JPH11216625A - Hydraulic bolt fastening device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a time necessary for bolt fastening work. SOLUTION: A bolt 3 is provided with an upper half screw part 30 corresponding to an upper half flange 1, a lower half screw part 32 corresponding to a lower half flange 2 and an extended part 36 extended from the upper half screw part 30 and having a tip screw part 34 formed on its tip side. Upper and lower half nuts 20 and 22 and a tension nut 24 are engaged with the screw parts 30, 32 and 34 of the bolt 3. Between the upper half nut 20 and the tension nut 24, plural stages of hydraulic parts 4 and 4' stacked on each other are provided. The hydraulic parts 4 and 4' are fitted with play in the bolt 3 and elongated/contacted in the axial direction of the bolt 3 by hydraulic pressure. Between the hydraulic part 4' and the upper half flange 1, a base member 5 is interposed. Thus, since the hydraulic parts 4 and 4' are reduced in diameter, a plurality of bolts close to each other are simultaneously fastened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bolt tightening device for tightening a pair of flanges with bolts, and more particularly to a hydraulic bolt tightening device for tightening bolts in a state where the bolts are stretched by hydraulic pressure.

[0002]

2. Description of the Related Art Generally, in a casing divided into two such as a steam turbine, flanges provided on each casing are fastened by a large number of bolts.
Then, in order to prevent leakage of high-pressure steam or the like from the inside of the casing, once tightened bolts are stretched and then tightened again, so that the pair of flanges are strongly tightened by the bolts. In this case, as a means for extending the bolt, a method of heating by inserting a heater into the center hole of the bolt was generally used. However, there is a problem that the bolt material is deteriorated by heating and a long time is required for cooling. For this reason, a method of extending a bolt by hydraulic pressure has recently been used.

Here, FIG. 10 shows a conventional example of a hydraulic bolt tightening device for extending a bolt by hydraulic pressure.
In FIG. 10, the bolt tightening device includes a pair of flanges 10 having bolt holes 101a and 102a corresponding to each other.
1 and 102 are connected to the bolt holes 101a and 102
It is configured to be tightened by a bolt 103 penetrating through a. The bolt 103 is connected to the upper half flange 10.
1 and the lower half flange 102
And a lower half threaded portion 132 corresponding to. And
An upper half nut 120 and a lower half nut 122 are screwed into the upper half screw portion 130 and the lower half screw portion 132 of the bolt 103, respectively.

[0004] A hydraulic portion 104 composed of a combination of a puller 150 and a base 160 is attached to the upper half screw portion 130 of the bolt 103. This hydraulic unit 10
The fourth puller 150 is screwed into the upper half screw portion 130 of the bolt 103 above the upper half nut 120. The bottom of the base 160 is in contact with the upper flange 101 outside the upper nut 120. The hydraulic pump P is connected to the base 160 via the hydraulic pipe 7. The puller 150 is configured to be pushed up against the base 160 by the hydraulic pressure supplied from the hydraulic pump P.

When a bolt is tightened by such a bolt tightening device, first, the upper half nut 120 and the lower half nut 122 are temporarily tightened. Next, hydraulic pressure is supplied from the hydraulic pump P to the hydraulic part 104, and the puller 150 is pushed up against the base 160, so that the bolt 1
03 is extended in the axial direction by a predetermined amount (see a two-dot chain line in FIG. 10). At this time, the upper half nut 120 and the upper half flange 10
A gap corresponding to the extension of the bolt 103 is formed between the upper nut 120 and the upper nut 120 until the gap disappears. Next, the tightening is completed by lowering the hydraulic pressure supplied from the hydraulic pump P to zero.

Here, in the above-described tightening operation, the elongation of the bolt 103 is measured, and it is confirmed whether or not the elongation has reached the elongation (target elongation value) corresponding to the target tightening force. There is a need to. And bolt 10
Conventionally, as means for measuring the elongation of FIG.
Measurement means as shown in FIG.

First, FIG. 11 shows a mechanical extensometer 60 having a bar-shaped portion 62 inserted into a center hole 136 of a bolt 103. In the mechanical extensometer 60, the tip of the rod-shaped portion 62 abuts a step 136 a formed on the bottom side of the center hole 136 of the bolt 103, and the length of the bolt 103 is mechanically determined based on the abutting portion. It is configured to perform measurement in a targeted manner. Then, before and after the hydraulic pressure is supplied to the hydraulic part 104, the bolt 10 by the mechanical extensometer 60 is used.
3 and measure the length of the bolt 103 from the difference in length.
Are looking for growth.

Next, FIG. 12 shows an ultrasonic extensometer 70 having an ultrasonic transceiver 72. The ultrasonic extensometer 70 can measure the elongation of the bolt 103 based on the time that the ultrasonic wave transmitted from the ultrasonic transceiver 72 reciprocates inside the bolt 103. Also,
FIG. 13 shows a laser extensometer 80 having a laser transceiver 82. This laser extensometer 80
In the center hole 136 of the bolt 103, the laser beam transmitted from the laser
The elongation of the bolt 103 can be measured based on the time from when the light is reflected by the reflector 84 provided on the opposite side to the laser 36 and returns to the laser transceiver 82 again.

[0009]

The hydraulic bolt tightening apparatus as described above has the following problems. That is, since the hydraulic unit 104 composed of the puller 150 and the base 160 is a single unit (one-stage configuration), the hydraulic pressure supplied to the hydraulic unit 104 needs to be relatively high in order to sufficiently extend the bolt 103. is there. For this reason, in view of strength, the outer diameter of the hydraulic portion 104 must be increased. The puller 150 of the hydraulic unit 104 is
Of the hydraulic part 10 because it is screwed into the upper half screw part 130 and pulls the bolt 103 directly.
4 increases the outer diameter.

[0010] Since the outer diameter of the hydraulic portion 104 is increased in this way, when the bolts are adjacent to each other and adjacent to each other as in a casing of a steam turbine or the like, such an adjacent portion is not used. It becomes difficult to simultaneously perform the tightening operation by the bolt tightening device for the matching bolt. In addition, the puller 150 of the hydraulic unit 104 becomes a large heavy component in order to fulfill the role described above,
The workability of assembling is deteriorated. For this reason, there is a problem that the time required for the bolt tightening operation becomes long.

Further, in the tightening operation, the hydraulic unit 104
If the elongation of the bolt 103 due to the deviation from the target value,
It is necessary to reset the magnitude of the hydraulic pressure supplied from the hydraulic pump P to the hydraulic section 104 so that the elongation of the bolt 103 becomes the target value, and repeat the tightening work. However, conventionally, since the setting of the hydraulic pressure is manually performed and manually performed, it takes a long time to set the hydraulic pressure. For this reason,
The time required for the bolt tightening operation is further increased.

The present invention has been made in view of the above points, and has as its object to provide a hydraulic bolt tightening device capable of shortening the time required for bolt tightening work.

[0013]

A first means is a bolt tightening apparatus for tightening a pair of flanges having corresponding bolt holes with bolts penetrating the bolt holes, wherein the bolts are: One side threaded portion corresponding to the one side flange, another side threaded portion corresponding to the other side flange, and an extension portion extending from the one side threaded portion and having a tip threaded portion formed at the tip side thereof. One side nut, the other side nut and the tension nut, each of which is screwed to the one side thread portion, the other side thread portion and the distal end thread portion of the bolt, between the one side nut and the tension nut. A plurality of hydraulic parts which are loosely fitted to the bolts, stacked on each other, and which can be expanded and contracted in the axial direction of the bolts by hydraulic pressure, respectively; Oite a device with hydraulic bolt, characterized in that a base member which is interposed between the plurality of hydraulic unit and the one side of the flange.

According to the first means, when tightening the pair of flanges, first, the one-side nut, the other-side nut and the tension nut are temporarily tightened. Next, the bolts are extended in the axial direction by a predetermined amount via the tension nuts by extending the plurality of hydraulic units by hydraulic pressure. Next, after tightening the one-side nut by the bolt extension, the hydraulic pressures of the plurality of hydraulic units are released, and the tightening is completed.

According to such means, since the plurality of hydraulic units are stacked on each other, the diameter of each hydraulic unit can be reduced as compared with the case where the hydraulic unit is solely used. Also, since each hydraulic part is loosely fitted to the bolt and configured to extend the bolt via the tension nut, compared to a configuration in which the bolt is directly extended by the hydraulic part screwed to the bolt, Each hydraulic section can be further reduced in diameter.

The second means is the first means, wherein the hydraulic part of the plurality of hydraulic parts that contacts the base member and the base member are formed into spherical shapes whose contact surfaces correspond to each other. It was formed.

According to the second means, in the first means, even if the bolt is mounted with the axis line inclined with respect to the pair of flanges, the base member and
Since the surface pressure of the contact surface with the hydraulic part abutting on the contact surface can be kept uniform in the circumferential direction, the reliability and stability of bolt tightening can be maintained.

According to a third aspect, in the first or second aspect, each of the hydraulic units has a heat-resistant hydraulic seal member.

According to the third means, in the first or second means, the hydraulic part is kept attached even under high temperature conditions, for example, when used for a casing flange of a steam turbine. I can put it.

[0020] A fourth means is the device according to any one of the first to third means, wherein the tension nut is divided into a plurality in the circumferential direction, and the divided tension nut is connected to the tip end. It is further provided with a fastening ring for binding together at the outer periphery of the screw portion.

According to this fourth means, in any one of the first to third means, the tension nut divided into a plurality of parts is assembled from the side on the outer periphery of the threaded end of the bolt, By binding this with a fastening ring, it is possible to reduce the time required for mounting the tension nut as compared with a case where the tension nut is screwed in from the tip of the tip screw portion.

Fifth means is a measuring means for measuring elongation of the bolt in the axial direction by the plurality of hydraulic units in any one of the first to fourth means;
Based on the difference between the target value of the elongation of the bolt and the elongation measured by the measuring means, the hydraulic pressure supplied to the plurality of hydraulic units is automatically adjusted to a magnitude such that the elongation of the bolt becomes the target value. And a hydraulic pressure setting means for setting the hydraulic pressure.

According to the fifth means, in any one of the first to fourth means, in the bolt tightening operation between the pair of flanges, the elongation of the bolt by the hydraulic part is different from the target value. Even in such a case, the hydraulic pressure supplied to the plurality of hydraulic units can be automatically set by the hydraulic pressure setting unit to a magnitude such that the elongation of the supplied bolt becomes a target value. Therefore, even when it is necessary to reset the hydraulic pressure, the tightening operation can be promptly performed.

[0024]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 9 are diagrams showing an embodiment of a hydraulic bolt tightening device according to the present invention.
In the embodiment of the present invention shown in FIGS. 1 to 9, the same components as those in the conventional example shown in FIGS.

[First Embodiment] First, a first embodiment of the present invention will be described with reference to FIGS. In FIG. 1, a hydraulic bolt tightening device includes a pair of flanges 1 and 2 having bolt holes 1a and 2a corresponding to each other.
It is configured to be tightened by bolts 3 penetrating the bolt holes 1a and 2a.

The bolt 3 has an upper half screw portion (one side screw portion) 30 corresponding to the upper half flange (one side flange) 1.
And a lower half screw portion (other side screw portion) 32 corresponding to the lower half flange (other side flange) 2 and an extension extending from the upper half screw portion 30 and having a tip screw portion 34 formed at the tip end thereof. And a portion 36. Also, the upper half nut 30, lower half nut 22, and tension nut 2 of the upper half screw part 30, lower half screw part 32 and tip screw part 34 of the bolt 3, respectively.
4 is screwed.

As shown in FIGS. 1 and 2 in an enlarged manner, between the upper half nut 20 and the tension nut 24, there are provided four stages of hydraulic parts 4, 4 'stacked on each other. . Each of these hydraulic parts 4, 4 'is loosely fitted to the bolt 3, and is extendable in the axial direction of the bolt 3 by hydraulic pressure.

Outside the upper half nut 20, a base member 5 having a substantially cylindrical shape is interposed between the plurality of hydraulic portions 4, 4 'and the upper half flange 1. Here, counterbores 1b and 2b are formed around the openings of the bolt holes 1a and 2a of the pair of flanges 1 and 2, respectively. As shown best in FIG. 2, between the counterbore 1 b of the upper half flange 1 and the bottom surface 28 of the upper half nut 20 and the bottom surface 58 of the base member 5, the bearing strength is higher than the material of the upper half flange 1. A washer 6 made of a material having a high thickness is interposed. This is because the outer diameter of the base member 5 is within the range of the counterbore 1b of the upper half flange 1, so that the outer diameter of the upper half nut 20 disposed inside the base member 5 Becomes considerably smaller than before, and the bottom surface 2 of the upper half nut 20
This is because the pressure applied to 8 increases.

Here, as shown in FIG. 2, the bottom surface 49 of the lowermost hydraulic portion 4 'which comes into contact with the base member 5 of the four-stage hydraulic portions 4, 4' is formed in a spherical shape projecting downward. And the base member 5 which comes into contact with the bottom surface 49 of the hydraulic part 4 '.
The upper surface 59 is formed in a spherical shape depressed downward corresponding to the bottom surface 49 of the hydraulic portion 4 '. Also, the upper half nut 20
An insertion hole 26 for inserting a handle is formed in an upper portion of the base member 5, and a cutout window 52 corresponding to the insertion hole 26 is formed in the base member 5.

Next, each of the hydraulic portions 4, 4 'has a movable portion 40 corresponding to the outer periphery of the bolt 3, and base portions 42, 42' arranged outside the movable portion 40. Also,
The movable part 40 and the base parts 42, 42 'of each hydraulic part 4, 4'
Between the external hydraulic seal 43 and the internal hydraulic seal 4.
5 (hydraulic seal members 43, 45) are provided. A hydraulic distribution member 8 is attached to one side of the bases 42, 42 'of the hydraulic parts 4, 4', as shown in FIG.
A hydraulic pump P is connected to a coupler 9 of the hydraulic distribution member 8 via a hydraulic pipe 7. And the hydraulic pump P
Is distributed to the hydraulic portions 4, 4 'by the hydraulic distribution member 8, and acts on the hydraulic seals 43, 45 of the hydraulic portions 4, 4'.

Next, a procedure of a tightening operation by the bolt tightening device of the present embodiment will be described. When the pair of flanges 1 and 2 are tightened by the bolt tightening device, first, the upper half nut 20, the lower half nut 22, and the tension nut 24 are temporarily tightened. Next, the bases 42, 4 of the hydraulic units 4, 4 'are operated by the hydraulic pressure supplied from the hydraulic pump P.
By pushing the movable portion 40 upward with respect to 2 ', the bolt 3 is pulled upward by the tension nut 24, and the bolt 3 is extended in the axial direction by a predetermined amount. Thus, a gap corresponding to the extension of the bolt 3 is formed between the bottom surface 28 of the upper half nut 20 and the washer 6. Next, the insertion hole 26 of the upper half nut 20 is inserted through the cutout window 52 of the base member 5.
After tightening the upper half nut 20 until the above clearance is eliminated, the hydraulic pressure supplied from the hydraulic pump P to the hydraulic parts 4, 4 'is reduced to zero, and tightening is completed. Complete.

The case where the four-stage hydraulic units 4, 4 'are used has been described above. However, since the hydraulic units 4, 4' are stacked on each other, they can be easily separated for each stage. Therefore, by changing the number of stages of the hydraulic portions 4, 4 'to three or five or more, the bolt tightening force can be changed stepwise regardless of the change in the hydraulic pressure supplied from the hydraulic pump P. it can. In this case, for the difference in the number of stages of the hydraulic portions 4, 4 ', the length of the extension portion 36 of the bolt 3 is changed, or the position of the tension nut 24 is changed according to the number of stages of the hydraulic portions 4, 4'. This can be coped with by forming the tip screw portion 34 to be somewhat long so that it can be moved.

Next, the operation of the present embodiment having such a configuration will be described. According to the present embodiment, since the plurality of hydraulic portions 4, 4 'are stacked on each other, the diameter of each hydraulic portion 4, 4' can be reduced as compared with the case where the hydraulic portion is single. Each of the hydraulic portions 4 and 4 ′ is configured to be loosely fitted to the bolt and to extend the bolt 3 through the tension nut 24. Therefore, the bolt is directly screwed by the hydraulic portion screwed to the bolt 3. The diameter of each of the hydraulic portions 4, 4 'can be further reduced as compared with a configuration in which the hydraulic portions are extended.

For this reason, a plurality of bolts 3
In this case, the tightening operation by the bolt tightening device can be performed at the same time.
The time required for the tightening work can be reduced.
As an example, FIG. 3 shows the upper half flange 1 of the steam turbine casing. In this case, the adjacent bolt holes 1a (for example, the bolt holes 1a indicated by reference numerals A and B) are close to each other. Also, by installing the bolt tightening device of the present embodiment within the range of each counterbore 1b, the tightening operation can be performed at the same time.

Also, a hydraulic part 4 ′ that contacts the base member 5.
The base portion 42 'and the base member 5 have contact surfaces 49 and 59 formed in spherical shapes corresponding to each other, so that the axis of the bolt 3 should be Even when assembled in a tilted state, the surface pressure of the contact surfaces 49 and 59 between the base member 5 and the base portion 42 'of the hydraulic portion 4' that comes into contact with the base member 5 is kept uniform in the circumferential direction. Therefore, the reliability and stability of the tightening of the bolt 3 can be maintained.

The hydraulic seals 4 of the hydraulic parts 4 and 4 '
For example, when applied to a casing flange of a steam turbine for nuclear power generation, a working temperature of 350 is used.
It is preferable to use a heat-resistant material that can withstand about ° C.
In this case, since the temperature during normal use of the turbine is lower than 300 ° C., the bolt tightening device can be left attached even during the operation of the turbine, so that the time required for the bolt tightening work is greatly reduced. Can be shortened.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 4, in the present embodiment, the tension nut 24
The first embodiment differs from the first embodiment in that a split-type tension nut 24A is used in place of the first embodiment and a tightening ring 24B is further provided, and other configurations are the same as those in the first embodiment shown in FIGS. Is the same as

As shown in FIG. 4A, the tension nut 24A is divided into three divided bodies 24a in the circumferential direction. Further, as shown in FIGS. 4A and 4B, the tightening ring 24B combines the tension nut 24A divided into the plurality of divided bodies 24a into one at the outer periphery of the tip screw portion 34 of the bolt 3. It is for unity.

Next, the operation of the present embodiment having such a configuration will be described. According to the present embodiment, the tension nut 24A divided into the plurality of divided bodies 24a is
By assembling from the side to the outer periphery of the tip screw portion 34 of the bolt 3 and binding it with the tightening ring 24B, the time required for attaching the tension nut 24A is reduced as compared with the case of screwing into the tip screw portion 34. Can be shortened.

As shown in FIG. 5, the threaded end 34 of the bolt 3 and the threaded portion 24b of the tension nut 24A
It is preferable to use a square screw in order to facilitate the work of assembling the tension nut 24A. In this embodiment, the tension nut 24A is divided into three divided bodies 2.
Although the case where the tension nut 24A is divided is described, the tension nut 24A may be divided into two or four or more divided bodies 24a.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 6, in the present embodiment, a mechanical extensometer (measuring means) 60 for measuring the axial elongation of the bolt 3 and a data processing device (sequentially connected to the mechanical extensometer 60) The second embodiment differs from the first embodiment in that a hydraulic pressure setting unit 65, a pressure control device 67, and a printer 69 are provided, and other configurations are the same as those in the first embodiment shown in FIGS.

In FIG. 6, the mechanical extensometer 60 has a bar-shaped portion 62 extending into the center hole 36 of the bolt 3, and the tip of the bar-shaped portion 62 is connected to the lower half screw portion 32 of the center hole 36 of the bolt 3. It is in contact with the step 36a formed on the side. Then, the mechanical extensometer 60 mechanically measures the length of the bolt 103 based on the contact portion. The length of the bolt 3 is measured by a mechanical extensometer 60 before and after the supply of the hydraulic pressure to the hydraulic units 4, 4 ', and the elongation of the bolt 3 is obtained from the difference in the length.

Further, the data processor 65 determines the hydraulic pressure supplied to the hydraulic units 4 and 4 ′ based on the difference between the target value of the elongation of the bolt 3 and the elongation measured by the mechanical extensometer 60. This is for automatically setting the size of the bolt 3 so that the elongation becomes the target value. The pressure control device 67 is for controlling the oil pressure supplied from the hydraulic pump P to the oil pressure set by the data processing device 65.

Next, the steps of the tightening operation by the bolt tightening device of this embodiment and the operation of the device will be described with reference to FIG. First, regarding the point of temporarily tightening the upper half nut 20, the lower half nut 22, and the tension nut 24,
This is the same as in the first embodiment. Next, in FIG. 7, first, a target value λ of elongation corresponding to the tightening force of the bolt 3 and an initial set hydraulic pressure p supplied from the hydraulic pump P to the hydraulic units 4, 4 'are set (step S1).

Next, a signal of the initially set hydraulic pressure p is transmitted from the data processing device 65 to the pressure control device 67 (step S).
2). Then, the pressure control device 67 controls the hydraulic pump P to increase the hydraulic pressure supplied to the hydraulic units 4, 4 'to the initially set hydraulic pressure p, and the bolt 3 is extended (step S).
3). Next, until the gap created between the bottom surface 28 of the upper half nut 20 and the washer 6 due to the extension of the bolt 3 is eliminated.
The upper half nut 20 is further tightened (step S4). Then, the hydraulic pressure supplied from the hydraulic pump P to the hydraulic units 4, 4 'is reduced to zero (step S5), and the temporary tightening is completed.

Here, the actual elongation λ 'of the bolt 3 is measured by the extensometer 60 (step S6). Then, in the data processing device 65, the measured elongation λ ′
Is determined to be within the range of the target value λ (step S7). If it is within the range of the target value λ, the result is output to the printer 69 (step S8), and the tightening operation is started. The process ends (step S9). On the other hand, the measured elongation λ '
Is not within the range of the target value λ, the data processing device 6
At 5, the resetting of the hydraulic pressure supplied to the hydraulic units 4, 4 'is performed as follows (steps S10 to S1).
3).

First, the value of the difference Δλ between the target value λ and the measured elongation λ ′ is calculated (step S10). Here, the data processing device 65 stores in advance the relationship between the elongation λ of the bolt 3 and the tensile stress σ based on the material properties (elastic coefficient and the like) of the bolt 3, and the stress σ of the bolt 3 and the hydraulic portions 4, 4 ′ The data of the relationship (stress-hydraulic curve) with the hydraulic pressure p supplied to the storage device is stored. Then, based on these data, first, the value of the corrected stress Δσ is calculated from the value of Δλ (Step S11), and then the corrected hydraulic pressure Δσ is calculated from the value of the corrected stress Δσ.
The value of p is calculated (Step S12). Then, the set oil pressure p is reset from the value of the corrected oil pressure Δp by p = p + Δp (step S13).

Then, based on the set hydraulic pressure p reset in step S13, the bolt tightening operation and the measurement of the bolt elongation λ 'are performed again as described above (steps S2 to S7).
Are performed until the bolt elongation λ ′ falls within the range of the target value λ (Step S7).
13 → S2) is repeated.

Next, the operation of the present embodiment having such a configuration will be described. According to the present embodiment, even in the case where the elongation λ ′ of the bolt 3 due to the hydraulic units 4 and 4 ′ is deviated from the target value λ in the bolt tightening operation, the hydraulic unit 4 is , 4 'can be automatically set to such a value that the elongation of the bolt 3 becomes a target value. Therefore, even when it is necessary to reset the hydraulic pressure, the tightening operation can be promptly performed.

Next, two modified examples of this embodiment will be described with reference to FIGS. First, the first type shown in FIG.
In the modification of the embodiment, as a measuring means for measuring the axial elongation λ ′ of the bolt 3, an ultrasonic extensometer 7 having an ultrasonic transceiver 72 is used instead of the mechanical extensometer 60 shown in FIG.
0 is used. As shown in FIG. 8, in the present modification, an ultrasonic transceiver 72 is attached to the end face of the lower half screw portion 32 of the bolt 3. Then, in the ultrasonic extensometer 70, the ultrasonic wave transmitted from the ultrasonic transmitter / receiver 72 inside the material of the bolt 3 is reflected on the end face on the tip screw portion 34 side and returns to the ultrasonic transmitter / receiver 72 again. From the time to come and the speed of the bolt 3 in the material,
The length of the bolt 3 at that time can be measured.

Next, a second modification shown in FIG. 9 uses a laser extensometer 80 having a laser transceiver 82 instead of the mechanical extensometer 60. As shown in FIG. 9, in the present modification, the center hole 3 of the bolt 3
6, a laser transmitter / receiver 82 and a reflector 84 are provided in the opening on the lower half screw portion 32 side and the opening on the tip screw portion 34 side, respectively.
And are attached. And laser type extensometer 80
In the central hole 36, the time required for the laser beam sent from the laser transceiver 82 to be reflected by the reflector 84 and returned to the laser transceiver 82 again, and the speed in the atmosphere, The length of the bolt 3 can be measured.

[0052]

According to the present invention, since a plurality of hydraulic portions are stacked on each other, the diameter of each hydraulic portion can be reduced as compared with a case where only one hydraulic portion is provided. Also, since each hydraulic part is loosely fitted to the bolt and configured to extend the bolt via the tension nut, compared to a configuration in which the bolt is directly extended by the hydraulic part screwed to the bolt, Each hydraulic section can be further reduced in diameter. For this reason, even with a plurality of bolts that are close to each other, the tightening operation by the bolt tightening device can be performed simultaneously, so that the time required for such a bolt tightening operation can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a hydraulic bolt tightening device according to the present invention.

FIG. 2 is an enlarged view of a main part of the bolt tightening device shown in FIG.

FIG. 3 is a partial plan view illustrating the arrangement of bolt holes in a flange to which the hydraulic bolt tightening device according to the present invention is applied;

FIG. 4A is a plan view showing the periphery of a tension nut in a second embodiment of the hydraulic bolt tightening device according to the present invention, and FIG. 4B is a longitudinal sectional view of the same.

5 is a partial longitudinal sectional view showing a thread structure of a tension nut shown in FIG. 4;

FIG. 6 is a longitudinal sectional view showing a third embodiment of the hydraulic bolt tightening device according to the present invention.

7 is a flowchart showing the steps of a tightening operation and the operation of the apparatus in the bolt tightening apparatus shown in FIG. 6;

FIG. 8 is a longitudinal sectional view showing a first modified example of the hydraulic bolt tightening device shown in FIG. 6;

FIG. 9 is a longitudinal sectional view showing a second modified example of the hydraulic bolt tightening device shown in FIG. 6;

FIG. 10 is a longitudinal sectional view showing an example of a conventional hydraulic bolt tightening device.

11 is a diagram showing a state in which a mechanical extensometer is mounted in the hydraulic bolt tightening device shown in FIG. 10;

FIG. 12 is a diagram showing a state in which an ultrasonic extensometer is mounted in the hydraulic bolt tightening device shown in FIG. 10;

FIG. 13 is a diagram showing a state in which a laser extensometer is mounted in the hydraulic bolt tightening device shown in FIG. 10;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper half flange (one side flange) 1a Bolt hole of upper half flange 2 Lower half flange (other side flange) 2a Bolt hole of lower half flange 3 Bolt 4, 4 'Hydraulic part 5 Base member 6 Washer 20 Upper half Nut 22 Lower half nut 24, 24A Tension nut 24B Tightening ring 30 Upper half screw part 32 Lower half screw part 34 Tip screw part 36 Extension part 43, 45 Hydraulic seal member 49 Spherical contact surface of hydraulic part 59 Spherical surface of base member Contact surface 60 Mechanical extensometer (measuring means) 65 Data processing device (hydraulic setting means) 70 Ultrasonic extensometer (measuring means) 80 Laser extensometer (measuring means)

 ──────────────────────────────────────────────────の Continuing on the front page (72) Takashi Ashiha 2-4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Keihin Works Co., Ltd. (72) Inventor Kiyoji Mineta 10-17 Sasamekitamachi, Toda City, Saitama Prefecture Inside Applied Power Japan Co., Ltd. (72) Inventor Yoshinori Nakamura 10-17 Sasame Kitamachi, Toda City, Saitama Prefecture Inside Applied Power Japan Co., Ltd. (72) Seiichi Horiguchi 10-17 Sasame Kitamachi, Toda City, Saitama Applied Power Inside Japan Co., Ltd.

Claims (5)

[Claims] 1. A bolt tightening device for tightening a pair of flanges having bolt holes corresponding to each other by bolts penetrating the bolt holes, wherein the bolt is one side corresponding to one of the flanges. A screw part, an other-side screw part corresponding to the flange on the other side, and an extension part extending from the one-side screw part and having a tip screw part formed on the tip side thereof, one side of the bolt A threaded part, a threaded nut on the other side, and a threaded nut on the other side, a nut on the other side, and a tension nut, between the one side nut and the tension nut, which is loosely fitted to the bolt. A plurality of hydraulic parts that are stacked on each other and that can be expanded and contracted in the axial direction of the bolt by hydraulic pressure, respectively, and the plurality of hydraulic parts outside the one-side nut. A hydraulic bolt tightening device, comprising: a base member interposed between the one side flange and the one side flange. 2. A hydraulic system according to claim 1, wherein the hydraulic section of the plurality of hydraulic sections, which is in contact with the base member, and the base member are formed so that their contact surfaces are mutually spherical. Item 2. The hydraulic bolt tightening device according to Item 1. 3. The hydraulic bolt tightening device according to claim 1, wherein each of the hydraulic parts has a heat-resistant hydraulic seal member. 4. The tension nut is further divided into a plurality in a circumferential direction thereof, and further includes a tightening ring for binding the divided tension nuts together on the outer periphery of the tip screw portion. The hydraulic bolt tightening device according to any one of claims 1 to 3, wherein: 5. A measuring means for measuring an elongation of the bolt in the axial direction by the plurality of hydraulic units, and based on a difference between a target value of the elongation of the bolt and an elongation measured by the measuring means. 5. The apparatus according to claim 1, further comprising a hydraulic pressure setting unit configured to automatically set hydraulic pressure supplied to the plurality of hydraulic units to a magnitude such that the elongation of the bolt becomes a target value. The hydraulic bolt tightening device according to any one of claims 1 to 6.