JPWO2007043143A1 - Liquid pressure device - Google Patents

Abstract

The hydraulic nut 21 assembles the turbine case 12 by screwing the bolt 15 inserted through the insertion hole 13b of the turbine case 12 in a state where a tensile force is applied in advance, and the cylinder 22 and the piston disposed in the turbine case 12 are assembled. 23. An intermediate piston 27 is attached to a pressure chamber 26 defined by the cylinder 22 and the piston 23 so as to be movable in the axial direction. The intermediate piston 27 causes the pressure chamber 26 to be a first pressure chamber 26a and a second pressure chamber. 26b. The cylinder 22 is formed with a first oil supply port 31 for supplying hydraulic pressure to the first pressure chamber 26a, and the piston 23 is formed with a second oil supply port 32 for supplying hydraulic pressure to the second pressure chamber 26b. Therefore, the piston 23 can be operated regardless of the hydraulic pressure supplied from either the first oil supply port 31 or the second oil supply port 32.

Description

  The present invention relates to a fluid pressure device that screw-couples a bolt inserted through an insertion hole of a member to be fastened in a state where a tensile force is applied in advance.

  Conventionally, when assembling a turbine case of a steam turbine or a gas turbine used in a power plant such as a power plant, a fastening method using bolts and nuts is often used. However, in such a fastening method, most of the tightening torque applied to the nut opposes rotational friction on the seat surface, so it is difficult to increase the axial force of the bolt and obtain a high fastening force. Therefore, when such a high fastening force is required, a hydraulic nut that is screw-coupled in a state where a tensile force is previously applied to the bolt by hydraulic pressure is used.

  The hydraulic nut includes an annular cylinder disposed on the turbine case and a piston that is mounted so as to be movable in the axial direction with respect to the cylinder. A pressure chamber is defined between the cylinder and the piston. An oil supply port for supplying hydraulic pressure to the pressure chamber is formed in the cylinder or the piston. In addition, a screw hole is formed in the axial center of the piston, and a bolt inserted into the insertion hole of the turbine case is screwed into this screw hole. When hydraulic pressure is supplied to the chamber, a tensile force is applied to the bolt. In addition, a lock ring is attached to the outer periphery of the piston by screw connection. When the tension is applied to the bolt, the lock ring is rotated to a position in contact with the axial end surface of the cylinder to release the hydraulic pressure in the pressure chamber. The axial force of the bolt is supported by the cylinder via the lock ring. As a result, the hydraulic nut is screw-coupled with a tensile force applied to the bolt, and a high fastening force can be obtained by increasing the axial force of the bolt. When removing the tightened hydraulic nut from the bolt, supply the specified hydraulic pressure to the pressure chamber again to operate the piston until the lock ring is separated from the axial end face of the cylinder, and then move the lock ring sufficiently from the axial end of the cylinder. Rotate until left. Then, when the hydraulic pressure is released with the lock ring sufficiently loosened, the axial force of the bolt is released and the hydraulic nut can be removed from the bolt.

  On the other hand, a fastening direction using a bolt tensioner is known in order to screw-connect a nut with a tensile force applied to the bolt in advance. The bolt tensioner has a cylinder, and a nut accommodating chamber is provided on the lower side of the cylinder, and the cylinder is arranged on the turbine case so that the tip of the bolt to which the nut has been loosely fastened is covered with the nut accommodating chamber. Is done. A piston is assembled in the cylinder so as to be movable in the axial direction, and a pressure chamber is defined by the piston and the cylinder. A screw hole is formed in the axial center of the piston, and this screw hole is detachably screwed to the tip of the bolt housed in the nut housing chamber. Then, the hydraulic pressure was supplied to the pressure chamber with the piston screwed to the bolt, the nut was tightened with the tensile force applied to the bolt, and the hydraulic pressure in the pressure chamber was released to generate an axial force on the bolt. In this state, the nut can be fastened to the bolt. After the fastening operation is completed, the screw connection between the piston and the bolt is released, and the bolt tensioner is removed from the turbine case. When removing the fastened nut from the bolt, the bolt tensioner is again placed on the turbine case, the piston is screwed to the bolt, and hydraulic pressure is supplied to the pressure chamber. Then, with the piston operated until the nut is separated from the turbine case, the nut is sufficiently loosened to release the hydraulic pressure, whereby the axial force of the bolt can be released and the nut can be removed from the bolt.

  Since a high fastening force is required to assemble the turbine case, a large number of bolts are arranged side by side at a small pitch in the turbine case. Therefore, the outer diameter dimensions of the hydraulic nut and the bolt tensioner are limited, and the pressure receiving area of these pistons may not be set sufficiently large. Therefore, in order to apply a predetermined tensile force to the bolt, it is necessary to increase the hydraulic pressure supplied to the pressure chamber, and in some cases, an ultrahigh pressure of 250 Mpa or more may be set. With such an ultra-high pressure, the seal member mounted on the sliding portion between the cylinder and the piston cannot withstand the hydraulic pressure, and there is a risk of hydraulic pressure leakage from the pressure chamber.

  If the pressure chamber seal failure occurs when fastening the hydraulic nut to the bolt, there is no axial force on the bolt, so it is possible to remove the hydraulic nut from the bolt and reuse it after replacing the seal member. Is possible. However, if a seal failure occurs when the hydraulic pressure is supplied to the pressure chamber to remove the hydraulic nut fastened with the axial force generated on the bolt, the piston may be operated by the original pressurization. It is impossible to loosen the lock ring and remove the hydraulic nut. In this case, in order to remove the hydraulic nut from the bolt, it is necessary to cut the lock nut with a cutter or the like, which makes it difficult to remove the hydraulic nut.

  Also, in the bolt tensioner, if hydraulic pressure leakage occurs in the pressure chamber during the nut tightening operation, it is necessary to replace the bolt tensioner itself during the operation, and the workability is reduced.

  An object of the present invention is to provide a liquid pressure device that can easily continue operation even if a pressure chamber seal failure occurs.

  The liquid pressure device according to the present invention is a liquid pressure device that is screw-coupled in a state where a tensile force is applied to a bolt inserted through an insertion hole of a member to be fastened, and is a first load receiver disposed on the member to be fastened. A second load that includes a member and a screw hole that is screw-coupled to the bolt, and is assembled to the first load receiving member so as to be movable in the axial direction and to form a pressure chamber by the first load receiving member. A receiving member, an intermediate piston which is assembled in the pressure chamber so as to be movable in the axial direction, and which divides the pressure chamber into a first pressure chamber and a second pressure chamber; and the first load receiving member; A first liquid pressure supply port that supplies liquid pressure to the first pressure chamber and a second liquid pressure supply that is formed in the second load receiving member and supplies the liquid pressure to the second pressure chamber. Outside the mouth and one of the first and second load receiving members And a lock ring that supports the axial force of the bolt in contact with the other axial end surface of the first and second load receiving members. The first and second liquids The second load receiving member can be operated even when liquid pressure is supplied from any of the pressure supply ports.

  The liquid pressure device according to the present invention is a liquid pressure device in which a nut is screw-coupled in a state where a tensile force is applied in advance to a bolt inserted through an insertion hole of a member to be fastened, and is detachably disposed on the member to be fastened. A first load receiving member, and a screw hole that is detachably coupled to the bolt, and is assembled to the first load receiving member so as to be movable in the axial direction, and pressure is applied by the first load receiving member. A second load receiving member that defines a chamber; an intermediate piston that is assembled in the pressure chamber so as to be axially movable; and that divides the pressure chamber into a first pressure chamber and a second pressure chamber; A first liquid pressure supply port that is formed in one load receiving member and guides the liquid pressure to the first pressure chamber; and formed in the second load receiving member and has a liquid pressure in the second pressure chamber. A second liquid pressure supply port for guiding Characterized in that the can operate a second load receiving member either from be supplied liquid pressure of the second liquid pressure supply port.

  The liquid pressure device of the present invention includes a first seal member that prevents leakage of liquid pressure from the first pressure chamber, and a second seal member that prevents leakage of liquid pressure from the second pressure chamber. Is attached to the intermediate piston.

  According to the present invention, since the second load receiving member can be operated regardless of whether the liquid pressure is supplied from either the first or second liquid pressure supply port, either the first or the second liquid pressure supply port can be operated. Even if the liquid pressure leaks from the pressure chamber, the liquid pressure can be supplied to the other pressure chamber to operate the second load receiving member, and the fastening operation with the bolt can be continued. The workability of the liquid pressure device can be improved. Even if a seal failure occurs in one of the first and second pressure chambers, the second load receiving member can be operated by supplying liquid pressure to the other pressure chamber without repairing the failure. So you can work quickly in an emergency.

  Further, according to the present invention, the first seal member for preventing leakage of liquid pressure from the first pressure chamber to the intermediate piston and the second seal member for preventing leakage of liquid pressure from the second pressure chamber. Therefore, even if the liquid pressure leaks from one of the pressure chambers due to damage to one of the first and second sealing members, the airtightness of the other pressure chamber is caused by the other sealing member. Can be ensured and the second load receiving member can be operated reliably.

It is sectional drawing which shows a part of gas turbine using the hydraulic nut which is one embodiment of this invention. It is a perspective view which shows the detail of the hydraulic nut shown in FIG. It is sectional drawing which shows the use condition (before hydraulic pressure supply) of the hydraulic nut shown in FIG. It is sectional drawing which shows the use condition of a hydraulic nut at the time of supplying hydraulic_pressure | hydraulic from a 2nd fueling opening. It is sectional drawing which shows the use condition of a hydraulic nut at the time of supplying hydraulic_pressure | hydraulic from a 1st oil supply port. It is sectional drawing which shows the detail of the bolt tensioner which is other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  A gas turbine 11 shown in FIG. 1 is used in a power plant such as a power plant. A turbine shaft (not shown) that converts high-temperature and high-pressure gas heat energy into mechanical energy is provided in a turbine case 12. Contained.

  The turbine case 12 which is a member to be fastened is formed so as to be divided into an upper case 13 and an under case 14, and bolts 15 are provided in the insertion holes 13 b and 14 b formed in the flanges 13 a and 14 a of the cases 13 and 14. It is inserted. The bolt 15 is inserted from the one flange 14a side, and a tip portion thereof protrudes from the other flange 13a side, and a hydraulic nut 21 as a fluid pressure device is screwed to the screw portion 15a. As a result, the flanges 13 a and 14 a are sandwiched between the head portion 15 b of the bolt 15 and the hydraulic nut 21 to assemble the turbine case 12. At that time, the hydraulic nut 21 is screw-coupled in a state where a tensile force is applied to the bolt 15, and the turbine case 12 is firmly fastened with the bolt 15 after fastening being in a state where an axial force is generated.

  2 is a perspective view showing details of the hydraulic nut shown in FIG. 1, FIG. 3 is a cross-sectional view showing a usage state (before hydraulic pressure supply) of the hydraulic nut shown in FIG. 2, and FIG. It is sectional drawing which shows the use condition of the hydraulic nut at the time of supplying hydraulic pressure. As shown in FIG. 2, the hydraulic nut 21 has a cylinder 22 as a first load receiving member and a piston 23 as a second load receiving member, and the outer shape thereof is formed in a substantially cylindrical shape. Yes.

  As shown in FIG. 3, the cylinder 22 is formed in a bottomed cylindrical shape in which a disk-shaped bottom wall portion 22a and a cylindrical side wall portion 22b are integrated by cutting a steel material. The fastening surface 22c formed on the lower surface of 22a is arranged on the flange 13a of the turbine case 12. Further, a cylinder chamber 24 is formed inside the side wall portion 22b, and a screw portion 15a of the bolt 15 protruding from the flange 13a is inserted through a through hole 22d provided in an axis of the bottom wall portion 22a to be cylinder chamber. 24 protrudes inside.

  On the other hand, the piston 23 is formed in a substantially annular shape in which the large-diameter cylindrical portion 23 a and the small-diameter cylindrical portion 23 b are integrated by cutting a steel material, and the outer peripheral surface of the large-diameter cylindrical portion 23 a is the cylinder chamber 24. The piston 23 is assembled to the cylinder 22 so as to be movable in the axial direction by being in sliding contact with the inner peripheral surface and the outer peripheral surface of the small diameter cylindrical portion 23b being in sliding contact with the inner peripheral surface of the through hole 22d. A screw hole 25 is formed in the axial center of the piston 23, and the piston 23 is screwed to the screw portion 15 a of the bolt 15 in the screw hole 25. Accordingly, when the piston 23 moves in a direction away from the cylinder 22 (upward in FIG. 2) with the bolt 15 screwed to the screw hole 25 of the piston 23, the bolt 15 is applied with a tensile force by the piston 23. Become.

  An annular pressure chamber 26 is defined by these members between the cylinder 22 and the piston 23. When the piston 23 moves in the direction away from the cylinder 22, that is, in the axial direction away from the flange 13a, the volume of the pressure chamber 26 is increased. Has come to increase. An intermediate piston 27 is assembled in the pressure chamber 26 so as to be movable in the axial direction with respect to the cylinder 22 and the piston 23. The intermediate piston 27 is formed in an annular shape in sliding contact with the inner peripheral surface of the cylinder chamber 24 at the outer peripheral portion and in sliding contact with the outer peripheral surface of the piston 23 at the inner peripheral portion, and the pressure chamber 26 is connected to the first pressure chamber 26a. The second pressure chamber 26b is divided into two in the axial direction.

  The cylinder 22 is formed with a first oil supply port 31 as a first liquid pressure supply port in order to supply liquid pressure, that is, hydraulic pressure using hydraulic oil as a working medium, into the first pressure chamber 26a. . The first oil supply port 31 has a connecting portion 31a that opens to the side surface of the cylinder 22, and a guide hole 31b that penetrates from the connecting portion 31a to the first pressure chamber 26a. A hydraulic pump (not shown) is connected to the connecting portion 31a. The hydraulic pressure can be supplied from the hydraulic pump to the inside of the first pressure chamber 26a through the guide hole 31b.

  The piston 23 is formed with three second oil supply ports 32 as second liquid pressure supply ports in order to supply liquid pressure, that is, hydraulic pressure, into the second pressure chamber 26b. Each of these second oil supply ports 32 has a connection portion 32a that opens to the axial end surface of the piston 23, and a guide hole 32b that penetrates from the connection portion 32a to the second pressure chamber 26b, and the connection portion 32a. The hydraulic pump is connected to a hydraulic pump (not shown) so that the hydraulic pressure can be supplied from the hydraulic pump to the inside of the second pressure chamber 26b through the guide hole 32b. At this time, in the initial stage of hydraulic supply, any one of the second oil supply ports 32 is opened for venting, and after the inside of the second pressure chamber 26b is filled with hydraulic oil, the connection portion 32a is not shown in the figure. You may make it obstruct | occlude with.

  In this embodiment, the piston 23 is provided with three second oil supply ports 32 for supplying hydraulic pressure to the second pressure chamber 26b. Can be set. Further, the air vent port may be formed separately from the second oil filler port 32.

  In order to prevent leakage of the hydraulic pressure supplied to the first pressure chamber 26 a, a seal member 33 a that is in sliding contact with the outer peripheral surface of the small diameter cylindrical portion 23 b is attached to the bottom wall portion 22 a of the cylinder 22, and the outer periphery of the intermediate piston 27 is A first seal member 34 slidably in contact with the inner peripheral surface of the cylinder chamber 24 is mounted on the axial end of the first pressure chamber 26a side of the first piston 25a, and the first pressure chamber 26a on the inner peripheral portion of the intermediate piston 27 is attached. A first seal member 35 that is in sliding contact with the outer peripheral surface of the small-diameter cylindrical portion 23b is attached to the axial end portion on the side. Further, in order to prevent leakage of the hydraulic pressure supplied to the second pressure chamber 26b, a seal member 33b slidably contacting the inner peripheral surface of the cylinder chamber 24 is attached to the outer peripheral portion of the large-diameter cylindrical portion 23a of the piston. A second seal member 36 slidably in contact with the inner peripheral surface of the cylinder chamber 24 is attached to the axial end of the outer peripheral portion of the intermediate piston 27 on the second pressure chamber 26 b side. A second seal member 37 slidably in contact with the outer peripheral surface of the small-diameter cylindrical portion 23b is attached to the axial end of the second pressure chamber 26b.

  As described above, in the hydraulic nut 21, different seal members are attached to the intermediate piston 27 for the first pressure chamber 26 a side and the second pressure chamber 26 b side. That is, the first pressure chamber 26a and the second pressure chamber 26b are kept airtight by separate seal members, and even if one of the pressure chambers leaks hydraulic pressure, The chamber is not caused to leak hydraulic pressure.

  As shown in FIG. 2, a lock ring 41 is mounted on the outer peripheral portion of the piston 23 in order to support the axial force of the bolt 15 applied to the piston 23. The lock ring 41 is formed in an annular shape from a steel material, and as shown in FIG. 3, a female thread portion 41a is formed on the inner peripheral surface thereof, and the lock ring 41 has a large diameter of the piston 23 at the female thread portion 41a. It is screwed to a male screw portion 23c formed on the outer peripheral portion of the cylindrical portion 23a. Therefore, the lock ring 41 can be moved in the axial direction with respect to the piston 23 by rotating the lock ring 41. Further, the axial end surface (lower end surface in FIG. 3) perpendicular to the axial direction of the lock ring 41 is a load support surface 41b, and this load support surface 41b is located on the opening side of the side wall portion 22b of the cylinder 22. It faces the axial end face 22e. Then, by rotating the lock ring 41 in the circumferential direction, the load support surface 41b of the lock ring 41 and the axial end surface 22e of the cylinder 22 can be brought into contact with each other.

  Next, the operation of such a hydraulic nut will be described.

  First, as shown in FIG. 3, the hydraulic nut 21 is arranged so that the cylinder 22 is arranged in the upper case 13, and the screw portion 15 a of the bolt 15 inserted through the through hole 22 d is screwed into the screw hole 25 of the piston 23. Combine. At this time, no hydraulic pressure is supplied to the first pressure chamber 26 a and the second pressure chamber 26 b, and the piston 23 is close to the cylinder 22.

  Next, a hydraulic pump (not shown) is connected to the second oil supply port 32, and hydraulic oil is supplied from the second oil supply port 32 to the inside of the second pressure chamber 26b with a predetermined pressure by the hydraulic pump. In this case, the hydraulic pressure supplied to the second pressure chamber 26b is, for example, an ultra-high pressure of about 250 Mpa. When the hydraulic pressure is supplied, the piston 23 moves in a direction to increase the volume of the second pressure chamber 26b, that is, in a direction away from the cylinder 22, and the bolt 15 screwed to the piston 23 is screwed as shown in FIG. The part 15a moves in the axial direction together with the piston 23, and a tensile force is applied, and the bolt 15 extends in the axial direction by this tensile force. At this time, the lock ring 41 moves together with the piston 23 and moves to a position where a gap L is generated between the load support surface 41b and the axial end surface 22e of the cylinder 22 as shown by a one-dot chain line in FIG. .

  Next, the lock ring 41 is rotated and moved to a position where the load support surface 21b abuts on the axial end surface 22e of the cylinder 22 (a position indicated by a solid line in FIG. 4). The supply of hydraulic pressure to 26b is stopped. When the supply of hydraulic pressure is stopped, the hydraulic pressure in the second pressure chamber 26b decreases, and an axial force due to the elastic force of the bolt 15, that is, a load approaching the cylinder 22, is applied to the piston 23. Since the load support surface 41b of the lock ring 41 is in contact with the axial end surface 22e of the cylinder, the axial force of the bolt 15 is supported by the lock ring 41, that is, the cylinder 22 via the piston 23, toward the cylinder 22 side of the piston 23. Movement is restricted. Thereby, even after the hydraulic pressure is released, the bolt 15 is maintained in a state where an axial force is generated, and the fastening surface 22c of the hydraulic nut 21 strongly contacts the flange 13a due to the axial force of the bolt 15, and the turbine case 12 is strong. To be concluded.

  On the other hand, for example, when the hydraulic nut 21 is removed from the bolt 15 and the fastening of the turbine case 12 is released in order to perform maintenance or inspection of the gas turbine 11, the second oil supply port 32 is used to loosen the lock ring 41. The specified hydraulic pressure is supplied again to the second pressure chamber 26b. That is, the specified oil pressure is supplied again from the second oil supply port 32 to the second pressure chamber 26b, and the piston 23 is operated in the axial direction until the lock ring 41 is separated from the axial end surface 22e of the cylinder 22, and in that state the lock is performed. By releasing the hydraulic pressure while the ring 41 is sufficiently loosened and the lock ring 41 is sufficiently loosened, the axial force of the bolt 15 is released and the hydraulic nut 21 is removed from the bolt 15.

  FIG. 5 is a cross-sectional view showing a usage state of the hydraulic nut when the hydraulic pressure is supplied from the first oil supply port. In the hydraulic nut 21, the hydraulic pressure is supplied from the first oil supply port 31 instead of the second oil supply port 32. Also, the piston 23 can be operated in the axial direction. As shown in FIG. 5, when hydraulic pressure is supplied from the first oil supply port 31 to the inside of the first pressure chamber 26a, the intermediate piston 27 reduces the volume of the second pressure chamber 26b by the hydraulic pressure, and the first pressure chamber 26a. After the intermediate piston 27 comes into contact with the axial end surface of the piston 23, the piston 23 is operated in the axial direction by being pushed by the intermediate piston 27. Therefore, when the hydraulic pressure is supplied from the second oil supply port 32 to the second pressure chamber 26b in order to remove the hydraulic nut 21 from the bolt 15, the sealing member 33b for maintaining the airtightness of the second pressure chamber 26b, Even when 36 and 37 cannot withstand the high pressure and are damaged and the second pressure chamber 26b cannot be increased to a predetermined hydraulic pressure, the hydraulic pressure is supplied from the first oil supply port 31 to the first pressure chamber 26a. As a result, the piston 23 can be operated to apply a pulling force to the bolt 15. That is, in this hydraulic nut 21, the pressure chamber 26 is divided into two by the intermediate piston 27. Therefore, when one of the second pressure chambers 26b generates a hydraulic pressure leak, the first oil supply port 32 is used instead of the first oil supply port 32. The oil pressure can be supplied from the oil supply port 31 to the first pressure chamber 26a to operate the piston 23 in the axial direction.

  As described above, in the hydraulic nut 21, the piston 23 can be operated regardless of whether the hydraulic pressure is supplied from the first oil supply port 31 or the second oil supply port 32, so that the hydraulic pressure leaks from the second pressure chamber 26b. Even if this occurs, the piston 23 can be operated by supplying hydraulic pressure to the first pressure chamber 26a. Therefore, even if hydraulic pressure leaks from the pressure chamber 26, the fastening operation and the removing operation of the hydraulic nut 21 with the bolt 15 can be continued, thereby improving the working efficiency of the hydraulic nut 21. be able to. Further, even if the hydraulic nut 21 must be used urgently without replacing each seal member due to maintenance, in the unlikely event that a hydraulic leak occurs in the second pressure chamber 26b, the other Since the piston 23 can be operated by supplying hydraulic pressure to the pressure chamber 26a, it is possible to quickly perform work in an emergency. Further, even if hydraulic pressure leaks from the pressure chamber 26, it is not necessary to cut the lock ring 41, so that the work at the time of trouble avoidance is facilitated and the safety of the work is improved.

  The hydraulic nut 21 prevents the hydraulic pressure leakage from the first pressure members 26 and 35 and the first pressure members 26 b and the second pressure chamber 26 b to prevent the hydraulic pressure leakage from the first pressure chamber 26 a to the intermediate piston 27. Since the second seal members 36 and 37 are mounted, even if one of the first and second seal members is damaged and one of the pressure chambers leaks hydraulically, the other seal is sealed. The member can ensure the airtightness of the other pressure chamber. Therefore, the piston 23 can be reliably operated when the oil supply port is changed and the hydraulic pressure is supplied.

  FIG. 6 is a cross-sectional view showing details of a bolt tensioner according to another embodiment of the present invention. In FIG. 6, members corresponding to those described above are denoted by the same reference numerals.

  A bolt tensioner 51 as a liquid pressure device shown in FIG. 6 is for screw-connecting a nut 52 in a state where a tensile force is applied in advance to the bolt 15 for fastening the turbine case 12. In this state, the nut 52 is screwed to obtain a large fastening force.

  In the hydraulic nut 21 shown in FIG. 2, the piston 23 is actuated by the hydraulic pressure supplied to the pressure chamber 26 to apply a pulling force to the bolt 15, and the lock ring 41 is brought into contact with the cylinder 22 in this state, whereby the bolt 15 The axial force is supported by the lock ring 41 to maintain the bolt 15 in a state where the axial force is generated. In contrast, the bolt tensioner 51 has the same structure as that of the hydraulic nut 21 with respect to the structure for applying a pulling force to the bolt 15, but the lock ring 41 is not provided and the axial force of the bolt 15 is increased. It is different from the hydraulic nut 21 in that it is supported by the nut 52.

  Therefore, a cylindrical nut housing portion 53 is formed in the cylinder 22 of the bolt tensioner 51 on the flange 13a side of the pressure chamber 26. In the cylinder 22 of the bolt tensioner 51, the bolt 15 is placed inside the nut housing portion 53. It is arranged on the upper case 13 so as to be detachable. Note that a nut 52 is lightly screw-coupled to the bolt 15 in advance, and the nut 52 is disposed in the nut accommodating portion 53 together with the bolt 15.

  A window portion 54 is formed in the nut housing portion 53, and a nut 52 is tightened from the window portion 54. In order to facilitate the tightening operation of the nut 52, a nut adapter 55 is fitted into the nut 52. The nut adapter 55 has an engagement hole 55a on the outer peripheral surface and is inserted from the window portion 54. By engaging the handle 56 with the engagement hole 55a and operating the handle 56, the nut 52 can be turned.

  The procedure of the fastening operation by such a bolt tensioner 51 will be described. First, the bolt tensioner 51 is disposed on the bolt 15 to which the nut 52 is lightly screw-connected, and the bolt 15 is screw-connected to the screw hole 25 of the piston 23. . Next, the hydraulic pressure is supplied from the second oil supply port 32, the hydraulic pressure in the second pressure chamber 26 b is increased, the piston 23 is moved away from the cylinder 22, and a tensile force is applied to the bolt 15. When a tensile force is applied, the bolt 15 extends in the axial direction, and the nut 52 moves together with the bolt 15 in a direction away from the flange 13a of the upper case 13, so that a gap is formed between the nut 52 and the upper case 13. In this state, since the nut 52 can be freely rotated, the handle 56 is inserted from the window portion 54 and the nut 52 is fastened to the upper case 13 again to bring the upper case 13 and the nut 52 into contact with each other. When the hydraulic pressure supplied to the second pressure chamber 26b is discharged from this state, the bolt 15 contracts in the axial direction, so that the nut 52 is fastened to the bolt 15 in a state where the axial force is applied. The nut 52 strongly contacts the upper case 13 by the axial force of the bolt 15, and loosening of the fastening is prevented. When the fastening operation between the nut 52 and the bolt 15 is completed, the bolt tensioner 51 is removed from the upper case 13, and the placement location is moved for the subsequent fastening operation between the bolt 15 and the nut 52.

  Also in such a bolt tensioner 51, the pressure chamber 26 defined by the cylinder 22 and the piston 23 is divided into two in the axial direction by the intermediate piston 27, and the hydraulic pressure supplied from the second oil supply port 32 is the second. Even when leaking from the pressure chamber 26b, the hydraulic pressure is supplied from the first oil supply port 31 formed in the cylinder 22 to increase the pressure in the first pressure chamber 26a to operate the piston 23 and to tighten the nut 52. Alternatively, removal work can be performed. Therefore, even if the second pressure chamber 26b leaks during the fastening operation of a large number of bolts 15, the operation can be continued by supplying the hydraulic pressure from the first oil supply port 31, so that another bolt There is no need to interrupt the work to prepare the tensioner, and the workability is improved. In this case, maintenance such as replacement of the seal member is performed after the work is completed.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the present embodiment, the hydraulic nut 21 is used for assembling the turbine case 12. However, the present invention is not limited to this, and the hydraulic nut 21 may be used for fastening other members to be fastened.

  In the present embodiment, hydraulic pressure is supplied to the pressure chamber 26. However, the pressure chamber 26 is not limited to this, and any other liquid may be used as long as it is incompressible and fluid, such as water. Liquid pressure may be supplied.

  Further, in the present embodiment, the first oil pressure is mainly supplied from the second oil supply port 32 to the second pressure chamber 26b to operate the piston 23, and when the second pressure chamber 26b causes a hydraulic leak, the first pressure is supplied. Although the hydraulic pressure is supplied from the fuel filler port 31 to the first pressure chamber 26a, the present invention is not limited to this, and the first fuel filler port 31 is mainly used and the second fuel filler port 32 is used as a spare. Good.

  Furthermore, in the present embodiment, the cylinder 22 is provided as the first load receiving member, and the piston 23 is provided as the second load receiving member. However, the present invention is not limited to this, and the first load receiving member A piston portion may be provided, and a cylinder portion may be provided on the second load receiving member.

  Furthermore, in the present embodiment, the lock ring 41 is mounted on the outer peripheral surface of the piston 23, but the present invention is not limited thereto, and the lock ring 41 may be mounted on the outer peripheral surface of the cylinder 22. In this case, the piston 23 is formed with an axial end surface that can come into contact with the load support surface 41 b of the lock ring 41.

  The present invention can be applied when a strong fastening structure is required, such as assembling a turbine case of a steam turbine or a gas turbine used in a power plant such as a power plant.

Claims (3)

A fluid pressure device that is screw-coupled in a state in which a tensile force is applied to a bolt inserted through an insertion hole of a member to be fastened,
A first load receiving member disposed on the fastened member;
A second load receiving member that includes a screw hole that is screw-coupled to the bolt, and is assembled to the first load receiving member so as to be movable in the axial direction, and defines a pressure chamber by the first load receiving member; ,
An intermediate piston, which is assembled in the pressure chamber so as to be movable in the axial direction, and divides the pressure chamber into a first pressure chamber and a second pressure chamber;
A first liquid pressure supply port formed in the first load receiving member for supplying liquid pressure to the first pressure chamber;
A second liquid pressure supply port formed in the second load receiving member for supplying liquid pressure to the second pressure chamber;
Screwed to the outer periphery of one of the first and second load receiving members and supports the axial force of the bolt in contact with the other axial end surface of the first and second load receiving members And a locking ring
2. The liquid pressure device according to claim 1, wherein the second load receiving member can be operated even when liquid pressure is supplied from any of the first and second liquid pressure supply ports. A fluid pressure device that screw-couples a nut in a state in which a tensile force is applied in advance to a bolt inserted through an insertion hole of a fastened member,
A first load receiving member that is detachably disposed on the fastened member;
A second load that includes a screw hole that is detachably coupled to the bolt, and is assembled to the first load receiving member so as to be movable in the axial direction, thereby defining a pressure chamber by the first load receiving member; A receiving member;
An intermediate piston, which is assembled in the pressure chamber so as to be movable in the axial direction, and divides the pressure chamber into a first pressure chamber and a second pressure chamber;
A first liquid pressure supply port formed in the first load receiving member for guiding the liquid pressure to the first pressure chamber;
A second liquid pressure supply port that is formed in the second load receiving member and guides the liquid pressure to the second pressure chamber;
2. The liquid pressure device according to claim 1, wherein the second load receiving member can be operated even when liquid pressure is supplied from any of the first and second liquid pressure supply ports.   3. The liquid pressure device according to claim 1, wherein a first seal member for preventing leakage of liquid pressure from the first pressure chamber and a second for preventing leakage of liquid pressure from the second pressure chamber are provided. A liquid pressure device comprising: a sealing member attached to the intermediate piston.

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