REPAIR ANNOUNCEMENT METHOD AND APPARATUS FOR ELECTRIC INJECTION MOLDING MACHINE

• US 20070093976A1
• Filed: 09/26/2006
• Published: 04/26/2007
• Est. Priority Date: 09/28/2005
• Status: Active Grant

• Current Assignee: Toshiba Kikai Kabushiki Kaisha (Shibaura Machine Co., Ltd.)
• Original Assignee: Toshiba Kikai Kabushiki Kaisha (Shibaura Machine Co., Ltd.)
• Inventors: Morita, Tomonori, NISHIZAWA, MAKOTO, Tokuyama, Harumichi
• Granted Patent: US 7,369,964 B2
• Time in Patent Office: Days
• US Class Current: 702/56
• CPC Class Codes: G01H 13/00 Measuring resonant frequency
• CPC Class Codes: G01M 13/028 Acoustic or vibration analysis
• CPC Class Codes: G05B 23/0283 Predictive maintenance, e.g. involving the monitoring of a system and, based on the monitoring results, taking decisions on the maintenance schedule of the monitored system; Estimating remaining useful life [RUL] preventive maintenance, i.e. planning maintenance according to the available resources without monitoring the system G06Q10/06

Abstract

White noise is applied to a servocontrol system of a servomotor in order to measure a frequency characteristic of a mechanical component in an electric injection molding machine, and a signal from an encoder is applied to a fast Fourier converter. Data from the fast Fourier converter is applied to a memory unit, and the content of the memory unit is displayed on a display unit in the form of a board diagram. Repair announcement is issued when a deviation of the resonant frequency of each mechanical component with respect to data at an initial setting time exceeds a predetermined value.

Claims

1. A repair announcement method for announcing a repair of a mechanical component, comprising:

measuring a frequency response characteristic of the mechanical component at an initial installation state of the mechanical component;

determining a first frequency corresponding to a resonance point of the mechanical component according to measurement data at the initial installation state;

measuring the frequency response characteristic of the mechanical component after a predetermined operating time elapses;

determining a second frequency corresponding to a resonance point of the mechanical component according to measurement data after the predetermined operating time elapses; and

issuing the repair announcement by judging that a timing of repairing the mechanical component corresponding to the resonance point has arrived when a deviation between the first frequency and the second frequency exceeds a predetermined allowable value.

2. The repair announcement method according to claim 1, wherein said each measuring is executed by applying white noise to a servocontrol system of a servomotor serving as the mechanical component.

3. The repair announcement method according to claim 1, wherein in said each measuring, each measurement data is stored on a memory, and the stored data is read from the memory and displayed together on a board diagram on a screen of display means.

4. The repair announcement method according to claim 3, wherein the third step is executed plural times, so that data of plural measurement are written together on the board diagram on the screen of the display means so as to display a change over time.

5. A repair announcing apparatus which announces repair of a mechanical component, comprising:

a first device which measures a frequency response characteristic of the mechanical component at an initial installation state of the mechanical component;

a second device which determines a first frequency corresponding to a resonance point of the mechanical component according to the measurement data of the first device;

a third device which measures a frequency response characteristic of the mechanical component after a predetermined operating time elapses by means of the second device;

a fourth device which determines a second frequency corresponding to the resonance point of the mechanical component according to measurement data of the third device; and

a fifth device which issues the repair announcement by judging that a timing of repairing the mechanical component corresponding to the resonance point arrives when a deviation between the first frequency and the second frequency exceeds a predetermined allowable value.

6. A repair announcing apparatus according to claim 5, wherein the first device includes:

a servomotor arranged in an electric injection molding machine;

a servocontrol system for the servomotor;

a white noise generator which generates white noise to be applied to the servocontrol system;

an encoder which feeds back a rotation of the servomotor;

a fast Fourier converter which receives a difference between white noise from the white noise generator and an output of the encoder and applies fast Fourier conversion to the difference;

a memory unit which stores output data from the fast Fourier converter; and

a display device which displays contents of the memory device.

7. The repair announcing apparatus according to claim 6, wherein the memory unit includes:

a first memory area which stores output data from the fast Fourier converter; and

a second memory area which stores data of the first memory area, a resonant frequency of a peak value corresponding to said each mechanical component calculated based on the data, and a deviation value of the resonant frequency with respect to the data at initial setting time.

8. The repair announcing apparatus according to claim 7, wherein the memory unit further includes a program which converts data of the first memory area to the second memory area and stores the converted data.

9. The repair announcing apparatus according to claim 8, wherein the memory unit further includes a program which displays data of the second memory on the screen of the display device in the form of a board diagram.

10. The repair announcing apparatus according to claim 6, further comprising a servocontrol system mode changing device which changes the servocontrol system to a measurement mode in order to activate the first device effectively.