JPH0366571A - Large nut attachment/detaching device - Google Patents

Abstract

PURPOSE:To grasp a nut surely and stably at all times by detecting the positional relation in the bolt shaft center direction of a nut rotating member and the nut face, and providing a means controlling the movement in the bolt shaft center direction of the rotating member so that the groove engaging part of the nut rotating member may be engaged with the groove of a nut based on this detection result. CONSTITUTION:A nut rotating and driving part 60 of a spline shaft 63, etc., is relatively descended to a link 51 because of the device upper part containing the spline shaft 63 continuing with its descent even in case of the descent of the nut rotating and driving part 60, etc., being stopped. A detecting body provided at the nut rotating and driving part 60 comes in the detection range of a sensor 53 to detect the detection part of the detecting body. The detection signal transmitted from this sensor 53 is input to a control device 70 and a driving motor 68 is stopped by a command signal transmitted from the control device 70. At this time, the pressing force of a claw 64 to the nut is decided by the stroke of the nut rotating and driving part 60 until the sensor 53 is operated after a claw 64 for rotating the nut being brought into contact with the upper end of the nut.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for attaching and detaching a large nut, and particularly to a device suitable for attaching and detaching a nut used in a nuclear reactor pressure vessel.

[Conventional technology]

As shown in FIG. 11, the reactor pressure vessel is constructed such that an upper mirror 1 and a body 2 are connected by stand bolts 3, and the entire pressure vessel is hermetically sealed. FIG. 12 shows details of how the upper mirror 1 and the body 2 are connected by the stud bolts 3. As shown in FIG. 12, the stud bolt 3 connects the fuselage flange 2A of the fuselage 2 with the threaded portion 3A of the stud bolt 3, protrudes from the upper surface thereof, and passes through the through hole IB formed in the upper mirror flange LA. A threaded portion 3B at the other end projects above the upper mirror flange IA. The upper mirror 1 and the body 2 are connected to this threaded portion 3B with a stud bolt 3 via a nut 4 and a washer 5.

A large number of stud bolts 3 are arranged in close proximity to each other in the circumferential direction of the upper mirror flange IA so that the nuts 4 and the washers almost contact each other. The nut 4 and the washer 5 have a cylindrical shape, and the nut 4 has grooves 4A radially formed at its upper end for loosening the nut, and the washer 5 has grooves as shown in FIG. 5A is formed.

In the reactor pressure vessel, the upper mirror 1 is closed during the annual periodic inspection for fuel exchange, and when the upper mirror 1 is opened, all nuts 4 and washers 5 attached to the stud bolts 3 are removed. When closing the upper mirror 1, attach a nut 4° washer 5 to the stud bolt 3 and tighten the upper mirror 1.

Conventionally, the work of attaching and detaching these nuts and washers has been done manually, but it is possible to reduce the exposure of workers to radiation. Due to the need to shorten the working time under 11 environment, a nut and washer attachment/detaching device that performs these operations remotely and automatically has been developed and put into practical use.

As this attachment/detachment device, there is one shown in FIGS. 14 and 15. (Japanese Unexamined Patent Publication No. 62-79975) This attachment/detachment device runs in the turning direction along an annular track 10 fixed to the upper mirror l of the reactor pressure vessel with a mount 9 as shown in FIG. It is used by being suspended from the station 11 by the lifting arm 12. In addition, 13 shown in FIG. 13(B) is a bolt cleaning device, and 14 is a stud tensioner, but the bolt cleaning device 13. A description of the stud tensioner 14 will be omitted here; the attachment/detachment device shown in FIG. 14 is attached to the nut 4.
Fig. 15 shows the state in which the washer 5 is gripped, and the nut 4.
The state before the washer 5 is gripped is shown. When the nut 4 and washer 5 screwed onto the stud bolt 3 are removed by the attachment/detachment device 8, the nut 4 and washer 5 are first grasped by the following operation. That is, by moving the station 11 in the turning direction and the radial direction shown in FIG. 13, the central axis of the device is brought into alignment with the central axis of the intended stud bolt 3. The lifting arm 12 shown in FIGS. 13, 14, and 15 is driven to lower the entire nut attaching/detaching device 8 toward the nut 4 by a certain stroke.

In this case, the entire nut attaching/detaching device 8 descends with a constant stroke, but after that, the lifting arm 12 of FIG.
Motor 15, motor mounting plate 16° support plate 17. Natsu 1
8 and the fixed shaft 19A (hereinafter referred to as the upper member) is fixed and does not move. The parts other than the upper member are lowered from the state shown in FIG. 15 to the state shown in FIG. 14 by the operation of the air cylinder 22. The amount of descent at this time is
It is measured by a rotary encoder 69 attached to a motor 68 shown in FIG. 13(B). Further, the nut rotation drive section 24 of the nut attaching/detaching device 8 is lowered in advance, and the chuck 27 is left open.

In FIG. 15, when the motor 15 is rotated clockwise, the first
The parts other than the above-mentioned upper member in Fig. 5 are lowered from the state shown in Fig. 15 to the state shown in Fig. 14, and the rotating pawl 2
9 comes into contact with the upper surface of the nut 4, and the parts other than the above-mentioned upper member in FIG. 15 are stopped.

Then, move the motor 15 to the left and right, and rotate the rotation pawl 29.
Rotate until it fits into the groove 4A of the nut 4.

Thereafter, the air in the air cylinder 22 is released and the chuck 27 is closed by the spring 32 as shown in FIG. (
Groove 5A of washer 5 with locking pawl 27A of chuck 27
After that, rotate the motor 15 to the left and remove the nut 4 from the stud bolt 3. (Loosen the nut 4 from the stud bolt 3) By the way, as shown in FIG. 15, the nut 4 is provided with several grooves 4A into which the rotating claws 29 fit. When inserted, the locking pawl 27A is positioned to fit into the groove 5A of the washer 5. Normally, the position of the groove 4A of the nut 4 and the position of the rotating pawl 29 do not match, so when the nut attaching/detaching device 8 is lowered, the rotating pawl 29 does not always fit into the groove 4A of the nut 4. For this reason, the rotating pawl 29 may ride on the upper end of the wide nut 4. In this case as well, the lifting arm 12 is lowered to a position where the rotating pawl 29 is attached to the nut 4 714A. Therefore, the nut rotation drive unit 24 to which the rotating pawl 29 is attached slides on the spline structure and rises relative to the fixed shaft C (which rotates but does not move up and down) that descends together with the lifting arm 12. do.

(Problems to be Solved by the Invention) The conventional nut attaching/detaching device described above does not take into consideration the vertical positional deviation of the nut 4, and has the following problems.

When the nut attaching/detaching device 8 is pressed against the nut 4 in order to lock the nut 4, the amount of movement (stroke amount) of the nut attaching/detaching device 8 is always constant. Therefore, if the nut 4 is loosened too much by the stud tensioner 14 shown in FIG. The amount of shrinkage becomes excessive, and the OKW force applied to the rotation pawl 29 and the nut 4 due to the pressing force becomes larger than the rotational torque of the motor 15, and the motor 15 may become unable to rotate. Further, the nut 4 may rotate in the same positional relationship as the rotating pawl 29, and the groove 4A of the nut 4 may not be able to engage the rotating pawl 29.

On the other hand, when the nut 4 is located at a relatively lower position because the rotating pawl 29 does not reach the nut 4 or the groove 4A of the nut 4 even if the nut attaching/detaching device 8 is moved with the same stroke from the track 10, is the engaging pawl 27 of the chuck 27.
A may not reach the position of the groove 5A of the washer 5.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a large-sized nut attachment/detachment device that can always stably attach/detach a nut even when the positional relationship between the nut and the nut attachment/detachment device does not correspond sufficiently. The goal is to provide equipment.

[Means for Solving the Problem] The above object is to detect the positional relationship in the bolt axis direction between the nut surface and the nut rotating member that engages with the groove on the upper end surface of the nut and rotates the nut. This is achieved by providing means for controlling the amount of movement of the nut rotating member in the bolt axial direction so that the nut rotating member engages with the nut groove based on this detection result.

[Effect]

A signal is output when the nut rotating member moves a predetermined distance (distance corresponding to the depth of the nut groove) toward the nut from the position where the nut rotating pawl contacts the nut. However, when this signal is output, the movement of the nut rotating member toward the nut is stopped.

Therefore, regardless of the positional relationship between the nut rotating member and the nut, the nut rotating member stops at the same position relative to the nut. As a result, the frictional force between the nut-rotating member, for example, the nut-rotating pawl, is always kept constant, and the torque of the motor for moving the nut-rotating member toward the nut is insufficient, and the nut is The phenomenon of rotation following the rotation pawl is eliminated.

In addition, if the nut rotating member has a chuck that engages with the groove of a washer attached to the nut to remove the washer from the bolt, and the positional relationship between the chuck and the nut rotating pawl is set in advance, the chuck The phenomenon of the washer not reaching the groove is also eliminated.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a cross-sectional view showing one embodiment of the large nut attachment/detaching device of the present invention, FIG. 2 is a detailed view of the lower part of FIG. 1 including the nut rotation drive unit, and FIGS. 3(A) and (B) are FIG. 4 is a perspective view of the nut gripping mechanism shown in FIG. 1, and FIG. 5 is a perspective view of a nut and washer to which the large nut attaching/detaching device of the present invention is applied. In Fig. 1, the numbers in parentheses correspond to the symbols shown in Figs. 14 and 15. shows the chuck with its legs open.

As shown in FIG. 1, this large nut attaching/detaching device has a motor 41 mounted on a motor mounting plate 42 attached to a lifting arm 40, and an output shaft 43 of the motor 41 connected to a gear 44.
The spline shaft 45 is connected to the spline shaft 45 through the spline shaft 45 . gear 4
6 meshes with the gear 44 and the ball screw shaft 47
The rotation of the ball screw shaft 47 connects the spline hub 50 via the ball nut 49 and the bearing.
And the nut rotation drive unit 60 connected to the spline hub 50 is driven in the vertical direction. A sensor 53 is installed on the surface of the air cylinder fixing plate 51 to which the air cylinder 52 is attached. A ring 54 is provided at the tip of the air cylinder 51, and the ring 57 can be moved downward through a ring 55 and a bearing 56 against the biasing force of a spring 58. A plurality of plates 59 are fixed to the ring 57 at predetermined intervals in the circumferential direction on the lower surface thereof. As shown in FIG. 3, an elliptical hole 61A is formed which is fixed to the inner surface of the chuck 61 and is inclined radially inward toward the upper side of the hole, and has a prismatic space inside. Plate 59 is loosely fitted to 61B,
In addition, the pin 59A fixed to the side surface of the plate 59 is connected to the oval hole 6.
It is loosely fitted into 1A. Therefore, the chuck 61 can swing about the fulcrum 65A with respect to the cylinder 65 as the hand 59 moves in the vertical direction.

A rotating shaft 62 is connected and fixed to the spline hub 50, and a spline shaft 63 is connected and fixed to the rotating shaft 62. A detection body 48 is provided on the spline shaft 63 corresponding to the installation position of the sensor 53, and a spline hub 66 is provided to be slidable in the axial direction, and a bearing is provided between the spline hub 66 and the air cylinder fixing plate 51. It is arranged. A ring 57 is fixed to the spline hub 66, and a cylinder 65 is connected to the spline hub 66, and a spring 58 is installed between the cylinder 65 and the ring 57. Further, a compression spring 67 is installed between the cylinder 65 and the lower end of the spline shaft 63.
5 is designed to provide a restoring force in the vertical direction.

Furthermore, the lifting arm 40 can be raised and lowered by a drive motor 68 whose rotation amount is controlled by a command from a control device 70 shown in FIG. The amount of rotation of the drive motor 68, that is, the amount of vertical movement of the nut attaching/detaching device 8 can be measured based on the amount of vertical movement of the lifting arm 40.

Next, the operation of the large nut attaching/detaching device described above will be explained.

By turning and moving the station 11 in the radial direction as shown in FIGS. Align the washer 5 with the center axis of the stud bolt 3 to be gripped. At this time, the nut rotation drive unit 60 has been wound up in advance, and the chuck 61 is in an open state.

Next, as shown in FIGS. 13(A) and 13(B), the entire attachment/detachment device 8 is lowered by the lifting arm 40 by driving the drive motor 68 shown in FIGS. 13(A) and (B).
4 comes into contact with the nut 4, the nut rotating pawl 64. A guide plate 31, a cylinder 65, a spline hub 66 connected to the cylinder 65, and a ring 51 fixed or connected to the spline hub 66 via a bearing. Air cylinder 5
2° ring 54. Ring 55. Ring 57. The plate 59, chuck 61, etc. are stopped together.

On the other hand, the lifting arm 40. Motor 41. Motor installation F
i42. Motor output shaft 43. Gear 44. Spline shaft 4
5. Gear 46. Ball screw shaft 47, pole nut 49. Spline hub 50. Nut drive section 60. The spline shaft 63 continues to descend.

Therefore, even if the nut rotation drive unit 60 etc. stops descending, the upper part of the device including the spline shaft 63 continues to descend, so the nut rotation drive unit 60 such as the spline shaft 63 descends relative to the link 51. do. Therefore, as shown in FIG. 6, the detecting body 48 provided on the nut rotation driving section 60 enters the detection range of the sensor 53, and the detecting section 48A of the detecting body 48 is detected as shown in FIG. sensor 53
The detection signal is manually inputted to the control device 70 shown in FIG. 10, and the drive motor 68 is stopped by a command signal from the control device 70.

The control device ff170 has a stroke larger than the stroke of the nut rotation drive unit 60 when the rotation pawl 64 contacts the upper end of the nut 4 and stops, and rotates while the rotation pawl 64 enters the groove 4A of the nut 4. A value smaller than the stroke of the nut rotation drive section 60 when the pawl 64 and the nut 4 come into contact and stop is input as the set value, and the position where the drive motor 68 stops and the nut rotation drive section 60 stops. Compare the stroke and setting value. As a result of the comparison,
The stroke at the position where the nut rotation drive unit 60 stops is
If it is smaller than the set value, it is determined that the rotation pawl 64 is not engaged with the groove 4A of the nut 4, and a rotation command signal is output from the tag control device 70 to the drive motor 41, and the drive motor 41 is operated at a low speed. As the nut rotates, the nut rotating pawl 64 rotates on the nut 4 as shown in FIG. 8, and is locked in the groove 4A of the nut 4 as shown in FIG.

At this time, the pressing force of the nut rotation pawl 64 against the nut 4 is determined by the stroke of the nut rotation drive unit 60 after the nut rotation pawl 64 contacts the upper end of the nut 4 until the sensor 53 is activated. , is always a constant value, and the pressing force is not too small or too large due to a change in the position of the nut 4 or a change in the mounting position of the nut attaching/detaching device 8, etc., and the nut rotating pawl 64 is reliably locked in the groove 4A of the nut 4. be able to.

Thereafter, when the piston of the air cylinder 52 is moved upward, the pressing action of the ring 54 at the tip of the piston against the ring 55 is released, and the ring 55 moves upward together with the slope 59 due to the urging force of the spring 57 and the compression spring 67. As a result, as shown in FIG. 3, the bottle 59A fixed to the plate 59 comes into contact with the upper end of the oval hole 61, closing the chuck 61 and locking it in the groove 5A of the washer 5.

Further, as a result of the comparison, if the stroke of the nut rotation drive unit 60 is larger than the set value, it is determined that the nut rotation pawl 64 is locked in the groove 4A of the nut 4, and the piston of the air cylinder 52 is moved upward. Then, the chuck 61 is closed and locked in the groove 5A of the washer 5 using the same mechanism as described above.

As described above, in the large nut attachment/detaching device of the present invention,
Even if the nut 4 is floating, even if the mounting position of the nut attaching/detaching device 8 is shifted upward, or even if the nut rotating pawl 64 rides on the groove 4A of the nut 4 as shown in FIG. The nut rotation pawl 64 in the lower member that moves up and down in synchronization with the spline hub 66 descends until the detection part 48A of the detection body 48 is detected, so that the nut 4 is not pressed more than necessary and the motor 41
The nut rotation pawl 6 is inserted into the groove 4A of the nut 4 by the rotation of the nut 4.
4 can be fitted.

Further, even if the mounting position of the nut attaching/detaching device 8 is shifted upward, the nut 4 is lowered until the nut rotation pawl 64 hits the nut 4, and then the sensor 53 detects the detection object 48.
The nut 4. is lowered until it detects the detection part 48A of the nut 4. The nut attaching/detaching device 8 can be reliably lowered regardless of the position of the washer 5, and the chuck 61 allows the nut 4. Washer 5 can be grabbed.

In the embodiment described above, the sensor 53 is fixed to the air cylinder +
Although an example has been shown in which the sensor 53 is installed on the spline hub 66 other than the air cylinder fixing plate 51 and the detection part 48A of the detection body 48 is provided on the spline shaft 63 in the nut rotation drive part 60, Provided on members that go up and down,
The detection section 48A may be provided on the side of another member that moves up and down integrally with the spline shaft 63.

〔Effect of the invention〕

As described above, according to the present invention, even if the positional relationship between the nut attachment/detachment device and the nut to be attached/detached changes, the nut can always be stably and reliably grasped. The work of attaching and detaching the nut screwed into the stand bolt can be automated with high reliability, and the exposure of workers to radiation can be reduced.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the large nut attachment/detaching device of the present invention, Fig. 2 is a detailed view of the lower part of Fig. 1 including the nut rotation drive section, and Fig. 3 is (A>). (B) 4 is a perspective view of the nut gripping mechanism shown in FIG. 1, FIG. 5 is a perspective view of a nut and washer to which the large nut attachment/detaching device of the present invention is applied, and FIG.
Figures 8 and 9 are detailed views of part A in Figure 1, Figures 8 and 9 are explanatory diagrams showing the positional relationship of the nut attaching/detaching device, nut, and washer corresponding to Figures 6 and 7, respectively. Fig. 10 shows the control I thread system of the lifting motor of the nut attaching/detaching device according to the present invention. Fig. 11 is a sectional view of the nuclear pressure vessel, Fig. 12 is an enlarged sectional view of section A in Fig. 11, and Fig. 13 (A) is a sectional view of the nuclear pressure vessel. FIG. 13(B) is a plan view of an automatic nut attaching/detaching device in which the large nut attaching/detaching device according to the present invention is installed; FIG. 13(B) is a side view of FIG. 13(A);
FIGS. 14 and 15 are cross-sectional views showing the state in which a nut and washer are gripped in a conventional large nut attachment/detachment device. 4...Nut, 4A...Groove, 5...
...Washer, 5A...Groove, 31...
・Guidance board, 40... Lifting arm, 41...
...Motor, 43...Motor output shaft, 45.
... Spline shaft, 47 ... Ball screw shaft, 48 ... Detection object, 48A ...
・Detection part, 50...Spline hub, 52...
...Air cylinder, 53...Sensor, 54
...Ring, 55...Ring, 56.
...Ring, 58 ...Spring, 59
...Plate, 60...Nut rotation drive section,
61... Chuck, 62... Rotating shaft,
63...Spline shaft, 64...Nut rotation pawl, 65...Cylinder, 66...
・Spline hub, 67...Spring, 68
...Motor, 69...Rotary encoder, 70...Control device.

Claims (2)

[Claims] (1) Move a large nut that is screwed onto the bolt and has a groove on its upper end surface from the axial center side of the bolt to the nut side,
In the nut rotating member that engages with the groove to rotate the nut, the positional relationship between the nut rotating member and the nut surface in the bolt axis direction is detected, and the nut is rotated based on the detection result. A device for attaching and removing a large nut, characterized in that means is provided for controlling the amount of movement of the rotating member in the bolt axis direction so that the groove engaging portion of the rotating member engages with the groove of the nut. (2) a spline shaft in which the nut rotating member is provided so as to be movable up and down in the axial direction of the bolt via a drive motor;
a detecting section for detecting the position of the spline shaft, the detection section being provided to be movable up and down with respect to the spline shaft in synchronization with the spline hub fitted to the spline shaft, and comprising an engaging section that is engaged with a groove of a nut; Claim (1) further comprising: a control unit that controls the amount of movement of the spline shaft in the bolt axial direction by the drive motor based on the detection result.
A device for attaching and detaching the large nut described.