JP2005188956A - Motor abnormality detection device and electrical equipment provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate reference value setting of unusual dermination, and enable it to detect an abnormality certainly, with respect to an abnormality detection device using a current detection means for detecting the current which flows into the motor. <P>SOLUTION: The motor abnormality detection device is provided with a current detection means 14 for detecting the current which flows into a motor 9, and a determining means by a microcomputer which reads a maximum I0 of the current at the time of the motor starting and a current value I1 at the time of the steady state of the motor, and judges an abnormality when the difference of the maximum I0 and the current value I1 is below a predetermined value. The predetermined value of the difference between the maximum I0 and the current value I1 is made variable. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a motor abnormality detection device that determines abnormality of a motor based on a value of a current flowing through the motor, and an electric device including the motor abnormality detection device.

  For example, a high-pressure airflow generator used in a hand dryer for drying wet hands after cleaning has been devised to prevent foreign matter from being sucked in. However, if foreign matter is sucked in for some reason, the motor may lock and abnormally heat up. As means for protecting the lock of the motor, there are a method using a temperature fuse and a current fuse, and a method for detecting the motor current. In addition, there exist some which are disclosed by patent document 1 and patent document 2 as this kind of prior art.

JP-A-4-256720 JP-A 63-309232

  The one that protects the motor lock with a temperature fuse or a current fuse cuts off the power supply to the motor due to an abnormal temperature or current. However, depending on the motor characteristics, the rate of temperature rise is fast, and the thermal fuse may not follow this rate. In addition, there is no sufficient difference between the current value when the motor is normal and the current value when the motor is locked, and it may be difficult to set the current fuse.

  What detects the current of the motor determines that the motor is abnormal when the value of the current flowing through the motor exceeds a predetermined reference value continuously for a predetermined time. It is configured not to malfunction due to an instantaneous excessive current such as a starting current. In either case, the motor abnormality is determined by comparing a predetermined reference value for abnormality determination with an actual current value.

  In the case of a commutator motor or the like, if it is normal, a larger current flows at the time of startup. However, if the motor locks for some reason, a larger current flows than in the steady state. These motor currents fluctuate due to environmental changes such as power supply voltage and temperature. Due to the detection error of the current detection means, a deviation occurs between the actual current value and the detected current value. For this reason, as in the prior art, when a motor abnormality is determined by comparing a predetermined abnormality determination reference value with an actual current value, a value that does not cause a malfunction is set in consideration of these fluctuations and detection errors. However, depending on the magnitude of fluctuation and detection error, the difference between the maximum value of normal current and the minimum value of abnormal current may be reduced. As a result, there is a risk of malfunction, and an appropriate abnormality determination reference value may not be set, and even if it can be set, it cannot be easily set.

  The present invention has been made in order to solve the above-described conventional problems, and the problem is that an abnormality determination standard for a motor abnormality detection device using current detection means for detecting a current flowing through a motor is provided. It is to make setting of the value easy and to make it possible to detect an abnormality reliably. It is another object of the present invention to provide an electric device equipped with the motor abnormality detection device and capable of protecting the motor from motor abnormality.

  In order to solve the above-mentioned problems, the present invention reads a current detection means for detecting a current flowing through a motor, a maximum current value I0 when the motor is started, and a current value I1 when the motor is stationary, and the maximum value I0 and the current value I1. And means for determining that the difference is less than a predetermined value is determined to be abnormal.

  In another invention, the current detection means for detecting the current flowing through the motor, the maximum current value I0 at the start of the motor and the current value I1 at the steady state of the motor are read, and the difference between the maximum value I0 and the current value I1 is A means having a determination means for determining an abnormality when the value is equal to or less than a predetermined value and having a motor abnormality detection device that makes the predetermined value variable is adopted.

  According to the present invention, whether or not the motor is abnormal is determined by the difference between the maximum current value I0 when the motor is started and the current value I1 when the motor is stationary. This makes it difficult to set a reference value for abnormality determination, so that a motor abnormality can be reliably detected.

  In a hand dryer as an electrical apparatus embodying the present invention, a high-pressure airflow generator for generating a high-speed airflow is incorporated in a main body box having a hand insertion portion configured as a concave space having an open front surface. . The high-pressure air flow generated by the high-pressure air flow generator is guided to an air nozzle provided on the upper surface of the manual insertion portion. This air nozzle irradiates the hand insertion part with a high-speed air flow, blows away the water adhering to the hand put in the hand insertion part, and collects it in the drain container provided in the water receiving part below the hand insertion part. It is like that.

  The hand insertion unit is provided with a hand detection unit that detects the inserted hand. When the hand is detected by the hand detection unit, the high-pressure airflow generator operates to inject a high-speed airflow into the hand insertion unit and blow away moisture attached to the hand. The high-pressure airflow generator includes a motor such as a commutator motor and a turbo fan that is rotated by the motor.

  The commutator motor of the high-pressure airflow generator is driven by a motor drive circuit controlled by a microcomputer, and motor abnormality is monitored by a motor abnormality detector. The motor abnormality detection device includes current detection means for detecting a current flowing through the commutator motor and determination means using a microcomputer. The microcomputer reads the maximum current value I0 when starting the motor and the current value I1 when the motor is steady to determine whether the motor is abnormal. When the difference between the maximum value I0 and the current value I1 is less than a predetermined value, the motor is in the locked state. Determination is made, the commutator motor is stopped via the motor drive circuit, and motor abnormality is displayed. The starting current is an instantaneous excessive current. If there is little difference between the maximum value I0 and the current value I1 when the motor is steady, it is determined that the motor is abnormal. It is difficult to be influenced by detection errors, it is easy to set a reference value for abnormality determination, and motor abnormality can be reliably detected.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing the entire hand dryer according to the present embodiment, FIG. 2 is a block diagram of a motor abnormality detection device, FIG. 3 is a flowchart showing a control operation of the microcomputer, and FIG. FIG. 5 is an explanatory diagram showing changes in the motor current value when the motor is locked, and FIG. 6 is a motor current value when the motor is locked during driving. It is explanatory drawing which shows the change of. In the hand drying device of the present embodiment, the high pressure air by the high pressure air flow generator 3 incorporated in the main body box 2 having the hand insertion portion 1 is sent to the vicinity of the hand insertion port, and the process following the hand insertion port. A high-speed air flow is formed as a working air flow related to hand drying that blows away moisture into the hand insertion portion 1 as a space. The main body box 2 is composed of a base 4 forming a rear outer shell and a resin front panel 5 forming a front outer shell.

  The hand insertion portion 1 is formed as a concave sink-like space in which the front and both sides are open and can be inserted and removed in the lower front portion of the main body box 2, and has a lower jaw portion 6 constituting a water receiving portion of the lower structure. The upper jaw 7 of the upper structure. The lower jaw 6 is inclined downward toward the front, and a drain outlet is provided at the lower end of the inclination. A drain container 8 having an open container structure for storing water dripped from the drain port is provided below the lower jaw part 6 so as to be detachable in the front-rear direction. The drain container 8 is provided with a removable lid.

  The high-pressure airflow generator 3 includes a motor 9 such as a commutator motor, and a turbo fan that is rotated by the motor 9. In this embodiment, the intake side is directly above the manual insertion portion 1 of the main body box 2. It is mounted on the base 4 side. The intake side of the high-pressure airflow generator 3 faces a ventilation path open at the lower end provided in the vertical direction on the back side of the main body box 2 in the vicinity of the back side of the manual insertion portion 1. The air can be sucked in through the air filter 10 that can be removed by inserting and removing in the front-rear direction.

  A plurality of air outlets of the high-pressure airflow generator 3 are opened in the radial direction at intervals in the circumferential direction on the outer periphery of the circular cup-shaped fan casing. The outside of the fan casing is covered with a circular cup-shaped casing provided with a guide path in a direction along the rotational direction of the turbofan, and the high-pressure air sent from the high-pressure airflow generator 3 is received at the end of the guide path of the casing. An air nozzle 11 that is converted into a high-speed air flow and blows out to the manual insertion portion 1 is connected. The air nozzle 11 is assembled with an opening formed in the upper part of the hand insertion portion 1 near the hand insertion port with a jet port facing downward, and a high-speed air current is blown to the hand placed in the hand insertion portion 1 to The water droplets on the hand are peeled off and blown away from the surface of the hand without rubbing. The upper jaw portion 7 on the back side of the air nozzle 11 has a window fitted with a translucent window member, and a hand detection unit for detecting a hand is formed in the window.

  The hand detection unit detects a hand inserted into the hand insertion unit 1 and includes an infrared light emitting element and an infrared light receiving element. When the hand is detected by the hand detection unit, the high-pressure airflow generator 3 is operated via the drive circuit 13 by the processing of the microcomputer 12 to inject the high-speed airflow into the hand insertion unit 1 and blow off the moisture adhering to the hand. . The motor 9 of the high-pressure airflow generator 3 is monitored for motor abnormality by a motor abnormality detector. The motor abnormality detection device includes a current detection unit 14 that detects a current flowing through the motor 9, a determination unit using the microcomputer 12, and a display unit 15. The microcomputer 12 reads the maximum current value I0 at the time of starting the motor and the current value I1 when the motor is steady to determine whether the motor is abnormal, and when the difference between the maximum value I0 and the current value I1 is equal to or less than a predetermined value, Determination is made, the motor 9 is stopped via the drive circuit 13, and a display of motor abnormality is displayed on the display unit 15. The start-up current is an instantaneous excessive current, and if there is little difference between the maximum value I0 and the current value I1 when the motor is steady, it is determined that the motor is abnormal. It is difficult to be influenced by detection errors, it is easy to set a reference value for abnormality determination, and motor abnormality can be reliably detected.

  The control operation of the microcomputer 12 will be described with reference to the flowchart of FIG. 3 specifically showing motor abnormality detection. In step # 1 of FIG. 3, it is determined whether or not motor driving is started. If the driving is started, the process proceeds to step # 2, and if not, the process returns to step # 1. In step # 2, a starting current check is performed and the process proceeds to step # 3. In step # 3, it is determined whether or not a predetermined time has elapsed. If it has elapsed, the process proceeds to step # 4. If not, the process returns to step # 2. In step # 4, a process for determining the maximum value I0 of the starting current is performed, and the process proceeds to step # 5. In step # 5, the current value I1 when the motor is steady is checked, and the process proceeds to step # 6. In step # 6, it is determined whether maximum value I0-current value I1 ≧ predetermined value. If maximum value I0-current value I1 ≧ predetermined value, the motor is normal in step # 7 and proceeds to step # 8. If the maximum value I0−the current value I1 ≧ the predetermined value is not satisfied, the process proceeds to step # 9, where the motor 9 is stopped and a motor abnormality is displayed on the display unit 15. In step # 8, it is determined whether or not the motor is being driven. If the motor is being driven, the process returns to step # 5. If not, the process returns to step # 1.

  In step # 6, the determination of maximum value I0−current value I1 ≧ predetermined value is the state of FIG. 4 showing the change of the motor current value in the normal state, and the motor current value varies depending on the power supply voltage and temperature. Even in this case, there is a clear difference between the maximum value I0 of the starting current and the current value I1 when the motor is stationary. In step # 6, the determination that the maximum value I0−current value I1 ≧ predetermined value is not satisfied is the motor current value when the motor 9 is locked during driving, FIG. 5 showing the change of the motor current value when the motor 9 is locked. It is the state of FIG. 6 which shows the change of a value. The current value I1 when the motor is in a steady state is a current value from a predetermined time after the start of motor driving to a stop of driving, so that an abnormality can be reliably detected even when the motor 9 is locked during driving as shown in FIG. it can. By making the predetermined value variable in the determination of maximum value I0−current value I1 ≧ predetermined value, it is possible to operate with a value suitable for the device and to easily cope with the motor change. In order to make the predetermined value variable, the program of the microcomputer 12 may be changed, or the value of a switch or the like may be changed to be taken into the microcomputer 12.

  In the case where the rotational speed of the motor 9 can be variably controlled, it may be difficult to make a determination based on the difference between the motor current at startup and the motor current at steady state when the rotational speed is changed during driving. In such a case, the motor abnormality can be detected more reliably by combining with other abnormality determination methods such as temporarily switching from the determination based on the difference to the determination based on the reference value.

  The present invention is not limited to the hand dryer, and can be widely used for electric devices having a fan motor such as a vacuum cleaner when it is necessary to protect the lock of the motor.

It is sectional drawing of a hand dryer. (Embodiment 1) It is a block block diagram of a motor abnormality detection apparatus. (Embodiment 1) It is the flowchart showing the control operation of the microcomputer which showed abnormality detection specially. (Embodiment 1) It is explanatory drawing which shows the change of the motor electric current value at the time of normal. (Embodiment 1) It is explanatory drawing which shows the change of a motor electric current value when a motor is locked. (Embodiment 1) It is explanatory drawing which shows the change of a motor electric current value when a motor locks in the middle of a drive. (Embodiment 1)

Explanation of symbols

  3 High-pressure airflow generator, 9 Motor, 12 Microcomputer, 14 Current detection means, 15 Display unit.

Claims (3)

  Current detection means for detecting the current flowing through the motor, the maximum current value I0 when the motor is started, and the current value I1 when the motor is in a steady state are read, and abnormal when the difference between the maximum value I0 and the current value I1 is less than a predetermined value A motor abnormality detection device comprising determination means for determining   The motor abnormality detection device according to claim 1, wherein a predetermined value of a difference between the maximum value I0 and the current value I1 is variable.   Current detection means for detecting the current flowing through the motor, the maximum current value I0 at the time of motor start-up and the current value I1 at the time of motor steady state are read, and abnormal when the difference between the maximum value I0 and the current value I1 is less than a predetermined value An electrical apparatus provided with a motor abnormality detection device having a determination means for determining

Images