Motor bearing wear detecting device

• US 20050155436A1
• Filed: 01/13/2005
• Published: 07/21/2005
• Est. Priority Date: 01/15/2004
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Teikoku Denki Seisakusho
• Original Assignee: Kabushiki Kaisha Teikoku Denki Seisakusho
• Inventors: Abe, Masaru, Otake, Eiji, Takahashi, Noboru
• Granted Patent: US 7,235,965 B2
• Time in Patent Office: Days
• US Class Current: 73/811
• CPC Class Codes: G01B 7/144 Measuring play on bearings
• CPC Class Codes: G01M 13/04 Bearings

Abstract

Reinforcing rings are provided around the cylindrical outer surface of a stator can of a canned motor, near the front and rear ends of a stator of the canned motor respectively. An axial position detecting coil A is wound around the cylindrical outer surface of at least one of the reinforcing rings. The axial position of a rotor is detected by an inductance of the axial position detecting coil A. The axial position detecting coil A is installed by winding a coil around at least one of the reinforcing rings. The invention reduces the influence exerted by change in the radial position of the rotor on the output to the axial position detecting coil A to a negligible level and enables detection of the axial position of the rotor and axial zero adjustment without the necessity of considering change in the radial position of the rotor.

Claims

1. A motor bearing wear detecting device comprising:

an axial position detecting coil provided near at least one end of a stator of a motor in such a manner as to be wound around the outer surface of a container that contains at least part of a rotor of said motor, and

an axial position detecting device detecting the axial position of said rotor by voltages induced in said axial position detecting coil.

5. A motor bearing wear detecting device as claimed in claim 1, wherein:

said container is one of a stator can and a reinforcing ring that is provided around said stator can.

6. A motor bearing wear detecting device as claimed in claim 1, wherein:

said motor bearing wear detecting device having a magnetic member provided at an end of the rotor, where an axial position detecting coil is located.

2. A motor bearing wear detecting device comprising:

an axial position detecting coil provided near at least one end of a stator of a motor in such a manner as to be wound around the outer surface of a container that contains at least part of a rotor of said motor,

a high frequency signal applying device applying high frequency signals to said axial position detecting coil,

an inductance detecting device detecting the inductance of said axial position detecting coil to which a high frequency signal has been applied, and

an axial position detecting device detecting the axial position of said rotor by the inductance of said axial position detecting coil.

3. A motor bearing wear detecting device as claimed in claim 2, wherein:

said axial position detecting device comprises;

a temperature measuring means for measuring the temperature of said axial position detecting coil and

a temperature correction device performing temperature correction based on the temperature measured by said temperature measuring device.

4. A motor bearing wear detecting device as claimed in claim 2, wherein:

said high frequency signal applying device applies to said axial position detecting coil a high frequency signal generated by superimposing DC current over a sine wave, said DC current having the same value as an effective value of the sine wave;

said motor bearing wear detecting device having;

a sine wave signal detecting device detecting a sine wave signal from among the signals output from said axial position detecting coil, to which the high frequency signal has been applied; and

a DC resistance detecting device detecting;

a DC resistance value from among the signals output from said axial position detecting coil, to which the high frequency signal has been applied; and

said inductance detecting device detects an inductance of said axial position detecting coil, said inductance being a sine wave signal detected by said sine wave signal detecting device after subtracting therefrom the DC resistance value detected by said DC resistance detecting device.