JP2012042320A - Method and device for measuring load distribution of rolling bearing, outer ring of which strain sensor is mounted on - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for measuring the load distribution of a rolling bearing, the outer ring of which a strain sensor is mounted on, capable of precisely determining the load distribution of the rolling bearing using a simple structured measuring device.SOLUTION: In the method for measuring the load distribution of a rolling bearing, the inner ring of the rolling bearing is fixed to the fixed shaft thereof, and the outer ring thereof, which the strain sensor is mounted on, is rotated. A small hole 4A is provided in the circumferential direction in the vicinity of the raceway surface of the rotating outer ring which is disposed and rotated in the outside of the inner ring, and an optical fiber 5, to which a strain sensor part 6 is attached, is inserted into the small hole 4A. And, a recessed groove 4B is formed in the outside of the position where the strain sensor part 6 is disposed in the outer ring 4. Rolling elements 3 are provided between the inner ring and the outer ring 4. The optical fiber 5 is connected to a strain measuring device 11 through a rotary joint 9 which is disposed in the axial direction of the fixed shaft and is rotating. The output signal is taken out from the strain sensor part 6 through the optical fiber 5. Therefore, the strain is detected while the rolling bearing is rotated and the rolling elements 3 passes through the position of the strain sensor part 6.

Description

  The present invention relates to a load distribution measuring method and device for a strain bearing with a built-in strain sensor in an outer ring in a rolling bearing that is used with an inner ring fixed and an outer ring rotated, and in particular, an optical fiber in the outer ring of the rolling bearing. The strain sensor part equipped in is arranged, and the load distribution of the entire bearing is obtained by detecting the strain when the rolling element passes through the position.

FIG. 7 is a view showing an attachment portion of an optical fiber and a strain sensor part in a rolling body of a conventional load distribution measuring device for a rolling bearing.
In this figure, 101 is a rotating shaft, 102 is an inner ring of a rolling bearing fixed to the rotating shaft 101, 103 is a rolling element of the rolling bearing, 104 is an outer ring of the rolling bearing, and 105 is formed in the rolling element 103 of the rolling bearing. A thin hole 106, an optical fiber inserted into the thin hole 105, and a strain sensor 107 provided in the optical fiber 106.

  In this way, the narrow hole 105 is provided by electric discharge machining at the center of the rolling element 103 of the rolling bearing. The inventors of the present application have detected the strain generated in the rolling element 103 by inserting and bonding the optical fiber 106 equipped with the strain sensor portion 107 into the narrow hole 105 and obtaining the load distribution of the entire bearing. (See Patent Document 1 below).

JP 2007-183105 A

  However, in the rolling bearing load distribution measuring method disclosed in Patent Document 1 described above, the strain sensor unit 107 is arranged in the rolling element 103 that performs rotation and revolution, and the rolling bearing is rotated to dynamically When performing measurement, although not shown, the measurement apparatus becomes complicated. In particular, there has been a problem that a first optical fiber rotary joint and a second optical fiber rotary joint are required to cope with the rotation and revolution of the rolling element 103, respectively.

  In view of the above situation, the present invention provides a load distribution measuring method for a rolling bearing with a built-in strain sensor on an outer ring and a device for the load distribution that can accurately determine the load distribution of the rolling bearing with a measuring device having a simple configuration. For the purpose.

In order to achieve the above object, the present invention provides
[1] In a load distribution measuring method of a strain bearing with a built-in strain sensor to an outer ring, the inner ring is fixed and the outer ring rotates. The inner ring is fixed to the fixed shaft of the rolling bearing, and the outer ring A narrow hole is provided in the circumferential direction in the vicinity of the raceway surface of the outer ring that is arranged and rotated, an optical fiber equipped with a strain sensor unit is inserted into the narrow hole, and the position of the strain sensor unit of the outer ring is arranged. A rotary that forms a notch groove on the outer side, includes a rolling element between the inner ring and the outer ring, derives an output signal from the strain sensor unit with the optical fiber, and is arranged in the axial direction of the fixed shaft and rotates. An optical fiber is connected to a strain measuring instrument through a joint, and the rolling bearing is rotated to detect strain when the rolling element passes through the position of the strain sensor unit.

  [2] In a load distribution measuring device for a rolling bearing with a built-in strain sensor on the outer ring, the inner ring is fixed and the outer ring rotates, and the inner ring of the rolling bearing fixed to the fixed shaft and the outer ring An optical fiber disposed in a narrow hole formed in the circumferential direction near the raceway surface of the outer ring that is disposed in the direction of rotation, a strain sensor unit provided in the optical fiber, and the strain sensor unit of the outer ring A notch groove formed on the outer side of the arrangement position, a rolling element arranged between the inner ring and the outer ring, a rotary joint arranged and rotated in the axial direction of the fixed shaft, and via the rotary joint A strain measuring instrument connected by an optical fiber, and detecting the strain when the rolling element passes through the position of the strain sensor by rotating the rolling bearing. To.

[3] In the load distribution measuring device for a rolling bearing with a built-in strain sensor on the outer ring described in [2] above, a fiber Bragg grating strain sensor (FBG sensor) is used as the strain sensor. .
[4] In the load distribution measuring apparatus for a rolling bearing with a built-in strain sensor on the outer ring described in [2] above, a Fabry-Perot interference type strain sensor is used as the strain sensor.

  According to the present invention, an accurate load distribution of a rolling bearing can be obtained with a measuring device having a simple configuration.

It is a schematic diagram which shows the attachment part of the optical fiber equipped with the strain sensor part in the load distribution measurement apparatus of the strain sensor built-in type rolling bearing to the outer ring which shows the Example of this invention. 1 is an overall view of a load distribution measuring device for a rolling bearing with a built-in strain sensor to an outer ring showing an embodiment of the present invention. It is a block diagram of the outer ring | wheel of the strain sensor built-in type rolling bearing to the outer ring | wheel which shows the Example of this invention. It is a schematic diagram of the strain sensor part of the fiber Bragg grating system of the load distribution measuring device of the strain sensor built-in type rolling bearing to the outer ring of the present invention. It is a schematic diagram of the strain sensor part of the Fabry-Perot interference type of the load distribution measuring device for the rolling bearing with a built-in strain sensor to the outer ring of the present invention. It is a figure which shows the strain distribution by the load distribution measurement of the strain sensor built-in type rolling bearing to the outer ring | wheel of this invention. It is a figure which shows the attachment part of the optical fiber in the rolling body of the conventional load distribution measuring apparatus of a rolling bearing, and a strain sensor part.

  The load distribution measuring method of the strain sensor built-in type rolling bearing to the outer ring according to the present invention is a rolling bearing in which the inner ring of the rolling bearing is fixed and the outer ring rotates, and the inner ring is fixed to the fixed shaft of the rolling bearing. A narrow hole is provided in the circumferential direction in the vicinity of the raceway surface of the outer ring that is arranged on the outer side of the outer ring, an optical fiber equipped with a strain sensor unit is inserted into the narrow hole, and the strain sensor unit of the outer ring is disposed. A notch groove is formed outside the position, a rolling element is provided between the inner ring and the outer ring, an output signal from the strain sensor unit is led out by the optical fiber, and is arranged in the axial direction of the fixed shaft. An optical fiber is connected to a strain measuring instrument through a rotating rotary joint, and the rolling bearing is rotated to detect strain when the rolling element passes through the position of the strain sensor unit.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a schematic diagram showing an optical fiber mounting portion equipped with a strain sensor portion in a load distribution measuring apparatus for a rolling bearing with a built-in strain sensor on an outer ring according to an embodiment of the present invention. FIG. Fig. 1 (b) is an enlarged view of part A of Fig. 1 (a), Fig. 2 is an overall view of a load distribution measuring device for the rolling bearing, and Fig. 3 is a configuration diagram of an outer ring of the rolling bearing with a built-in strain sensor. 3 (a) is a circumferential cross-sectional view (cross-sectional view taken along the line BB of FIG. 3 (b)), FIG. 3 (b) is a view seen from the outside of the outer ring, and FIG. It is CC sectional view taken on the line of Fig.3 (a).

  In these drawings, 1 is a fixed shaft, 2 is an inner ring of a rolling bearing fixed to the fixed shaft 1, 3 is a rolling element that rotates and revolves, 4 is an outer ring that is arranged outside the rolling element 3 and rotates, 4A Is a narrow hole formed in the circumferential direction of the outer ring 4, 4A ′ is a thin hole for taking out the optical fiber formed to let out the optical fiber, and 4B is a notch formed outside the thin hole 4A of the outer ring 4. A groove 5 is an optical fiber inserted into the narrow hole 4A in the outer ring 4, 5 'is an optical fiber disposed between the rotary joint 9 and the strain measuring instrument 11, and 6 is a strain sensor provided in the optical fiber 5. , 7 is a housing that rotates together with the outer ring 4, 8 is fixed to the housing 7 and rotates together with the housing 7, a rotary jig for attaching the rotary joint 9, 10 is a rotary joint support jig, 11 is a strain measuring instrument, 12 LAN cable, 13 a personal computer (PC), 14 is a load, 15 indicates the load distribution of the rolling bearing.

As shown in FIG. 2, the strain sensor unit 6 is disposed in the circumferential direction in a narrow hole 4 </ b> A formed in the circumferential direction in the vicinity of the raceway surface of the outer ring 4, and is connected by an optical fiber 5 ′ via a rotary joint 9. The strain measuring instrument 11 is connected. A PC 13 is connected to the strain measuring instrument 11 via a LAN cable 12 or the like.
With this configuration, an output signal from the strain sensor unit 6 disposed on the outer ring 4 is output via the optical fiber 5, and is obtained by the strain measuring instrument 11 and the PC 13 from the measured strain of the outer ring 4. By appropriately processing the strain data, the load of the rolling bearing can be obtained, and the load distribution 15 can be obtained.

Note that the strain sensor unit 6 is only required to be arranged in a single row on the outer ring 4, and therefore, here, a fiber Bragg grating (FBG) system as shown below can be used.
FIG. 4 is a schematic diagram of a strain sensor unit of a fiber Bragg grating system of a load distribution measuring device for a rolling bearing with a built-in strain sensor on an outer ring according to the present invention.

In FIG. 4A, the attachment end 21 b of the FBG sensor 21 is optically connected to the tip of the optical fiber 22. In the core 21a of the FBG sensor 21, n Bragg diffraction gratings G1 to Gn are arranged at appropriate intervals in the longitudinal direction. The left end of the core 21a of the FBG sensor 21 and the right end of the core 22a of the optical fiber 22 are optically connected. When a laser beam L1 having a wide-band wavelength component as shown in FIG. 4B is incident on the FBG sensor 21 from the optical fiber 22, the incident laser beam L1 is transmitted to the Bragg diffraction gratings G1 to Gn. Reflected as a laser beam having a component of a wavelength λ in a narrow band centered on a predetermined wavelength λ ₀ (see FIG. 4C) determined according to each arrangement interval value and refractive index value, FIG. It returns to the optical fiber 22 as reflected laser light L2 shown in FIG. Here, when distortion occurs in the FBG sensor 21, since the arrangement interval value and the refractive index value of each of the Bragg diffraction gratings G1 to Gn change, the wavelength band of the reflected laser light L2 is, for example, in FIG. As indicated by the broken line, the Bragg wavelength, which is the center wavelength of the band, changes from λ ₀ to λ ₁ . By obtaining this change, the strain value of the FBG sensor 21 can be measured.

Further, instead of the FBG sensor, a Fabry-Perot interference type strain sensor may be used.
FIG. 5 is a schematic diagram of a strain sensor unit using a Fabry-Perot interference type strain sensor of a load distribution measuring apparatus for a rolling bearing with a built-in strain sensor on an outer ring according to the present invention.
The Fabry-Perot interference type strain sensor 31 includes a substantially cylindrical strain receiving member 32 as shown in FIG. The optical fiber 30 is inserted into an attachment end 32 a which is one end of the strain receiving member 32 and attached by an adhesive 33 or the like. The substantially cylindrical strain receiving member 32 is formed of a material that can be deformed in accordance with an external strain, for example, a synthetic resin.

  Further, the Fabry-Perot interference type strain sensor 31 is arranged so that the first mirror 34 and the second mirror 35 face each other with the cavity length D in between. The first mirror 34 is a half mirror, and a part of the laser light L incident from the optical fiber 30 is reflected by the reflecting surface 34a and a part thereof is allowed to pass. The second mirror 35 is a total reflection mirror, and reflects the laser light incident through the first mirror 34 by the reflection surface 35a.

  In the Fabry-Perot interferometric strain sensor 31 having such a configuration, the cavity length D is proportional to the wavelength modulation due to light reflection based on the principle of the Fabry-Perot interferometer. For this reason, the cavity length D can be measured by detecting the wavelength modulation between the incident light and the reflected light. Since the cavity length D changes according to the strain change of the substantially cylindrical strain receiving member 32, the strain value can be measured by obtaining the change of the cavity length D.

Furthermore, although not shown, rolling elements are arranged in a double row, and an FBG sensor or a Fabry-Perot interference type strain sensor is arranged as a strain sensor section on each of the outer rings, so that a plurality of optical fibers can be used at a plurality of locations. It can also be configured to measure strain.
FIG. 6 is a diagram showing a strain distribution measured by a load distribution measuring device for a rolling bearing with a built-in strain sensor on the outer ring of the present invention, and FIG. 6 (a) is a diagram showing a strain distribution at the first rotation of the outer ring. 6 (b) is a diagram showing the strain distribution of the second rotation of the outer ring, similarly, the number of times is sequentially overlapped up to a certain number of revolutions, and FIG. 6 (c) is a diagram showing the strain distribution in which all measured values are superimposed, FIG. (D) is a figure which shows rolling element load distribution obtained by performing data processing. 6A to 6C, the horizontal axis indicates an angle (rolling element position), the vertical axis indicates strain, the horizontal axis in FIG. 6D indicates an angle (rolling element position), and the vertical axis indicates The rolling element load is shown.

As shown in these figures, according to the present invention, the load distribution of the rolling bearing can be measured.
In addition, this invention is not limited to the said Example, Based on the meaning of this invention, a various deformation | transformation is possible and these are not excluded from the scope of the present invention.

  INDUSTRIAL APPLICABILITY The load distribution measuring method and apparatus for a rolling bearing with a built-in strain sensor on an outer ring according to the present invention can be used as a tool for measuring the load distribution of a rolling bearing capable of accurate measurement with a simple configuration.

DESCRIPTION OF SYMBOLS 1 Fixed shaft 2 Inner ring 3 Rolling element 4 Outer ring 4A Narrow hole 4A 'Thin hole for taking out optical fiber 4B Notch groove 5, 5', 22, 32 Optical fiber 6 Strain sensor part 7 Housing 8 Rotating jig 9 Rotary joint 10 Rotary joint Support jig 11 Strain measuring instrument 12 LAN cable 13 Personal computer (PC)
DESCRIPTION OF SYMBOLS 14 Load 15 Rolling bearing load distribution 21 FBG sensor 21a FBG sensor core 21b FBG sensor mounting end 22a Optical fiber core 31 Fabry-Perot interference type strain sensor 32 Strain receiving member 32a Strain receiving member mounting end 33 Adhesive 34 First mirror (half mirror)
34a Reflective surface of first mirror 35 Second mirror 35a Reflective surface of second mirror D Cavity length G1 to Gn n Bragg diffraction gratings L laser light L1 incident laser light L2 reflected laser light

Claims (4)

  A rolling bearing in which the inner ring is fixed and the outer ring rotates, the inner ring is fixed to the fixed shaft of the rolling bearing, and a narrow hole is provided in the circumferential direction near the raceway surface of the outer ring that is disposed outside the inner ring and rotates. An optical fiber equipped with a strain sensor section is inserted into the narrow hole, and a notch groove is formed outside the position where the strain sensor section of the outer ring is disposed, and a rolling element is formed between the inner ring and the outer ring. An output signal from the strain sensor unit is derived by the optical fiber, the optical fiber is connected to a strain measuring instrument via a rotary joint arranged and rotated in the axial direction of the fixed shaft, and the rolling bearing is rotated. A load distribution measuring method for a rolling bearing having a strain sensor built into the outer ring, wherein the strain when the rolling element passes through the position of the strain sensor section is detected. A rolling bearing in which the inner ring is fixed and the outer ring rotates,
(A) an inner ring of the rolling bearing fixed to a fixed shaft;
(B) an optical fiber disposed in a narrow hole formed in the circumferential direction in the vicinity of the raceway surface of the outer ring disposed and rotated outside the inner ring;
(C) a strain sensor unit provided in the optical fiber;
(D) a notch groove formed outside the position where the strain sensor portion of the outer ring is disposed;
(E) a rolling element disposed between the inner ring and the outer ring;
(F) a rotary joint arranged and rotated in the axial direction of the fixed shaft;
(G) a strain measuring instrument connected by an optical fiber through the rotary joint;
(H) A load distribution measuring device for a rolling bearing with a built-in strain sensor to an outer ring, wherein the rolling bearing is rotated to detect strain when the rolling element passes through the position of the strain sensor section.   3. A load distribution measuring apparatus for a rolling bearing with a built-in strain sensor in an outer ring according to claim 2, wherein a strain sensor (FBG sensor) of a fiber Bragg grating system is used as the strain sensor section. Load distribution measuring device for sensor built-in type rolling bearings.   3. A load distribution measuring apparatus for a rolling bearing with a built-in strain sensor on an outer ring according to claim 2, wherein a Fabry-Perot interference-type strain sensor is used as the strain sensor section. Load distribution measuring device.