JP7404146B2 - Rotation status judgment device - Google Patents

Description

The present invention relates to a rotational state determining device.

Conventionally, when coating a web such as a film with a coating liquid, rolls have been used to transport the long web. For example, a backup roll is placed near the die, a pump pumps the coating liquid into a liquid reservoir inside the die, and the web held and conveyed by the backup roll is conveyed from the discharge port of the die leading to this liquid reservoir. Apply the coating liquid to.

Patent No. 5593967

In the above-mentioned coating apparatus, rotation failure may occur due to changes in the roll itself or its bearings over time, or due to assembly accuracy.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a rotational state determining device that can determine the rotational state of a rotating body and a support portion that supports the rotating body when the rotating body is rotated by a motor.

The present invention provides a motor for rotating a rotating body rotatably supported by a support part, a current detecting means for detecting a drive current of the motor as a detected value I(t) as a time for measuring t, and a current detecting means for detecting a drive current of the motor as a detected value I(t). a torque detection means for detecting the torque T(t), a conversion means for converting the torque T(t) into a current value to obtain a converted value Ik(t), and the detected value I(t) and the converted value. An estimated regenerative current d(t) is obtained from Ik(t), and a matching rate e within the measurement time range t0 is calculated from this estimated regenerative current d(t), and the lower the matching rate e, the more the rotating body or The rotational state determining device includes: determining means for determining that the rotational state of the support portion is poor.

According to the present invention, the rotational state of the rotating body or the support portion can be determined based on the matching rate e.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of a rotation state determination device showing an embodiment of the present invention. It is a flowchart for calculating a matching rate. FIG. 3 is an explanatory diagram of an experiment using an air clutch. It is an explanatory diagram of an experiment when there is a failure in a bearing. It is a table showing data of an experiment when using an air clutch. 2 is a table showing data of experimental results when there is a failure in the bearing. It is a graph of Experiment 1. It is a graph of Experiment 2. This is a graph of Experiment 3. This is a graph of Experiment 4. This is a graph of Experiment 5. This is a graph of Experiment 6. It is a graph of Experiment 7. It is a graph of Experiment 8. This is a graph of Experiment 9. It is a graph of Experiment 10.

Hereinafter, a rotational state determining device 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 16. The rotational state determining device 10 of this embodiment is provided in a conveying device 12 that conveys the web W using rolls 14.

(1) Conveyance device 12
The transport device 12 will be explained with reference to FIG. The conveyance device 12 conveys the web W using rolls 14 . Examples of the elongated web W include film, metal foil, paper, and cloth. The roll 14 is made of metal or rubber, for example.

A base 20 is placed on a horizontal floor, and a pair of left and right legs 22 and 24 are erected from the base 20. A ball bearing (hereinafter referred to as "bearing") 26 is provided on the left leg 22, and a bearing 28 is provided on the right leg 24. A pair of left and right rotating shafts 16 and 18 protruding from the roll 14 are rotatably supported by a pair of left and right bearings 26 and 28, respectively. As a result, the roll 14 is horizontally arranged and rotated to convey the web W.

A motor 30 that rotates the roll 14 is provided with a speed reduction device 32 , and a drive shaft 34 protrudes from the speed reduction device 32 and is connected to the rotation shaft 16 on the left side of the roll 14 via a coupling device 36 . The motor 30 is, for example, an AC servo motor, and is rotated by a drive circuit 38.

The drive circuit 38 is connected to the control unit 40 and can control the rotation direction and rotation speed via the drive circuit 38. Further, through the drive circuit 38, the drive current I(t) and torque T(t) for rotating the motor 30 can be detected in time series.

A control unit 40 consisting of a computer can control the rotation speed and rotation direction of the motor 30 by an operator's operation, and the roll 14 rotates based on the rotation speed and rotation direction to convey the web W. The control unit 40 obtains a match rate e, which will be explained in detail later. The matching rate e is a value that can be determined to be normal in the rotational state of the roll 14 itself or the bearings 26 and 28 supporting the roll 14 if it is larger than the normal reference value b. This matching rate e will be explained next. Note that the "rotating state" means that the roll 14 is in a good rotating state when the roll 14 is normal, and the roll 14 itself has uneven weight and is unbalanced when rotating, or the left and right pair is unbalanced. When the rotation axes 16 and 18 are misaligned and cannot rotate along horizontal axes, the rotational condition is poor.As for the bearings 26 and 28, when the bearings 26 and 28 are normal, the rotational condition is good; If there is insufficient oil between the balls, inner ring, and outer ring, and friction occurs, the rotational condition will be poor.

(2) Match rate e
The inventor conducted a study to be able to objectively judge the rotational state of rolls and bearings, and focused on the regenerative current of the motor. The regenerative current of the motor increases if the rotational conditions of the rolls, bearings, etc. are poor. However, since this regenerative current cannot be directly measured from the motor, the inventor focused on the motor drive current and torque, and considered the matching rate e related to the regenerative current from both of them. Hereinafter, the definition of the match rate e will be explained according to the method for determining the match rate e. The flowchart in FIG. 2 is a flowchart illustrating the arithmetic processing performed by the control unit 40 to obtain the match rate e.

In step S1, the control unit 40 initializes the count C=0 and the time t=0. This count C will be explained later. t is a chronological time during measurement within the measurement time range t0. Then, the process advances to step S2.

In step S2, the control unit 40 measures the drive current I(t) and torque T(t) of the motor 30 at time t. These I(t) and T(t) are measured by the control unit 40 through the drive circuit 38. Then, the process advances to step S3.

In step S3, the control unit 40 converts the detected torque T(t) into a converted value Ik(t) corresponding to the current value using the following equation (1).

Ik(t)=I0*T(t)/T0...(1)

However, I0 is the rated current of the motor 30, and T0 of the motor 30 is the rated torque. Then, the process advances to step S4.

In step S4, the control unit 40 calculates the estimated regenerative current d(t) using the following equation (2), and compares it with the allowable range a of the estimated regenerative current.

d(t)=|Ik(t)-I(t)|>a...(2)

The estimated regenerative current d(t) is not the value of the regenerative current itself, but is a value related to the value of this regenerative current. a is an allowable range, for example, the resolution accuracy of the current value measured by the drive circuit 38. If the estimated regenerative current d(t) is smaller than the allowable range a, the rotation state at time t is considered good and the process proceeds to step S6 (in the case of n); if it is larger, the rotation state at time t is considered bad and the process proceeds to step S5 ( y).

In step S5, the control unit 40 increments the count C by 1 and proceeds to step S6. This count C counts when the estimated regenerative current d(t) at time t is larger than the allowable range a and the rotational state is poor.

In step S6, the control unit 40 sets the time to t=t+1 and proceeds to step S7.

In step S7, if the time t is greater than the predetermined measurement time range t0 (for example, 80 seconds), the measurement is determined to have ended and the process proceeds to step S8; if it is smaller, the process returns to step S2 to continue the measurement and performs the measurement again.

In step S8, the control unit 40 calculates the match rate e (%) within the measurement time range t0 from the following equation (3), and compares the match rate e (%) with the normal reference value b.

Match rate e=(C0-C)/CO*100=>b...(3)

However, C0 is the number measured within the measurement time range t0, and b is a predetermined normal reference value for determining whether the rotational state is good or bad, and is, for example, 95%. If the matching rate e is larger than the normal reference value b, it is determined that the rotational condition within the measurement time range t0 is good and the process proceeds to step S9 (in the case of y); if it is smaller, the rotational condition within the measurement time range t0 is determined to be bad and the process proceeds to step S10. Proceed to (in case of n).

In step S9, since the count C is larger than the normal reference value b, the control unit 40 determines that the roll 14 and the bearings 26 and 28 connected to the motor 30 are normal, and the process ends.

In step S10, since the count C is smaller than the normal reference value b, the control unit 40 determines that there is an abnormality in the roll 14, the bearing 26, or the bearing 28, and ends the process.

This determination may be made in real time all the time, but may also be made, for example, once a day, once a week, or once a month using a predetermined measurement time range t0.

The following experiments 1 to 10 will prove that this idea is correct.

(3) Experiments 1 to 6
In order to prove the above theory, the inventor conducted experiments 1 to 6 in which the rotational state of the roll 14 was determined based on the matching rate e. In this case, instead of the roll 14, a rotating shaft 44 connected to the coupling device 36 was attached to the air clutch 42. Note that this rotating shaft 44 is rotatably supported by normal bearings 26 and 28 filled with oil and fat.

Experiments were conducted both when an air pressure of 0.06 MPa was applied to the air clutch 42 (with rotational resistance) and when the air clutch 42 was not used at all (with no rotational resistance). When an air pressure of 0.06 MPa is applied, this is a model when the roll 14 is in a bad rotation state, and when no air clutch 42 is used, it is a model when the roll 14 is in a good rotation state. It is assumed that no force is applied to the rotating shaft 44, that is, 0 kg.

The results of this experiment are shown in the table of FIG. In Experiments 1 to 6, Experiments 1, 3, and 5 are in a normal state in which the air clutch 42 is not used, and Experiments 2, 4, and 6 are in a faulty state in which the air clutch 42 is used. The rotating shaft 44 was rotated at a rotation speed of 50 rpm in Experiments 1 and 2, 150 rpm in Experiments 3 and 4, and 300 rpm in Experiments 5 and 6. In the graphs of FIGS. 7 to 12, the vertical axis is the value of current (A), and the horizontal axis is time t (seconds). Moreover, the black circles represent the detected value I(t) of the drive current actually detected, and the white circles represent the converted value Ik(t).

In Experiment 1, the match rate e was 100% as shown in FIG. 7, and it can be determined that it is normal. In this experiment, it was determined based on the match rate e that the air clutch 42 was not used and was in a normal state.

In Experiment 2, as shown in FIG. 8, the match rate e was 87.1%, which was lower than the normal reference value of 95% and could be judged to be abnormal. In this experiment, it was determined based on the matching rate e that the air clutch 42 was being used in an abnormal state.

In Experiment 3, the match rate e was 100% as shown in FIG. 9, and it can be determined that it is normal. In this experiment, it was determined based on the match rate e that the air clutch 42 was not used and was in a normal state.

In Experiment 4, as shown in FIG. 10, the match rate e was 88.9%, which is lower than the normal reference value of 95% and can be judged to be abnormal. In this experiment, it was determined based on the matching rate e that the air clutch 42 was being used in an abnormal state.

In Experiment 5, the matching rate e was 100%, as shown in FIG. It can be determined that it is normal. In this experiment, it was determined based on the match rate e that the air clutch 42 was not used and was in a normal state.

In Experiment 6, as shown in FIG. 12, the match rate e was 92.2%, which was lower than the normal reference value of 95% and could be judged to be abnormal. In this experiment, it was determined based on the matching rate e that the air clutch 42 was being used in an abnormal state.

In this way, when rotational resistance is generated by the air clutch 42, the match rate e becomes smaller than the normal reference value b, and it can be determined that the rotational state of the roll 14 is poor based on the match rate e.

(4) Experiments 7 to 10
Next, experiments 7 to 10 were conducted in which the rotational state of the bearing 28 was determined based on the matching rate e of the bearing 26. In this case, if the oil and fat inside the bearings 26 and 28 are removed, the rotational condition is considered to be bad, and if there is oil and fat as usual, it is considered to be normal. A weight 46 was attached to the rotating shaft 44 in place of the weight of the roll 14. Note that this weight 46 is rotatable together with the rotating shaft 44.

In Experiments 7 and 9, there was oil, and in Experiments 8 and 10, there was no oil. Further, as operating conditions, the weight 46 is 300 kg, the rotation speed of the rotating shaft 44 is 200 rpm in Experiments 47 and 8, and 300 rpm in Experiments 9 and 10. The results of this experiment are shown in the table of FIG. In the graphs of FIGS. 13 to 16, the vertical axis is the value of current (A), and the horizontal axis is time t (seconds). Moreover, the black circles represent the detected value I(t) of the drive current actually detected, and the white circles represent the converted value Ik(t).

In Experiment 7, as shown in FIG. 13, the matching rate e was 100%, which can be determined to be normal. In this experiment, it was determined that the bearings 26 and 28 were in a normal state with oil and fat.

In Experiment 8, as shown in FIG. 14, the matching rate e was 88.4%, which is lower than the normal reference value of 95%, so it can be determined that it is abnormal. In this experiment, it was determined based on the matching rate e that the bearings 26 and 28 were in an abnormal state with no oil or fat.

In Experiment 9, as shown in FIG. 15, the matching rate e was 97.1%, which is higher than the normal reference value of 95%, so it can be determined to be normal. In this experiment, it was determined based on the match rate e that the bearings 26 and 28 were in a normal state with oil and fat.

In Experiment 10, as shown in FIG. 16, the match rate e was 83.3%, which is lower than the normal reference value of 95%, and therefore can be determined to be abnormal. In this experiment, it was determined based on the matching rate e that the bearings 26 and 28 were in an abnormal state with no oil or fat.

In this way, if the rotational state of the bearings 26 and 28 is also poor, it can be determined based on the match rate e.

(5) Effects According to the present embodiment, by measuring the driving current and torque of the motor 30 in time series and determining the matching rate e, it is possible to determine whether the rotational state of the roll 14 and the bearings 26, 28 is good or bad. You can judge whether

Example of change

In the above embodiment, the roll 14 has been described, but the roll 14 is not limited to one used in a coating device and may be any other roll as long as it is rotated by a motor.

In the above embodiment, the roll 14 is used as the rotating body, and the bearings 26 and 28 are used as the supporting parts, but instead of this, a door and a bearing that opens and closes, a motor and a bearing that rotates an arm in a robot's work, etc. may be used. good.

Although one embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and gist of the invention, as well as within the scope of the invention described in the claims and its equivalents.

DESCRIPTION OF SYMBOLS 10... Rotation state determination device, 12... Conveyance device, 14... Roll, 16... Rotating shaft, 18... Rotating shaft, 26... Bearing, 28... Bearing, 30... ... Motor, 32 ... Speed reduction device, 34 ... Drive shaft, 36 ... Coupling device, 38 ... Drive circuit, 40 ... Control unit

Claims (7)

a motor that rotates a rotating body rotatably supported by a support part;
current detection means for detecting the drive current of the motor as a detection value I(t), where t is a measurement time;
Torque detection means for detecting torque T(t) of the motor;
a conversion means for converting the torque T(t) into a current value to obtain a converted value Ik(t);
An estimated regenerative current d(t) is obtained from the detected value I(t) and the converted value Ik(t), and a matching rate e within the measurement time range t0 is obtained from the estimated regenerative current d(t). a determining means for determining that the smaller the ratio e is, the worse the rotating state of the rotating body or the supporting portion is;
A rotation state determination device having: When the converted value is the rated current of the motor as I0 and the rated torque of the motor as T0, the conversion means converts the converted value Ik(t) into:

Ik(t)=I0*T(t)/T0

The rotation state determination device according to claim 1, wherein the rotation state determination device determines the rotation state from the following. The determining means determines that the estimated regenerative current d(t) at time t is:

d(t)=|Ik(t)−I(t)|

Within the measurement time range t0,

d(t)>a

Count the number C that satisfies (however, a is within a predetermined tolerance range), and from this count C

Match rate e (%) = (C0-C)/CO*100

(however, C0 is the number measured in the measurement time range t0),
The rotational state determining device according to claim 2. The determining means is
When the matching rate e is larger than a predetermined normal reference value b, it is determined to be normal, and when it is smaller, it is judged to be abnormal;
The rotational state determining device according to claim 3. The support part is a bearing,
The rotating body is a roll,
The rotational state determining device according to claim 1. Detecting a drive current value I(t) and a torque T(t) of a motor that rotates a rotating body rotatably supported by a support part,
Converting the torque T(t) into a current value to obtain a converted value Ik(t),
Determining an estimated regenerative current d(t) from the detected value I(t) and the converted value Ik(t),
Determine the matching rate e within the measurement time range t0 from the estimated regenerative current d(t),
It is determined that the smaller the matching rate e is, the worse the rotational state of the rotating body or the support part is.
How to judge rotation status. to the computer,
Detecting a drive current value I(t) and a torque T(t) of a motor that rotates a rotating body rotatably supported by a support part,
Converting the torque T(t) into a current value to obtain a converted value Ik(t),
Determining an estimated regenerative current d(t) from the detected value I(t) and the converted value Ik(t),
Determine the matching rate e within the measurement time range t0 from the estimated regenerative current d(t),
It is determined that the smaller the matching rate e is, the worse the rotational state of the rotating body or the support part is.
Rotation status judgment program for executing certain tasks.

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