JPH0688182B2 - Stud attachment / detachment device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stud bolt attachment / detachment device, and more particularly to a device suitable for efficient attachment / detachment work of a reactor pressure vessel main flange bolt.

<Prior art and its problems> As shown in Fig. 13, the reactor pressure vessel has an upper lid 1 and a fuselage 2
Are connected by a stud bolt 3 and a nut 4 to seal the entire pressure vessel. Fig. 14 shows the details of the tightening part. The main flange 5 and the stud bolt 3
Is screwed in.

By the way, since the reactor pressure vessel is regularly inspected once a year, the work of opening and closing the upper lid 1 is performed. At this time, after all nuts 4 and washers 6 have been removed, approximately 25 stud bolts 3 are removed from the main flange 5 for the purpose of fuel replacement, inspection of stud bolts 3, LDRM (detector assembly) replacement, etc. Be done. Usually, this removal work is performed with the upper lid 1 attached for the purpose of reducing exposure and preventing danger.

The stud bolts used in the SWR reactor pressure vessel are as shown in Fig. 15 and Fig. 16. In one example, one stud bolt has a weight of 250 kg, a diameter of 150 mm and a length of 1800 mm. In FIG. 15, there are threaded parts 7 and 8 on the upper and lower parts of the bolt. The bolt top 9 has a hexagonal prism shape, has a hole 10 in the center thereof, and has a thread 11 inside the hole 10. In FIG. 16, the bolt top 12 has a cylindrical shape, and the central hole 13 has a butterfly nut shape.

Conventionally, as a bolt attaching / detaching device of the type shown in FIG.
An attaching / detaching device 14 shown in FIGS. 17 to 19 has been developed. (Special public relations
59-37197) The above-mentioned conventional technology aims at semi-automating the stud bolt attachment / detachment work, and does not consider the following two points.

(1) In the prior art, the stud bolt 3 is gripped by screwing with the threaded portion 11 in the center of the bolt, and this screwing and unthreading must be done manually, which reduces the work time in the radiation situation. The need to shorten.

(2) The implant portion 15 of the stud bolt 3 may be stuck due to rust or the like because it is submerged during a regular inspection of the reactor.
The rotational torque required to release this sticking is very large, and the prior art requires a large device.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, to provide a small and fully automated bolt attaching / detaching device, and to improve efficiency of the stud bolt attaching / detaching work and reduce exposure of workers.

<Purpose of the Invention> The present invention provides a device capable of easily pulling out and tightening a stud bolt of a nuclear pressure vessel which has a small exposure dose and can be remotely operated by giving a rotational impact force to the stud bolt when attaching and detaching the stud bolt. There is.

<Summary of Means> In summary, the present invention is for attaching and detaching a stud bolt for a nuclear power pressure vessel, and a spline shaft having a projection fitted to the top hole of the stud bolt at the lower end to freely move up and down in the outer cylinder, A cylinder with a flange for spline connection with the spline shaft, an impact force applying member for imparting an impact force for loosening or tightening a stud bolt coaxially with the cylinder to the spline shaft, and an impact force applying member required for impact This is a stud attachment / detachment device that includes a drive device that accumulates and imparts various types of energy and a cylinder device that grips and pulls up the upper part of the stud bolt.

<Example 1> An example of the present invention is shown in Figs.

1 to 3 are overall views of the apparatus. Six bolt attaching / detaching units 18 are mounted on the frame body 17. FIG. 4 is a sectional view of the bolt attaching / detaching unit 18.

The air cylinders 19, 20 and the motor 21 are fixed to the frame body 17. A piston 22 of the air cylinder 19 is connected to a spline shaft 25 via a connecting plate 23 and a bearing 24. On the other hand, as shown in FIG. 7, a wide pinion gear 27 is connected to the motor 21 via a torque limiter 26. The pinion gear 27 meshes with a flywheel 29 having a screw portion 28 inside. The threaded portion 28 of the flywheel is screwed into the threaded portion 31 of the tube 30. Spline hubs 32 and 33 are attached to both ends of the cylinder 30.
25 passes. Each spline hub is supported by a bearing 34, and on one side thereof, projections 37 and 38 that engage with the recesses 35 and 36 of the flywheel 29 are provided.

Further, as shown in FIGS. 5 and 6, the lower end portion of the spline shaft 25 is provided with a projection 40 having a shape fitting the ceiling plate of the support arm 39 and fitting to the hole 13 at the top of the bolt. There is.

Also, at the tip of the support arm 39, a bolt shank portion 41 and a screw portion
There is a protrusion 44 shaped to fit the curve 43 between 42. Support arm
The length of the 39 is sized so that the projection 44 contacts the curve 43 when the projection 40 enters the hole 13. On the other hand, inside the outer cylinder 45 fixed to the frame 17, the piston of the air cylinder 20 is
There are arms 47 connected to 46 and a plate 48 restrained in vertical and circumferential movements. A solid sliding material 49 is attached to the inner surface of the plate 48 and is in contact with the support arm 39 via a friction piece 50.

<Embodiment 2> FIG. 12 shows an example in which a coil 54 and a magnet disk 55 are used as a mechanism for transmitting a rotational force from the flywheel 52 to the spline hub 53 in the above-described bolt attaching / detaching device.

In this embodiment, a coil 54 is wound around a flywheel 52, and both ends thereof are taken out by a slip ring 56 to a fixed portion. The coil 54 is supported on the cylinder 58 by a bearing 57. Further, a disk 55 of a permanent magnet or an electromagnet is attached to the spline hub 53.

When loosening the fixed stud bolt 3, first use the coil 54
Rotate with both ends electrically open to store kinetic energy. After the flywheel 52 has sufficient kinetic energy, if both ends of the coil are short-circuited or connected with low resistance, or a current is applied to the coil, an electromagnetic force acts between the magnet disk 55 and the coil 54 to cause the flywheel 52. The kinetic energy possessed by the is transmitted to the spline hub 53 to release the fixing of the bolt.

In the case of this embodiment, since the flywheel 52 and the spline hub 53 do not mechanically contact with each other, the impact noise when releasing the fixing of the bolts is small, and the life of the device can be expected to be extended.

<Operation> Using the device configured as above, the stud bolt 3
The procedure for attaching / detaching will be described below.

When removing the stud bolt 3, as shown in FIG. 10, the device 8 (reference: JP-A-56-157964) is placed on the upper cover flange 51 so that the center of each bolt and the center of each bolt attaching / detaching unit are aligned. Put it on. Next, the air pressure applied to the air cylinder 19 is lowered, and the spline shaft 25 is lowered until the protrusion 44 contacts the shank portion 41 at the top of the bolt (see FIG. 4). Then the motor 21
And rotate it in the direction A shown in FIG. Flywheel
Since 29 is screwed to the cylinder 30, it descends by rotation, and when the notch 36 of the flywheel and the projection 38 of the flange of the cylinder 30 mesh with each other, as shown in FIGS. 7 and 9, the spline shaft 25 begins to rotate (see FIG. 9 of the EE cross section of FIG. 7). When the protrusion 40 is rotated until it coincides with the hole 13 at the top of the bolt, the protrusion 40 falls into the hole 13 and fits therein (see FIG. 6). After fitting, the arm 47 is pushed down by the double action air cylinder 20. This allows the arm 47 and the board
The convex portions of 48 come into contact with each other, and the plate 48 moves inward. This movement pushes the support arm 39 inward through the friction piece 50,
44 contacts the curved portion 43 of the bolt and is fixed. In this way, the stud bolt 3 is gripped by the support arm 39.

Next, the air cylinder 19 is supported by applying a slightly larger pressure than just canceling the weight of the stud bolt, and the motor 21 is rotated in the B direction in the figure. The motor 21 drives the pinion 27, and both of them serve as a drive device that gives the flywheel 29 the energy required for the impact force. The rotation of the pinion 27 causes the flywheel 29 to rotate, and the flywheel 29 is raised by the screw portion 28 on the inner surface (see FIG. 4). At this time,
The spline shaft 25 does not rotate because it is fitted to the bolt. After the flywheel (a member forming the impact force imparting member) 29 rises while rotating and has sufficient kinetic energy, the flywheel 29 reaches the flange of the cylinder 30,
The notch 35 and the protrusion 37 mesh with each other (see FIG. 8).

As a result, the kinetic energy of the flywheel 29 is instantaneously transmitted to the spline shaft 25, and the stud bolt 3 is rotated with a large force to release the fixation. The large pressure at this time is not transmitted to the motor 21 by the torque limiter 26, and the motor is protected from impact. After the fixation is released, the stud bolt 3
The torque required for the rotation of 1 is small, and the bolt 3 is pulled out from the threaded portion of the main flange 5 by the rotational force of the motor 21. When the bolt 3 is pulled out, it is moved up to the position shown in FIG. 4 by the action of the air cylinder 19. At this time, friction piece 50
Goes up while sliding on the surface of the solid sliding member 49, and the bolt continues to be gripped.

After the removal of the six stud bolts is completed, the bolt attaching / detaching device 8 is lifted by a crane or the like as shown in FIG. 11 and moved to the bolt storage location. To remove the bolt from the attachment / detachment device, the arm cylinder 47 is pulled upward by the air cylinder 20. This releases the bolt instantly. (6th
See figure).

The bolt is attached to the main flange 5 in the reverse order of the above.

<Effects> By carrying out the present invention, the time required to attach / detach the bolts is shortened to about 5 minutes since the gripping / opening rotational impact force of the stud bolts is remotely and automatically applied. In addition, the number of workers can be reduced by half, and a small device can be removed by a mechanism that gives an impact rotational force to a bolt, even a bolt having an implanted portion fixed.

By completely automating the attachment / detachment of the reactor pressure vessel stud bolt, which has conventionally been done manually or semi-automatically, there is an effect of reducing the exposure of the worker and shortening the work time.

[Brief description of drawings]

1 is a plan view of an apparatus according to an embodiment of the present invention, FIG. 2 is a front view of the apparatus of FIG. 1, FIG. 3 is a view taken along line AA 'of FIG. 1, and FIG. FIG. 5 is a vertical sectional view of a bolt attaching / detaching unit of the apparatus of the first embodiment, FIG. 5 is a view taken along line AA ′ of FIG. 4, FIG. 6 is a perspective view of a holding mechanism of the bolt attaching / detaching unit, and FIG. FIG. 8 is a detailed view of the part B, FIG. 8 and FIG. 9 are development views showing the state of the parts C and D of FIG. 7 when meshed, and FIG. 10 is an atomic view of the device according to one embodiment of the present invention. FIG. 11 is a side view showing a state of being installed on a furnace pressure vessel upper mirror flange, FIG. 11 is a front view showing a state in which a stud bolt is lifted by an apparatus according to the present invention, and FIG. 12 is a second embodiment of the present invention. Fig. 13 is a longitudinal sectional view of the reactor pressure vessel, and Fig. 14 is a longitudinal sectional view of Fig.
Fig. 15 is a sectional view of a stud bolt in an implanted state showing the details of the portion A in the figure, Fig. 15 and Fig. 16 are longitudinal sectional views showing an example of a stud bolt used for closing the upper mirror of a reactor pressure vessel, Fig. 17 Is a plan view of a conventional bolt attaching / detaching device, FIG. 18 is a front view thereof, and FIG. 19 is a vertical sectional view of a bolt attaching / detaching unit of the conventional bolt attaching / detaching device. It is drawing which shows time. 3 …… Stud bolt, 13 …… Hole 19 …… Air cylinder, 21 …… Motor 25 …… Spline shaft, 27 …… Pinion gear 29,52 …… Handwheel, 30 …… Cylinder 35,36 …… Recess, 37, 38 …… Projection 39 …… Support arm, 41 …… Shank part, 44 …… Projection 47 …… Arm, 55 …… Magnet disk

Claims (4)

[Claims] 1. A spline shaft for attaching and detaching a stud bolt for a nuclear power pressure vessel, wherein a spline shaft is provided at a lower end thereof so as to be fitted with a top hole of the stud bolt, and which can freely move up and down in an outer cylinder. A cylinder with a flange for spline connection, an impact force applying member that imparts to the spline shaft an impact force that loosens or tightens the stud bolt that is coaxial with the cylinder, and the energy required for impact is applied to the impact force applying member. A stud attachment / detachment device comprising a drive device for accumulating and a cylinder device for gripping and pulling up an upper part of a stud bolt. 2. A cylinder with a flange for spline-connecting the impact force applying member to a spline shaft, a spline hub abutting against the flange, a flywheel screwed to a threaded portion on the outer circumference of the cylinder, and upper and lower parts of the cylinder. Claims characterized in that it is composed of a set of protrusions provided on the flywheel that is attached and detached in accordance with the rotation direction of the flange and the flywheel, a pinion gear that applies a rotational force to the flywheel and connects it, and a motor for driving the pinion gear. The stud bolt attachment / detachment device according to item 1. 3. The impact force applying member is connected to a cylinder having a magnet disk as a flange, a flywheel for spline connection to a spline shaft, and one of the upper and lower flanges according to a command to rotate the spline shaft. An electromagnetic coil that gives
The stud bolt attaching / detaching device according to claim 1, comprising a pinion gear and a drive device for driving the pinion gear. 4. A cylinder device for gripping an upper part of a stud bolt and pulling it up or down is connected to a fluid-driven cylinder, a connecting plate, a spline shaft, a spline shaft, and a shank portion of the stud bolt. 4. A support arm with a projection that forms a cylinder, and a cylinder having a brace that presses the support arm inward of the shaft center. The cylinder according to claim 1, further comprising: Stud bolt attachment / detachment device.