JPS63237874A - Nut automatic clamping device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides a method for tightening a nut with a specified torque using an external power.
Concerning long-length equipment.

(Prior art) When fixing two members using bolts and nuts,
In order to obtain an appropriate tightening force, the rotation of the drive source is controlled so that the nut tightening torque is a reference value. To manage this tightening torque, the torque of the nut tightening shaft is detected, and after this torque exceeds the standard value, the specified angle is maintained while only controlling the rotation angle. (Japanese Patent Application Laid-Open No. 58-56776) has also been proposed, but due to the relative accuracy of the bolt and nut, torque fluctuations occur at the approach stage until the parts come into contact, and the material and washer of the bolt and nut have also been proposed. In addition to the problem that the torque at the start of tightening due to category +i changes, an error occurs in detecting the point in time when the torque exceeds the reference torque, and it is not possible to obtain the member tightening force with the specified torque. Even if the specified torque is reached during the approach process due to screw thread loosening, screw cutting, etc., the tightening is judged to have been completed and the tightening is stopped, resulting in a problem of low fixing reliability.

(Objective) The present invention was made in view of such problems, and its object is to provide an automatic nut tightening M that can tighten nuts with high reliability. be.

(Summary of the Invention) In other words, the present invention is characterized by a torque detecting means connected to a rotary power source that drives the nut gripping tool, and a torque detecting means connected to a rotary power source that drives a nut gripping tool, a first reference torque is set, and contact detection means outputs a signal when the signal from the torque detection means exceeds the reference torque; a standard tightening state storage means in which a second reference torque, a third reference torque at the time of completion of tightening, and a path length until reaching the second and third reference torques are set; and a second reference torque.
, determining whether the third reference torque has been reached, and stopping the rotary power source when the second and third reference torques have been passed through with a predetermined path length, and when it is no longer possible to pass through the second and third reference torques normally. The point is that it is equipped with a determination means.

(Example) The details of the present invention will be described below based on illustrated examples.

FIG. 1 shows an embodiment of the present invention, in which reference numeral 1 denotes a motor that serves as a source of rotational power for driving a nut trench 6, and a rotating shaft 2 has a torque for detecting rotational torque. A detector 3 and a rotation angle detector 4 for detecting a rotation angle are attached, and driving power is supplied to the power supply terminal 5 from a control bag [10, which will be described later. .

Reference numeral 10 denotes a control device characterized by the present invention, and reference numeral 11 in the figure is a contact detection circuit, in which the nut reaches the first reference torque preset by the setting device 18, that is, the nut is tightened on the member to be tightened in a normal state. A torque Q1 that is generated when abutment is made is set, and a contact signal is output when the signal from the torque detector 3 reaches a first reference torque. Reference numeral 12 denotes a standard tightening state memory circuit, which is accessed by the contact signal and outputs the torque Ja generated during normal tightening in accordance with the clock pulse from the timer circuit 13.
As shown in the figure, for tightening from the time of contact, the address is the time lower than the process, the torque value is data Q (T), and the second reference torque Q2 is set at an intermediate time, that is, ΔT1 from the time of contact.
Then, the third reference torque Q3 at the time of completion of tightening after a time ΔT2 from this point is stored in a semiconductor memory circuit.

Reference numeral 14 denotes a judgment circuit, which inputs the data Q (T) from the standard tightening state storage circuit 12 and the signal from the torque detector 3, and when the signal progresses to the second reference torque Q2 while matching the stored data. The time ΔT1 required for Compare 3 standard torque Q3a,
- It is configured to output a tightening completion signal in case of failure, and to output a stop signal in case of disagreement.

That is, if the signal from the torque detector 3 deviates from the data in the tightening state storage circuit 12, the motor drive circuit 1
It is configured to output a stop signal at 6, and a completion signal when the change occurs.

Next, the operation of the apparatus configured as described above will be explained based on the flowchart and operation diagram shown in FIG. 3.4.

When the nut trench 6 is set on the nut M and the motor 1 is driven, the nut M moves toward the tightening member. In the process of approaching this member, the nut receives a load when it comes into contact with the washer, so the output torque of the motor 1 increases and the torque from the torque detector 3 is set as the first standard in the contact detection circuit 11. Reach Leher Q1. The contact detection circuit 1] outputs a contact signal to access the tightening state storage circuit 12, and starts reading out the torque pattern data Q(T) in accordance with the clock signal from the timer circuit 13. The determination circuit 14 compares the read torque pattern data Q (T) with the torque signal from the torque detector 3. During this tightening process, if the nut M screws, the output of the torque detector 3 will exceed the second reference torque Q2 at a point earlier than the preset time ΔT1 (Fig. 4B). , As a result, the determination circuit 14
outputs a stop signal to cut off power to the motor 1 and stop the tightening operation, and also issues an alarm to notify the operator that a tightening abnormality has occurred.

When the tightening process progresses normally up to the second reference torque Q2,
Subsequently, the signal from the torque detector 3 is compared with the torque pattern data Q (T). In this process, the signal from the torque detector 3 or the torque pattern data Q (
T)! When the third reference torque Q3 is reached in this manner, the determination circuit 14 outputs a signal to output a tightening completion signal and stops the motor 1.

As a result, the tightening torque of the nut M is controlled from the time of contact with the member until the completion of tightening, and the member is fixed with a specified torque in cooperation with the bolt.

On the other hand, the time ΔT after passing the second reference torque Q2
If the third reference torque Q3 is not reached even after 2 elapses (dotted line C in Figure 4), there is a high possibility that the screw bulge remains, so the determination circuit 14 outputs a stop signal. The motor 1 is then stopped, and at the same time an alarm is issued to notify the operator that an abnormality has occurred.

In this embodiment, the nut M is rotated at the same speed as in the abroche process during the tightening process, but the contact detection signal from the contact detection circuit 11 is used as shown in FIG. By using the rotation speed changing circuit 19 that reduces the rotation speed of the motor 1 in response to the rotation speed, the tightening torque from the time of contact can be controlled more accurately.

FIG. 6 shows a second embodiment of the present invention, and reference numeral 12' in the figure is a tightening state memory circuit, and as shown in FIG. (or rotation angle) N
is the address, the torque value is data Q (N), and the second reference torque Q at ΔN1 from the intermediate point, that is, the time of contact.
2 and a third reference torque Q3 at the time of completion of tightening after rotation number ΔN2 from this point are stored in a semiconductor memory circuit. 14' is a judgment circuit, which is a standard tightening state memory circuit 12.
The data Q (N) from ° and the signal from the torque detector 3 are input, and the second reference torque Q
When the process has progressed to 2, the number of revolutions ΔN1 required for this process is compared, and if it fails, it proceeds to the next step, and if it does not fail, it outputs a stop signal, and roughly the number of revolutions ΔN2 has elapsed. At this point, the signal from torque detector 3 and the third reference torque Q
3, and if they match, a tightening completion signal is output, and if they do not match, a stop signal is output. That is, if the signal from the torque detector 3 deviates from the data in the tightening state storage circuit 12', a stop signal is output to the motor drive circuit 16, and if the signal deviates from the data in the tightening state storage circuit 12', a completion signal is output. It is already configured.

In this embodiment, when the torque from the torque detector 3 reaches the first reference level Q1, the contact detection circuit 11 outputs a contact signal, accesses the tightening state storage circuit 12', and detects the rotation angle. The 0 judgment circuit 14' starts reading out the torque pattern data Q (N) in accordance with the rotation signal from the rotation signal from the device 4.
(N) and the torque signal from the torque checker 3 are compared. During this tightening process, if the nut M is screwed, the output of the torque detector 3 will exceed the second reference torque Q2 at a rotational speed lower than the preset rotational speed ΔN1. As a result, the determination circuit 14' outputs a stop signal to cut off power to the motor and stop the tightening operation, and also issues an alarm to notify the operator that a tightening abnormality has occurred.

When the tightening process progresses normally up to the second reference torque Q2,
Subsequently, the signal from the torque detector 3 is compared with the torque pattern data Q (N). In this process, the signal from the torque detector 3 is changed to the torque pattern data Q (
When the third reference torque Q3 is reached, the determination circuit 14' outputs a signal to output a tightening completion signal and stops the motor 1.

As a result, the tightening torque of the nut M is controlled from the time of contact with the member until the completion of tightening, and the member is fixed with a specified torque in cooperation with the bolt.

On the other hand, from the time when the second reference torque Q2 is passed, the rotation speed Δ
N218: If the third reference torque Q3 is not reached even after passing, there is a high possibility that screw burr has occurred, so the determination circuit 14' outputs a stop signal to stop the motor 1, and at the same time (This alarm is issued to notify the operator that an abnormality has occurred.

According to this embodiment, it is possible to read out the torque pattern data Q (N) in accordance with the signal from the rotation angle detector 4, thereby preventing deviations in data read quimming due to fluctuations in the rotational speed of the motor 1. be able to.

In addition, in the above-mentioned embodiment, at the time of contact, the tightening intermediate point,
Although three points, ie, the tightening completion point and the tightening completion point, are monitored, it is clear that the same effect can be achieved even if the torque change after the contact is successively compared with the reference torque data and monitored.

In addition, in the above-mentioned embodiment, in order to simplify the explanation, the case where screw cutting and screw gazing occur before the second reference torque Q2 has been taken as an example, but 8' in FIG.
, C', even if the second reference torque occurs after the second reference torque Q2, the process of reaching the third reference torque Q3 is different from the normal one, so the motor is stopped and the subsequent tightening process is stopped. It is clear that it works like this.

Furthermore, in the above embodiment, pass/fail is determined based on the path length required to reach the second reference torque and the torque at the stage after the path length required to complete tightening. It is clear that the same effect can be obtained by determining the path length required for the process or the torque at the stage after passing through each path length.

Furthermore, in the above embodiment, the data at each point in time is stored in a dictionary format, but it is also possible to store the data as a function with the number of revolutions or time as an independent variable and the torque as a dependent variable. It is clear that this effect is achieved.

Roughly speaking, the above embodiment has been explained using an electric motor as the drive source, but it is clear that it can be similarly applied to an example using a fluid motor using hydraulic pressure or pneumatic pressure as an energy source. .

(Effects) As explained above, according to the present invention, the torque increase process from the time when the nut and the member to be tightened come into contact until the time when tightening is completed is monitored, and only when this is normal, normal tightening is performed. In addition, if there is a deviation during the process, it is judged as a tightening failure, so it is possible to ensure that there are no tightening failures due to screw force misalignment during the abroche process or tightening process, or missing parts due to defects in washers or parts. It is possible to achieve highly reliable fixation by detecting the

In addition, just by changing the data representing the standard tightening condition,
Highly reliable tightening can be performed regardless of material or shape.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a device showing an embodiment of the present invention, Fig. 2 is a schematic diagram showing the data contents of a tightening state memory circuit in the same device, and Fig. 3.4 is a schematic diagram of the same device as above. FIG. 5.6 is a configuration diagram showing another embodiment of the present invention, and FIG. 7 is a schematic diagram showing data contents of the tightening state storage circuit in the device shown in FIG. 6. .

Claims (1)

[Claims] A torque detecting means connected to a rotational power source that drives the nut gripping tool, a first reference torque when the nut contacts a member to be tightened in a normal approach state is set, and a signal from the torque detecting means is set. contact detection means that outputs a signal when the reference torque is exceeded; at least one second reference torque during the tightening process in a normal tightening state; a third reference torque at the time of completion of tightening; determining the standard tightening state storage means in which the path length to reach the third reference torque is set, and the manner in which the second and third reference torques are reached;
An automatic nut tightening device comprising determining means for stopping the rotary power source when the second and third reference torques have been passed with a predetermined path length and when the rotating power source cannot be passed normally.