JP5638312B2 - Load distribution measuring method and apparatus for rolling bearing with built-in strain sensor on inner ring - Google Patents

Description

  The present invention relates to a load distribution measuring method and apparatus for a strain bearing with a built-in strain sensor in an inner ring in a rolling bearing that is used with an outer ring fixed and an inner ring rotated, and in particular, an optical fiber in the inner 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. The thin holes 10 7 and 10 7 are optical fibers inserted into the thin holes 105, and 10 6 is a strain sensor section provided in the optical fiber 10 7 .

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. By inserting the optical fiber 10 7 adhering to equip the sensor unit 106 strain in that the fine hole 105, rolling detect strain generated in the moving body 103, which was set to determine the load distribution of the whole bearing present invention (See Patent Document 1 below).

  Further, the inventors of the present application have proposed a load distribution measuring method and apparatus for a rolling bearing with a built-in strain sensor on the inner ring (see Patent Document 2 below).

  FIG. 8 is a diagram showing a conventional load distribution measuring device for a rolling bearing with a built-in strain sensor on an inner ring.

  In this figure, 201 is a rotating shaft, 202 is a rotating inner ring of a rolling bearing fixed to the rotating shaft 201, 202A is a narrow hole formed in the axial direction of the inner ring 202, and 203 is a narrow hole 202A in the inner ring 202. An optical fiber to be inserted, 203 ′ is an optical fiber disposed between the rotary joint 208 and the strain measuring instrument 209, 204 is a strain sensor unit provided in the optical fiber 203, and 205 is a rolling element that rotates and revolves. 206, an outer ring fixed to the housing, 207 a support for the rotary joint 208, 210 a LAN cable, and 211 a personal computer (PC).

  The strain sensor unit 204 is arranged in the axial direction in a narrow hole 202A formed in the axial direction of the inner ring 202, and is supported by a single support 207 fixed to the rotating shaft 201 by optical fibers 203 and 203 ′. It is connected to the strain measuring instrument 209 via the rotary joint 208. A PC 211 is connected to the strain measuring instrument 209 via a LAN cable 210 or the like.

JP 2007-183105 A JP 2009-216664 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.

  Further, according to Patent Document 2, an optical fiber is provided in which a narrow hole 202A is provided in the axial direction in the vicinity of the raceway surface of the inner ring 202 fixed to the rotating shaft 201 of the rolling bearing, and the strain sensor unit 204 is provided in the narrow hole 202A. Since 203 is inserted, there is a problem that the load of the rolling bearing cannot be sufficiently detected and the load distribution cannot be measured accurately.

  In view of the above situation, the present invention provides a load distribution measuring method and apparatus for a rolling bearing with a built-in strain sensor in an inner ring, which 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 for a rolling bearing with a built-in strain sensor on an inner ring, a rolling bearing in which an outer ring is fixed and an inner ring rotates, and the inner ring strain sensor portion fixed to the rotating shaft of the rolling bearing includes: A notch groove for increasing the circumferential strain of the inner ring as much as possible without reducing the mechanical strength of the inner ring as much as possible, and for obtaining an accurate load distribution of the rolling bearing by the strain sensor at the center side of the position where it is arranged Is formed so as not to circulate over the circumferential direction, and provided with a narrow groove in the circumferential direction for inserting an optical fiber equipped with the strain sensor portion at the bottom of the notch, and is disposed outside the inner ring and the inner ring. A rolling element between the outer ring and the output signal from the strain sensor unit is derived by the optical fiber, and is arranged in the axial direction of the rotating shaft and supported by a support fixed to the rotating shaft. An optical fiber is connected to a strain measuring instrument through a single rotary 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 apparatus for a rolling bearing with a built-in strain sensor on an inner ring, the rolling ring is a rolling bearing in which an outer ring is fixed and an inner ring rotates, the inner ring of the rolling bearing fixed to a rotating shaft, and a circle of the inner ring A notch groove formed in the circumferential direction is formed, a narrow groove is provided at the bottom of the notch, an optical fiber inserted into the narrow groove, a strain sensor portion equipped in the optical fiber, and a strain sensor portion of the inner ring are provided. the center side of the position to be disposed, the formed so as not to lap over the circumferential direction, as much as possible to increase the strain of the inner ring in the circumferential direction without weakening the mechanical strength of the inner ring, precisely by the strain sensor unit A notch groove for determining a load distribution of the rolling bearing, a rolling element disposed between the inner ring and an outer ring disposed outside the inner ring, and an axial direction of the rotating shaft, and the rotation Fixed to shaft A single rotary joint supported by the supporting member and a strain measuring instrument connected by an optical fiber through the rotary joint, and the rolling bearing is rotated to position the strain sensor unit. It is characterized by detecting a strain when passing through.

  [3] In the load distribution measuring apparatus for a rolling bearing with a built-in strain sensor to the inner ring described in [2] above, a fiber Bragg grating type optical fiber strain sensor (FBG sensor) is used as the strain sensor section. And

  [4] In the load distribution measuring apparatus for a rolling bearing with a built-in strain sensor in the inner ring described in [2], a Fabry-Perot interference type strain sensor is used as the optical fiber 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 measuring apparatus of the strain sensor built-in type rolling bearing to the inner ring which shows the Example of this invention. 1 is an overall view of a load distribution measuring apparatus for a rolling bearing with a built-in strain sensor on an inner ring, showing an embodiment of the present invention. It is a block diagram of the inner ring | wheel of the strain sensor built-in type rolling bearing to the inner ring | wheel which shows the Example of this invention. It is a schematic diagram of the strain sensor part of the fiber Bragg grading method of the load distribution measuring device of the rolling bearing with built-in strain sensor to the inner 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 inner 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 inner 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. It is a figure which shows the load distribution measuring apparatus of the conventional strain bearing built-in type rolling bearing to an inner ring | wheel.

The load distribution measuring method for a strain bearing with a built-in strain sensor in an inner ring according to the present invention is a rolling bearing in which an outer ring is fixed and an inner ring rotates, and the inner ring strain sensor portion fixed to the rotating shaft of the rolling bearing includes: A notch groove for increasing the circumferential strain of the inner ring as much as possible without reducing the mechanical strength of the inner ring as much as possible, and for obtaining an accurate load distribution of the rolling bearing by the strain sensor at the center side of the position where it is arranged Is formed so as not to circulate over the circumferential direction, and provided with a narrow groove in the circumferential direction for inserting an optical fiber equipped with the strain sensor portion at the bottom of the notch, and is disposed outside the inner ring and the inner ring. A rolling element is provided between the outer ring and the output signal from the strain sensor unit is derived by the optical fiber, and is arranged in the axial direction of the rotating shaft and supported by a support fixed to the rotating shaft. Ru The optical fiber connected to a strain measuring instrument via the one rotary joint, wherein the position of the strain sensor portion by rotating the rolling bearing rolling elements strain detecting a as it passes through.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a schematic view showing an optical fiber mounting portion equipped with a strain sensor portion in a load distribution measuring device for a rolling bearing with a built-in strain sensor on an inner ring showing an embodiment of the present invention. FIG. Configuration diagram, 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 inner ring of the rolling bearing with a built-in strain sensor. FIG. 3A is a circumferential sectional view thereof (a sectional view taken along the line CC of FIG. 3B), and FIG. 3B is a sectional view taken along the line BB of FIG. 3 (c) is a sectional view taken along the line DD of FIG. 3 (a).

In these drawings, 1 is a rotating shaft, 2 is an inner ring that rotates on a rolling bearing fixed to the rotating shaft 1, and 2B is formed inside the narrow groove 2A of the inner ring 2 to weaken the mechanical strength of the inner ring as much as possible. In addition, a notch groove for obtaining an accurate load distribution of the rolling bearing by the strain sensor section, 2A is a narrow groove formed in the circumferential direction of the inner ring 2, and 2A 'is inclined from the narrow groove 2A to the side surface of the inner ring. provided in a portion extending, an optical fiber dispensing small hole which is formed in order to take out the optical fiber to the outside, 3 denotes an optical fiber to be inserted into the narrow groove 2A in the inner ring 2, 3 'is rotary joint 11 and the strain measuring instrument 4 is a strain sensor unit provided in the optical fiber 3, 5 is a rolling element that rotates and revolves as the inner ring rotates, 6 is an outer ring fixed to the housing 7, 8 is load, 9 Load distribution of the rolling bearing, 10 the support of the rotary joint 11, 13 LAN cable, 14 shows a personal computer (PC).

As shown in FIG. 2, the strain sensor unit 4 is arranged in the circumferential direction in the narrow groove 2A formed in the circumferential direction of the inner ring 2, the optical fiber 3 and 3 via a single rotary joint 11 ' Is connected to the strain measuring instrument 12. A PC 14 is connected to the strain measuring instrument 12 via a LAN cable 13 or the like.

  With this configuration, an output signal from the strain sensor unit 4 disposed on the inner ring 2 is output via the optical fiber 3 and obtained from the measured strain of the inner ring 2 by the strain measuring instrument 12 and the PC 14. By appropriately processing the strain data, the load of the rolling bearing can be obtained, and the load distribution 9 can be obtained.

  Note that the strain sensor unit 4 is only required to be arranged in a single row on the inner ring 2, and therefore, here, the fiber Bragg grading (FBG) system as described below is used.

  FIG. 4 is a schematic diagram of a strain sensor unit of a fiber Bragg grading system of a load distribution measuring device for a rolling bearing with a built-in strain sensor in an inner 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, a Fabry-Perot interference type strain sensor may be used as the strain sensor section of the present invention.

  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 in an inner 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, inside the Fabry-Perot interference type strain sensor 31, the first mirror 34 and the second mirror 35 are arranged to face each other with the cavity length E interposed therebetween. 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 E 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 E can be measured by detecting the wavelength modulation between the incident light and the reflected light. Since the cavity length E 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 E.

  Furthermore, although not shown in the drawing, the bearings are arranged in a double row, and an FBG sensor or a Fabry-Perot interference type strain sensor is arranged as an optical fiber strain sensor in each of the inner rings, so that a plurality of locations can be obtained with a plurality of optical fibers. It can also be configured to measure strain.

  FIG. 6 is a schematic diagram showing a strain distribution measured by a load distribution measuring device for a rolling bearing with a built-in strain sensor on the inner ring of the present invention, and FIG. 6 (a) is a diagram showing a strain distribution at the first rotation of the inner ring, FIG. 6 (b) is a diagram showing the strain distribution of the second rotation of the inner ring, and 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 with all measured values superimposed. 6 (d) is a diagram showing a 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 the inner ring according to the present invention can be used as a load distribution measuring tool for a rolling bearing that can perform accurate measurement with a simple configuration.

DESCRIPTION OF SYMBOLS 1 Rotating shaft 2 Inner ring 2A Narrow groove 2A 'Narrow hole for taking out optical fiber 2B Notch groove 3, 3', 22, 30 Optical fiber 4 Strain sensor part 5 Rolling element 6 Outer ring 7 Housing 8 Load 9 Rolling bearing load distribution 10 Rotary Joint support 11 Rotary joint 12 Strain measuring instrument 13 LAN cable 14 Personal computer (PC)
DESCRIPTION OF SYMBOLS 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 34a First Reflective surface of mirror 35 35 Second mirror 35a Reflective surface of second mirror E Cavity length G1 to Gn n Bragg gratings L laser beam L1 incident laser beam L2 reflected laser beam

Claims (4)

A rolling bearing in which the outer ring is fixed and the inner ring rotates, and the mechanical strength of the inner ring is not reduced as much as possible at the center of the position where the strain sensor portion of the inner ring fixed to the rotating shaft of the rolling bearing is disposed. the inner ring of increasing the strain in the circumferential direction, a notch groove for determining the load distribution of precise rolling bearing by the strain sensor unit, said formed so as not to lap over the circumferential direction, the strain notch bottom A circumferential narrow groove for inserting an optical fiber equipped with a sensor unit is provided, and a rolling element is provided between the inner ring and the outer ring arranged outside the inner ring, and an output from the strain sensor unit A signal is derived by the optical fiber, and the optical fiber is connected to the strain measuring instrument via a single rotary joint that is arranged in the axial direction of the rotating shaft and supported by a support fixed to the rotating shaft. Previous Load distribution method for measuring strain sensor built-rolling to the inner ring, characterized by detecting the distortion of when the rolling elements the position of the strain sensor unit rotates the rolling passes. A rolling bearing in which the outer ring is fixed and the inner ring rotates,
(A) an inner ring of the rolling bearing fixed to the rotating shaft;
(B) forming a notch groove formed in the circumferential direction of the inner ring, providing a narrow groove at the bottom of the notch, and an optical fiber inserted into the narrow groove;
(C) a strain sensor unit provided in the optical fiber;
(D) toward the center of the position where the strain sensor portion of the inner ring is arranged, the so formed as not to lap over the circumferential direction, the strain of the inner ring in the circumferential direction without much as possible weakening the mechanical strength of the inner ring It was increased, and the notch groove for determining the load distribution of precise rolling bearing by the strain sensor unit,
(E) a rolling element disposed between the inner ring and an outer ring disposed outside the inner ring;
(F) a single rotary joint that is arranged in the axial direction of the rotary shaft and supported by a support fixed to the rotary shaft;
(G) a strain measuring instrument connected by an optical fiber through the rotary joint;
(H) A load distribution measuring apparatus for a rolling bearing with a built-in strain sensor in an inner 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 inner ring according to claim 2, wherein a fiber Bragg grating type optical fiber strain sensor (FBG sensor) is used as the strain sensor. Load distribution measuring device for rolling bearing with built-in strain sensor.   3. A load distribution measuring apparatus for a rolling bearing with a built-in strain sensor in an inner ring according to claim 2, wherein a Fabry-Perot interference type strain sensor is used as the optical fiber strain sensor. Bearing load distribution measuring device.