JP2000117357A - Vibration tool work judgment device - Google Patents

Abstract

(57) [Summary] [Problem] To accurately judge whether or not work with a vibrating tool has been performed normally. SOLUTION: A vibration sensor is attached to a vibration tool such as caulking impact, and a vibration waveform of the vibration tool is detected by the vibration sensor. During the two seconds starting 0.1 seconds after the start of the operation of the vibrating tool, the number of the bottom values of the detected vibration waveform that are below the lower limit value _Vmin is counted, and the operation is performed when the counted number is four or more. Is determined to have been performed normally. Since the bottom value of the vibration waveform is high in an abnormal state where the vibrating tool is idling, the number of counts of the bottom value of the vibration waveform below the lower limit value _Vmin does not become four or more. Determines that the work is not performed normally and issues an alarm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration sensor for detecting vibration associated with the operation of a vibration tool, and a confirmation means for judging whether or not the work by the vibration tool has been normally performed based on the waveform of the detected vibration. And a work determination device for a vibrating tool comprising:

[0002]

2. Description of the Related Art In a bolt and nut tightening device for automatically tightening bolts and nuts, a torque sensor is arranged in a torque transmission system from a motor as a drive source to a rotating shaft having a socket, and the torque sensor detects the torque. A motor that stops driving the motor when the tightening torque reaches a specified value and ends the tightening operation is known from Japanese Patent No. 2540710.

[0003]

By the way, in such a bolt and nut tightening device, it can be determined whether or not the tightening work has been normally performed based on whether or not the tightening torque has reached a specified value. With a vibrating tool, such as Impact, which caulks a part of a nut that is screwed into a bolt to prevent loosening of the nut, it is not possible to make a determination based on the torque described above. It is necessary to determine whether or not it has been done.

[0004] The present invention has been made in view of the above-described circumstances, and has as its object to accurately determine whether or not work by a vibrating tool has been normally performed.

[0005]

In order to achieve the above object, the invention described in claim 1 comprises a vibration sensor for detecting vibration accompanying the operation of a vibration tool, and a vibration sensor based on a waveform of the detected vibration. A determining means for determining whether or not the work by the tool has been performed normally, the work determining apparatus for a vibrating tool, wherein the determining means determines a bottom of a vibration waveform within a predetermined period during operation of the vibrating tool. Count the number of values below the lower limit among the values, judge that the work was performed normally when the count number was above the reference value, and that the work was not performed normally when the count number was less than the reference value It is characterized by determining.

According to the above configuration, the number of the bottom values of the vibration waveforms that are below the lower limit value among the bottom values of the vibration waveform within a predetermined period during the operation of the vibration tool is counted. When a heavy workload is applied, the bottom value of the vibration waveform decreases, so that the count number exceeds the reference value and it can be determined that the work was performed normally. If the operation is not performed normally and a sufficient workload is not applied, the bottom value of the vibration waveform is increased, so that the count number is less than the reference value and it is determined that the operation is not performed normally. be able to. As described above, by paying attention to the bottom value of the waveform of the vibration that changes according to the magnitude of the work load, it is possible to accurately determine whether or not the work has been normally performed,
In addition, since the number of bottom values below the lower limit value is counted within a predetermined period, more accurate determination can be made by eliminating the influence of noise and the like.

According to a second aspect of the present invention, in addition to the first aspect, the predetermined period starts with a time delay from the start of the operation of the vibrating tool.

According to the above configuration, the predetermined period for determining whether or not the work has been performed normally starts with a time delay from the start of the operation of the vibrating tool. And the determination accuracy can be improved.

According to a third aspect of the present invention, in addition to the configuration of the first aspect, an alarm is issued when the determining means determines that the work has not been performed normally.

According to the above configuration, an alarm is issued when the work by the vibrating tool is not performed normally, so that the operator can be notified of the occurrence of the abnormal state and prompted to take appropriate measures.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

1 to 3 show an embodiment of the present invention. FIG. 1 is an overall configuration diagram of a work confirming device for a vibrating tool.
Is a graph showing a vibration waveform in a normal state, and FIG. 3 is a graph showing a vibration waveform in an abnormal state.

As shown in FIG. 1, a bolt 1 protruding from the upper end of a suspension damper is passed through the upper wall of a wheel house and fastened with a nut 2 in an automobile production line. The tool is caulked with the caulking impact 3 to prevent loosening. Caulking Impact 3 is provided with a crimping head 5 to reciprocally vibrate in air supplied from the air supply source 4, the inside of the groove portion 1 ₁ of the bolt 1 by abutting the caulking head 5 to the flange 2 ₁ of the nut 2 It is designed to be crimped to fit into.

A vibration sensor 6 is provided on the grip portion of the caulking impact 3, and the output of the vibration sensor 6 is amplified by an amplifier 7 and input to an analog controller 8. The analog controller 8 constituting the determination means of the present invention analyzes the waveform of the vibration amplified by the amplifier 7 and determines whether the caulking operation by the caulking impact 3 has been performed normally. The determination result is input to the sequencer 9, and when it is determined that the caulking operation was not performed normally,
The alarm means 10 consisting of a buzzer and a lamp is activated by a command from the sequencer 9 to issue an operator's alarm,
The conveyor 11 of the production line is stopped.

The graphs shown in FIGS. 2 and 3 show vibration waveforms obtained by amplifying the output of the vibration sensor 6 provided for the impact 3 by the amplifier 7. FIG. 2 shows that the caulking head 5 of the impact 3 is correct. FIG. 3 corresponds to a state in which the caulking head 5 is not in contact with the nut 2 and the caulking operation is normally performed.

In general, when a load acts on the caulking head 5 of the caulking impact 3, the bottom value (valley valley value) of the vibration waveform is low.
The bottom value tends to increase during idle driving when no load is applied to the tire. Therefore, a lower limit value V _min that is higher than a normal bottom value in a normal state and lower than a general bottom value in an abnormal state is set in advance, and a predetermined time delay from the start of the operation of the caulking impact 3 (for example, during a predetermined time period which is initiated with a 0.1 sec) (e.g., 2 seconds), counts the number of those below the lower limit value V _min among the bottom value of the waveform. The start of the operation of the caulking impact 3 can be detected, for example, based on the operation of a switch for commanding the operation and the stop of the caulking impact 3.

Therefore, during the operation of the caulking impact 3,
Lower limit value V within a predetermined period of 2 seconds _minLess than
If the bottom count is greater than the reference value (for example, 4 times)
Then, the analog controller 8 has the caulked impact 3
It is determined that the caulking work has been performed correctly. Mark in Figure 2
The numbers a, b, c and d are lower limit values V_minBottom of waveform below
The first to fourth data values are shown. Meanwhile, Scarecrow
In the case where the impact 3 hit
As shown in FIG._minWaveform below
Count value of the bottom value does not exceed the reference value
Therefore, when the predetermined period elapses, the analog control
The caulking work is performed correctly when impact 3
It is determined that it has not been done.

As described above, when the analog controller 8 determines that the caulking impact 3 is not correctly caulking, the alarm means 10 is activated by a command from the sequencer 9 and an alarm is issued to urge the operator to take appropriate countermeasures. Is issued, and the conveyor 11 of the production line is temporarily stopped until the treatment is completed. As a result, it is possible to prevent a situation in which an incomplete product flows on the conveyor 11 of the production line without completing the caulking operation.

Further, since the detected vibration waveform is not stable immediately after the start of the operation of the impact 3, the bottom value of the waveform may be lower than the lower limit value V _min even in an abnormal state. Since 0.1 seconds after the start is set as the start point of the predetermined period in which the determination is performed, counting can be started after the vibration waveform is stabilized, and occurrence of erroneous determination can be effectively prevented. In addition, since the reference value of the bottom number count is set to a plurality of times (four times), even if the bottom value of the waveform generated due to noise or the like is erroneously counted, the caulking impact 3 is correctly performed. Is not erroneously determined to have been performed.

Although the embodiments of the present invention have been described in detail above, various design changes can be made in the present invention without departing from the gist thereof.

For example, in the embodiment, the predetermined period is set to 2 seconds, the time delay is set to 0.1 seconds, and the reference value is set to 4 times, but these values can be changed as appropriate. The vibrating tool is not limited to the caulking impact 3 of the embodiment.

[0022]

As described above, according to the first aspect of the present invention, the number of the bottom values of the vibration waveform which are below the lower limit value within the predetermined period during the operation of the vibration tool is counted. If the work with the vibrating tool was performed normally and a sufficient work load was applied, it was determined that the work was performed normally because the count value became equal to or more than the reference value because the bottom value of the vibration waveform was reduced. If the work with the vibrating tool is not performed normally and a sufficient workload is not applied, the count value becomes less than the reference value because the bottom value of the vibration waveform increases. As a result, it can be determined that the work is not performed normally. In this way, by paying attention to the bottom value of the waveform of the vibration that changes according to the magnitude of the work load, it is possible to accurately determine whether or not the work has been performed normally. Is counted, the influence of noise and the like can be eliminated, and a more accurate determination can be made.

According to the invention described in claim 2,
Since the predetermined period for determining whether or not the work has been performed normally starts with a time delay from the start of the operation of the vibrating tool, it is possible to prevent the determination from being performed in an unstable state immediately after the start of the operation of the vibrating tool. Thus, the determination accuracy can be improved.

According to the third aspect of the present invention,
Since an alarm is issued when the work by the vibrating tool is not performed normally, it is possible to notify the worker of the occurrence of the abnormal state and to prompt an appropriate measure.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a work confirmation device for a vibration tool.

FIG. 2 is a graph showing a vibration waveform in a normal state.

FIG. 3 is a graph showing a vibration waveform at the time of abnormality.

[Explanation of symbols]

3 Impact (vibration tool) 6 Vibration sensor 8 Analog controller (judgment means) V _min lower limit

Claims (3)

[Claims] 1. A vibration sensor (6) for detecting vibration associated with the operation of a vibration tool (3), and determining whether or not the work by the vibration tool (3) has been normally performed based on a waveform of the detected vibration. And a determining means (8) for determining the operation of the vibrating tool, wherein the determining means (8) determines a value of the bottom value of the vibration waveform within a predetermined period during the operation of the vibrating tool (3). Count the number below the lower limit ( _Vmin ), and when the count is equal to or greater than the reference value, determine that the work was performed normally,
A work judging device for a vibrating tool, wherein it is judged that the work was not performed normally when the count number is less than a reference value. 2. The work judging device for a vibration tool according to claim 1, wherein the predetermined period starts with a time delay from the start of the operation of the vibration tool. 3. The work judging device for a vibrating tool according to claim 1, wherein an alarm is issued when the judging means judges that the work was not performed normally.