JPH04176575A - Device and method for fastening bolt - Google Patents

Abstract

PURPOSE:To correctly obtain the fastening axial tension of a bolt by fastening a nut only in the state of adding a desired axial tension on the bolt. CONSTITUTION:A nut 4 is turned and loosely fastened after passing a bolt 3 through a fixing member 2 initially. The nut 4 is then fastened by a nut runner 10 in the state of the nut 4 being not rotated in the state of the bolt 3 being stretched from the nut fastening face with a preset axial tension by the actuation of a hydraulic cylinder 20, thereafter the bolt fastening is performed with the stretch of the bolt 3 being released.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bolt fastening device and a bolt fastening method that perform safe and reliable bolt fastening by managing the fastening axial force of the bolt.

"Conventional technology" FIG. 3 is a diagram showing a conventional fastening device.

A fastening method using a conventional fastening device will be described below.

A bolt 3, a nut 4, and a washer 5 were used to fix the fixing members 1 and 2.

In order to control the tightening axial force of the bolt 3, a hole 6 with a depth within a certain error range is machined in the direction of the central axis of the bolt 3, a heater 7 is inserted into the hole 6, and the current flowing through the heater 7 is The temperature of the heater 7 was controlled and the length of the bolt 3 was changed by thermal expansion.

The fastening procedure is as follows: (1) A heater 7 is inserted into the hole 6, voltage is supplied to the heater 7 from a power source 8, and the bolt 3 is heated to a desired temperature (for example, 500° C.).

- After a certain period of time has elapsed, when the bolt 3 thermally expands and reaches the desired length, temporarily tighten the nut 4 and stop supplying the voltage.

■The temperature of the bolt 3 drops to room temperature, and the bolt 3 shrinks due to heat and becomes fully tightened.

(2) Take out the heater 7 in the hole 6, measure the depth of the hole 6 with the bolt 3 at room temperature, and calculate the axial force from the rate of change in the depth of the hole 6.

If the desired axial force is not obtained, repeat steps ① to ②.

``Problem to be solved by the invention'' In the conventional fastening method, the thermal expansion of the bolt 3 is used, so a large amount of electric power is required to pull the bolt, and the time spent on thermal expansion of the bolt and the bolt Each of these had the disadvantage of requiring a long time to cool down.

When tightening the nuts, the bolts are hot, so if you are not careful, you could get burned.

Also, if there is metal debris between the bolt or nut and the fixing member, or if the fixing member is distorted and there is a gap between the fixing members, it will not be possible to crush it when temporarily tightened.
It was not possible to accurately obtain the axial force due to the heat shrinkage of the bolt.

An object of the present invention is to provide an energy-saving bolt fastening device and bolt fastening method that eliminates the above-mentioned drawbacks, allows fastening work to be performed in a short time and with simple work, and allows accurate fastening axial force to be obtained. It is in.

The bolt fastening device of the present invention, in a fastening means using bolts and nuts, passes the bolt through a fastening member and attaches the nut, and the threaded tip of the bolt protruding from the nut surface is screwed into a predetermined position. A tensioning means for pulling in the axial direction with force, a measuring means for indirectly measuring the force applied to the bolt by the tensioning means, and a state in which the bolt is pulled when the value measured by the measuring means reaches a predetermined force. and a fastening means for tightening the nut (with the tensioning means activated).

"Function" Bolts 3 are passed through the holes of fixing members 1 and 2, and nuts 4 are screwed into the bolts 3 through washers 5, and temporarily tightened.

Thereafter, the socket 12 of the nut runner lO is inserted into the nut 4, and the female threaded part 32 of the connecting fitting 30 is screwed into the threaded end of the bolt 3. While supplying the hydraulic pressure generated by the hydraulic device 40 to the cylinder 20, the tip of the fully threaded portion of the bolt 3 is connected to the connecting fitting 30 while measuring the force applied to the bolt 3 until the desired axial force is achieved. It is pulled by a hydraulic cylinder 20 via the hydraulic cylinder 20.

When the desired axial force is reached (the bolt 3 is pulled), the nut 4 is tightened by the nut runner lO. The cylinder 20 of hydraulic pressure generated by the hydraulic system 40
When the supply to the cylinder 20φ nut runner lO, the bolt 3, the fixing member 1, and the connecting fitting 30 are released, the force is transferred to the nut 4, the bolt 3, and the fixing members 1 and 2.

Therefore, the bolt can be tightened easily and accurately in a short time with a desired axial force.

"Example" FIG. 1 is a sectional view showing a bolt fastening device of the present device. FIG. 2 is a diagram showing a state in which a bolt is tightened using the bolt fastening device of the present invention.

This will be explained below using FIGS. 1 and 2.

1 and 2 are fixing members for fixing each other, such as flanges of the device. 3, 4 and 5 are a bolt, a nut and a washer, respectively.

lO is a stand for a hydraulic cylinder 20, which will be described later, and a bolt 3.
This is a nut runner for tightening the nut while applying tension to the nut.

The nut runner lO includes a cylindrical pedestal 11 and the pedestal 1.
A socket 12 of the nut runner rotatably clamped by a plurality of bearings 13 on the lower part of the inner surface of the nut runner, a disc-shaped gear 14 provided on the upper outer periphery of the socket 12, and a sliding bearing 18 connected to the pedestal. A shaft 16 pivotally supported by 11
A gear 15 is attached to the tip of the gear and is paired with the -wheel 14.
and a hexagonal head 17 of a bolt attached to the other end of the shaft 16. The gears 14 and 15 constitute a bevel gear.

Reference numeral 20 denotes a hollow hydraulic cylinder whose piston moves in the direction of extension due to oil pressure, and when the oil pressure becomes smaller than a predetermined value, the piston moves in the direction of contraction due to the action of a plurality of cylinders.

The hydraulic cylinder 20 is composed of a convex cylinder 21 as a cylinder tube, an O-ring oil seal, etc., and is inserted into the inner surface of the circle WR21 through a plurality of sealing materials 23 and 24 to prevent oil from flowing out. A piston 22 consisting of a cylinder with a cross-sectional shape, a ring 25 attached to the other end of the cylinder 21, and a ring 25 that is sandwiched between the ring 2B and the piston 22 and when no hydraulic pressure is applied to the piston. It is composed of a plurality of springs 26 that push down the hydraulic pipe 22, and an injection joint 27 and a drain joint 28 for hydraulic piping.

Reference numeral 30 is a mushroom-shaped cylinder having a female threaded portion at its tip that is compatible with a bolt, and is a connecting fitting used by screwing the female threaded portion into the tip of the fully threaded portion of the bolt 3.

The connecting fitting 30 includes a cylinder 31 with an inverted cross section and a female threaded part 32 that fits the thread of the bolt 3 at the tip, and a cylinder 31 that is attached to the disk-shaped (thick part) end face of the cylinder 31 and rotates the cylinder 31. The cylinder 40 is composed of a plurality of handles 33 for adjusting the pressure required by the cylinder 20, and a hydraulic pressure generating device consisting of an oil tank, a hydraulic pump, an electric motor, etc., and a hydraulic pressure supplied from the hydraulic generating device to the pressure required by the cylinder 20. A hydraulic control device consisting of a pressure control valve, a direction control valve, etc. for adjustment, and a cylinder 2
A portable hydraulic system comprising a hydraulic pressure gauge 41 for displaying the hydraulic pressure applied to the cylinder 20, and a pressure control valve 42 provided in the hydraulic control device for regulating the hydraulic pressure inside the cylinder 20. be.

An oil feed pipe 43 that carries oil discharged with hydraulic pressure regulated by a pressure control valve 42 in the hydraulic system 40 is connected to the injection joint 27 of the cylinder 20. When the oil carried by the oil pipe 43 is sent into the cylinder 20, the piston 2
2 is pushed out. Moreover, the sealing material 2 of the cylinder 20
The oil leaking from 2 and 23 is returned into the hydraulic system 40 by a drain connected to the drain joint 28.

The operation of this device will be explained below.

Fixing members 1 and 2 such as flanges used for attaching a plurality of members are fixed using bolts 3, bolts and washers 5 through the holes of the fixing members 1 and 2, to the extent that no axial force is generated on the bolts 3. It is fastened (temporarily).

Insert the socket 12 of the nut runner lO into the nut 4, and place the nut runner lO on the fixing member 2 (.

The stepped portion 29 of the cylinder 30 connected to the hydraulic system 40 by piping is mounted on the base 11 of the nut runner IO. The connecting fitting 30 is passed through the hollow part of the cylinder 20, and the female threaded part 32 of the connecting fitting 30 is screwed into the fully threaded part of the bolt 3, so that the connecting fitting 30 and the piston 22 are brought into pressure contact.
(This is the state shown in Fig. 1.) When the hydraulic system 40 is operated, the cylinder 2011, nut runner 10, bolt 3, fixing member l, and connecting fitting 30
A force is generated at , pushing up the piston 22 of the cylinder 20 and stretching the bolt attached to the tip of the connecting fitting 30. At this time, while checking the scale of the pressure gauge 41, adjust the pressure control valve 42 to match the desired axial force. Note that the scale of the pressure gauge 41 corresponds to the force (axial force) applied to the bolt 3.

After that, when the hexagonal head 17 of the nut runner lO is turned with a socket wrench, the socket) 12 is opened via the gears 14 and 15.
The nut 4 attached to the bolt 3 also rotates, and the bolt 3 is fastened by the nut 4. (This is the state shown in Fig. 8.) At this time, if the nut 4 is turned until the pointer of the pressure gauge 41 changes in the direction of O, the bolt 3 will be tightened with the desired axial force. ,Become.

After tightening the bolt 3 with the desired axial force, the hydraulic system is stopped and a direction control valve (not shown) is activated to convert the oil in the cylinder 20 into an oil tank (not shown). Then, the force generated in the cylinder 20 @ nut runner 10, bolt 3, fixing member 1, and connecting fitting 30 is transferred to the nut 4, bolt 3, fixing members 1 and 2.

After removing the connecting fitting 30, the cylinder 30, the hydraulic device 40, and the nut runner 10 are removed, and the bolt fastening work is completed.

In this embodiment, the nut is rotated by turning the hexagon head 17 of the Nut Runner IO with a socket wrench, but instead of the hexagon head of the Nut Runner IO, turning the handle or
The shaft 16 may be rotated by an electric motor, and a drop in pressure may be detected and the motor may be stopped.

``Effects of the Invention'' By using the present invention, only the nuts are fastened while applying the desired axial force to the bolts, so metal debris between the bolts and nuts and the fixing member is crushed. At the same time, by compressing the gap between the fixing members 1 and 2 caused by the distortion of the fixing members 1 and 2 with the bolt head and the nut runner °10, the bolt tightening force can be accurately obtained. A fastening device and method can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a bolt fastening device of the present device. FIG. 2 is a diagram showing a state in which a bolt is tightened using the bolt fastening device of the present invention. FIG. 3 is a diagram showing a conventional fastening device. "Explanation of symbols" 1 and 2...fixing member,

Claims (2)

[Claims] (1) In a fixing means using bolts and nuts, a tensioning means for passing the bolt through the fixation member, attaching the nut, and pulling the threaded end of the bolt protruding from the nut surface in the axial direction with a predetermined force; A measuring means that indirectly measures the force applied to the bolt, and when the value measured by the measuring means reaches a predetermined force, the nut is tightened while the bolt is pulled (the pulling means is activated). A bolt fastening device comprising a fastening means. (2) In the fastening method using bolts and nuts, first pass the bolt through the fastening member, then turn the nut to tighten it loosely, and then stretch the bolt from the nut tightening surface with a predetermined axial force. A bolt fastening method in which the nut is tightened so that it does not rotate, and then the tension of the bolt is released and the bolt is tightened.