JPS5856146Y2 - Simultaneous tightening device for multiple screws - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a simultaneous screw tightening device that can tighten a plurality of screws at the same time with a predetermined tightening torque.

Normally, when tightening a certain member with multiple bolts, nuts, or other screws (hereinafter referred to as bolts), it is not possible to reach the same final tightening torque for each bolt at the same time, resulting in the following problems. .

For example, as shown in FIG. 1, the sector cover C of the steering gear S is attached using three bolts Ba, B5. When fixing to housing H with Bc, each bolt Ba, Bb.

If the tightening torques Bc are not the same, uniform tightening force cannot be obtained at each location, and the sector cover C cannot be sufficiently tightened to the housing H.

Previously, each port) B8. In order to tighten B, , Bc at the same time with the same torque, a bolt tightening device has been put into practical use which is provided with the same number of nut runners as the number of bolts to be tightened and configured to operate these nut runners simultaneously.

This conventional bolt tightening device will be explained based on FIG. 2.

The nut runner 1 includes a rotation drive unit 2 consisting of an air motor or the like.
, a torque increasing part 3 consisting of a planetary gear mechanism or the like that decelerates the rotation and increases the rotational torque, an output part 7 having a socket 4 that fits into the bolt head attached to the output shaft 5 and having a speed switching mechanism 6, etc. The main component is a torque detection section 8 having a torque transducer that detects the torque of the output shaft 5.While the output section 7 is tightening the bolt, the torque detection section 8 detects the tightening torque, and the tightening torque is detected by the torque detection section 8. When the torque reaches a predetermined value, the air supplied to the drive section 2 of the nut runner is cut off in response to a torque detection signal to stop the drive section 2.

Note that air maintained at a constant pressure is supplied to the drive unit 2 so that a predetermined tightening torque is applied to the bolt.

According to this bolt tightening device, in theory each bolt is tightened to a predetermined tightening torque by each nut runner, and the tightening is completed, and each bolt can be tightened in a short time, but in reality, Each port) B8 as shown in Figure 3.
．． When the tightening of Bo is completed, there is a time difference between 1b and 1o, so the final tightening torque reached the specified tightening torque.

For Ba, B, the tightening torque decreases while tightening the last bolt Bc, and when the tightening is completed, all bolts reach the specified tightening torque. It was difficult to make it happen.

The present invention was developed in view of the above, and its purpose is to use a nut runner device installed in accordance with the number of bolts to be tightened to tighten each bolt for a predetermined period of time even after all bolts have reached a predetermined torque. By installing a timer device that continuously operates the nut runner to apply a predetermined tightening torque, we provide a simultaneous bolt tightening device that can uniformly tighten all bolts to the predetermined torque in an extremely short time. It's about doing.

The present invention will be explained below with reference to embodiments shown in FIGS. 4 to 7.

FIG. 4 shows a first embodiment of the present invention, and this example shows a bolt simultaneous tightening device for simultaneously tightening three bolts.

In the same figure, la, lb, and IC are the runners 1 to runners provided corresponding to each bolt, and among these, 8a, 8b
.

8C is a tightening 1 herk detection section, and 2a, 2b, and 2C are drive sections.

Air adjusted to a constant pressure is supplied to the drive units 2a, 2b, and 2C so that the tightening torque becomes a predetermined value.

Tightening torque detection unit 8 for each nut runner la, lb, and IC
a.

8b, 8C include preamplifiers 9a, 9b, 9C and main amplifier 10a, which amplify the detected torque signal.
10 b, 10 C are connected, and comparators 11 a, 11 b, 11 C are connected to compare the detection signal with a predetermined tightening torque (reference tightening torque) signal, and the bolts are further connected to a predetermined tightening torque. a timer device 12 that operates when T reaches and stops the nut runner after a set time T;
a, 12b, and 12c are connected.

Each of these timer devices 12a, 12b, 12C
is each drive unit 2a.

2b, 2C, and is configured to stop the driving parts 2a, 2b, 2C by a predetermined signal from a comparator, and their outputs are AND-coupled 13 and connected to a tightening completion display device 14, etc. ing.

According to this bolt simultaneous tightening device, each nut runner la, lb, and IC operate at the start of operation, and each bolt Ba,
Tighten Bb and Bc.

Bolts Ba and B6 at this time. FIG. 5 shows the relationship between each tightening torque Bc and the time required for tightening.

During this tightening work, the tightening torque detectors aa, ab, and ac constantly detect the tightening torque of each bolt, and this detection signal is sent to the preamplifiers 9a, 9b, 9C and the main amplifier 1.
The torque is amplified by 0a, 10b, 10C and compared with the standard tightening torque set in advance by comparators 11a, 11b, 11C, and continues as long as the detection signal is lower than the standard tightening torque. Te Natsutranna 1a.

lb, IC tightens bolts Ba, Bb, and Bo.

Then, as shown in FIG. 5, when one bolt (in this example, bolt Ba) reaches the reference torque, the comparator 11
A signal is output from a to the timer device 12a, and the nut runner 1a is controlled so that air at a constant pressure is supplied to the driving portion 2a for a set time T to maintain a predetermined tightening torque.

In other words, when the tightening torque reaches a predetermined value, a normal nut runner immediately cuts off the air supplied to the drive section and stops the operation of the drive section, but in this example, the tightening torque reaches a predetermined value. However, for a certain period of time T, air at a constant pressure is supplied to the drive part to keep the drive part in continuous operation, so that the bolt can be further tightened by constantly applying a predetermined tightening torque from the nut runner to the bolt. I'll leave it as that.

Note that the drive part of the nut runner is supplied with air that is regulated to a constant pressure so that the tightening torque reaches a predetermined value. There is no need to worry about tightening it.

Therefore, in the case of this example, when the bolt B8 first reaches the predetermined tightening torque, constant pressure air is supplied to the drive section of the nut runner during the time period T during which the timer device 12a is activated, and the predetermined tightening torque is maintained. continues to act, and other Pol l-B5. B
Even if the tightening torque decreases as the tightening process progresses, the tightening operation is performed again and the tightening torque is maintained at a predetermined value.

Next, the tightening torque reaches the predetermined value.)Bb
The same applies to

When the final bolt Bc reaches a predetermined value, the timer device 12C is activated, and after the set time T, the air supplied to the drive section is cut off and the tightening work is completed.

When all Natsu runners 1a, lb, and IC are stopped,
The signal is output for the first time by the AND connection 13 to the tightening completion display device 1
4 to indicate completion of tightening or to instruct the next operation of the runner device.

Here, each timer device 12a, 12b, 12
The set time T of C must be such that the last bolt reaches the predetermined tightening torque within the time T set in the timer device corresponding to Pol 1, which first reaches the predetermined tightening torque. As a result, if the set time T is short, problems similar to those of the conventional method as described above occur.

Furthermore, since it is difficult to predict which volt will reach the predetermined value last, it is necessary to provide each nut runner with a timer device.

The same applies to the second embodiment described later.

This is because if the nut runner is stopped at the same time as the last bolt reaches the predetermined value, the tightening torque will fluctuate after the stop and there is a risk that the nut runner will deviate greatly from the predetermined value. By supplying constant pressure air to the nut runner's drive part for a certain period of time and continuing to apply the specified tightening torque to each bolt, fluctuations in the tightening torque after the nut runner stops are suppressed to an extremely small level and the tightening torque of each bolt is stabilized. This is based on the reason that it can be converted into

From the above, the device of this embodiment can reliably tighten a plurality of bolts to a predetermined torque in a short time.

FIG. 6 shows a second embodiment of the invention.

In this example, Buno amplifiers 9a, 9b, 9c and a main amplifier 10a are provided for each nut runner la, lb, and IC, respectively.

10b and 10c are connected, and further a comparator 11a.

Connect 11b and 11c.

And these comparators 11a, 11b, 1
1 The output of C is AND-combined 13 and then the timer device 12
and further connected to the tightening completion display device 14.

Each nut runner la, lb, IC drive unit 2a
, 2b, and 2C are commonly associated with the timer device 12.

According to this bolt simultaneous tightening device, as shown in FIG. 7, until the last bolt Bc reaches the predetermined tightening torque, the predetermined tightening torque is reached before that.
8. The nut runners 1a and 1b of B5 are drive parts 2a and 2.
B is supplied with constant pressure air and continues to operate with a predetermined tightening torque applied to bolts Ba and Bb, and during the set time TM from when the last bolt Bc reaches the predetermined value, all The nut runners 1a, 1b, and IC are activated and continue to apply a predetermined tightening torque to each bolt, and after the set time TM has elapsed, the nut runner drive parts 2a, 2b, 2
The air supplied to C is cut off and all nut runners 1
a, 1b, and 1C are stopped.

In this case, the timer device 12 controls all the bolts Ba. Bb,
AND connection 13 when Bo reaches the predetermined tightening torque
Its action begins.

In this embodiment, since only one timer device is provided, the structure is simpler and the cost can be lowered compared to the previous embodiment.

As in the case of the above embodiment, the nut runner is left in operation for a certain period of time even after the last bolt reaches the predetermined tightening torque, and the predetermined tightening torque continues to be applied to each bolt. The decrease in the tightening torque becomes extremely small, and the tightening torque becomes stable.

As described above, according to the present invention, even after the tightening torque of a plurality of bolts reaches a predetermined value, the predetermined time set longer than the time until the last bolt is tightened to the predetermined tightening torque is maintained. By installing a timer device that can continuously operate the nut runner, the bolts that have reached the predetermined torque first will not loosen again, and the tightening torque of each bolt that has been tightened will become unstable. This has great practical effects, such as being able to reliably tighten a plurality of bolts to a predetermined tightening torque in a short period of time without causing any problems.

[Brief explanation of drawings]

Figure 1 is a perspective view of the steering gear, Figure 2 is a schematic diagram of the nut runner, Figure 3 is a conventional tightening-handling diagram, Figure 4 is a diagram of the configuration of the device of the present invention, and Figure 5 is its configuration. Tightening characteristics diagram,
FIG. 6 is a configuration diagram of another embodiment, and FIG. 7 is a diagram of its tightening characteristics. 1 a, 1 b, IC...-Nut runner, 2a, 2b, 2C... Drive section, 8a,
8b, 8C...Torque detection section, 9a, 9
b, 9C... Briand, 10a. 10 b, 10 c --- Main amplifier, 11 a
, 11b, 11C...Comparator, 1
2, 12 a 12 b, 12 C...Timer device, 13...And combination, 14...
-Display device, Ba, B6. Bc・・・Bolt, T
, TM...Setting time.

Claims (3)

[Scope of utility model registration request] (1) In a simultaneous tightening device for multiple screws, which is equipped with as many nut runners as the number of screws to be tightened, the operation of which can be stopped when a predetermined tightening torque is reached, the nut runner remains in operation even after the predetermined tightening torque is reached for all screws. A simultaneous tightening device for a plurality of screws, characterized in that a timer device is attached to the nut runner to continuously operate the nut runner while applying a predetermined tightening torque to the screws for a certain period of time. (2) The simultaneous tightening device for a plurality of screws as set forth in claim (1), characterized in that a timer device is provided corresponding to each nut runner. (3) A timer device is provided in the service circuit of each nut runner so that it is activated when all the screws reach a predetermined tightening torque.
1) Simultaneous tightening device for multiple screws as described in item 1).