JPH11294421A - Hydraulic bolt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily operate a nut with small force by fitting nuts for closing a through hole on both ends of a bolt shaft part having the through hole in the lengthwise direction, providing a lubricant port communicated to the through hole on one end nut, and mounting a fastening nut threadedly engaged with the bolt shaft part between the two nuts. SOLUTION: A bolt shaft part 2 is inserted through the bolt hole of a flange F, a fastening nut 5 is threadely fitted to the bolt shaft part 2, and nuts 3, 4 are fitted to both ends of the bolt shaft part 2. When high hydraulic pressure is applied to the through hole 20 from the lubricant port 30 of one nut 3, the bolt shaft part 2 is extended in the lengthwise direction by the hydraulic pressure. Then the fastening nut 5 is lightly fastened to closely fit the fastening nut 5 and the nut 4 to be a blank cap to flange F. When the hydraulic pressure is returned to zero, the bolt shaft part 2 is contracted to return to the original state, and the flange F is strongly fastened by the fastening nut 5 and the nut 4 to be flank cap.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object to be fastened by tightening a nut for tightening after applying a hydraulic pressure to extend a bolt shaft, releasing the hydraulic pressure and returning the bolt shaft to its original length. The present invention relates to a hydraulic bolt capable of strongly fastening (tightening).

[0002]

2. Description of the Related Art A combination of a bolt and a nut is used for tightening an object to be fastened. In particular, when an object to be fastened is used, for example, when it is used for mounting an engine of a large ship, or when it is used for mounting a casing of a high-pressure steam turbine or the like, a high-torque fastening is required.

The following means are used for conventional nut tightening. That is, a spanner or a torque wrench is used for a small bolt, and a bolt tensioner is used for a large bolt. Further, as a device in which the bolt itself is devised, there is a device in which a heating wire is mounted in the bolt, and the nut can be further tightened by using thermal expansion.

[0004]

In the above-mentioned small type, the frictional resistance of the nut contact surface is a major obstacle,
Due to the roughness of the contact surface, the magnitude of the torque varies, and a large force is required to securely tighten the nut with a spanner or a torque wrench. For the bolt tensioner, a large bolt is extended and the nut is further tightened.However, a large hollow hydraulic jack is required, which requires a lot of labor and labor.
The problem is the high cost. Further, when a heating wire is mounted in the bolt, the bolt itself is heated, and thus there is a problem in that the operation involves danger.

The present invention solves such a problem, and provides a bolt which can operate the nut easily with a small force and at a low cost.

[0006]

According to a first aspect of the present invention, there is provided a hydraulic bolt, wherein nuts for sealing the through hole are attached to both ends of a bolt shaft having a through hole in a longitudinal direction. Is formed as a cylinder, one of the nuts is provided with a lubrication port communicating with the cylinder, and a tightening nut screwed to the bolt shaft is mounted between the two nuts. One of the nuts at both ends is a so-called blind plug and the other is a lubrication port.

First, this hydraulic bolt is separated from each component. Next, a bolt shaft portion is attached to the workpiece, a tightening nut is attached to the bolt shaft portion, nuts are attached to both ends of the bolt shaft portion, and high pressure oil pressure is applied from a lubrication port of one of the nuts. Bolt shaft longitudinal direction (axial direction) by hydraulic pressure
To stretch. Then, the tightening nut is lightly tightened so that the nut, which is the blind plug, is brought into close contact with the workpiece. Then, when the oil pressure is returned to zero, the bolt shaft portion contracts and returns to the original position, and the object to be fastened is strongly tightened by the tightening nut and the nut serving as the blind plug. In order to release the tightening of the work, the high pressure oil pressure is applied from the lubrication port of the nut to expand the bolt shaft, and in this state, the tightening nut is loosened and the oil pressure is returned to zero.

In the hydraulic bolt according to the second aspect of the present invention, a cylinder is formed by hollowing out a bolt shaft portion having a bolt head from a tip end thereof in a longitudinal direction without penetrating the cylinder, and attaching the cylinder to a tip end of the bolt shaft portion. A nut for sealing is provided, an oil supply port is provided in the nut to communicate with the cylinder, and a tightening nut screwed to the bolt shaft is mounted between the nut and the bolt head.

In the bolt according to the first aspect of the present invention, a nut as a so-called blind plug is attached to one end of a pipe-shaped bolt shaft having a through hole in a longitudinal direction, and a cylinder is formed in the bolt shaft. On the other hand, the bolt according to the second aspect of the present invention is formed by hollowing out a bolt shaft portion having a bolt head from a tip portion thereof in a longitudinal direction without penetrating the bolt shaft portion. That is, both have substantially the same structure. Therefore, the nut having the lubrication port and the tightening nut are removed from the bolt shaft having the bolt head, the bolt shaft having the bolt head is mounted on the object to be fastened, and the tightening nut is mounted on the bolt shaft and the lubrication hole is mounted. After installing a nut having a nut, apply high-pressure oil pressure from the lubrication port of this nut, lightly tighten the tightening nut, and bring the tightening nut and the bolt head into close contact with the workpiece, and then return the oil pressure to zero. To operate.

A hydraulic bolt according to a third aspect of the present invention is the hydraulic bolt according to the first or second aspect, wherein the tightening nut is slidably provided with respect to the bolt shaft, instead of being screwed. A wedge is mounted between the tightening nut and the bolt shaft portion in a direction toward a workpiece. That is, the bolt shaft is only threaded at both ends.

When high pressure oil pressure is applied from the lubrication port of the nut, the oil pressure causes the bolt shaft to move in the longitudinal direction (axial direction).
To stretch. Then, the tightening nut is lightly pushed in the direction of the object to be fastened, and the tightening nut and the nut serving as the blind plug are brought into close contact with the object to be fastened in the hydraulic bolt of claim 1, and the tightening nut and the nut are tightened with the hydraulic bolt of claim 2 When the hydraulic pressure is returned to zero after the bolt head is brought into close contact with the workpiece, the bolt shaft contracts and returns to the original position.At this time, the wedge is moved between the tightening nut and the bolt shaft. As a result, the object to be fastened is strongly tightened. To release the tightening of the work, the high pressure oil is applied from the lubrication port of the nut to extend the bolt shaft, and in this state, the wedge is pulled in the direction opposite to the work to be tightened. The oil pressure can be returned to zero after releasing the nut. The fastening nut is slidably provided instead of screwed to the bolt shaft part.
This is because it is necessary to allow the wedge to slide on the surface of the bolt shaft.

A hydraulic bolt according to a fourth aspect of the present invention is the hydraulic bolt according to the third aspect, wherein a piston for urging the wedge in a direction opposite to the direction of the workpiece is inserted into the tightening nut. And a lubricating port communicating with the cylinder is provided.

[0013] When releasing the tightening of the workpiece, high pressure oil pressure is applied from the lubrication port of the nut to extend the bolt shaft, and in this state, the wedge is pulled in the direction opposite to the direction of the workpiece, thereby tightening. With this hydraulic bolt, the hydraulic bolt applies hydraulic pressure to the lubrication port of the tightening nut and pushes the piston, so that the piston causes the wedge to perform a required operation.

According to a fifth aspect of the present invention, there is provided a hydraulic bolt according to the first or second aspect, wherein the tightening nut is slidably provided with respect to the bolt shaft, instead of being screwed. A lock groove is formed in a side surface of the bolt shaft portion, and a slide rod of a solenoid is inserted into a through hole provided in the tightening nut toward the lock groove.

When a high oil pressure is applied from the oil inlet of the nut, the oil pressure causes the bolt shaft to expand in the longitudinal direction.
Therefore, when the tightening nut is lightly pushed in the direction of the workpiece, the slide rod of the tightening nut moves to the position of the lock groove on the side surface of the bolt shaft. After that, when the hydraulic pressure is returned to zero, the bolt shaft portion contracts and returns to the original position, and the workpiece is strongly tightened by the tightening nut locked by the slide rod. The number of lock grooves is not limited to one, and a plurality of lock grooves may be provided in the longitudinal direction (axial direction) of the bolt shaft portion. It is desirable that the hydraulic bolt according to the fifth aspect of the present invention be provided with a lock groove having a lock groove that matches the thickness of the workpiece.

A hydraulic bolt according to a sixth aspect of the present invention is the hydraulic bolt according to the first or second aspect, wherein the tightening nut is a split nut divided into a plurality of parts, and the split nut is provided around the bolt shaft. The split nut is detachably provided instead of being screwed, and a holding member is attached to the split nut.

When a high oil pressure is applied from the oil inlet of the nut, the oil pressure causes the bolt shaft to expand in the longitudinal direction.
Therefore, a split nut is mounted between the nut and the workpiece. Since the split nut is divided into a plurality of parts, the split nut can be mounted so as to surround the bolt shaft without passing through the bolt shaft. After that, fixing the split nut by fixing the split nut to the split nut and operating to return the oil pressure to zero, the bolt shaft part shrinks and tries to return to the original, and the split nut strongly tightens the workpiece Become. It should be noted that a split nut matching this dimension is used because of the relationship between the hydraulic pressure applied in advance and the extension distance of the bolt shaft.

[0018]

FIG. 1 shows a first embodiment of the present invention. The hydraulic bolt 1 is provided with nuts 3 and 4 for sealing the through holes at both ends of a pipe having a through hole in the longitudinal direction (axial direction) (to be a bolt shaft 2).
The through hole is formed as a cylinder 20. One of the nuts 3 is provided with a lubrication port 30 communicating with the cylinder 20, and a fastening nut 5 screwed to the bolt shaft portion 2 is mounted between the two nuts 3, 4. One of the nuts 3, 4 at both ends is a so-called blind plug, and the other nut 3 is a lubrication port. Screws are threaded on the outer peripheral portion of the bolt shaft portion 2 over the entire length, and nuts 3 and 4 are formed.
And the fastening nut 5 is screwed into this. An O-ring is mounted around the cylinder 20 as usual.

Prior to use, the nut shaft 3, the nut 3,
4 and / or one of them, and the fastening nut 5 are removed. Next, as shown in FIG. 1, the bolt shaft portion 2 is inserted into the bolt hole of the workpiece (here, the flange F),
After tightening the tightening nut 5 on the bolt shaft 2 and attaching the nuts 3 and 4 to both ends of the bolt shaft 2, when high pressure oil pressure is applied from the lubrication port 30 of one of the nuts 3,
This hydraulic pressure causes the bolt shaft 2 to extend in the longitudinal direction. Then, the fastening nut 5 is lightly tightened so that the fastening nut 5 and the nut 4 serving as the blind plug are brought into close contact with the flange F. Next, when the hydraulic pressure is returned to zero, the bolt shaft portion 2 contracts and returns to the original position, and the flange F is strongly tightened by the tightening nut 5 and the nut 4 serving as the blind plug. In order to release the tightening of the flange F, the lubrication port 30 of the nut 3 is again
Higher hydraulic pressure is applied to the cylinder 20 to increase the bolt shaft 2
May be extended, and in this state, the tightening nut 5 may be loosened, and then the oil pressure may be returned to zero.

FIG. 2 shows a second embodiment of the present invention. The hydraulic bolt 10 has a cylinder 61 formed by hollowing out a bolt shaft portion 60 having a bolt head 6 (that is, a so-called bolt) from a distal end portion of the bolt shaft portion 60 in the longitudinal direction without penetrating the bolt shaft portion. A nut 3 for sealing the cylinder 61 is attached to a tip of the cylinder 60,
The lubrication port 30 communicating with the cylinder 61 is connected to the nut 3.
And a fastening nut 5 screwed to the bolt shaft portion 60 is screwed between the nut 3 and the bolt head 6.

Therefore, first, the nut 3 having the lubrication port 30 and the tightening nut 5 are removed from the bolt shaft portion 60 having the bolt head 6 by turning, and the bolt shaft portion 60 having the bolt head 6 on the flange F in FIG. The nut 3 having the lubrication port 30 is attached after screwing the tightening nut 5 to the bolt shaft portion 60 and then applying high-pressure hydraulic pressure from the lubrication port 30 of the nut 3 to the cylinder 61 to tighten the nut. After the nut 5 is lightly tightened to bring the tightening nut 5 and the bolt head 6 into close contact with the flange F, an operation is performed to return the hydraulic pressure to zero.
It is also possible to provide an oil inlet on the bolt head 6 side, in which case the other nut side is a so-called blind plug.

FIG. 3 shows a third embodiment of the present invention. The hydraulic bolt 11 is characterized in that a nut 40 as a so-called blind plug is integrated with one end of the pipe (which constitutes the bolt shaft portion 2) in the first embodiment by welding, not by screwing. . Reference numeral 40 denotes a welded portion.

With this configuration, the nut 40 functions as a bolt head, and the bolt head and the shaft portion 2 form a so-called bolt. Note that, instead of the shaft portion 2 and the nut 40, the shaft portion 2 and the nut side having the lubrication port 30 may be integrated by welding.

FIG. 4 shows a tightening nut portion according to a fourth embodiment of the present invention. The hydraulic bolt 12 is provided with a thread at both ends of a pipe (formed as a bolt shaft portion 2) having a through hole in a longitudinal direction (axial direction), and nuts 3 and 4 for sealing the through hole. To form the through hole with the cylinder 20. One of the nuts 3 is provided with a lubrication port 30 communicating with the cylinder 20, and between the two nuts 3 and 4, a tightening nut 7 and a holding nut 70 that slide on the bolt shaft 2 are mounted. As shown in FIG. 4, a wedge 71 was mounted between the tightening nut 7 and the bolt shaft portion 2 in the direction of the workpiece. For this reason, the space in which the wedge 71 fits is naturally
It is provided on the side. The tightening nut 7 is formed with a cylinder 73 in which a piston 74 for urging the wedge 71 in a direction opposite to the direction of the object to be fastened is provided, and an oil inlet 75 communicating with the cylinder 73 is provided. . An O-ring is mounted around the cylinder 73 as usual.
The tip of the piston 74 is formed so as to be sharpened so as to protrude the notch 72 of the wedge 71. Screws are threaded on the outer peripheral portion of the tightening nut 7 and the inner peripheral portion of the holding nut 70 so that they are screwed together. In addition, the wedge 7 is always urged toward the object to be fastened.
A spring 76 for pressing 1 is provided inside the holding nut 70 at a position facing the wedge 71.

When a high-pressure oil pressure is applied to the cylinder 20 from the oil inlet 30 of the nut 3, the bolt shaft 2 is extended in the longitudinal direction by the oil pressure. Then, the presser nut 70 is lightly pushed in the direction of the object to be fastened, and the tightening nut 7 and the nut 4 serving as the blind plug are brought into close contact with the object to be fastened. At this time, the wedge 71 bites between the tightening nut 7 and the bolt shaft portion 2 and the tightening nut 7 is fixed, so that the object to be fastened is strongly tightened. . Next, to release the tightening of the workpiece,
By applying a hydraulic pressure higher than 0 to extend the bolt shaft portion 2 and applying a hydraulic pressure to the lubrication port 75 of the tightening nut 7 and pushing the piston 74 in this state, the distal end of the piston 74 becomes a notch of the wedge 71. By pushing the wedge 71 in the direction opposite to the direction of the object to be fastened, the wedge 71 is released to release the action of the wedge 71 and the tightening nut 7 is released. Thereafter, the two oil pressures may be returned to zero.

FIG. 5 shows a fifth embodiment of the present invention. This hydraulic bolt 13 is characterized in that a spring 77 is added to the above-described fourth embodiment. The spring 77 is placed between the holding nut 70 and the nut 3.

According to this configuration, the fastening and the releasing of the workpiece can be remotely controlled. That is, at the time of fastening, high pressure oil pressure is applied to the cylinder 20 from the oil inlet 30 of the nut 3, but the tightening nut 7 and the nut 4 serving as the blind plug come into close contact with the workpiece by the force of the spring 77.
Conversely, when the fastening is released, hydraulic pressure is applied to the lubrication port 75 of the tightening nut 7 to push the piston 74, so that the piston 74 pushes the wedge 71 in a direction opposite to the direction of the object to be fastened, thereby canceling the action of the wedge 71. These operate autonomously. Note that the tightening nut 7 and the nut 4 which is the blind plug are used.
It is conceivable to use a spring material other than the coil-shaped spring 77, a magnet, a combination of a cylinder and a piston, or the like in order to bring the member into close contact with the workpiece. According to the present embodiment, fastening and unfastening of an object to be fastened can be performed by remote control, which means that work can be performed safely and that a plurality of hydraulic bolts are operated simultaneously (simultaneously). It means you can do it. In addition, since the pressurization is performed at the same pressure, there is also an effect that the fastening management is easy and the dispersion hardly occurs.

FIG. 6 shows a sixth embodiment of the present invention. FIG. 6 illustrates the tightening nut 5 and the bolt shaft 2 of the hydraulic bolt 14, and only this portion will be described. In the range of the bolt shaft portion 2 on which the tightening nut 5 can act, no screw is threaded on the bolt shaft portion 2, and the tightening nut 5 is provided slidably with respect to the bolt shaft portion 2 at this position. Have been. A lock groove 21 is engraved on a side surface of the bolt shaft portion 2, and a solenoid 8 is inserted into a through hole 50 provided in the tightening nut 5 toward the lock groove 21.
Slide rod 80 was inserted. By energizing the solenoid 8, the slide rod 80 can be inserted into or removed from the lock groove 21.

When high pressure oil pressure is applied from the lubrication port 30 of the nut 3, the bolt shaft 2 is extended in the longitudinal direction by this oil pressure. Then, lightly push the tightening nut 5 toward the workpiece,
When the tightening nut 5 and the nut 4 serving as the blind plug are brought into close contact with the workpiece, the slide rod 80 of the tightening nut 5 moves to the position of the lock groove 21 on the side surface of the bolt shaft 2. Here, when the solenoid 8 is energized so that the slide rod 80 is fitted into the lock groove 21 and the hydraulic pressure is returned to zero, the bolt shaft 2 contracts and returns to the original position.
The object to be fastened is strongly tightened by the tightening nut 5 locked by the slide rod 80. In order to release the tightening of the workpiece, the lubrication port 30 of the nut 3 is used.
When the bolt shaft 2 is extended by applying a higher oil pressure,
Since the lock groove 21 comes to a position where the slide rod 80 can be easily extracted from the lock groove 21, the slide rod 80 may be extracted from the lock groove 21 by operating the solenoid 8.

Next, FIGS. 7 and 8 show a seventh embodiment of the present invention. This hydraulic bolt 15 is in the longitudinal direction (axial direction).
Nuts 3 and 4 for sealing the through-hole are attached to both ends of a bolt shaft portion 2 having a through-hole, and the through-hole is formed as a cylinder 20.
In addition, an oil inlet 30 communicating with the cylinder 20 is provided, a split nut 9 divided into two is mounted between the two nuts 3 and 4, and a ring 90 as a presser is mounted on the split nut. The split nut 9
The outer diameter of the nut 9 is made to match the outer diameter of the nut 3 when the nut is mounted on the bolt shaft 2, and the inner diameter of the ring 90 is the outer diameter of the nut 3, that is, the split diameter when the nut is mounted on the bolt shaft 2. The outer diameter of the nut 9 is matched. As long as this relationship is satisfied, a screw may or may not be cut in the bolt shaft portion 2 at this portion.

Therefore, first, the ring 90 is moved around the nut 3, high-pressure oil pressure is applied to the cylinder 61 from the lubrication port 30 of the nut 3, and when the bolt shaft portion 2 is extended by a predetermined length, the bolt shaft portion 2 A split nut 9 is mounted around the split nut 9 (see FIG. 8), and a ring 90 is attached to the split nut 9.
Is displaced from the nut 3 and mounted (at this time, the split nut 9 and the nut 4 come into close contact with the flange F), and thereafter, the hydraulic pressure is returned to zero. Split nuts do not loosen due to vibration. Although the split nut 9 used here is a two-part nut, it may be a three-part, four-part nut or the like. In addition to the ring 90, a spring pinch or the like can be used for the holding member.

FIG. 9 shows an eighth embodiment of the present invention. In this embodiment, the split nut 91 has a stepped portion 92.
The axial length of the step portion 92 is larger than the axial length of the ring 90.

In the above-described seventh embodiment, the ring 90 is moved around the nut 3. However, in the eighth embodiment, this is not necessary.
You just have to play around. Because split nut 91
When attaching to the ring 90, the step portion 92 of the split nut 91 is used.
The reason is that the ring 90 may be removed by using. After that, the ring 90 is shifted from the step portion 92 and attached to the split nut 91. As a result, the outer diameter of the split nut 91 is not affected by the outer diameter of the nut 3.

In the present invention, the components of the above embodiments can be used in other embodiments as needed. For example, with respect to the invention of claim 2, a configuration in which an oil inlet is provided on the bolt head side is also possible.
This is also the scope of the present invention. In the fourth embodiment described above, the spring 76 for pressing the wedge 71 is provided inside the holding nut 70 at a position facing the wedge 71.
A configuration that does not require the spring 76 is also possible. In this case, the holding nut 70 is not required. This is because when a high pressure oil pressure is applied to the cylinder 20 from the lubrication port 30 of the nut 3 and the bolt shaft 2 is extended, the wedge 7 is manually moved.
1 is pulled in the direction opposite to the direction of the object to be fastened, so that the tightening nut 7 can be released. This configuration is also effective for those that are not operated remotely as described above.

[0035]

As described above, the hydraulic bolt of the present invention has a cylinder provided in the bolt shaft. The high pressure oil pressure is applied to the cylinder from the oil inlet to extend the bolt shaft in the longitudinal direction, and the nut is lightly covered. It is possible to strongly tighten the object to be fastened only by operating the oil pressure to return to zero after hitting the object.

Therefore, the present invention has an effect that the nut can be easily operated with a small force and the operation is low cost.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view illustrating a first embodiment.

FIG. 2 is a partial cross-sectional view illustrating a second embodiment.

FIG. 3 is a partial sectional view showing a third embodiment.

FIG. 4 is a partial sectional view showing a fourth embodiment.

FIG. 5 is a partial sectional view showing a fifth embodiment.

FIG. 6 is a partial sectional view showing a sixth embodiment.

FIG. 7 is a partial sectional view illustrating a seventh embodiment.

FIG. 8 is a partial plan view showing a seventh embodiment.

FIG. 8 is a partial sectional view showing an eighth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic bolt 10 Hydraulic bolt 11 Hydraulic bolt 12 Hydraulic bolt 13 Hydraulic bolt 14 Hydraulic bolt 15 Hydraulic bolt 16 Hydraulic bolt 2 Pipe 20 Cylinder 21 Lock groove 3 Nut 30 Lubrication port 4 Nut 40 Nut 41 Welding part 5 Tightening nut 50 Through hole 6 Bolt Head 60 Bolt Shaft 61 Cylinder 7 Tightening Nut 70 Holding Nut 71 Wedge 72 Notch 73 Cylinder 74 Piston 75 Oil Filling Port 76 Spring 77 Spring 8 Solenoid 80 Slide Rod 9 Split Nut 90 Pressing Ring 91 Split Nut 92 Step

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[Procedure amendment]

[Submission date] August 5, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view illustrating a first embodiment.

FIG. 2 is a partial cross-sectional view illustrating a second embodiment.

FIG. 3 is a partial sectional view showing a third embodiment.

FIG. 4 is a partial sectional view showing a fourth embodiment.

FIG. 5 is a partial sectional view showing a fifth embodiment.

FIG. 6 is a partial sectional view showing a sixth embodiment.

FIG. 7 is a partial sectional view illustrating a seventh embodiment.

FIG. 8 is a partial plan view showing a seventh embodiment.

FIG. 9 is a partial sectional view showing an eighth embodiment.

[Description of Signs] 1 Hydraulic Bolt 10 Hydraulic Bolt 11 Hydraulic Bolt 12 Hydraulic Bolt 13 Hydraulic Bolt 14 Hydraulic Bolt 15 Hydraulic Bolt 16 Hydraulic Bolt 2 Pipe 20 Cylinder 21 Lock Groove 3 Nut 30 Lubrication Hole 4 Nut 40 Nut 41 Welding Part 5 Tightening Nut 50 Through hole 6 Bolt head 60 Bolt shaft 61 Cylinder 7 Tightening nut 70 Holding nut 71 Wedge 72 Notch 73 Cylinder 74 Piston 75 Lubrication port 76 Spring 77 Spring 8 Solenoid 80 Slide rod 9 Split nut 90 Press ring 91 Split Nut 92 Step

Claims (6)

[Claims] 1. A nut for sealing the through hole is attached to both ends of a bolt shaft portion having a through hole in a longitudinal direction, the through hole is formed as a cylinder, and lubrication is performed by passing one nut through the cylinder. A hydraulic bolt having an opening and a fastening nut screwed into the bolt shaft between the two heads. 2. A cylinder is formed by hollowing out a bolt shaft portion having a bolt head from a tip portion thereof in a longitudinal direction without penetrating, and a nut for sealing the cylinder is attached to a tip portion of the bolt shaft portion. A hydraulic bolt comprising: a nut provided with a lubrication port communicating with the cylinder; and a fastening nut screwed into the bolt shaft portion between the nut and a bolt head. 3. The fastening nut is slidably provided on the bolt shaft portion instead of being screwed, and a wedge is mounted between the fastening nut and the bolt shaft portion in the direction of a workpiece. The hydraulic bolt according to claim 1, wherein the hydraulic bolt is provided. 4. A cylinder in which a piston for urging the wedge in a direction opposite to the direction of an object to be fastened is formed in the tightening nut, and a lubrication port communicating with the cylinder is provided. The hydraulic bolt according to claim 3, wherein 5. The fastening nut is slidably provided with respect to the bolt shaft portion instead of being screwed, and a lock groove is formed on a side surface of the bolt shaft portion, and the tightening nut is directed toward the lock groove. 3. The hydraulic bolt according to claim 1, wherein a slide rod of a solenoid is inserted into a through hole provided in the attached nut. 6. A split nut in which the tightening nut is divided into a plurality of parts. The split nut is detachably provided around the bolt shaft, not by screwing, and a holding member is attached to the split nut. The hydraulic bolt according to claim 1, wherein the hydraulic bolt is formed by: