JP6686972B2 - Electromagnetic mechanism state diagnosis method and state diagnosis apparatus - Google Patents

Description

  The present invention relates to a technique for diagnosing a state of an electromagnetic mechanism that operates electromagnetically, such as a motor braking mechanism and a clutch.

  Electromagnetic mechanisms that operate electromagnetically, such as motor braking mechanisms and clutches, are used in various technical fields. For example, many electromagnetic mechanisms are incorporated into articulated robots for producing vehicles.

  Patent Document 1 discloses a technique for diagnosing a brake state. The technique of Patent Document 1 sets a diagnosis mode for diagnosing the state of the brake. According to Patent Document 1, the voltage is detected in the diagnostic mode. The detected voltage data is used for diagnosing the state of the brake.

JP, 2015-100878, A

  The diagnostic technique of Patent Document 1 requires setting of a diagnostic mode. Therefore, the diagnostic technique of Patent Document 1 requires suspension of the use of a device (for example, a robot) incorporating a brake. In addition, the diagnostic technique of Patent Document 1 requires repeated voltage drop work in order to determine the voltage for diagnosing the state of the brake. This means that the brake state diagnosis takes a long time.

  It is an object of the present invention to provide a technique that enables quick diagnosis of the state of an electromagnetic mechanism without interrupting the use of a device incorporating the electromagnetic mechanism.

A state diagnosis method according to an aspect of the present invention is provided with a coil that generates a magnetic flux so as to separate a movable iron core that sandwiches a sandwiching member in cooperation with a fixed member from the fixed member in response to supply of an exciting current. It is used for diagnosing the condition of an electromagnetic mechanism having a fixed iron core. State diagnosis method, measuring the time change of the excitation current, the step of generating current data representing the time change, based on the current data, a layer of wear powder between the movable iron core and the fixed iron core. Determining whether formation has occurred in the electromagnetic mechanism. The step of determining whether or not the layer formation has occurred in the electromagnetic mechanism is such that if the maximum value at which the exciting current turns from increase to decrease is not found from the current data, the layer formation is caused by the electromagnetic mechanism. If the maximum value and the minimum value at which the excitation current turns from the decrease to the increase are found from the current data, the difference value between the maximum value and the minimum value. Is compared with a predetermined threshold value, and if the difference value is below the threshold value, it is determined that the layer formation is occurring in the electromagnetic mechanism.

  According to the above configuration, since the sandwiching member of the electromagnetic mechanism is sandwiched between the movable iron core and the fixed member, the sandwiching member is inevitably worn. Abrasion powder generated as a result of wear of the holding member may be accumulated between the fixed iron core and the movable iron core. As a result, the abrasion powder may hinder the movement of the movable iron core.

  The step of measuring the time change of the exciting current and generating the current data representing the time change may be performed in an environment where a device incorporating the electromagnetic mechanism is normally used. Therefore, the state diagnosis method does not require temporary suspension of use of the device incorporating the electromagnetic mechanism.

  When the exciting current is increased and exceeds a predetermined value, the movable iron core approaches the fixed iron core. The movement of the movable iron core results in a change in magnetic flux. As a result, the coil generates a back electromotive force according to Lenz's law. The counter electromotive force generated by the coil causes a current in the opposite direction to the exciting current. Therefore, if the movable iron core moves properly, the maximum value at which the exciting current turns from increasing to decreasing appears in the current data. On the other hand, the fact that the maximum value at which the exciting current turns from increasing to decreasing does not appear in the current data means that the movable core has not moved in the electromagnetic mechanism. Therefore, the state of the electromagnetic mechanism is accurately diagnosed by detecting the presence or absence of the maximum value in the current data representing the time change.

Unlike conventional diagnostic techniques that require repeated voltage drop work, the state diagnostic method involves diagnosing the state of the electromagnetic mechanism by generating current data representing the time change of the exciting current and analyzing the current data. It does not require any special operation for diagnosis as it allows. Therefore, the state of the electromagnetic mechanism is quickly diagnosed . When the abrasion powder forms a layer between the movable iron core and the fixed iron core, the moving amount of the movable iron core decreases by the thickness of the layer. The decrease in the moving amount of the movable iron core appears in the current data as a decrease in the difference value between the maximum value and the minimum value. According to the above configuration, since the difference value between the maximum value and the minimum value is compared with a predetermined threshold value, the formation of the layer of wear powder between the movable iron core and the fixed iron core is quick and accurate. To be diagnosed .

Regarding the above configuration, the step of determining whether or not the layer formation occurs in the electromagnetic mechanism is such that if the maximum value or the minimum value does not appear within a predetermined period, the layer formation is the electromagnetic field. Determining that the mechanism has occurred.

  When the movement of the movable iron core is stopped by the fixed iron core, the counter electromotive force disappears. As a result, the exciting current increases until it reaches a steady state. Therefore, if the movable iron core is properly moving in the electromagnetic mechanism, the minimum value at which the exciting current turns from decrease to increase appears after the maximum value.

  If the holding member is very worn, the moving distance of the movable core becomes long. The increase in the moving distance of the movable iron core results in the extension of the period until the time when the maximum value or the minimum value appears in the current data. According to the above configuration, if the maximum value or the minimum value does not appear within the predetermined period, it is determined that an abnormality has occurred in the electromagnetic mechanism. Will be diagnosed.

Regarding the above configuration, the state diagnosis method, in the step of determining whether the layer formation is occurring in the electromagnetic mechanism, if it is determined that the layer formation is occurring in the electromagnetic mechanism, The method may further include the step of generating a wear warning signal indicating that the holding member is worn.

According to the above structure, in determining whether the layer formation has occurred in the electromagnetic mechanism, if the layer forming a determination is made that the generated electromagnetic mechanism, the wear of the clamping member has occurred Since the wear warning signal indicating that is generated, an operator who diagnoses the electromagnetic mechanism can specify the content of layer formation .

Regarding the above configuration, the state diagnosis method, in the step of determining whether the layer formation is occurring in the electromagnetic mechanism, if it is determined that the layer formation is occurring in the electromagnetic mechanism, The method may further include the step of generating a clogging warning signal indicating that clogging has occurred between the movable iron core and the fixed iron core.

According to the above configuration, during the in determining whether the layer formation has occurred in the electromagnetic mechanism, if the layer forming a determination is made that the generated electromagnetic mechanism, a stationary iron core and the movable core Since the clogging warning signal indicating that the clogging has occurred is generated, the operator who diagnoses the electromagnetic mechanism can specify the content of the layer formation .

A state diagnosis device according to another aspect of the present invention is provided with a coil that generates a magnetic flux so as to separate a movable iron core that sandwiches a sandwiching member in cooperation with a fixing member from the fixing member in response to supply of an exciting current. It is used for diagnosing the condition of the electromagnetic mechanism having a fixed iron core. The state diagnostic device measures a time change of the exciting current, and a data generation unit that generates current data representing the time change, and based on the current data, wear powder between the movable iron core and the fixed iron core. And a determination unit that determines whether or not the layer formation is occurring in the electromagnetic mechanism. If the maximum value at which the excitation current changes from increase to decrease is not found from the current data, the determination unit determines that the layer formation occurs in the electromagnetic mechanism, and determines the maximum value and the excitation current. If the minimum value that turns from the decrease to increase is found from the current data, the difference value between the maximum value and the minimum value is compared with a predetermined threshold value, and the difference value is the threshold value. If it is below, it is determined that the layer formation occurs in the electromagnetic mechanism.

According to the above configuration, since the sandwiching member of the electromagnetic mechanism is sandwiched between the movable iron core and the fixed member, the sandwiching member is inevitably worn. Abrasion powder generated as a result of wear of the holding member may be accumulated between the fixed iron core and the movable iron core. As a result, the abrasion powder may hinder the movement of the movable iron core.

The data generation unit may measure a time change of the exciting current and generate current data representing the time change under an environment where a device incorporating the electromagnetic mechanism is normally used. The condition diagnostic device can acquire current data without requiring temporary suspension of use of the device in which the electromagnetic mechanism is incorporated.

When the exciting current is increased and exceeds a predetermined value, the movable iron core approaches the fixed iron core. The movement of the movable iron core results in a change in magnetic flux. As a result, the coil generates a back electromotive force according to Lenz's law. The counter electromotive force generated by the coil causes a current in the opposite direction to the exciting current. Therefore, if the movable iron core moves properly, the maximum value at which the exciting current turns from increasing to decreasing appears in the current data. On the other hand, the fact that the maximum value at which the exciting current turns from increasing to decreasing does not appear in the current data means that the movable core has not moved in the electromagnetic mechanism. Therefore, the determination unit can confirm the presence or absence of the maximum value in the current data representing the time change and accurately diagnose the state of the electromagnetic mechanism.

Unlike conventional diagnostic techniques that require repeated voltage drop work, the state diagnostic device can diagnose the state of the electromagnetic mechanism by generating current data representing the time change of the exciting current and analyzing the current data. , Does not require any special operation for diagnosis. Therefore, the state of the electromagnetic mechanism is quickly diagnosed. When the abrasion powder forms a layer between the movable iron core and the fixed iron core, the moving amount of the movable iron core decreases by the thickness of the layer. The decrease in the moving amount of the movable iron core appears in the current data as a decrease in the difference value between the maximum value and the minimum value. According to the above configuration, since the difference value between the maximum value and the minimum value is compared with a predetermined threshold value, the formation of the layer of wear powder between the movable iron core and the fixed iron core is quick and accurate. To be diagnosed .

With regard to the above configuration, the data generation unit may include a Hall sensor.

According to the above configuration, since the data generating unit includes the Hall sensor, the time change of the exciting current can be accurately represented in the current data.

Regarding the above configuration, the data generation unit may include a DC battery that supplies electric power to the Hall sensor.

According to the above configuration, since the data generation unit includes the DC battery that supplies the electric power to the hall sensor, noise is less likely to get on the current data.

  With regard to the above configuration, the electromagnetic mechanism may be a braking mechanism of a motor. The sandwiching member may be a brake plate.

  According to the above configuration, the state diagnosis device can accurately and quickly diagnose the state of the braking mechanism of the motor.

  With regard to the above configuration, the electromagnetic mechanism may be a clutch mechanism. The sandwiching member may be a clutch plate.

  According to the above configuration, the state diagnosis device can accurately and quickly diagnose the state of the clutch mechanism.

  The condition diagnosis technique described above allows a quick diagnosis of the condition of the electromagnetic mechanism without interrupting the use of the device in which the electromagnetic mechanism is incorporated.

1 is a schematic block diagram of an exemplary condition diagnosis device. It is a schematic sectional drawing of the braking mechanism used as an electromagnetic mechanism diagnosed by the state diagnostic device shown in FIG. 3 is a schematic graph showing a change over time of an exciting current obtained when the braking mechanism shown in FIG. 2 is normally operating. 6 is a flowchart showing an exemplary process executed by a determination unit of the state diagnostic device shown in FIG. 1. 3 is a schematic graph showing a relationship between a thickness of a layer of wear powder formed between a movable iron core and a fixed iron core of the braking mechanism shown in FIG. 2 and a change with time of an exciting current. 6 is a flowchart showing an exemplary process executed by a determination unit of the state diagnostic device shown in FIG. 1. 3 is a schematic graph showing a relationship between a thickness of a brake plate of the braking mechanism shown in FIG. 2 and a change with time of an exciting current. 6 is a flowchart showing an exemplary process executed by a determination unit of the state diagnostic device shown in FIG. 1. FIG. 2 is a schematic circuit diagram from an ammeter to a computer of the condition diagnostic device shown in FIG. 1. 3 is a graph of output data from a hall sensor used as an ammeter of the state diagnostic device shown in FIG. 1.

  FIG. 1 is a schematic block diagram of an exemplary condition diagnostic device 100. The state diagnosis device 100 will be described with reference to FIG. 1.

  The state diagnostic device 100 includes an ammeter 110 and a computer 120. The ammeter 110 measures the exciting current supplied from the power supply PSC to the coil CIL. The ammeter 110 may be a general hall sensor or another detection device capable of detecting an exciting current. The principle of this embodiment is not limited to a specific detection device used as the ammeter 110.

  The power supply PSC and the coil CIL are used as part of an electromagnetic mechanism (not shown). The electromagnetic mechanism may be a braking mechanism built into the motor. Alternatively, the electromagnetic mechanism may be a common electromagnetic clutch. The principles of this embodiment are not limited to a particular device formed as an electromagnetic mechanism.

  The ammeter 110 may be always incorporated in a circuit for supplying an exciting current from the power supply PSC to the coil CIL. In this case, the ammeter 110 can detect the time change of the exciting current while the electromagnetic mechanism is being used. That is, the worker can acquire the current data representing the time change of the exciting current without interrupting the normal use of the electromagnetic mechanism.

  The electromagnetic mechanism may be incorporated in an articulated robot used for vehicle assembly, welding, and painting. Since the state diagnostic device 100 can obtain current data without disturbing the normal use of the electromagnetic mechanism, the articulated robot performs tasks such as vehicle assembly, welding, and painting during the state diagnosis of the electromagnetic mechanism. Can continue.

  The ammeter 110 produces a detection signal representative of the detected current. The detection signal is output from the ammeter 110 to the computer 120 over time.

  The computer 120 includes a storage unit 121, a determination unit 122, and a signal generation unit 123. The storage unit 121 stores the data of the current value represented by the detection signal over time. As a result, the current data representing the time change of the exciting current is stored in the storage unit 121. The storage unit 121 may be a general hard disk, a USB memory, or another storage medium. The principle of this embodiment is not limited to a specific device used as the storage unit 121. Regarding the present embodiment, the data generation unit is exemplified by the ammeter 110 and the storage unit 121.

  The determination unit 122 reads the current data from the storage unit 121. The determination unit 122 refers to the current data and determines whether or not an abnormality has occurred in the electromagnetic mechanism. The determination unit 122 may be a CPU (Central Processing Unit) that executes a program designed to analyze current data.

  The determination unit 122 generates a determination result indicating whether or not the abnormality has occurred in the electromagnetic mechanism. The determination result is output from the determination unit 122 to the signal generation unit 123. If the abnormality has occurred in the electromagnetic mechanism, the signal generation unit 123 generates a warning signal indicating what abnormality has occurred in the electromagnetic mechanism. The warning signal is output from the signal generation unit 123 to a predetermined warning device (not shown: for example, a monitor device or a voice device). As a result, the abnormality generated in the electromagnetic mechanism is notified to the operator by an image displayed by the monitor device or a sound output from the audio device.

  FIG. 2 is a schematic sectional view of a braking mechanism BRM used as an electromagnetic mechanism. The braking mechanism BRM will be described with reference to FIGS. 1 and 2.

  The braking mechanism BRM is incorporated in a motor (not shown). FIG. 2 schematically shows the motor shaft MSF as part of the motor. The motor shaft MSF extends along a predetermined rotation axis RAX.

  The braking mechanism BRM includes, in addition to the power source PSC and the coil CIL described with reference to FIG. 1, a fixed iron core FIC, a movable iron core AMT, a side plate SPT, a brake plate BRP, a guide rod GRD, a coil spring. And CSP. Each of the fixed iron core FIC, the coil CIL, the movable iron core AMT, the brake plate BRP, and the side plate SPT is an annular member arranged substantially concentric with the rotation axis RAX. The motor shaft MSF penetrates these annular members.

  The fixed iron core FIC is fixed in the extending direction of the rotation axis RAX. The fixed iron core FIC includes a facing surface FSF facing the movable iron core AMT. The guide rod GRD extends from the facing surface FSF in the extending direction of the rotation axis RAX. The side plate SPT is fixed to the tip of the guide rod GRD. Therefore, like the fixed iron core FIC, the side plate SPT is also fixed in the extending direction of the rotation axis RAX. Unlike the fixed iron core FIC and the side plate SPT, the movable iron core AMT is guided by the guide rod GRD and can move in the extending direction of the rotation axis RAX.

  The coil CIL is embedded in an annular groove formed in the facing surface FSF. When the exciting current is supplied from the power supply PSC to the coil CIL, the movable iron core AMT is attracted to the fixed iron core FIC by the magnetic flux generated from the coil CIL.

  A part of the coil spring CSP is embedded in the fixed iron core FIC, while the other part of the coil spring CSP projects from the facing surface FSF. When the attractive force due to the magnetic flux generated from the coil SIL falls below the elastic force of the coil spring CSP, the movable iron core AMT is pushed out toward the side plate SPT by the coil spring CSP.

  The brake plate BRP is arranged between the movable iron core AMT and the side plate SPT. Therefore, when the movable iron core AMT is pushed toward the side plate SPT by the coil spring CSP, the brake plate BRP is sandwiched between the movable iron core AMT and the side plate SPT. In the present embodiment, the fixing member is exemplified by the side plate SPT. The holding member is exemplified by the brake plate BRP.

  The braking mechanism BRM is generally housed in a case (not shown). Therefore, most of the abrasion powder generated by the abrasion of the brake plate BRP collects in the case. As a result, even if the magnetic flux generated from the coil CIL under the supply of the exciting current from the power source PSC to the coil CIL exerts a force on the movable iron core AMT in the direction away from the side plate SPT, the movable iron core AMT is Sometimes you can't attract to the FIC. The abrasion of the brake plate BRP means a decrease in the thickness of the brake plate BRP. A decrease in the thickness of the brake plate BRP results in an increase in the movable distance of the movable iron core AMT. The present inventors have developed a technique for diagnosing the state of the braking mechanism BRM, using the characteristic of the time change of the exciting current obtained when the movable iron core AMT operates normally as a criterion.

  FIG. 3 is a schematic graph showing the time change of the exciting current obtained when the braking mechanism BRM is operating normally. With reference to FIGS. 1 to 3, the time change of the exciting current obtained when the braking mechanism BRM is normally operating will be described.

  The power supply PSC starts supplying the exciting current to the coil CIL from time “0”. The brake plate BRP is sandwiched between the movable iron core AMT and the side plate SPT at time “0”.

  The power supply PSC gradually increases the exciting current until the approach of the movable iron core AMT to the fixed iron core FIC is started. As a result, the movable iron core AMT starts approaching the fixed iron core FIC at time “t1”. When the movable iron core AMT approaches the fixed iron core FIC, the coil CIL generates a counter electromotive force. As a result, a current in the opposite direction to the exciting current flows through the coil CIL. Therefore, the current value measured by the ammeter 110 gradually decreases.

  The movable iron core AMT reaches the facing surface FSF of the fixed iron core FIC at time “t2”. The current value measured by the ammeter 110 continues to fall in the period from time “t1” to time “t2”.

  When the movable core AMT reaches the facing surface FSF, the movable core AMT stops, so that the counter electromotive force disappears. As a result, the current value measured by the ammeter 110 increases to the rated current after the time “t2”.

  If the abrasion powder generated from the brake plate BRP accumulates between the movable iron core AMT and the fixed iron core FIC, the movable iron core AMT may not approach the fixed iron core FIC. In this case, the maximum value at which the current value measured by the ammeter 110 changes from increase to decrease (see the data point at time “t1” in FIG. 3) does not appear in the current data stored in the storage unit 121. That is, the current value measured by the ammeter 110 continues to increase from time “0” and reaches the rated current. Therefore, the determination unit 122 can verify whether or not the maximum value exists in the current data stored in the storage unit 121, and determine whether or not the abnormality has occurred in the braking mechanism BRM.

  FIG. 4 is a flowchart showing an exemplary process executed by the determination unit 122. The process executed by the determination unit 122 will be described with reference to FIGS. 1 and 4.

(Step S110)
The determination unit 122 reads the current data from the storage unit 121. Then, step S120 is executed.

(Step S120)
The determination unit 122 verifies whether the maximum value exists in the current data. If the determination unit 122 finds the maximum value in the current data, step S130 is executed. In other cases, step S140 is executed.

(Step S130)
The determination unit 122 generates a determination result indicating that the braking mechanism BRM is normal. The determination result is output from the determination unit 122 to the signal generation unit 123. The signal generator 123 generates a notification signal indicating the determination result. The notification signal is output to a notification device such as a monitor device or a voice device, and the operator is notified by the notification device that the braking mechanism BRM is normal.

(Step S140)
The determination unit 122 generates a determination result indicating that the braking mechanism BRM is abnormal. The determination result is output from the determination unit 122 to the signal generation unit 123. The signal generator 123 generates a notification signal indicating the determination result. The notification signal is output to a notification device such as a monitor device or a voice device, and the operator is notified by the notification device that an abnormality has occurred in the braking mechanism BRM.

<Other features>
The designer can give various characteristics to the above-mentioned condition diagnosis apparatus 100. The features described below do not limit the design principle of the condition diagnostic device 100 described above.

(Diagnosis using maximum and minimum values)
The above-described diagnostic processing monitors the presence / absence of a maximum value and determines whether the braking mechanism BRM is normal / abnormal. In this case, the abnormality of the braking mechanism BRM may not be detected until the brake plate BRP stops moving. On the other hand, the braking mechanism BRM may need to be repaired before the brake plate BRP becomes stuck. The present inventors have developed a diagnostic technique that makes it possible to detect not only the maximum value but also the minimum value and detect an abnormality in the braking mechanism BRM before the brake plate BRP stops moving. An exemplary diagnostic technique for diagnosing whether or not an abnormality has occurred in the braking mechanism BRM using the maximum value and the minimum value will be described below.

  FIG. 5 is a schematic graph showing the relationship between the thickness “LT” of the layer of wear powder formed between the movable iron core AMT and the fixed iron core FIC, and the time change of the exciting current. With reference to FIGS. 2, 4 and 5, the relationship between the layer thickness “LT” of wear debris and the change in the excitation current with time is explained.

  FIG. 5 shows a state in which the thickness "LT" of the layer of wear powder formed between the movable iron core AMT and the fixed iron core FIC is "0", "x1" (x1> 0), " The state of "x2" (x2> x1), the state of "x3" (x3> x2), and the distance "GAP" between the fixed iron core FIC and the movable iron core AMT pressing the brake plate BRP against the side plate SPT. An equal state (GAP> x3) is shown. When the thickness "LT" of the wear debris layer exceeds "x3", the maximum value does not appear in the current data. In this case, the diagnostic technique described with reference to FIG. 4 is effective. On the other hand, when the thickness "LT" of the abrasion powder layer is less than "x2", the diagnostic technique described with reference to FIG. 4 provides a determination result that the braking mechanism BRM is normal. However, if the layer thickness "LT" of wear debris exceeds "x1", repair of the braking mechanism BRM may be desirable for the environment of use of the device in which the braking mechanism BRM is incorporated. As the layer of wear debris grows (ie, the thickness "LT" of the layer of wear debris increases), the difference value between the maximum and minimum values in the current data becomes smaller. If the difference value between the maximum value and the minimum value when the thickness "LT" of the wear debris layer is "x1" is set as a predetermined threshold "TDF", the wear debris layer The fact that the thickness “LT” exceeds “x1” can be detected as an abnormality of the braking mechanism BRM.

  FIG. 6 is a flowchart showing an exemplary process executed by the determination unit 122. The process shown in FIG. 6 may be defined as the process in step S120 described with reference to FIG. The process executed by the determination unit 122 will be described with reference to FIGS. 1, 4, and 6.

(Step S121)
After step S110 described with reference to FIG. 4, step S121 is executed. The determination unit 122 verifies whether the maximum value exists in the current data. If the determination unit 122 finds the maximum value in the current data, step S124 is executed. In other cases, step S140 described with reference to FIG. 4 is executed.

(Step S124)
The determination unit 122 finds the minimum value at which the time change of the excitation current turns from decrease to increase from the current data. The determination unit 122 then subtracts the minimum value from the maximum value and calculates the difference value “DIF”. After the calculation of the difference value “DIF”, step S127 is executed.

(Step S127)
The determination unit 122 compares the difference value “DIF” with the threshold value “TDF”. If the difference value “DIF” is greater than or equal to the threshold value “TDF”, step S130 described with reference to FIG. 4 is executed. In other cases, step S140 is executed.

(Diagnosis using the maximum and minimum time positions)
The state diagnosis device 100 may diagnose whether or not an abnormality has occurred in the braking mechanism BRM by using the time positions of the maximum value and the minimum value as the determination reference. A diagnostic technique using the time positions of the maximum value and the minimum value as a criterion is described below.

  FIG. 7 is a schematic graph showing the relationship between the thickness “BT” of the brake plate BRP and the time change of the exciting current. With reference to FIGS. 1, 2 and 7, the relationship between the thickness “BT” of the brake plate BRP and the time change of the exciting current will be described.

  In FIG. 7, the thickness "BT" of the brake plate BRP is "0", "y1", "y2" (y1> y2), and "y3" (y2>). y3) and “y4” (y3> y4). Without the formation of the layer of wear debris, the thinner the brake plate BRP, the longer the moving distance of the movable iron core AMT (that is, the distance “GAP” increases). As the moving distance of the movable iron core AMT becomes longer, the period from the start of supplying the exciting current from the power supply PSC to the coil CIL to the time at which the maximum value and the minimum value appear becomes longer. Therefore, the state diagnostic device 100 determines whether or not an abnormality has occurred in the braking mechanism BRM based on the period from the time when the supply of the exciting current from the power supply PSC to the coil CIL is started to the time when the maximum value and the minimum value appear. Can be diagnosed.

  FIG. 8 is a flowchart showing an exemplary process executed by the determination unit 122. The process executed by the determination unit 122 will be described with reference to FIGS. 1 and 8.

(Step S202)
The determination unit 122 reads the current data from the storage unit 121. Then, step S204 is executed.

(Step S204)
The determination unit 122 refers to the current data and finds the time when the exciting current starts to increase. Then, step S206 is executed.

(Step S206)
The determination unit 122 sets the time parameter “t” by setting the time when the exciting current starts to increase to “0”. Then, step S208 is executed.

(Step S208)
The determination unit 122 adds a predetermined sampling time “smt” (sampling time of the ammeter 110) to the time parameter “t”. Then, step S210 is executed.

(Step S210)
The determination unit 122 refers to the value of the exciting current corresponding to the value of the time parameter “t” set in step S208, and determines whether the exciting current is decreasing. If the exciting current is decreasing, step S212 is executed. In other cases, step S208 is executed.

(Step S212)
The determination unit 122 compares the value of the time parameter “t” with a predetermined first threshold value “tt1”. If the value of the time parameter “t” exceeds the first threshold value “tt1”, step S214 is executed. In other cases, step S216 is executed. For the present embodiment, the predetermined period may be exemplified by the period represented by the first threshold “tt1”.

(Step S214)
The determination unit 122 generates a determination result indicating that the brake plate BRP is worn. The determination result is output from the determination unit 122 to the signal generation unit 123. The signal generation unit 123 generates a wear warning signal indicating that the brake plate BRP is worn. The wear warning signal is output to a notification device such as a monitor device or a voice device, and the operator is notified by the notification device that the brake plate BRP is worn.

(Step S216)
The determination unit 122 adds a predetermined sampling time “smt” (sampling time of the ammeter 110) to the time parameter “t”. Then, step S218 is performed.

(Step S218)
The determination unit 122 refers to the value of the exciting current corresponding to the value of the time parameter “t” set in step S216, and determines whether the exciting current is increasing. If the exciting current is increasing, step S220 is executed. In other cases, step S216 is executed.

(Step S220)
The determination unit 122 compares the value of the time parameter “t” with a predetermined second threshold value “tt2” (> tt1). If the value of the time parameter "t" exceeds the second threshold value "tt2", step S214 is executed. In other cases, step S222 is executed. For the present embodiment, the predetermined period may be exemplified by the period represented by the second threshold value "tt2".

(Step S222)
The determination unit 122 refers to the value of the exciting current corresponding to the value of the time parameter “t” at the time of executing step S212 as the maximum value. The determination unit 122 refers to the value of the exciting current corresponding to the value of the time parameter “t” at the time of executing step S222 as the minimum value. The determination unit 122 subtracts the minimum value from the maximum value to calculate the difference value “DIF”. After the calculation of the difference value “DIF”, step S224 is executed.

(Step S224)
The determination unit 122 compares the difference value “DIF” with the threshold value “TDF”. If the difference value "DIF" is greater than or equal to the threshold value "TDF", step S226 is executed. In other cases, step S228 is executed.

(Step S226)
The determination unit 122 generates a determination result indicating that the braking mechanism BRM is normal. The determination result is output from the determination unit 122 to the signal generation unit 123. The signal generator 123 generates a notification signal indicating the determination result. The notification signal is output to a notification device such as a monitor device or a voice device, and the operator is notified by the notification device that the braking mechanism BRM is normal.

(Step S228)
The determination unit 122 generates a determination result indicating that the movable iron core AMT and the fixed iron core FIC are clogged. The determination result is output from the determination unit 122 to the signal generation unit 123. The signal generator 123 generates a clogging warning signal indicating that clogging has occurred between the movable iron core AMT and the fixed iron core FIC. The clogging warning signal is output to a notification device such as a monitor device or a voice device, and the operator is notified by the notification device that a clogging has occurred between the movable iron core AMT and the fixed iron core FIC.

(Measurement of exciting current using Hall sensor)
The state diagnostic device 100 may use a Hall sensor as the ammeter 110. In this case, the exciting current is accurately measured.

  FIG. 9 is a schematic circuit diagram from the ammeter 110 to the computer 120. The ammeter 110 is described with reference to FIGS. 1 and 9.

  The ammeter 110 includes a Hall sensor 111 and a sensor power supply 112. The current supplied from the sensor power supply 112 to the Hall sensor 111 is orthogonal to the magnetic field caused by the exciting current. As a result, the Hall sensor 111 produces an electromotive force orthogonal to each of the magnetic fields resulting from the current from the sensor power supply 112 and the exciting current. The electromotive force is output to the computer 120 as an output from the hall sensor 111. The time change of the electromotive force corresponds to the time change of the exciting current. The storage unit 121 may store the time change of the electromotive force as the time change of the exciting current.

  FIG. 10 is a graph of output data from the hall sensor 111 obtained by using different types of sensor power supplies 112. The sensor power supply 112 is described with reference to FIGS. 9 and 10.

  The output data shown in section (a) of FIG. 10 is obtained under the condition that a DC battery is used as the sensor power supply 112. The output data shown in section (b) of FIG. 10 is obtained under the condition that a switching power supply is used as the sensor power supply 112. As is clear from the comparison between section (a) and section (b), the output data shown in section (a) is less noisy than the output data shown in section (b). Therefore, a DC battery is preferably used as the sensor power supply 112.

  The various features described above may be combined to suit the environment in which the electromagnetic mechanism is used.

  The braking mechanism BRM described above can be incorporated in a motor (not shown). The motor may be used for an articulated shaft of an articulated robot used for vehicle assembly, welding, and painting.

  An articulated robot has many motors. The diagnostic techniques described above may be used to simultaneously diagnose the condition of the braking mechanism BRM incorporated in each of these motors. In this case, current data corresponding to the output data shown in section (a) of FIG. 10 may be stored in the computer 120 in association with each of the plurality of motors mounted on the articulated robot. Therefore, the worker can complete the state diagnosis for many motors incorporated in the multi-joint robot in a short time.

  With respect to the embodiments described above, the braking mechanism BRM is illustrated as an electromagnetic mechanism. However, the principles of the embodiments described above may be applied to a clutch mechanism (not shown). A clutch plate (not shown) of the clutch mechanism is sandwiched between the movable iron core AMT and a predetermined fixing member, like the brake plate BRP described above. That is, in the clutch mechanism, the sandwiching member is exemplified by the clutch plate.

  Since the clutch plate is sandwiched between the movable iron core AMT and the predetermined fixing member, it is worn like the brake plate BRP described above. If the diagnostic technique of the above-described embodiment is applied to the clutch mechanism, the clutch plate is excessively thin and / or the abrasion powder from the clutch plate causes the movable iron core AMT and the fixed iron core FIC. The formation of a thick layer between them can be detected accurately and quickly.

  Regarding the above-described embodiment, if the braking mechanism BRM is normal, the operator is notified of the diagnostic result indicating the normality of the braking mechanism BRM. However, only the determination result indicating the abnormality of the braking mechanism BRM may be notified to the worker.

  For the above-described embodiment, the time change of the exciting current is measured using the ammeter 110. However, the time change of the voltage may be measured by using a voltmeter connected via a resistor to a circuit for supplying an exciting current from the power supply PSC to the coil CIL. The measured voltage may be converted into a current using the resistance value of the resistor. Therefore, the current data may be represented as a voltage change with time.

  The principles of the above-described embodiments are preferably used to diagnose various electromagnetic mechanism conditions.

100 ... ・ Status diagnosis device 110 ・ ・ ・ ・ ・ ・ Ammeter (data generation Part)
111 ... Hall sensor 112 ... Sensor power supply (DC battery)
121 ・ ・ ・ ・ Storage unit (data generation unit)
122 ・ ・ ・ ・ Judgment unit AMT ・ ・ ・ ・ Movable iron core BRM ・ ・ ・・ ・ ・ ・ ・ ・ Brake mechanism (electromagnetic mechanism)
BRP ... Brake plate (clamping member)
CIL ... Coil FIC ... Fixed iron core SPT ...・ ・ ・ ・ ・ Side plate (fixing member)

Claims (9)

To diagnose the state of an electromagnetic mechanism having a fixed iron core to which a coil that generates a magnetic flux so as to separate the movable iron core that sandwiches the holding member in cooperation with the fixed member from the fixed member according to the supply of the exciting current is attached. The condition diagnosis method of
Measuring the time change of the exciting current, and generating current data representing the time change,
Based on the current data, the step of determining whether or not the layer formation of wear powder between the movable iron core and the fixed iron core has occurred in the electromagnetic mechanism,
The step of determining whether the layer formation has occurred in the electromagnetic mechanism,
If the maximum value at which the exciting current turns from increasing to decreasing is not found from the current data, determining that the layer formation is occurring in the electromagnetic mechanism,
If the maximum value and the minimum value at which the excitation current turns from the decrease to the increase are found from the current data, the difference value between the maximum value and the minimum value is compared with a predetermined threshold value, and If the difference value is below the threshold value, it is determined that the layer formation has occurred in the electromagnetic mechanism. Said step of determining whether the layer formation has occurred in the electromagnetic mechanism, the maximum value or the minimum value, if not appear within a predetermined time period, the layer formation has occurred in the electromagnetic mechanism The method of claim 1, further comprising the step of: In the step of determining whether the layer formation has occurred in the electromagnetic mechanism, if the layer formed is determined to be occurring in the electromagnetic mechanism is made, the wear of the clamping member has occurred The condition diagnosis method according to claim 1, further comprising a step of generating a wear warning signal indicating In the step of determining whether or not the layer formation has occurred in the electromagnetic mechanism, if it is determined that the layer formation has occurred in the electromagnetic mechanism, between the movable iron core and the fixed iron core. The condition diagnosis method according to claim 1, further comprising a step of generating a clogging warning signal indicating that clogging has occurred. To diagnose the state of an electromagnetic mechanism having a fixed iron core to which a coil that generates a magnetic flux so as to separate the movable iron core that sandwiches the holding member in cooperation with the fixed member from the fixed member according to the supply of the exciting current is attached. A condition diagnostic device of
A data generation unit that measures the time change of the exciting current and generates current data representing the time change;
Based on the current data, a determination unit that determines whether or not a layer of wear powder between the movable iron core and the fixed iron core has occurred in the electromagnetic mechanism,
The determination unit,
If the maximum value at which the exciting current turns from increasing to decreasing is not found from the current data, it is determined that the layer formation is occurring in the electromagnetic mechanism,
If the maximum value and the minimum value at which the excitation current turns from the decrease to the increase are found from the current data, the difference value between the maximum value and the minimum value is compared with a predetermined threshold value, and If the difference value is below the threshold value, it is determined that the layer formation is occurring in the electromagnetic mechanism. The state diagnosis device according to claim 5, wherein the data generation unit includes a Hall sensor. The condition diagnostic apparatus according to claim 6, wherein the data generation unit includes a DC battery that supplies electric power to the Hall sensor. The electromagnetic mechanism is a motor braking mechanism,
The condition diagnosing device according to claim 5, wherein the holding member is a brake plate. The electromagnetic mechanism is a clutch mechanism,
The condition diagnosing device according to claim 5, wherein the holding member is a clutch plate.

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