JP4344401B2 - Rotating body measurement system - Google Patents

Description

  The invention according to the claims relates to a system for smoothly measuring strain, stress, temperature and the like generated in a rotating body.

An optical fiber is sometimes used as a sensor and a signal transmission means when measuring the strain and temperature of an object. An example is shown in FIG.
In the example of FIG. 9, white light is incident on the sensor (optical fiber sensor) 10 made of an optical fiber from the measuring means 20 via the optical fiber 22. The optical fiber sensor 10 has a minute cavity (not shown) inside, and reflects light of a specific wavelength according to the length of the cavity. The sensor 10 is affixed to the object to be measured, and itself expands and contracts according to the expansion and contraction of the object to be measured and changes in temperature, and changes the cavity length. When light enters, the sensor 10 reflects light having a wavelength corresponding to the cavity length. To do. Such reflected light is sent to the detector 20c via the optical fiber 22, and various measurements are performed through wavelength detection and the like. For example, it is possible to know the strain of the object to be measured from the correspondence between the cavity length and the wavelength of the reflected light, and to detect the temperature of the object to be measured based on the relationship with the thermal expansion. In addition to the example of FIG. 9, the transmitted light of the optical fiber sensor (that is, the light excluding the reflected light) is sent to the detector, and the wavelength is detected in the same manner as described above to know the strain, temperature, etc. Is also possible.

  In general, the use of optical fibers for strain and temperature measurement is less susceptible to noise even in the presence of electromagnetic noise compared to the use of strain gauges and thermocouples, and thus shielding as a noise prevention measure. There is an advantage that high measurement accuracy can be maintained even if it is not applied. Further, when an optical fiber is used as the sensor and the signal transmission means as described above, there is an advantage that an electric / optical conversion means for converting a signal between an electric signal and an optical signal is unnecessary.

An apparatus for measuring the temperature of a rotating body based on a related technique is described in Patent Document 1 below.
JP-A-4-339227

  Although the example shown in FIG. 9 can measure a stationary machine or structure, it is impossible to measure strain and temperature using a rotating body, that is, a rotating part of the machine or the like as a measurement site. This is because measures necessary for measurement of the rotating body such as prevention of twisting of the optical fiber between the rotating portion and the fixed portion are not taken.

Even when the temperature of the rotating body is measured with the apparatus described in Patent Document 1, improvement is still desired in the following points. That is,
-Optical coupling is required to connect optical fibers in a rotatable manner between the rotating portion and the fixed portion. Such a coupling requires a considerable cost, and since the permissible rotational speed is not high, it often prevents measurement in a high-speed rotational range.
-Since the optical coupling needs to be provided on the center line of the rotating part, it is difficult to simultaneously perform a plurality of measurements in one rotating body.

  The invention of the claims provides a system that can smoothly measure the distortion, temperature, and the like of a rotating body using an optical fiber, and intends to solve the above-described problems.

The rotating body measurement system according to claim 1 is:
a) Attach an optical fiber sensor (for example, a transmissive optical fiber sensor; the same shall apply hereinafter) with a different incident part and outgoing part to the measurement site on the rotating body, and connect optical fibers to the incident side and outgoing side of the sensor. Then, the end face of the optical fiber opposite to the sensor (the face on the side far from the connection surface with the sensor, the end face on the incident side and the exit side with respect to the sensor) is fixed on the rotating body. on the other hand,
b) An optical fiber is arranged in a non-rotating part adjacent to the rotating body, and a light source and a detector for returning light (transmitted light) from the sensor are connected to each optical fiber of the non-rotating part. And
c) The end face of the optical fiber in the non-rotating part is spaced from the orbit of the end face of the optical fiber on the rotating body (minimum distance that can stably maintain a non-contact state) and on the orbit. It is fixed so that the end faces face each other at a specific location.
The rotating body measurement system according to claim 2 is:
a) Attach an optical fiber sensor (for example, a reflection type optical fiber sensor; the same shall apply hereinafter) where the incident part and the emission part are the same on the rotating object to be measured, and connect an optical fiber to the input / output part of the sensor. While fixing the end surface of the optical fiber opposite to the sensor on the rotating body,
b) An optical fiber is disposed in a non-rotating part adjacent to the rotating body, and a light source and a detector for return light (reflected light) from the sensor are connected to the optical fiber of the non-rotating part.
c) The end face of the non-rotating part of the optical fiber is fixed so that the end face is spaced from the orbit of the end face of the optical fiber on the rotating body and the end faces face each other at a specific location on the orbit. --It is characterized by that.

The system according to claims 1 and 2 includes a case where the optical fiber sensor is made a light reflection type and a case where the optical fiber sensor is made a light transmission type. First, when the optical fiber sensor is of a light-reflective type (such as the example of FIG. 1), the single optical fiber on the rotating body referred to in a) above is sufficient as in the example of FIG. The end surfaces on the incident side and the emission side are the same (common). In that case, the optical fiber of the non-rotating part referred to in the above b) may be a series of light sources and detectors connected as in the example of FIG. On the other hand, when the optical fiber sensor is of a light transmission type, there are two optical fibers on the rotating body across the sensor, and the end surfaces on the incident side and the emission side exist separately. When the circular orbit of each end face is different, in c) above, the end face on the side connected to the light source of the non-rotating portion of the optical fiber is opposed to the end face on the incident side as described above, and With respect to the end face, the end face connected to the detector in the optical fiber of the non-rotating portion is opposed and fixed as described above.
Although not shown in FIG. 1, in the transmissive sensor, an optical fiber is connected to the other end surface of the sensor 10, and the transmitted light of the sensor 10 enters an optical fiber not shown. And the end surface of the optical fiber on the opposite side to the sensor 10 is disposed so as to face the end surface of the non-rotating portion of the optical fiber. In such an embodiment, by separately providing the opposing optical fiber, the illustrated coupler 20b is unnecessary, and the other end of the separately provided optical fiber is directly connected to the detector 20c. There is an advantage that the coupler 20b is not required and the device configuration is simplified. It should be noted that in the transmission type optical fiber sensor, light other than the reflected light is transmitted and detected, and the signal light is emitted in the opposite way from the reflective type and requires different signal processing. There is.

The rotating body measurement system according to these claims enables measurement of strain, temperature, stress, pressure, and the like at a measurement location on the rotating body by the following actions. That is,
1) First, the light emitted from the light source b) is emitted from the end face through the non-rotating portion of the optical fiber, and is incident on the incident-side end face of the optical fiber on the rotating body described in a). The transmission of light by making it enter in this way is performed through the space of the above distance between the two end faces when the end faces of both optical fibers arranged and fixed as shown in c) are opposed to each other at a specific location.
2) The optical fiber on the rotating body of a) including the above-mentioned incident side end face sends the light to the optical fiber sensor, and the optical fiber sensor is specified according to its own strain and temperature. The light of the wavelength is reflected and the other light is transmitted.
3) Return light (reflected light or transmitted light) in the optical fiber sensor is input to the detector through the optical fiber including the end face on the emission side in the above a) and the optical fiber in the above b). The transmission and reception of light from the optical fiber of a) to the optical fiber of b) is performed while the end faces of both optical fibers face each other at the above-mentioned specific position from the former emission-side end face to the latter end face. Is called.
4) The detector detects the wavelength of the input light and performs the appropriate conversion or calculation using itself or other means, thereby allowing the strain, temperature, stress or Indicates pressure etc.
Note that the above 1) to 4) are performed instantaneously based on the speed of light and the like.

The above rotating body measurement system has the following advantages.
・ Because the end face of the non-rotating part of the optical fiber connected to the light source or detector is placed in a non-contact state at a distance from the end face of the optical fiber on the rotating body as shown in c) above, an optical fiber sensor, etc. The optical fiber does not twist despite being on the rotating body. In addition, since there is no need to provide any coupling between the optical fiber on the rotating body and the optical fiber in the non-rotating part, there is no speed limitation due to the coupling and the like, and it is easy to cope with high-speed rotation. is there. The optical fiber on the rotating body does not need to be twisted or rotated, and its end face or the like may be fixed on the rotating body, so that high-speed rotation of the rotating body is not hindered.
-The non-rotating portion of the optical fiber may be disposed so that the end face of the optical fiber on the rotating body faces the end face only at a specific location on the circular orbit. That is, since it is not necessary to provide the end surfaces of both optical fibers on the line of the rotation center of the rotating body, it is also easy to simultaneously measure a plurality of measurement points in one rotating body.
-Since optical fibers are used as sensors and signal transmission means, they are less susceptible to noise even in an electromagnetic environment, enabling highly accurate measurements, and converting signals between electrical and optical signals. Of course, there is a merit that a means to do this is unnecessary.

In addition to the above a), b) and c), the rotating body measuring system described in claim 3
d) The part where the light from the light source is transmitted from the end face of the non-rotating portion of the optical fiber to the end face of the optical fiber fixed on the rotating body so as to face it, and the return light from the optical fiber sensor on the rotating body At least one of the parts transmitted from the end face of the optical fiber to the end face of the optical fiber fixed to the non-rotating part so as to oppose it, ensures the amount of light exchanged between the end faces of both optical fibers. It is characterized by providing loss prevention means for doing this.

  The loss prevention means d) includes a means for adjusting the direction of light (alignment, etc.) in addition to a means for preventing the loss of light quantity.

  According to the rotating body measurement system of this claim, there is a non-contact portion with a distance between the end faces between the optical fiber of the non-rotating portion connected to the detector and the optical fiber on the rotating body. Nevertheless, highly accurate measurement is realized by appropriately transmitting the optical signal. This is because loss prevention means is provided between both end faces as described in d) above. If the same means suppresses the loss of the amount of light transmitted and received due to the signal transmission between the optical fibers sandwiching the end face, it is naturally possible to perform highly accurate measurement. The light that exits from the exit end face of the optical fiber on the rotating body and reaches the non-rotating part of the optical fiber is subjected to some attenuation in the transmission path. By using it, the measurement accuracy can be improved particularly effectively.

The rotating body measuring system according to claim 4 is characterized in that a lens is provided between the end face of the non-rotating portion of the optical fiber and the end face of the rotating portion of the optical fiber, particularly as the loss prevention means. The configuration shown in FIG. 3 is an example.
In the above-described lens optical system, when the light emitted from one fiber end face is directly condensed and incident on the other fiber end face by a convex lens, the light emitted from one fiber end face is once converted into parallel light by a collimator. When the light is received by a collimator and condensed on the other fiber end face, the light emitted from the one fiber end face is converted into parallel light by the collimator and prevented from diffusing and incident on the other fiber end face. The convex lens has a function of condensing the diffusing light emitted from the end face of the optical fiber at the focal point, and the collimator has a function of collimating the diffusing light emitted from the end face of the optical fiber. In the former case, it is necessary to focus the arrangement of the fiber end face on the incident side, and the arrangement is restricted. In addition, if the collimator is used to make the intermediate part parallel light, the distance may be slightly changed because the light is parallel light, and there is an advantage that the arrangement is not restricted.
As an embodiment of the invention of claim 4, the lens is provided in front of the end face of the non-rotating portion, but the lens can be arranged in front of the end face of the optical fiber on the rotating body. In an embodiment of claim 10 (described later), a lens is disposed in front of the end faces of the optical fibers of both the rotating body and the non-rotating portion so that the intermediate portion is not subjected to restrictions on arrangement as parallel light. It is possible to prevent diffusion of the emitted light and to prevent diffusion of the return light from the optical fiber sensor. As a result, the return light to the sensor increases, and accurate measurement is possible. In general, an optical measurement system is characterized in that it cannot be measured if the light intensity is low, or the accuracy is lowered even if it can be measured. In particular, when an optical fiber measurement system is applied to a rotating body that is the object of the present invention, transmission and reception of light between a rotating body and a non-rotating part must be intermittent. The light intensity decreases. The main object of the invention of claims 4 and 10 is to solve the problem that the light intensity is reduced by using a lens.

  In general, light is emitted from the end face of an optical fiber so as to spread (diffuse) at a certain opening angle determined according to the material (refractive index) of the optical fiber. Therefore, when optical fibers of the same diameter are arranged with their end faces facing each other at a distance, only a part of the light exiting one end face reaches the other end face, and the remaining light is emitted to the surroundings. Will be. However, when a lens is provided in front of one end face as in the measurement system of this claim, the loss of light is reduced by the action of the lens, and the amount of light transferred between the end faces is ensured and high-precision measurement is possible. It becomes possible.

  The rotating body measuring system according to claim 5 is a non-rotating portion of an optical fiber (such as one that receives light from the exit end face on the rotating body) at least on the end face (or as the loss prevention means described above) The optical fiber may be the entire length of the optical fiber), and has a larger cross section than the end face of the optical fiber on the rotating body facing the optical fiber. The configuration of FIG. 4 is an example of the system of this claim.

  Thus, if the optical fiber on the incident side of the non-rotating part has a large cross section, even if light is emitted so as to spread from the exit side end face of the optical fiber on the rotating body, most (or all) of the non-rotating part Can be transmitted to the optical fiber. If it does so, the amount of light quantity exchange between the said both end surfaces will be ensured, and a highly accurate measurement can be performed.

In the rotating body measuring system according to claim 6, an optical fiber sensor having a different incident portion and emitting portion is attached to a measurement location on the rotating body, and in particular, as the loss prevention means, a) On the incident side, the end face of the optical fiber on the rotator is made larger than the end face of the non-rotating portion of the optical fiber facing it, and / or b) on the exit side from the sensor, the light of the non-rotating portion The end face of the fiber is made larger than the end face of the optical fiber on the rotating body facing it ----.
By doing so, on the incident side to the optical fiber sensor, light emitted from the end face of the non-rotating portion of the optical fiber can be incident on the end face of the optical fiber on the rotating body with little loss, and on the outgoing side of the optical fiber sensor, the rotating body Light emitted from the upper end face of the optical fiber can be incident on the end face of the non-rotating portion with little loss. Therefore, light can be transmitted with high efficiency over the entire optical transmission path.
Note that “and / or” is described as above, in addition to the case where both a) and b) above are adopted in the system of this claim, and only one of a) or b) is adopted. It also means that it is included.

  The rotating body measurement system according to claim 7 is an optical fiber on the rotating body, particularly as an optical fiber on the rotating body (such as one that receives light from the output side end face on the rotating body) as the loss prevention means. A plurality of them are arranged along the circular orbit of the end face of the. FIG. 5 is an example of this system.

In order to allow the light emitted from the light source provided in the non-rotating part to reach the optical fiber sensor on the rotating body through the optical fiber, and to return the return light to the detector of the non-rotating part, it takes a little time even though it is light. Cost. Since the rotating body also rotates during that time, depending on the rotation speed, when the light is emitted from the end face of the optical fiber on the rotating body, the end face of the optical fiber in the non-rotating part is displaced from the exact facing position (lateral shift). The optical signal may not be sufficiently transmitted.
However, in the measurement system of this claim, since a plurality of optical fibers of the non-rotating part are arranged along the circular orbit of the end face of the optical fiber on the rotating body, it is easy to prevent such inconvenience. When the rotational speed of the rotating body increases, the light emitted from the end face of the optical fiber on the rotating body is simultaneously received by the end faces of a plurality of optical fibers adjacent to the circumferential direction of the non-rotating part and reliably detected. This is because it can be input to the device. Specifically, the optical fiber end face is spread without providing a lens so that light enters the optical fiber end faces at the same time on the non-rotating body, or the non-rotating body is defocused by the lens between the optical fiber end faces. An image that is long in the circumferential direction at a non-rotating portion is used so that light enters the end faces of the optical fibers simultaneously, or a cylindrical lens or the like is used as a lens between the end faces of the optical fibers (see the example in FIG. 6). It is preferable that the light enters the end faces of the plurality of non-rotating optical fibers at the same time.

In the rotating body measuring system according to claim 8, in particular, a part of the non-rotating portion of the optical fiber (such as one that receives light from the emission side end face) on the rotating body is formed by a pair of connectors as the loss prevention means. It is characterized by being separable.
For example, an optical power meter for measuring the facing accuracy between the end faces can be connected between the pair of connectors made separable (the configuration in FIG. 7 is an example thereof). In addition, a light source and a detector can be separately attached between the connectors, or a recorder can be connected separately. Therefore, in the system of this claim, the degree of freedom to cope with various tests is ensured, the equipment configuration is simplified as a result, and the equipment can be easily replaced when the connected equipment breaks down, improving the maintainability. There are advantages such as.

  In order to sufficiently transmit an optical signal between the optical fiber on the rotating body and the optical fiber in the non-rotating part, in order to improve the facing accuracy between the end faces of both optical fibers (accuracy regarding optical axis matching). It is also necessary to appropriately perform the so-called alignment work. In the system of this claim, since it is possible to connect an optical power meter to the optical fiber of the non-rotating part via a connector, an appropriate alignment operation can be performed. In other words, the optical power meter can measure the facing accuracy between the end faces by quantitatively displaying the amount of light transferred, and can be used while adjusting the position and angle of each of the above optical fibers and their end faces. By doing so, an appropriate alignment work is made possible. After completing the alignment work, if the optical fiber of the non-rotating part is connected to the original position with the connector, it is possible to perform highly accurate measurement with the amount of light exchanged between the two end faces. become.

  The rotating body measurement system according to claim 9 is provided with a lens between the end face of the optical fiber of the non-rotating part and the end face of the optical fiber of the rotating part as the loss prevention means, and the light from the light source, or The optical fiber is characterized in that the end face of the optical fiber that receives the light facing the optical fiber is made larger than the end face of the optical fiber from which the return light from the optical fiber sensor is emitted.

  According to a tenth aspect of the present invention, there is provided a rotating body measuring system according to claim 10, wherein the loss prevention means is a lens provided between the end face of the non-rotating portion of the optical fiber and the end face of the rotating portion of the optical fiber. A lens was provided in front of the end face, a lens was provided in front of the end face of the optical fiber on the rotating body, or a lens (convex lens, collimator, etc. for collecting light or adjusting the direction of light) was provided on both of them. It is characterized by.

According to the system of the ninth or tenth aspect, the light emitted from the end face of the optical fiber on the rotating body can be more reliably transmitted to the optical fiber of the non-rotating portion, which is particularly preferable in terms of measurement accuracy.
In addition, a lens is provided in front of the end face of the optical fiber of the non-rotating part, and a part of the optical fiber of the non-rotating part can be separated by a pair of connectors, for measuring the facing accuracy between the end faces between these connectors. It is also preferable that the optical power meter can be connected. As described above (Claim 10), lenses are provided on both the front end face of the non-rotating portion of the optical fiber and the front end face of the optical fiber on the rotating body, and the end face of the incident-side optical fiber is disposed opposite to the exit side. It is also possible to make the cross section larger than the end face of the optical fiber. Similarly, a lens is provided both at the front of the end face of the optical fiber of the non-rotating part and at the front of the end face of the optical fiber on the rotating body, and a part of the optical fiber of the non-rotating part can be separated by a pair of connectors. In the meantime, it is preferable to connect an optical power meter for measuring the facing accuracy between the end faces in terms of improving the measuring accuracy.

  According to the rotating body measuring system according to claim 1 and 2, since the optical fiber is not twisted, it is not necessary to rotate it, and it is not necessary to provide any coupling between the optical fibers. Is easy to deal with. In addition, it is possible to simultaneously measure a plurality of measurement points in one rotating body.

  According to the rotating body measuring system of the third aspect, the signal transmission between the end faces is appropriately performed by the action of the loss preventing means, so that highly accurate measurement can be performed.

  With the measurement system according to any one of claims 4 to 8, the loss prevention means can be configured at low cost, and high-precision measurement can be performed as described above.

  The measurement system according to claims 9 and 10 is particularly preferable in terms of measurement accuracy because the loss prevention means functions more effectively.

  An embodiment relating to the implementation of the invention is introduced in FIGS. FIG. 1 is a conceptual diagram showing the entire measurement system together with the rotating body 1, and FIG. 2 is a diagram showing a speed range that can be measured in the system of FIG.

  In FIG. 1, a rotating body 1 (for example, a propeller shaft or a gas turbine rotor) is connected to a driving source (or driven body) 3 while being supported by a bearing 2. In the system shown in the figure, strain, temperature, stress, pressure, and the like are measured at a location to be measured on the rotating body 1 (for example, a part of a propeller or a moving blade).

The configuration of the system shown in FIG. 1 is as follows.
a) First, an optical fiber sensor 10 having a property of reflecting light of a specific wavelength according to its own length change is attached to a measurement location on the rotating body 1 described above. This pasting is performed using an adhesive or the like. For example, when measuring the temperature, only one portion of the sensor 10 needs to be fixed. To measure strain and stress, both ends of the sensor 10 in the length direction are used. Is fixed at the point to be measured. An optical fiber 12 is connected to one end of the optical fiber sensor 10, and at least its end face (open end face opposite to the side connected to the sensor 10) 13 is fixed to the rotating body 1 and directed outward.

  b) In the non-rotating part close to the rotating body 1, the measuring means 20 including the halogen white light source 20a and the detector 20c and the optical fiber 22 connected thereto are installed. The optical fiber 22 has one end connected to the measuring means 20 by a connector 22x, but the other end face 23 is an open end face. The measuring means 20 is obtained by connecting an optical fiber 21a communicating with the connector 22x to a light source 20a and a detector 20c by a coupler 20b. The detector 20c is connected to a device 20d that performs data processing and recording and a device 20e that displays measured values. White light emitted from the light source 20a in the measuring means 20 reaches the optical fiber 22 through the coupler 20b and the optical fiber 21a, and is emitted to the outside from the end face 23 thereof. On the other hand, if there is light incident from the end face 23, it enters the measuring means 20 via the optical fiber 22, and is input to the detector 20c via the coupler 20b.

  c) The end face 23 of the optical fiber 22 connected to the measuring means 20 and provided in the non-rotating portion is provided at a position that can be opposed to the end face 13 of the optical fiber 12 provided on the rotating body 1 with a short distance. ing. In other words, the former end face 23 is separated from the orbit of the latter end face 13 rotating together with the rotating body 1 in the axial direction (axial direction of the rotating body 1), for example, by about 10 mm, and is located at one place on the orbit. And is fixed so as to face the latter end face 13 directly in front. The above distance may be smaller or larger. If it is small, the attenuation of light becomes small and a highly sensitive measurement is possible, but the arrangement adjustment becomes difficult. Moreover, if the distance is large, the degree of freedom of equipment arrangement increases and installation becomes simple.

  In such a measurement system, the strain and temperature can be measured for the measurement site of the rotating body 1 as follows. That is, 1) White light continuously emitted from the light source 20a of the measuring means 20 is emitted from the end face 23 through the optical fiber 22 of the non-rotating portion, and is rotated from the end face 13 at a position facing the end face 23. The light enters the upper optical fiber 12. 2) The white light traveling in the optical fiber 12 reaches the optical fiber sensor 10, and the sensor 10 reflects only light of a specific wavelength according to the strain and temperature of the sensor 10 itself and returns in the optical fiber 12. To the end face 13. 3) The reflected light from the optical fiber sensor 10 is emitted from the end face 13 of the optical fiber 12, and enters the optical fiber 22 in the non-rotating portion from the end face 23. 4) The reflected light entering the optical fiber 22 reaches the detector 20c of the measuring means 20, and the detector 20c detects the wavelength of the reflected light, and then the distortion, temperature, and stress of the rotating body 1 by the devices 20d and 20e. Alternatively, it is converted into pressure and displayed.

  By the way, since the light travels at a high speed, the incidence of white light from the end face 23 to the end face 13 and the emission of reflected light from the end face 13 to the end face 23 occur almost simultaneously when both end faces 13 and 23 face each other. The transmission and reception of light between both end faces is almost certainly performed. However, since the speed of light is also finite, the reflected light from the end face 13 to the end face 23 depends on the rotation speed of the rotating body 1, the rotation radius of the end face 13, or the length of the optical fiber 12 serving as a light transmission path. When the light is emitted, there is a case where the two end faces are displaced from the exact opposite positions (laterally displaced), and the reflected light is not properly transferred.

The diagram of FIG. 2 is a limit condition that can be measured in consideration of such points. That is, when the reflected light is emitted from the end face 13 to the end face 23, the gap between the two end faces causes a lateral shift of only 5% of the diameter of the optical fibers 12 and 22 (assuming the same diameter is used). This means that almost sufficient measurement is possible).
According to this, for example, when the rotating body 1 is rotated at 10000 rpm with the radius of rotation of the end face 13 being 0.10 m (10 cm), the length (one-way distance from the end face 13 to the sensor 10) is about 2.5 m. It can be seen that the measurement system of FIG. 1 has sufficient practicality.

  FIG. 3 is a conceptual diagram showing another embodiment of the invention. The optical fiber sensor 10 is attached to the measurement object of the rotating body 1, the end face 13 of the optical fiber 12 connected thereto is fixed on the rotating body 1 and faces outward (point a), and measuring means (Including a white light source, a detector, etc., not shown) and the optical fiber 22 are provided in the non-rotating portion, and the end face 23 of the optical fiber 22 can be opposed to the end face 13 of the optical fiber 12 on the rotating body. In this arrangement (points b) and c), this example is not different from that in FIG.

  However, in this example, a condensing convex lens 24 is provided in front of the end face 23 of the non-rotating portion of the optical fiber 22 to prevent loss of light quantity exchanged between the end faces 13 and 23. The lens 24 is attached to the tip of a cylindrical body 24 a that is slidable in the longitudinal direction with respect to the distal end portion of the optical fiber 22. It is preferable to adjust the position of the lens 24 together with the cylindrical body 24a and use the lens 24 at a position where the loss of the amount of light exchanged between the end faces 13 and 23 is the smallest. If the loss of the amount of light exchanged is reduced, highly accurate measurement is possible.

  When the lens 24 is used in this way, the distance L between the end faces 13 and 23 of the optical fibers 12 and 22 can be increased. This is because even if the distance L is increased, the loss of light quantity can be minimized. If the distance L can be increased in this way, a large space required for setting for measurement can be secured, and therefore the setting work becomes easy.

  4 (a) to 4 (c) are conceptual diagrams showing still another embodiment of the invention. There is no difference from the example of FIG. 1 in that the configurations of a) to c) described above are adopted, but in this example, a connector is provided at the end of the optical fiber 22 provided in the non-rotating part as shown in FIG. It is characterized in that an optical fiber 25 having a large diameter and a large cross section is connected via 25a. The end face 26 of the optical fiber 25 is made to face the end face 13 (circular orbit) of the optical fiber 12 on the rotating body 1.

  In this way, even if light is emitted so as to spread from the end face 13 of the optical fiber 12 on the rotating body 1, most of the light can be transmitted to the optical fiber 22 in the non-rotating part. Further, as shown in FIG. 4B, when the rotating body 1 rotates at a particularly high speed, the end face 13 of the optical fiber 12 is laterally displaced from the position of the optical fiber 22 in the non-rotating portion as shown in FIG. 4C. However, much of the light from the end face 13 can be received by the end face 26 of the optical fiber 25 and transmitted to the optical fiber 22. Due to such an action, in this system, the amount of light exchanged between the end faces 13 and 26 is ensured, and highly accurate measurement is possible.

In the illustrated example, the diameters of the core and cladding of the optical fibers 12 and 22 are 50 μm and 125 μm, respectively, and the diameters of the core and cladding of the optical fiber 25 are 100 μm and 140 μm, respectively.
The diameter of the optical fiber 12 disposed on the rotating body 1 may be increased and thickened like the optical fiber 25 of the non-rotating portion. In this way, although the loss of the return light increases, the loss due to the area difference between the end faces of the light source light can be reduced.

  5 (a) and 5 (b) are conceptual diagrams showing still another embodiment of the implementation of the invention. While adopting the configuration of a) to c) as in the example of FIG. 1 and the like, in this example, as shown in FIG. 5A, three optical fibers 22a, 22b and 22c are juxtaposed as non-rotating portion optical fibers 22. The end surfaces 23a, 23b, and 23c are positioned at a slight distance (preferably around several millimeters or less) along the circular orbit of the end surface 13 of the optical fiber 12 as shown in FIG. 5B. Is arranged.

  When the rotational speed of the rotating body 1 changes greatly, as a result of exceeding the limit condition shown in FIG. 2, the reflected light emitted from the end face 13 of the optical fiber 12 on the rotating body 1 is changed to the optical fiber so far. The end face 23 of 22 may not be able to receive light. However, when a plurality of optical fibers 22 are arranged and the end faces 23 are arranged along the above-mentioned track as in this example, the light from the end face 13 is simultaneously transmitted by the adjacent end faces 23 (23a, 23b, 23c). It is possible to receive enough. In addition, as shown in FIG. 6, the image of the light from the end surface 13 is elongated along the trajectory using the cylindrical lens 14 or the like, and similarly, the light from the end surface 13 is simultaneously received by the plurality of end surfaces 23. It can also be. Therefore, also in this embodiment, the accuracy of measurement using the optical fiber sensor 10 can be increased. Note that a plurality of optical fibers 25 juxtaposed can be combined into one at a portion close to the measuring means 20, and in this case, the system can exhibit the same function as described above.

  7 (a) and 7 (b) are conceptual diagrams showing another embodiment of the invention. This example is also the same as the previous example in that the configurations a) to c) are adopted, but the optical fiber 22 provided in the non-rotating part is connected by a pair of connectors 27A and 27B as shown in FIG. It is configured by two separable fibers 22A and 22B, and the alignment assisting device 30 shown in FIG. 7B can be connected to a connector 27A near the end face 23.

  In the alignment assisting device 30 in FIG. 7B, a visible light source 30a and an optical power meter 30c are connected to a connector 31 connectable to a connector 27A via a coupler 30b and an optical fiber. By connecting this to the connector 27A and causing the light source 30a and the optical power meter 30c to function, it is possible to quantitatively grasp the intensity of the reflected light from the optical fiber sensor 10, and thus the end face 23 of the optical fiber 22B. And the end surface 13 of the optical fiber 12 can be optimized in a short time (alignment accuracy). After performing such alignment work, if the measuring means 20 is used by connecting the connectors 27A and 27B as shown in FIG. 7A, a preferable light quantity is exchanged between the end faces 13 and 23. Measurement is realized.

  Although only examples in which the end face 13 of the optical fiber 12 is provided at the shaft end portion of the rotating body 1 have been described above, it goes without saying that the position of the end face 13 is not limited thereto. For example, as shown in FIG. 8, the end surface 13 can be provided on the peripheral surface of the rotating body 1. In that case, if the end face of the optical fiber of the non-rotating part is fixed at a distance from the specific place on the circular orbit of the end face 13, the strain, temperature, etc. of the rotating body 1 are fixed as in the above example. Measurement becomes possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an embodiment relating to an embodiment of the invention, and is a conceptual diagram showing an entire measurement system together with a rotating body 1. It is a diagram which shows the speed range etc. which can be measured in the system of FIG. It is a conceptual diagram which shows another form about implementation of invention. It is a conceptual diagram which shows another form about implementation of invention, FIG. 4 (a) is the figure which looked at the system from the side, (b) is the bb arrow line view in the same (a), and ( c) is a detailed view of a part of FIG. It is a conceptual diagram which shows another form about implementation of invention, Fig.5 (a) is the figure which looked at the system from the side, and the same (b) is the bb arrow line view in the same (a). It is a conceptual diagram which shows another form about implementation of invention. FIG. 7A is a conceptual diagram showing still another embodiment of the invention, FIG. 7A is a view of the system viewed from the side, and FIG. 7B is a concept showing the alignment assisting device 30 used in the system. FIG. It is a conceptual diagram which shows another form about implementation of invention. It is a conceptual diagram which shows the conventional system which measures the distortion | strain, temperature, etc. of an object using an optical fiber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating body 10 Optical fiber sensor 12 Optical fiber (on rotating body) 13 End surface 20 Measuring means 20a Light source 20c Detector 22/25 Optical fiber 23/26 End surface 24 Lens 30 Alignment assisting device 30c Light Power meter

Claims (10)

Attach an optical fiber sensor with a different incident part and exit part to the measurement site on the rotating body, connect optical fibers to the incident side and the exit side of the sensor, and end face of the optical fiber opposite to the sensor While fixing it on its rotating body,
An optical fiber is arranged in a non-rotating part adjacent to the rotating body, and a light source and a detector for return light from the sensor are connected to each optical fiber of the non-rotating part,
The end face of the non-rotating portion of the optical fiber is fixed so that the end face is spaced from the circular orbit of the end face of the optical fiber on the rotating body and the end faces face each other at a specific location on the circular orbit. Rotating body measurement system. Attach an optical fiber sensor with the same entrance and exit to the measurement area on the rotating body, connect an optical fiber to the input and exit of the sensor, and connect the end face of the optical fiber opposite to the sensor. While fixing on that rotating body,
An optical fiber is arranged in a non-rotating part adjacent to the rotating body, and a light source and a detector for returning light from the sensor are connected to the optical fiber of the non-rotating part,
The end face of the non-rotating portion of the optical fiber is fixed so that the end face faces away from the circular orbit of the end face of the optical fiber on the rotating body and at a specific location on the circular orbit. Rotating body measurement system.   The portion where the light from the light source is transmitted from the end face of the non-rotating portion of the optical fiber to the end face of the optical fiber fixed on the rotating body, and the return light from the optical fiber sensor is the light on the rotating body. At least one of the portions transmitted from the end face of the fiber to the end face of the optical fiber fixed to the non-rotating portion so as to face the end face, in order to ensure the amount of light exchanged between the end faces of both optical fibers. 3. The rotating body measurement system according to claim 1, further comprising a loss prevention unit.   4. The rotating body measuring system according to claim 3, wherein a lens is provided between the end face of the non-rotating portion of the optical fiber and the end face of the rotating portion of the optical fiber as the loss preventing means.   4. The rotating body according to claim 3, wherein, as the loss prevention means, the optical fiber of the non-rotating portion has a larger cross section than the end face of the optical fiber on the rotating body facing at least the end face. Measuring system. Attach an optical fiber sensor where the incident part and the emission part are different from the measured part on the rotating body, and as the loss prevention means,
On the incident side to the sensor, the end face of the optical fiber on the rotating body is made larger than the end face of the non-rotating part facing the non-rotating part, and / or on the emitting side from the sensor, the non-rotating part The rotating body measuring system according to claim 3, wherein the end face of the optical fiber is made larger than the end face of the optical fiber on the rotating body facing the end face.   4. The rotating body measuring system according to claim 3, wherein a plurality of non-rotating optical fibers are arranged along the circular orbit of the end face of the optical fiber on the rotating body as the loss preventing means.   4. The rotating body measuring system according to claim 3, wherein a coupler capable of separating a part of the non-rotating optical fiber by a pair of connectors is attached as the loss preventing means.   As the loss prevention means, an optical fiber that provides a lens between the end face of the optical fiber of the non-rotating part and the end face of the optical fiber of the rotating part and emits light from the light source or return light from the optical fiber sensor 4. The rotating body measuring system according to claim 3, wherein the end face of the optical fiber that enters the light facing the opposite end face has a larger cross section than the end face of the rotating body. As the loss prevention means, with respect to the lens provided between the end face of the optical fiber of the non-rotating part and the end face of the optical fiber of the rotating part, a lens is provided in front of the end face of the optical fiber of the non-rotating part or on the rotating body. 4. The rotating body measuring system according to claim 3, wherein a lens is provided in front of the end face of the optical fiber, or a lens is provided on both of them.

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