A system and method for simultaneously measuring plug bushing oil film pressure and temperature

Abstract

The application provides a system and method for simultaneously measuring the temperature and pressure of a cock-type bearing bush oil film. The system comprises a cock-type optical fiber sensor, an LD light source, a fiber coupler, a photodetector, a signal processing circuit and a computer, wherein: the cock-type optical fiber sensor is used for monitoring the temperature and pressure of the bearing bush oil film between the bearing bush and the thrust washer by using a double FBG probe; the LD light source and the fiber coupler are respectively used for providing a stable distributed feedback laser light source for the double probe; the photodetector is used for converting the optical signal with detection data into an electrical signal; the signal processing circuit is used for converting the electrical signal into a digital signal and transmitting the digital signal to the computer, so as to obtain the change information of the pressure and temperature of the bearing bush oil film. The application simultaneously measures the temperature and pressure of the oil film by using the cock-type optical fiber sensor, reduces the opening on the bearing bush, has the advantages of small volume, good stability, high sensitivity and strong anti-electromagnetic interference ability.

Description

Technical Field

[0001] This invention relates to the field of real-time measurement technology of bearing oil film condition, and more particularly to a system and method for simultaneously measuring the oil film pressure and temperature of a rotary bearing. Background Technology

[0002] The bearing shell is a crucial component of the friction pair in a sliding bearing. During operation, a lubricating oil film forms between the bearing shell and the thrust washer, providing cooling and lubrication for the friction pair. The state of this oil film largely reflects the operating condition of the equipment. Excessive temperature and pressure in the oil film can cause a sharp rise in the bearing shell temperature and localized deformation, potentially leading to bearing shell failure and disrupting normal equipment operation. Therefore, stable and accurate real-time measurement of the bearing shell oil film pressure and temperature is of paramount importance.

[0003] Traditional methods for real-time measurement of oil film pressure and temperature in thrust sliding bearings primarily employ semiconductors and distributed optical fibers as sensing units. These units are installed through multiple openings on the bearing surface to monitor the real-time temperature and pressure of the oil film at various points. However, semiconductor components are prone to damage, susceptible to electromagnetic interference during signal transmission, and exhibit a strong nonlinear relationship between their resistance and temperature / pressure signals, resulting in poor durability and measurement accuracy. Distributed optical fibers offer better sensing performance, but suffer from inconvenient installation and significant damage to the bearing surface. Fiber Bragg gratings (FBGs) are optical structures highly sensitive to changes in external environmental factors such as temperature and strain. Correspondingly, FBG probes are small in size and highly stable, allowing for multi-probe integration while maintaining sensing accuracy. Therefore, using a dual-FBG probe integrated structure for real-time measurement of bearing oil film pressure and temperature effectively overcomes the shortcomings of traditional methods and possesses significant engineering application value. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a system and method for simultaneously measuring the oil film pressure and temperature of a rotary valve bearing. This invention integrates oil film temperature and pressure measurement functions into a single rotary valve fiber optic sensor, reducing the need for openings in the bearing and offering advantages such as small size, good stability, high sensitivity, and strong anti-interference capability. By evenly distributing multiple rotary valve fiber optic sensors on the bearing, the real-time status of the overall bearing oil film can be accurately fed back, preventing equipment failure caused by bearing damage.

[0005] The technical means employed in this invention are as follows:

[0006] A system for simultaneously measuring the oil film pressure and temperature of a plug-type bearing includes: a plug-type fiber optic sensor, an LD light source, a fiber optic coupler, a photodetector, a signal processing circuit, and a computer, wherein:

[0007] The rotary fiber optic sensor is used to monitor the temperature and pressure of the bearing oil film between the bearing bush and the thrust plate using dual FBG probes.

[0008] The LD light source and fiber coupler are used to provide a stable distributed feedback laser source for the dual probes, respectively.

[0009] The photodetector is used to convert optical signals carrying detection data into electrical signals;

[0010] The signal processing circuit is used to convert electrical signals into digital signals and transmit them to a computer, thereby obtaining information on the pressure and temperature changes of the bearing oil film.

[0011] Furthermore, the plug-type fiber optic sensor includes a bearing plug and an FBG temperature and pressure sensor, wherein:

[0012] The bearing plug is made of copper with good thermal conductivity. It has stepped holes and threads inside, and a sealing ring is provided on the outer edge of the countersunk head. The thin layer on the end face undergoes slight deformation with changes in pressure.

[0013] The FBG temperature and pressure sensor is screwed into the bearing valve via a thread, and the depth of insertion is controlled by the lower edge of the screw head of the fixing screw, thereby determining the initial position of the sensor relative to the valve, i.e., the measurement zero point.

[0014] Furthermore, the FBG temperature and pressure sensor includes a pressure measuring unit, a connector, a temperature measuring unit, a fixing screw, and a limit knob, wherein:

[0015] The pressure measuring unit is used to measure the pressure information of the bearing oil film, and includes a top cap, a limiting cylinder, a pressure FBG probe, a spring, and a base;

[0016] The connector includes an internal thread, an external thread, and a through hole. The internal thread is used to connect to the pressure measuring unit, the external thread is used to connect to the fixing screw, and the through hole is used to lead out the optical fiber.

[0017] The temperature measuring unit is used to measure the temperature information of the bearing oil film, and includes a fixed cylinder and a temperature FBG probe.

[0018] The fixing screw includes an internal thread, an external thread, and an inner hole. The internal thread at the screw head end is used to connect to the limit knob, the internal thread at the other end is used to connect to the connector, the inner hole is used to insert the temperature measuring unit, and the external thread is used to connect to the bearing plug.

[0019] The limiting knob includes an external thread, which is used to connect to the fixing screw.

[0020] Furthermore, in the pressure measuring unit:

[0021] The top cap and base are made of high-strength carbon steel, with spring insertion holes on the end faces and stepped holes inside.

[0022] The pressure FBG probe is embedded in the stepped hole of the top cap and the base, and epoxy resin is injected into the hole for fixation.

[0023] The top of the limiting cylinder is provided with a limiting ring for limiting the spring during installation; the bottom of the limiting cylinder is provided with a circular groove and external threads for embedding into the base and connecting to the connector.

[0024] Furthermore, the top cap has a stepped shape, and the maximum outer diameter of the top cap is smaller than the inner diameter of the limiting cylinder.

[0025] Furthermore, the connector, fixing screw, limiting knob, limiting cylinder, and fixing cylinder are all made of copper with good thermal conductivity.

[0026] The present invention also provides an assembly method based on the above-mentioned system for simultaneously measuring the oil film pressure and temperature of a rotary valve bearing, comprising:

[0027] S1. Assemble the pressure testing unit:

[0028] After marking the end of the pressure FBG probe sensing area, insert the end of the pressure FBG probe into the stepped hole of the top cap, inject epoxy resin into the stepped hole using a syringe, and cure it.

[0029] Insert one end of the spring into the fixing hole of the top cap;

[0030] Insert the other end of the optical fiber into the stepped hole in the base;

[0031] Insert the other end of the spring into the spring socket of the base;

[0032] Make the marked area of ​​the pressure FBG probe flush with the end face of the base, and use a syringe to inject epoxy resin into the bottom stepped hole and cure it.

[0033] Insert the spring, pressure FBG probe, top cap and base, which are installed as one unit, into the inner hole of the limiting cylinder from the external thread end, so that the end face of the base is embedded in the circular groove of the limiting cylinder, thus completing the installation of the pressure measuring unit.

[0034] S2. Assemble the temperature measuring unit:

[0035] After marking the end of the sensing area of ​​the temperature FBG probe, insert the temperature FBG probe into the stepped hole of the fixed cylinder, so that the end of the temperature FBG probe is flush with one side of the fixed cylinder and the marked area is flush with the other side. Use a syringe to inject epoxy resin into the stepped hole and cure it to complete the installation of the temperature measuring unit.

[0036] S3. Assemble the FBG temperature and pressure sensor:

[0037] Connect the external thread end of the limiting cylinder to the internal thread end of the connector;

[0038] Connect the small-diameter end of the fixing screw to the external thread end of the connector;

[0039] Insert the fixing cylinder into the inner hole of the fixing screw from the screw head end;

[0040] Connect the limit knob to the screw head of the fixing screw to complete the assembly of the FBG temperature and pressure sensor;

[0041] S4. Assemble a plug-type fiber optic sensor:

[0042] Connect the FBG temperature and pressure sensor to the internal thread end of the bearing valve to complete the assembly of the valve-type fiber optic sensor.

[0043] The present invention also provides a measurement method based on the above-mentioned system for simultaneously measuring the oil film pressure and temperature of a rotary bearing, comprising:

[0044] When the equipment is running, a lubricating oil film is formed between the surface of the bearing bush and the end face of the thrust plate;

[0045] The thin layer on the end face of the bearing plug will undergo slight downward strain due to the oil film pressure. The top cap in contact with the thin layer will move downward accordingly, the spring will be compressed, and the pressure FBG probe fixed between the top cap and the base will also undergo strain.

[0046] Meanwhile, the countersunk end face of the bearing plug is in direct contact with the oil film to be measured. The heat transfer path from the oil film to the temperature FBG probe is made of copper with good thermal conductivity. Therefore, the temperature of the inner wall of the fixed cylinder is approximately the oil film temperature.

[0047] The center wavelength of the Bragg grating inside the pressure and temperature FBG probe will change with strain and temperature, respectively, thereby converting the pressure and temperature signals of the oil film into optical signals. After data processing, real-time information on the changes in oil film pressure and temperature can be obtained.

[0048] Compared with the prior art, the present invention has the following advantages:

[0049] 1. The present invention provides a system for simultaneously measuring the oil film pressure and temperature of a plug-type bearing. A single plug-type fiber optic sensor integrates the functions of measuring the oil film temperature and pressure of the bearing in a small volume, which can avoid multiple openings on the bearing and reduce damage to the bearing structure.

[0050] 2. The system provided by the present invention for simultaneously measuring the oil film pressure and temperature of a plug-type bearing bush has a plug-type fiber optic sensor that is fixed to the bearing bush by threads and a sealing ring, making installation simple, secure, and with good sealing performance.

[0051] 3. The system provided by this invention for simultaneously measuring the pressure and temperature of the oil film in a plug-type bearing has advantages such as good stability, high sensitivity, and strong anti-interference ability. It can accurately reflect the real-time status of the oil film in the bearing and avoid equipment failure caused by bearing damage.

[0052] Based on the above reasons, this invention can be widely applied in fields such as real-time measurement of bearing oil film status. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a structural diagram of the measurement system of the present invention.

[0055] Figure 2 This is a schematic diagram of the installation of the plug-type fiber optic sensor of the present invention on the bearing.

[0056] Figure 3 This is a structural diagram of the plug-type fiber optic sensor of the present invention.

[0057] Figure 4 This is a structural diagram of the bearing plug of the present invention.

[0058] Figure 5 This is a structural diagram of the FBG temperature and pressure sensor of the present invention.

[0059] Figure 6 This is a structural diagram of the pressure measuring unit of the present invention.

[0060] Figure 7 This is a structural diagram of the temperature measuring unit of the present invention.

[0061] Figure 8 This is a diagram of the connector structure of the present invention.

[0062] Figure 9 This is a structural diagram of the fixing screw of the present invention.

[0063] Figure 10 This is a structural diagram of the limiting knob of the present invention.

[0064] Figure 11 This is a schematic diagram illustrating the oil film temperature measurement principle of the present invention.

[0065] Figure 12 This is a schematic diagram illustrating the oil film pressure measurement principle of the present invention.

[0066] In the diagram: 1. Computer; 2. Signal processing circuit; 3. Photodetector; 4. Fiber optic coupler; 5. LD light source; 6. Plug-type fiber optic sensor; 7. Bearing; 8. Bearing oil film; 9. Thrust plate; 10. Bearing plug; 11. FBG temperature and pressure sensor; 12. Pressure measuring unit; 13. Connector; 14. Temperature measuring unit; 15. Fixing screw; 16. Limit knob; 17. Top cap; 18. Limiting cylinder; 19. Pressure FBG probe; 20. Spring; 21. Base; 22. Fixing cylinder; 23. Temperature FBG probe. Detailed Implementation

[0067] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0069] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0070] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0071] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0072] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0073] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0074] like Figure 1As shown, this invention provides a system for simultaneously measuring the oil film pressure and temperature of a plug-type bearing, comprising: a plug-type fiber optic sensor 6, an LD light source 5, a fiber optic coupler 4, a photodetector 3, a signal processing circuit 2, and a computer 1, wherein:

[0075] The plug-type fiber optic sensor 6 is used to monitor the temperature and pressure of the bearing oil film 8 between the bearing bush 7 and the thrust plate 9 using dual FBG probes.

[0076] The LD light source 5 and the fiber coupler 4 are used to provide a stable distributed feedback laser source for the dual probes, respectively.

[0077] The photodetector 3 is used to convert the optical signal carrying the detection data into an electrical signal.

[0078] The signal processing circuit 2 is used to convert electrical signals into digital signals and transmit them to computer 1, thereby obtaining information on the pressure and temperature changes of the bearing oil film 8.

[0079] In specific implementation, as a preferred embodiment of the present invention, such as Figure 3-5 As shown, the plug-type fiber optic sensor 6 includes a bearing plug 10 and an FBG temperature and pressure sensor 11, wherein:

[0080] The bearing plug 10 is made of copper with good thermal conductivity. It has stepped holes and threads inside, a sealing ring on the outer edge of the countersunk head, and a thin layer on the end face that undergoes slight deformation with changes in pressure.

[0081] The FBG temperature and pressure sensor 11 is screwed into the bearing cap plug via a thread, and the depth of insertion is controlled by the lower edge of the screw head of the fixing screw 15, thereby determining the initial position of the sensor relative to the cap plug, i.e., the measurement zero point. In this embodiment, preferably, the FBG temperature and pressure sensor 11 includes a pressure measuring unit 12, a connector 13, a temperature measuring unit 14, a fixing screw 15, and a limit knob 16, wherein:

[0082] The pressure measuring unit 12 is used to measure the pressure information of the bearing oil film 8, such as... Figure 6 As shown, it includes a top cap 17, a limiting cylinder 18, a pressure FBG probe 19, a spring 20, and a base 21; in this embodiment, preferably, in the pressure measuring unit 12:

[0083] The top cap 17 and base 21 are made of high-strength carbon steel, with spring 20 insertion holes on the end faces and stepped holes inside. The pressure FBG probe 19 is embedded in the stepped holes of the top cap 17 and base 21, and epoxy resin is injected into the holes for fixation. The top cap 17 has a stepped shape, and its maximum outer diameter is smaller than the inner diameter of the limiting cylinder 18. The top of the limiting cylinder 18 has a limiting ring for limiting the spring 20 during installation. The bottom of the limiting cylinder 18 has a circular groove and external threads for embedding into the base 21 and connecting to the connector 13. The connector 13, as shown... Figure 8 As shown, it is made of copper with good thermal conductivity and has a stepped shape. It includes internal threads, external threads and through holes. The internal threads are used to connect the pressure measuring unit 12, the external threads are used to connect the fixing screw 15, and the through holes are used to lead out the optical fiber.

[0084] The temperature measuring unit 14 is used to measure the temperature information of the bearing oil film 8, such as... Figure 7 As shown, the device includes a fixed cylinder 22 and a temperature FBG probe 23. The fixed cylinder 22 is made of copper with good thermal conductivity and has stepped holes on the inner sides of both ends. The temperature FBG probe 23 is embedded in the stepped holes of the fixed cylinder 22 and is fixed by injecting epoxy resin into the holes.

[0085] The fixing screw 15, such as Figure 9 As shown, it is made of copper with good thermal conductivity and includes internal threads, external threads and an inner hole. The internal thread at the screw head end is used to connect the limit knob 16, the internal thread at the other end is used to connect the connector 13, the inner hole is used to insert the temperature measuring unit 14, and the external thread is used to connect the bearing plug 10.

[0086] The limiting knob 16, as Figure 10 As shown, it is made of copper with good thermal conductivity and includes external threads for connecting and fixing screw 15.

[0087] This invention also provides an assembly method for a system that simultaneously measures the oil film pressure and temperature of a rotary valve bearing, comprising:

[0088] S1, Assemble pressure testing unit 12:

[0089] After marking the end of the sensing area of ​​the pressure FBG probe 19, the end of the pressure FBG probe 19 is inserted into the stepped hole of the top cap 17, and epoxy resin is injected into the stepped hole using a syringe and cured.

[0090] Insert one end of the spring 20 into the fixing hole of the top cap 17;

[0091] Insert the other end of the optical fiber into the stepped hole of the base 21;

[0092] Insert the other end of the spring 20 into the spring socket of the base 21;

[0093] Make the marked area of ​​the pressure FBG probe 19 flush with the end face of the base 21, and inject epoxy resin into the bottom stepped hole using a syringe and let it cure.

[0094] Insert the spring 20, pressure FBG probe 19, top cap 17 and base 21, which are installed as one unit, into the inner hole of the limiting cylinder 18 from the external thread end, so that the end face of the base 21 is embedded in the circular groove of the limiting cylinder 18, thus completing the installation of the pressure measuring unit 12.

[0095] S2, Assemble temperature measuring unit 14:

[0096] After marking the end of the sensing area of ​​the temperature FBG probe 23, insert the temperature FBG probe 23 into the stepped hole of the fixed cylinder 22, so that the end of the temperature FBG probe 23 is flush with one side of the fixed cylinder 22 and the marked area is flush with the other side. Use a syringe to inject epoxy resin into the stepped hole and cure it to complete the installation of the temperature measuring unit 14.

[0097] S3, Attach FBG temperature and pressure sensor 11:

[0098] Connect the external thread end of the limiting cylinder 18 to the internal thread end of the connector 13.

[0099] Connect the small-diameter end of the fixing screw 15 to the external thread end of the connector 13;

[0100] Insert the fixed cylinder 22 into the inner hole of the fixed screw 15 from the screw head end;

[0101] Connect the limit knob 16 to the screw head end of the fixing screw 15 to complete the assembly of the FBG temperature and pressure sensor 11;

[0102] S4. Assemble the plug-type fiber optic sensor 6:

[0103] Connect the FBG temperature and pressure sensor 11 to the internal thread end of the bearing plug 10 to complete the assembly of the plug-type fiber optic sensor 6.

[0104] This invention also provides a measurement method based on the above-described system for simultaneously measuring the oil film pressure and temperature of a plug-type bearing. The measurement principle is as follows: During equipment operation, a lubricating oil film forms between the surface of the bearing 7 and the end face of the thrust plate 9. The thin layer on the end face of the bearing plug 10 experiences slight downward strain due to the oil film pressure. The top cap 17, in contact with the thin layer, moves downward, compressing the spring 20. This causes the pressure FBG probe 19, fixed between the top cap 17 and the base 21, to strain. Simultaneously, the countersunk end face of the bearing plug 10 directly contacts the oil film to be measured. The heat transfer path from the oil film to the temperature FBG probe 23 is made of copper, which has good thermal conductivity. Therefore, the temperature of the inner wall of the fixed cylinder 22 can be approximated as the oil film temperature. The center wavelength of the Bragg grating inside the pressure and temperature FBG probes changes with strain and temperature, respectively, thereby converting the oil film pressure and temperature signals into optical signals. After data processing, real-time information on the changes in oil film pressure and temperature is obtained.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for simultaneously measuring the oil film pressure and temperature of a rotary valve bearing, characterized in that, include: The components include a plug-type fiber optic sensor (6), an LD light source (5), a fiber optic coupler (4), a photodetector (3), a signal processing circuit (2), and a computer (1), wherein: The plug-type fiber optic sensor (6) is used to monitor the temperature and pressure of the bearing oil film (8) between the bearing bush (7) and the thrust plate (9) using dual FBG probes; the plug-type fiber optic sensor (6) includes a bearing bush plug (10) and an FBG temperature and pressure sensor (11), wherein: The bearing plug (10) is made of copper with good thermal conductivity. It has stepped holes and threads inside, a sealing ring on the outer edge of the countersunk head, and a thin layer on the end face undergoes slight deformation with changes in pressure. The FBG temperature and pressure sensor (11) is screwed into the bearing cap plug by a thread, and the depth of screwing is controlled by the lower edge of the screw head of the fixing screw (15), thereby determining the initial position of the sensor relative to the cap plug, i.e., the measurement zero point; the FBG temperature and pressure sensor (11) includes a pressure measuring unit (12), a connector (13), a temperature measuring unit (14), a fixing screw (15), and a limit knob (16), wherein: The pressure measuring unit (12) is used to measure the pressure information of the bearing oil film (8), including a top cap (17), a limiting cylinder (18), a pressure FBG probe (19), a spring (20) and a base (21). The connector (13) includes an internal thread, an external thread and a through hole. The internal thread is used to connect the pressure measuring unit (12), the external thread is used to connect the fixing screw (15), and the through hole is used to lead out the optical fiber. The temperature measuring unit (14) is used to measure the temperature information of the bearing oil film (8), including a fixed cylinder (22) and a temperature FBG probe (23). The fixing screw (15) includes an internal thread, an external thread and an inner hole. The internal thread at the screw head end is used to connect the limit knob (16), the internal thread at the other end is used to connect the connector (13), the inner hole is used to insert the temperature measuring unit (14), and the external thread is used to connect the bearing plug (10). The limiting knob (16) includes an external thread for connecting the fixing screw (15). In the pressure measuring unit (12): The top cap (17) and the base (21) are made of high-strength carbon steel, with spring (20) insertion holes on the end face and stepped holes inside; The pressure FBG probe (19) is embedded in the stepped hole of the top cap (17) and the base (21), and epoxy resin is injected into the hole for fixation. The top of the limiting cylinder (18) has a limiting ring for limiting the spring (20) during installation; the bottom of the limiting cylinder (18) has a circular groove and external thread for embedding into the base (21) and connecting to the connector (13). The LD light source (5) and the fiber coupler (4) are used to provide a stable distributed feedback laser source for the dual probes, respectively. The photodetector (3) is used to convert the optical signal carrying the detection data into an electrical signal. The signal processing circuit (2) is used to convert electrical signals into digital signals and transmit them to the computer (1) to obtain information on the pressure and temperature changes of the bearing oil film (8).

2. The system for simultaneously measuring the oil film pressure and temperature of a rotary valve bearing according to claim 1, characterized in that, The top cap (17) has a stepped shape, and the maximum outer diameter of the top cap (17) is smaller than the inner diameter of the limiting cylinder (18).

3. The system for simultaneously measuring the oil film pressure and temperature of a rotary valve bearing according to claim 1, characterized in that, The connector (13), fixing screw (15), limiting knob (16), limiting cylinder (18) and fixing cylinder (22) are all made of copper with good thermal conductivity.

4. An assembly method for a system based on any one of claims 1-3 for simultaneously measuring the oil film pressure and temperature of a rotary valve bearing, characterized in that, include: S1, Assemble the pressure testing unit (12): After marking the end of the sensing area of ​​the pressure FBG probe (19), the end of the pressure FBG probe (19) is inserted into the stepped hole of the top cap (17), and epoxy resin is injected into the stepped hole using a syringe and cured. Insert one end of the spring (20) into the fixing hole of the top cap (17); Insert the other end of the optical fiber into the stepped hole of the base (21); Insert the other end of the spring (20) into the spring socket of the base (21); Make the marked part of the pressure FBG probe (19) flush with the end face of the base (21), inject epoxy resin into the bottom stepped hole using a syringe and cure it. Insert the spring (20), pressure FBG probe (19), top cap (17) and base (21) that are installed as one unit into the inner hole of the limiting cylinder (18) from the external thread end, so that the end face of the base (21) is embedded in the circular groove of the limiting cylinder (18), and the installation of the pressure measuring unit (12) is completed. S2, Assemble the temperature measuring unit (14): After marking the end of the sensing area of ​​the temperature FBG probe (23), insert the temperature FBG probe (23) into the stepped hole of the fixed cylinder (22) so that the end of the temperature FBG probe (23) is flush with one side of the fixed cylinder (22) and the marked area is flush with the other side. Use a syringe to inject epoxy resin into the stepped hole and cure it to complete the installation of the temperature measuring unit (14). S3. Assemble the FBG temperature and pressure sensor (11): Connect the external thread end of the limiting cylinder (18) to the internal thread end of the connector (13); Connect the small-diameter end of the fixing screw (15) to the external thread end of the connector (13); Insert the fixed cylinder (22) into the inner hole of the fixed screw (15) from the screw head end; Connect the limit knob (16) to the screw head of the fixing screw (15) to complete the assembly of the FBG temperature and pressure sensor (11); S4. Assemble the plug-type fiber optic sensor (6): Connect the FBG temperature and pressure sensor (11) to the internal thread end of the bearing plug (10) to complete the assembly of the plug-type fiber optic sensor (6).

5. A measurement method based on the system for simultaneously measuring the oil film pressure and temperature of a rotary valve bearing as described in any one of claims 1-3, characterized in that, include: When the equipment is running, a lubricating oil film is formed between the surface of the bearing (7) and the end face of the thrust plate (9); The thin layer on the end face of the bearing plug (10) will undergo a slight strain downward due to the oil film pressure. The top cap (17) in contact with the thin layer will move downward accordingly, and the spring (20) will be compressed, causing the pressure FBG probe (19) fixed between the top cap (17) and the base (21) to undergo strain accordingly. Meanwhile, the countersunk end face of the bearing plug (10) is in direct contact with the oil film to be tested. The heat transfer path from the oil film to the temperature FBG probe (23) is made of copper with good thermal conductivity. Therefore, the temperature of the inner wall of the fixed cylinder (22) is approximately the oil film temperature. The center wavelength of the Bragg grating inside the pressure and temperature FBG probe will change with strain and temperature, respectively, thereby converting the pressure and temperature signals of the oil film into optical signals. After data processing, real-time information on the changes in oil film pressure and temperature can be obtained.

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