traveling wheels and fastens a bolt for fixing the rail to a sleeper while traveling on the rail, wherein the bolt fastening mechanism is for rail fastening. A rail fastening robot comprising the torque wrench according to claim 1 or 2 as a fastening device for fastening a bolt.