JPH07272078A - Fault detection device - Google Patents

Abstract

PURPOSE:To provide the fault detection device which can speedily specify a fault place of a conveyance mechanism. CONSTITUTION:The fault detection device 1, which detects the fault of the conveyance mechanism including a motor M for conveyance, is equipped with a motor current detection part R1 which detects the motor current value of the motor M, a comparison part 4 which compares the detected motor current value with a reference current value set larger than a stationary current value obtained when the motor M is in a stationary state and smaller than a lock current value obtained when the motor M is locked, and a decision part 5 which decides whether or not the motor 5 is locked on the basis of the comparison result of the comparison part 4 obtained a specific time after the motor M is actuated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure detecting device for detecting a failure of a transport mechanism for transporting products in an automatic vending machine.

[0002]

2. Description of the Related Art For example, as a failure detection device for a transport mechanism such as an automatic vending machine, one using a carrier switch for detecting whether or not a transport belt for transporting a product is rotated is known. This conventional failure detection device includes a carrier switch mounted on a chassis on the side of a conveyor belt rotated by a motor, an engagement member mounted on the conveyor belt and engageable with the carrier switch, and a switch of the carrier switch. A failure detection unit that monitors a signal to detect a failure of the transport mechanism. When a product is transported, the motor rotates and the transport belt rotates accordingly. When the transport mechanism is operating normally, the transport belt rotates, and the engaging member engages with the carrier switch to turn on the carrier switch. When this ON signal is output to the failure detection unit, the failure detection unit determines that the transport mechanism is operating normally. On the other hand, when the ON signal is not input, the failure detection unit determines that a failure has occurred in the transport mechanism.

[0003]

However, in the conventional failure detecting device, when the carrier switch does not operate, it can be detected that the carrier mechanism has failed, but whether the carrier switch has failed. It is not possible to identify the location of the failure, whether the motor has a failure, or the failure of the conveyor belt or other components of the conveyor mechanism. For this reason, it takes a lot of time to find a failure point, and there is a problem that it cannot be quickly repaired.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a failure detection device capable of quickly identifying a failure location of a transport mechanism.

[0005]

[Means for Solving the Problems] In order to achieve the above object,
The failure detection device according to claim 1 is a failure detection device that detects a failure of a transport mechanism including a transport motor, and includes a motor current detection unit that detects a motor current value of the motor, and a detected motor current value. Is compared with a reference current value that is preset to a value that is larger than the steady current value when the motor is in the steady state and smaller than the lock current value when the motor is locked, and a predetermined value after the motor is started. It is characterized by further comprising: a determination unit that determines whether or not the motor is locked based on a comparison result of the comparison unit after a lapse of time.

The failure detection device according to claim 2 is the device according to claim 1.
In the failure detection device described above, the determination unit is characterized by further determining whether or not there is a failure in the motor based on the comparison result of the comparison unit when the motor is started.

[0007]

According to the failure detecting device of the first aspect, when the carrying motor operates, the motor current detecting section detects the value of the motor current flowing through the motor. The comparison unit sets the detected motor current value to a value that is larger than the steady current value that flows when the motor is in a steady state and smaller than the lock current value that flows when the motor locks due to a failure of the conveyor belt. It is compared with a preset reference current value. On the other hand, the determination unit determines whether the motor is locked or not based on the comparison result of the comparison unit after a predetermined time has passed after the motor is started, for example, a time when the motor is normally in the normal rotation state.
In this case, there is a characteristic that when the motor locks, it always becomes larger than the steady-state current value. Therefore, when the motor current value is larger than the reference current value, the motor is locked, and the transport mechanism other than the motor is locked. It is determined that some failure has occurred in the component part, and when the motor current value is smaller than the reference current value, it is determined that the motor is not locked. As a result, for example, when a failure occurs in the transport mechanism, it is possible to know whether the motor is locked,
As a result, it is possible to easily determine whether or not a failure has occurred in another component of the transport mechanism, such as the transport belt, so that the location of the failure can be identified in a short time.

According to the second aspect of the failure detecting apparatus, whether the comparing section compares the motor current value flowing at the time of starting the motor with the reference current value, and the judging section determines whether the motor has a failure or not. Determine whether or not. That is, the starting current flows at the time of starting the motor, and this starting current value is almost equal to the lock current value, so that it always becomes larger than the reference current value. Therefore, based on the comparison result of the comparison unit, for example, when the comparison result is that the motor current value is larger than the reference current value, it is determined that the motor has started, and if the comparison result is the reverse, it is determined that the motor has failed. To do. If it is determined that the motor has started, then it is determined whether or not the motor is locked, as described above, based on the comparison result of the comparison unit after a predetermined time has elapsed after the start. As a result, for example, when a failure occurs in the transport mechanism, it is possible to easily determine whether the motor has a failure, the motor has locked, or another component has a failure. Therefore, the failure location can be specified in a short time.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which a failure detection device according to an embodiment of the present invention is applied to a product discharge mechanism (conveyance mechanism) of a vending machine will be described in detail below with reference to the drawings.

FIG. 1 shows a part of the product discharge mechanism and a failure detection circuit 1 for detecting a failure of the product discharge mechanism.

The product discharging mechanism includes a carrying belt (not shown) for carrying products and a motor M for rotating the carrying belt.
And a power source 2 for supplying a DC power source to the motor M, and a motor driver 3 for operating the motor M. In this merchandise ejecting mechanism, a control unit (not shown) that performs all control such as selling of the vending machine when coins are put into the vending machine body (not shown) and a product is selected.
Outputs a motor drive signal to the motor driver 3. Then, based on the motor drive signal, the motor driver 3 operates the motor M, and the conveyor belt rotates in accordance with the operation of the motor M, so that the product is discharged to the product discharge port (not shown).

The failure detection device 1 judges whether or not a failure has occurred in a comparator (comparison section) 4 for comparing a voltage corresponding to a motor current value of the motor M with a reference voltage described later, and a product discharging mechanism. The unit 5 and the carrier switch S1 attached to the chassis on the side of the conveyor belt are provided.

One of the two input terminals of the motor M is connected to the power source 2 via a resistor (motor current detecting section) R1,
The other is connected to the motor driver 3. The control input terminal of the motor driver 3 is connected to the control unit, and the motor drive signal described above is input from the control unit.

One end of the resistor R1 on the power source 2 side is connected to the resistor R2.
It is connected to the ground via R3 and the volume RV1, and the other end on the motor M side is connected to the ground via resistors R4 and R5. The connection between the resistors R2 and R3 is connected to the plus input of the comparator 4, and the connection between the resistors R4 and R5 is connected to the minus input of the comparator 4. Further, a stabilizing capacitor C1 is connected in parallel to both input terminals of the comparator 4.

The output section of the comparator 4 is connected to one of the input sections of the judging section 5 and is also connected to a power source (not shown) for the failure detecting device 1 via a resistor R6 which is a pull-up resistor. .

The other two input parts of the judging part 5 are respectively connected to the control part and the carrier switch S1, and the motor drive signal is outputted from the control part. The output unit of the determination unit 5 is connected to the control unit, and a failure signal described later is output to the control unit. The carrier switch S1 is engaged with an engaging member on the conveyor belt to be turned on when the conveyor belt is rotated when the product is discharged, and outputs the turned-on switch signal to the determination unit 5.

When the motor drive signal is output from the control unit, the determination unit 5 monitors both the comparison signal (comparison result) from the comparator 4 and the switch signal from the carrier switch S1 to detect the motor M and the carrier. Switch S
1 and whether or not a failure has occurred in other components of the transport mechanism. Then, when any one of them is determined to be in failure, the failure detection device 1 outputs a failure signal to the control unit, and the control unit causes the printing device to print the failure content as described later.

Next, the operation of the failure detecting device 1 will be described with reference to FIG.

In this failure detection device 1, the reference voltage (voltage at point A shown in FIG. 1) is set by the following procedure. When the control unit outputs a motor drive signal to the motor driver 5, the motor M is started.
The starting current shown in (a) flows through the motor M. The reference voltage is set by the volume RV1 so that the output voltage of the comparator 4 changes from the L voltage (low voltage) to the H voltage (high voltage) when this starting current flows. Specifically, a voltage smaller than the negative input portion (point B in FIG. 1) voltage of the comparator 4 when a current (reference current) having a value slightly smaller than the maximum value of the starting current of the motor M flows into the motor M. Is set as the reference voltage. That is, this reference voltage is equal to the voltage at the terminal of the resistor R1 on the motor M side (point C in the figure) when the reference current flows, divided by the resistance values of the resistors R4 and R5. In addition, when the maximum value of the starting current is known in advance, the reference voltage may be set using a tester or the like so that a voltage slightly smaller than the maximum value is applied to the point A.

After the reference voltage is set as described above, when the motor drive signal is output from the control unit and the motor M is started,
The motor current value changes as follows. That is, the resistance R
1, a motor current flows, and a voltage drop occurs in the resistor R1.
In this case, when the motor current becomes larger than the reference current value shown in FIG. 2A, the voltage drop by the resistor R1 causes B
The voltage at the point becomes lower than the reference voltage at the point A. That is, the resistance R1 is proportional to the magnitude of the motor current flowing through the motor M.
The voltage drop at point B becomes lower than that when the reference current flows. As a result, the voltage at the point B becomes lower than the reference voltage at the point A, so that the output voltage of the comparator 4 changes from the L voltage to the H voltage.

When the motor M starts to stabilize and the motor current becomes smaller than the reference current value, the output voltage of the comparator 4 changes from H voltage to L voltage. As a result,
The comparator 4 outputs a pulse signal S1 as shown in FIG. Further, when the operation of the motor M is stable (steady state), the motor current becomes a steady current as shown in FIG. 2A, and the output voltage of the comparator 4 maintains the L voltage.

On the other hand, when the conveyor belt or the like fails and the conveyor belt does not rotate, the motor M is overloaded, and a lock current as shown in FIG. 2A flows. This lock current is a current having a value almost equal to the maximum value of the starting current, and when this lock current flows, the comparator 4
Outputs the H voltage S2 shown in FIG. 2A to the determination unit 5, similarly to when the starting current flows.

The judging section 5 makes a failure judgment based on the change characteristics of the motor current value as described above. That is, when the motor drive signal is output from the control unit, a change in the voltage output from the comparator 4 is detected, and it is determined whether or not a failure has occurred in the motor M. Specifically, since the time period during which the starting current flows immediately after the motor drive signal is output is about 0.1 seconds, from the time the motor drive signal is output to the time when 0.3 seconds elapses, for example. Then, when the H voltage is output from the comparator 4, the determination unit 5 reads this voltage change and determines that the motor M has started normally. on the other hand,
When the H voltage is not output from the comparator 4 within this 0.3 second, the determination unit 5 determines that the motor M has failed.

Further, the judging section 5 continues to monitor the output voltage of the comparator 4, and the H voltage is output from the comparator 4 after 0.3 seconds has elapsed from the time when the motor drive signal was output. And carrier switch S1
When the ON signal is not output from, it is determined that the motor M is locked and a failure occurs in the conveyor belt. That is, in this case, the determination unit 5 determines that the conveyor belt does not rotate and the motor M is overloaded. Then, when a failure occurs in the motor M and when it is determined that a failure occurs in the conveyor belt, the determination unit 5 outputs a motor failure signal and a conveyor belt failure signal to the controller.

Further, the judging section 5 is such that the motor M operates normally and is not locked, and the carrier switch S1
When the ON signal is not output from, it is determined that the carrier switch S1 has failed. That is, in this case, both the motor M and the conveyor belt are operating normally, a failure occurs in the carrier switch S1, and no ON signal is output even when the engaging member of the conveyor belt is engaged. To determine. Then, the carrier switch failure signal is output to the control unit.

Next, an example of printing when a failure is detected will be described with reference to FIG. This figure shows an example in which the control unit causes a printing device (not shown) to print when a motor failure signal is output from the determination unit 5 to the control unit.
In the figure, reference numeral 11 indicates the date and time when the printout is performed, reference numeral 12 indicates the date and time when the motor M operates, and reference numeral 13 indicates a failure code when a failure occurs ( In this case, a motor failure)
Is the number of the operated motor M, and reference numeral 15 is the motor M
16 indicates the time (seconds) from the time the motor M operates to the time the motor M locks, and the code 17 indicates the motor M.
Represents the time (seconds) each is locked. By this printing, it is possible to understand which constituent part of the merchandise discharging mechanism has failed at what time and facilitate failure analysis.

As described above, according to the present embodiment, by monitoring the ON signal of the carrier switch and the comparison signal of the comparison section 4, a failure occurs in any of the motor M, the conveyor belt and the carrier switch S1. Can be easily determined.

In the above embodiment, the determination unit 5 is
Although it is determined that the lock state has occurred when the H voltage is output from the comparator 4 after the lapse of a predetermined time, the invention is not limited to this.
However, when the H voltage is continuously output for a time longer than 0.3 seconds, it may be determined immediately that the locked state has occurred. This is because the time when the starting current flows is empirically known, and it is considered that the lock state occurs when the comparator 4 outputs the H voltage for a time longer than that time. is there.

In the present embodiment, an example in which a DC motor is used as the motor M has been described, but the present invention is not limited to this, and an AC motor may be used. In this case, the resistance R1
AC voltage is converted to DC voltage by picking up the voltage applied to both ends of the
If the converted DC voltage is input to the negative input section of the comparator 4 and the reference voltage is applied to the positive input section of the comparator 4, the circuit shown in this embodiment can be applied.

Further, in the present embodiment, an example in which the invention is applied to the product discharging mechanism of the vending machine has been described, but the invention is not limited to this, and the invention can be applied to failure detection of all other transport mechanisms.

[0031]

As described above, according to the failure detecting apparatus of the present invention, the judging section determines whether or not there is a motor failure based on the comparison result of the comparing section after a predetermined time has passed after the motor is started. Since the determination is made, the failure location of the transport mechanism can be quickly identified.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of a failure detection device according to an embodiment.

FIG. 2A is a current waveform diagram of a motor which is a target of failure detection by the failure detection device according to the present embodiment,
FIG. 6B is an output waveform diagram of the comparator of the failure detection device according to the present embodiment.

FIG. 3 is a diagram illustrating a print example of failure detection.

[Explanation of reference numerals] 1 failure detection device 4 comparator 5 determination unit M motor R1 resistance

Claims (2)

[Claims] 1. A failure detection device for detecting a failure of a transportation mechanism including a transportation motor, wherein a motor current detection section for detecting a motor current value of the motor, and the detected motor current value are A comparison unit that compares with a reference current value that is preset to a value that is larger than a steady current value when the motor is in a steady state and smaller than a lock current value when the motor is locked, and a predetermined value after starting the motor. A failure detection device comprising: a determination unit that determines whether or not the motor is locked based on a comparison result of the comparison unit after a lapse of time. 2. The failure detection device according to claim 1, wherein the determination section determines whether or not there is a failure in the motor, further based on a comparison result of the comparison section when the motor is started.