JP2010025671A - Fluid film thickness measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring apparatus which measures the two-dimensional distribution of the film thickness of a lubricant/sealing fluid interposed between the rotational sliding surfaces of an end face sealing member and an opposite member over the entire sliding surfaces with sub-micron order precision. <P>SOLUTION: The liquid film thickness measuring apparatus has: a housing which is rotatably coupled to a base and holds the end face sealing member; an opposite member which is arranged in a contactable manner with respect to the end face sealing member and has optical transparency; a fluid containing a fluorescent dye; a light source for applying excitation light; an optical axis adjustment mechanism; a stop; an optical filter holder; a linearization mechanism for diffusing the application shape of the excitation light from a point shape to a linear shape; an optical microscope provided with an objective and a beam splitter; an optical filter; a photographing unit for photographing a fluorescence image; and a rotational drive source for rotating the opposite member. The excitation light diffused to a linear shape is applied on one point on the circumference of the sliding surface of the end face sealing member in such a manner that it extends in the radial direction of the sliding surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a fluid film thickness measuring device that two-dimensionally measures a fluid film thickness at rest and during rotation in a contactless manner with respect to an end seal member such as a mechanical seal having a minute gap that changes in the circumferential direction.

  So-called end face seals that are sealed by contact between the cylindrical shaft end face and the mating flat surface, represented by mechanical seals, are widely used as machine elements for the purpose of preventing leakage of machine lubricants and various working fluids. . These end face seals are so-called contact-type seals that perform sealing by bringing both end faces (sealing faces) of the rotating ring and the stationary ring in sliding contact into contact with each other by a spring force or the like. In this end face seal, in order to maintain a good sealing state for a long period of time, a fluid lubrication film is formed between the sealing faces by a sealing fluid to prevent wear and roughness of the sealing faces, that is, the conflict between sealing and lubrication. It is necessary to satisfy both conditions. The sealing mechanism of the end face seal has not yet been fully elucidated, but it is thought that the size of the lubricating liquid film that satisfies the minute gap formed by the contact between the rotating ring and the stationary ring directly affects the sealing performance. Measuring the lubrication film thickness is one of the most effective measures for improving product quality by establishing a sealing performance evaluation method and elucidating the sealing mechanism of end face seals.

  Regarding the measurement of the fluid film thickness of the seal member, in Patent Document 1 below, there is a prior art using a fluorescence method for a sealing device mainly composed of an elastomer material such as rubber represented by an oil seal or an O-ring. is there. However, in the case of this prior art, the laser beam that is the excitation light is irradiated in the form of a dot, so that the film thickness of one point on the observation surface by the optical microscope or the film of multiple points when the point is scanned in one direction Effective only for thickness measurement. In general, an end face seal such as a mechanical seal has a undulation with a minute amplitude on one of the sealed end faces, and has a shape in which the gap changes instead of a constant gap in the circumferential direction of the sliding surface. Therefore, unlike the rubber material, in order to accurately observe the sealing phenomenon, it is necessary to measure the liquid film distribution around the entire sliding surface. For this reason, the above prior art cannot be directly applied to the end face seal member. On the other hand, the fluorescence method using an Xe lamp instead of a laser beam as a light source has a prior art of two-dimensional liquid film distribution measurement, but the oil film thickness to be measured is on the order of microns. The liquid film thickness between the sliding surfaces of the mechanical seal can be inferred to be on the order of submicrons. For measurement of such a thin film thickness, it is necessary to use a light source having a higher energy density and a fluorescent dye optimal for the light source.

JP 2001-264221 A

  The present invention has been made for the purpose of solving the above problems. That is, the present invention measures the two-dimensional distribution over the entire circumference of the sliding surface with submicron accuracy with respect to the film thickness of the lubricating / sealing fluid interposed between the rotational sliding surfaces of the end face seal member and the mating member. An object of the present invention is to provide a fluid film thickness measuring apparatus capable of performing the above.

  In order to achieve the above object, a fluid film thickness measuring apparatus according to claim 1 of the present invention is an apparatus for measuring a fluid film thickness on a sliding surface of an end face seal member, and is rotatably connected to a base. A housing for holding an end face seal member as a specimen, a mating member disposed so as to be in contact with the end face seal member held in the housing and having light transmission properties, and housed in the housing, the end face seal A fluid containing a fluorescent dye that is sealed by contact between a member and a counterpart member, a light source that emits excitation light, an optical axis adjustment mechanism for excitation light, an aperture for optical axis adjustment, an optical filter holder, A line-forming mechanism for diffusing the irradiation shape of the excitation light from a dot shape to a line shape, and a contact portion between the end face seal member and the counterpart member that are the measurement target region of the excitation light from the light source An optical microscope for guiding and enlarging a fluorescence image emitted from the fluid existing in the contact portion through an objective lens and guiding it to a beam splitter; an optical filter for removing light having the wavelength of the excitation light; and fluorescence obtained by the optical filter Excitation light that has an imaging device that captures an image, and a rotational drive source that rotates the mating member to realize a sliding state of the contact portion between the end face seal member and the mating member, and is diffused in the line shape Is irradiated at one place on the circumference of the sliding surface of the end face seal member and extending along the radial direction of the sliding surface.

  A fluid film thickness measuring apparatus according to a second aspect of the present invention is the fluid film thickness measuring apparatus according to the first aspect described above, wherein the excitation light irradiated position on the end face seal member held in the housing is arranged on the circumference. Housing rotation control means for rotating and stopping the housing at a constant pitch for positioning is provided.

  Since the fluid film thickness measuring apparatus according to the first aspect of the present invention having the above-described configuration has a housing rotatably connected to the base, an end face seal member as a specimen is first attached to the housing. The mounted end face seal member is in a state in which the sealing sliding surface is in contact with the mating member, and on the other hand, the fluid containing the fluorescent dye is accommodated in the housing. When the above preparation is completed, excitation light is emitted from the light source. The excitation light emitted from the light source passes through the diaphragm, passes through the filters installed in the optical filter holder, and is attenuated or wavelength-selected to an arbitrary intensity. The irradiation shape is diffused, reflected by the beam splitter, transmitted through the light-transmitting counterpart member, and irradiated to the fluid containing the fluorescent dye existing in the gap between the end face seal member and the counterpart member. The excitation light diffused in a line shape is irradiated at one place on the circumference of the sliding surface of the annular end face seal member, and the line extends along the radial direction of the annular sliding surface. It is supposed to be. The fluorescent dye contained in the fluid is excited by excitation light diffused in a line shape, and emits fluorescence having a wavelength different from the excitation light wavelength. The fluorescence image is magnified by an optical microscope having an objective lens, passes through a beam splitter, light having a wavelength other than the fluorescence wavelength is removed by an optical filter, is guided to an imaging device, and a fluorescence image is photographed. The fluorescence intensity is digitized from the obtained fluorescence image, and the film thickness is quantified based on a conversion curve from the fluorescence intensity measured in advance to the film thickness. As described above, measurement of one line (measurement at one place on the circumference) by the excitation light diffused in a line shape is performed. In this measurement, if the mating member is not rotated, the measurement is performed in a stationary state of the sliding surface, and if the mating member is rotated by a rotational drive source such as a motor, the measurement is performed in the rotating state of the sliding surface. .

  Next, since the housing is rotatably connected to the base as described above, the housing is rotated over a predetermined rotation angle. Since the optical system elements such as the light source and the optical microscope have a fixed position, the excitation light is always emitted toward a fixed portion. Therefore, if the housing is rotated, the end face sealing member held by the housing is also rotated. Therefore, the measurement is performed at a position different from the circumference of the first measurement, and this is performed the necessary number of times (for example, 100 times). repeat. As described above, measurement is performed over the entire circumference and entire surface of the sliding surface of the end face seal member.

  Since the measurement is repeated many times as described above, if the rotation angle can be quantified when the housing is rotated at a predetermined rotation angle (if it can be rotated at a constant angle), it is convenient for the work. Accordingly, in claim 2 of the present invention, there is provided housing rotation control means for rotating and stopping the housing at a constant pitch so as to position the excitation light irradiated position on the end face seal member held in the housing on the circumference. did. As a specific example of this control means, automatic rotation of a servo motor is conceivable, but a combination of a gear tooth provided on the housing side and a ratchet mechanism provided on the base side and meshing with the tooth may be used. For example, quantification by 360 degrees / tooth is possible.

  As the excitation light, laser light is used, but is not limited thereto. For example, an LED or other light source (an ultra-high pressure mercury light source, a xenon light source, a metal halide light source, It is conceivable to use light emitted from a halogen light source. Laser light is excellent in directivity, light condensing property, and monochromaticity. On the other hand, although LED is excellent in monochromaticity, directivity and condensing property are inferior to laser light. A general light source is inferior to laser light in both directivity and light condensing property, but a specific wavelength can be extracted by using a filter having wavelength selectivity.

  As described above, according to the present invention, the film thickness of the lubricating / sealing fluid interposed between the rotational sliding surfaces of the end face seal member and the mating member is subdivided into a two-dimensional distribution over the entire circumference of the sliding surface. It becomes possible to measure with an accuracy of micron order. If the housing rotation control means is provided, the housing rotation angle can be quantified, that is, the measurement angular displacement can be quantified.

  The end seal member is, for example, a sliding ring of a mechanical seal, and the sliding ring of the mechanical seal forms a flat sliding surface made of a hard material such as carbon, silicon carbide, or ceramic, so that a thin fluid film has a large area. Formed. On the other hand, since the measuring apparatus of the present invention irradiates excitation light in a line shape, it is particularly suitable for use in such a measuring object.

The present invention includes the following embodiments.
(1) Similar to the oil seal in the invention described in Patent Document 1, the liquid film distribution technique of the mechanical seal is applied by applying a liquid film measurement technique based on a fluorescence method, which enables accurate measurement even on a rough surface. A dimension measurement method was invented.
(2) The measurement position of an optical system such as a laser light source or an optical microscope is fixed. The portion where the seal ring is fixed has a structure that can freely rotate. The procedure of rotating the seal ring a little and measuring the line-shaped liquid film distribution is repeated to continuously measure the circumference of the sliding surface. After the measurement, it was possible to measure the two-dimensional liquid film distribution for one round of the sliding surface by connecting all the line-shaped liquid film distribution data.
(3) Currently, as a method of rotating the seal ring slightly, a soft plastic claw is engaged with the gear teeth of 100 teeth installed around the seal ring fixing base, and one rotation is divided into the number of gear teeth. The mechanism can be rotated. It is also conceivable to automate the rotation at the time of measurement with a motor.

(4) The two-dimensional liquid film distribution on the sliding surface of the mechanical seal can be dynamically measured with higher accuracy than the optical interference method.
(5) Based on the invention described in Patent Document 1, the laser is irradiated in a line shape on the radial cross section of the sliding surface of the mechanical seal, and the sliding surface is scanned while making a slight rotation, and the measurement data is connected. By combining them, an apparatus for measuring the two-dimensional liquid film thickness distribution of the mechanical seal could be constructed.
(6) By using this apparatus and the two-dimensional measurement method, it has become possible to quantitatively measure and evaluate the liquid film thickness distribution of the mechanical seal that could not be measured so far.
(7) Reason why it is more accurate than optical interferometry ... Interferometry is used for parts with low surface reflectance, such as parts with large surface roughness and uneven parts such as minute holes and grooves. The liquid film cannot be measured. On the other hand, since this two-dimensional measurement method uses a fluorescence method, a liquid film can be measured regardless of the reflectance of the surface.
(8) Reason that dynamic measurement can be performed .... Achieved in a short time of only about 10 ^-11 s for the fluorescent molecule to absorb the excitation light and for the electrons to transition to the excited state. Further, the time from the emission of fluorescence to the return to the original ground state and the absence of fluorescence is said to be on the order of 10 ^-9 s, depending on the type of fluorescent molecule. Such a method is called a laser fluorescence method or LIF (Laser Induced Florescence) method, and is characterized in that it can sufficiently cope with measurement of a liquid film change on the order of milliseconds and has excellent dynamic followability.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration explanatory view of a fluid film thickness measuring apparatus according to an embodiment of the present invention as viewed from the front direction. FIG. 2 is an enlarged view of part A of FIG. FIG. 3 is an explanatory diagram of the configuration of the measurement apparatus viewed from an oblique direction. The fluid film thickness measuring apparatus according to this embodiment is configured as follows.

  That is, first, a housing 2 is provided which is rotatably connected to the base 1 and holds an end face seal member 3 which is a specimen, and can contact the end face seal member 3 held in the housing 2. A mating member 4 is provided which is disposed on the surface and has optical transparency.

  The housing 2 is provided with a cylindrical shaft portion 2c on the inner peripheral portion of a disc-shaped bottom surface portion 2a in which a through hole 2b penetrating in the vertical direction is provided at the plane axial center portion, and also has a cylindrical side surface on the outer peripheral portion of the bottom surface portion 2a. A portion 2d is provided, and is rotatably connected to the base 1 via a bearing 5 disposed on the outer periphery of the shaft portion 2c. Further, the housing 2 holds an end face seal member 3 as a specimen in an airtight and detachable manner at an inner peripheral portion of the bottom surface portion 2a and at an upper end opening portion of the through hole 2b.

  The end surface seal member 3 is a seal member that seals with a cylindrical end surface portion, and is, for example, a sliding ring (rotating ring) on a rotating side or a sliding ring (fixed ring) on a fixed side, a seal lip, or an oil seal. In any case, it is held in the housing 2 with an end face portion (hereinafter also referred to as “sliding face”) 3a for sealing being directed upward. Further, if necessary, it is held in a state of being elastically biased upward by a spring (a state of being pressed against the counterpart member 4).

  The mating member 4 has a disk shape and is disposed above the end face seal member 3 so as to be able to contact the end face seal member 3 held in the housing 2. Accordingly, the mating member 4 has a lower surface (hereinafter also referred to as “sliding surface”) 4 a in contact with the sliding surface 3 a of the end surface seal member 3. The mating member 4 is fixed to the upper end portion of the rotating shaft 6 inserted through the through hole 2b of the housing 2, and the rotating shaft 6 is connected to a rotational drive source 7 such as a motor. Therefore, the mating member 4 can be rotated by driving the rotational drive source 7. In addition, the counterpart member 4 transmits light such as an optical glass substrate (optical flat) in order to transmit the excitation light 10 (hereinafter, also referred to as “laser light” because laser light is used as excitation light in this embodiment). It is comprised by the planar member which has.

  A fluid 8 is accommodated in the housing 2, that is, a fluid 8 containing a fluorescent dye that is sealed by contact between the end face seal member 3 and the counterpart member 4 is accommodated. The fluid 8 is composed of a liquid or gas in which a fluorescent dye is dissolved or mixed. The type of the fluid 8 is not particularly limited. For example, as the sealing fluid, an ethylene glycol aqueous solution in which the fluorescent dye is dissolved, lubricating oil, water, or the like is used. Composed. FIG. 4 shows the relationship between the excitation light absorption wavelength by the fluorescent dye and the fluorescence wavelength. In this way, the light is excited by light having a peak at a specific wavelength (absorption wavelength), and thereby emits fluorescence having a peak at a specific wavelength (fluorescence wavelength). The fluorescent dye to be dissolved or mixed in the fluid 8 is not particularly limited as long as it is excited by the laser light 10 and emits sufficient fluorescence. When gas is used as the fluid 8, a sealed chamber is set by providing a lid (not shown) on the housing 2. In this case, since the laser beam 10 is transmitted through at least a part of the housing 2, the light transmission property is set in the same manner as the counterpart member 4.

  The contact portion between the end face seal member 3 and the counterpart member 4 described above is a measurement region for fluid film thickness measurement, and the laser beam 10 is irradiated toward the measurement region. For this reason, the measuring apparatus includes a light source 9 for irradiating the laser beam 10, an optical axis adjusting mechanism 11 for the laser beam 10, an aperture 12, 13 for adjusting the optical axis, an optical filter holder 14, and a laser. A line forming mechanism 15 for diffusing a light irradiation shape from a point light source (dot shape) into a line shape, and a laser beam 10 from the light source 9 is guided to a contact portion between the end face seal member 3 and the counterpart member 4 which are measurement areas; An optical microscope 16 that expands the fluorescent image 17 emitted from the fluorescent substance contained in the fluid 8 existing in the contact portion through the objective lens 18 and guides it to the beam splitter 19 is provided, and further, the light having the wavelength of the laser light 10 is removed. And an imaging device 21 that captures the fluorescent image 17 obtained by the optical filter 20 is provided.

  The laser light 10 emitted from the light source 9 needs to have a large energy density and be in the excitation light wavelength range of the fluorescent dye contained in the fluid 8 in order to excite the fluid 8 containing the fluorescent dye and obtain sufficient fluorescence emission intensity. There is.

  In the optical axis adjustment mechanism 11, the mounting base of the light source 9 includes a fine movement adjustment mechanism in three directions of the vertical direction, the horizontal direction, and the vertical tilt angle, and two diaphragms 12 installed at the entrance of the optical microscope 16. The optical axis is adjusted to pass through 13.

  The optical filter holder 14 includes a mechanism for installing one or two optical filters, and attenuates the intensity of the laser light 10 at an arbitrary ratio by using, for example, an ND filter (attenuation filter). In addition, by installing a filter having wavelength selectivity such as a band pass filter or a long pass filter, even when the light source 9 having a wide wavelength range is used, only a wavelength suitable for the purpose is selected and extracted.

  The line forming mechanism 15 expands the irradiation light in a line shape by expanding the laser light 10 that is a point light source in only one direction. Although the measurement apparatus uses a commercially available lined lens as the line forming mechanism 15, for example, the same effect can be obtained by using a galvanometer mirror, a polygon mirror, an acoustooptic device, or the like.

  The imaging device 21 is configured by a CCD camera, for example, in order to capture the fluorescent image 17 magnified by the optical microscope 16.

  The beam splitter 19 uses a dichroic mirror that reflects the wavelength of the laser light 10 that is excitation light and has a wavelength selection that transmits the fluorescence wavelength emitted by the fluid 8 containing the fluorescent dye. The laser beam 10 expanded in a line shape by the line forming mechanism 15 is reflected by the beam splitter 19, passes through the light-transmitting counterpart member 4, and includes a fluorescent dye present in the gap between the sliding surfaces 3 a and 4 a. The fluid 8 is irradiated. As a result, the fluorescent dye in the fluid 8 is excited by the laser light 10 and emits fluorescence. Since the beam splitter 19 has wavelength selectivity as described above, the fluorescence magnified by the optical microscope 16 having the objective lens 18 passes through the beam splitter 19, passes through the optical filter 20, and is guided to the imaging device 21.

  The fluorescence image 17 includes a wavelength component of the laser beam 10 that is excitation light that cannot be completely removed by the beam splitter 19 immediately after passing through the beam splitter 19. Therefore, in the optical filter 20, only the fluorescence wavelength can be extracted with higher accuracy by passing the fluorescence image 17 through a band-pass filter (narrowband interference filter) that allows only the fluorescence wavelength to pass.

  The optical path will be described above. After the laser light 10 emitted from the light source 9 passes through the diaphragms 12 and 13, passes through the filters installed in the filter holder 14, and is attenuated or wavelength-selected to an arbitrary intensity. The irradiating shape is diffused from a point light source (dot) into a line shape by the line forming mechanism 15, reflected in the vertical direction by the beam splitter 19, and transmitted through the counterpart member 4 having optical transparency, and an end face seal member The fluid 8 containing the fluorescent dye existing in the gap between the member 3 and the counterpart member 4 is irradiated. As shown in FIG. 5, the laser beam 10 diffused in a line is irradiated at one place on the circumference of the sliding surface 3a of the annular end face seal member 3 (the irradiated portion is indicated by reference numeral 22). ), And the straight line extends along the radial direction of the sliding surface 3a of the annular end surface seal member 3. The length of the line is equal to or larger than the radial width of the sliding surface 3a, one end of the line is located further outside the outer diameter portion of the sliding surface 3a, and the other end of the line is the sliding surface 3a. It is preferable to be located further inside than the inner diameter portion. The fluorescent dye contained in the fluid 8 is excited by the laser light 10 diffused in a line shape, and emits fluorescence having a wavelength different from the excitation light wavelength. The fluorescent image 17 is magnified by the optical microscope 16 having the objective lens 18, passes through the beam splitter 19, light having a wavelength other than the fluorescent wavelength is removed by the optical filter 20, and is guided to the imaging device 21.

  In addition, the measurement apparatus is provided with housing rotation control means 23 for rotating and stopping the housing at a constant pitch in order to position the laser beam irradiated position 22 in the end face seal member 3 held in the housing 2 on the circumference. It has been. That is, since the position of the optical system element such as the optical microscope 16 is fixed, the laser beam 10 is always applied to one place on the circumference of the end face seal member 3. Therefore, in order to measure fluorescence over the entire sliding surface 3a of the end face seal member 3, the housing 2 is rotated little by little, and the measurement for one round of the sliding surface 3a is performed while shifting the measurement position. For this reason, the housing 2 is rotatable as described above, and the housing rotation control means 23 is provided to rotate the housing 2 at a constant pitch. Specifically, a servo motor 24 is used as the housing rotation control means 23. A gear tooth is provided on the outer periphery of the housing 2, a ratchet mechanism is provided on the base 1, and the teeth and the ratchet are engaged with each other. (In this case, the housing 2 is rotated manually).

  An example of a fluorescent image photographed by the measuring device is as shown in FIG. At this time, the end face seal member 3 is a sliding ring of a mechanical seal, the counterpart member 4 is an optical glass substrate (BK-7), the fluid 8 is an ethylene glycol aqueous solution in which a fluorescent dye is dissolved, and the optical filter 20 is ND-8 filters for reducing the laser beam 10 emitted from the laser light source 9 to 8% were applied. As shown in FIG. 6, it can be seen that a line-like fluorescent image is taken. Note that strong fluorescence is observed at both ends of the line-like fluorescent image in FIG. 6 due to a liquid pool adhering to the inner and outer peripheral sides of the mechanical seal. The fluorescence intensity was digitized from the fluorescence image of FIG. 6, and the film thickness was quantified based on a conversion curve from fluorescence intensity to film thickness measured in advance. The results are shown in FIG. The upper diagram in FIG. 7 is a graph obtained by converting the fluorescence intensity into the film thickness, and the lower diagram in FIG. 7 is a cross-sectional shape of the sliding surface measured in advance by a stylus shape measuring instrument. As shown in FIG. 7, the liquid film measurement between the sliding surfaces of the mechanical seal by the apparatus can measure the film thickness distribution of the cross section in the width direction including the roughness component of the sliding surface. It can be seen that the thickness of the mechanical seal, which can be inferred as an order, has a sufficiently applicable vertical resolution.

  Further, as described above, since the irradiation position of the laser beam 10 is fixed and is always irradiated to a certain position on the sliding surface 3a of the end face seal member 3, the sliding surface 3a is rotated by rotating the housing 2. A two-dimensional film thickness distribution over the entire circumference was measured. That is, the liquid film distribution measurement of the cross section in the mechanical seal width direction shown in FIGS. 6 and 7 is continuously performed while shifting the surface to be measured, and the two-dimensional film thickness distribution measurement is performed by connecting the measurement results. It was. In the measurement test, the housing rotation control means 23 is a combination of a gear tooth provided on the outer periphery of the housing 2 and a ratchet mechanism provided on the base 1, and the gear has 100 teeth. Used the gears. That is, by utilizing this gear and a ratchet mechanism meshed with the gear, the housing 2 and the mechanical seal fixed to the housing 2 are slightly rotated for each tooth of the gear, and the cross section in the mechanical seal width direction for each minute rotation. The liquid film distribution was measured. In the measurement, the end face seal member 3 and the mating member 4 are statically measured without sliding, and the mating member 4 connected to the rotational drive source 7 via the rotary shaft 6 is stationary. A dynamic measurement with rotation and sliding was performed.

  This two-dimensional measurement result is shown in FIG. FIG. 8A shows the measurement result of the liquid film distribution at rest. It can be seen that the surface to be measured has undulations for two wavelengths and is in contact with the mating surface at two points. FIG. 8B shows a liquid film distribution at a rotational speed of 100 rpm. Compared with the liquid film distribution at rest, it can be seen that the liquid film in the undulating valley decreases with rotation. This decrease in the liquid film is thought to be due to the generation of cavities associated with the generation of negative pressure in the widening gap at the back of the top of the swell. In order to express the liquid film distribution more clearly, the liquid film thickness was binarized. FIG. 8D shows the result at 100 rpm when the binarization threshold is 0.27 μm. The presence of two thin film regions on the surface to be measured, that is, the shape of cavitation accompanying rotational sliding can be identified more clearly. FIG. 8C shows the measurement result at 1000 rpm, and FIG. 8E shows the result of binarizing FIG. 8C at a threshold value of 0.57 μm. Compared to 100 rpm, the overall liquid film thickness of the sliding surface is increased at 1000 rpm. This is considered to be a result of the dynamic pressure action in the liquid film becoming remarkable due to the increase in the rotation speed. From the binarized image, it can be observed that the thin film region, that is, the cavitation extends longer in the circumferential direction than 100 rpm.

Structure explanatory drawing which looked at the fluid film thickness measuring apparatus which concerns on the Example of this invention from the front direction Part A enlarged view of FIG. Configuration explanatory view of the same measuring device viewed from an oblique direction Graph showing the relationship between the excitation light wavelength (absorption wavelength) spectrum and the fluorescence wavelength spectrum Explanatory drawing which shows an example of the mechanical seal sliding ring which is a specimen Explanatory drawing which shows an example of the image | photographed fluorescence image 6 is an explanatory diagram showing the liquid film thickness obtained by converting the fluorescence intensity read from the fluorescent image of FIG. 6 into a film thickness, and an explanatory diagram showing the shape of the laser light irradiation position measured in advance by a stylus type shape measuring instrument It is explanatory drawing which shows the two-dimensional measurement result of the film thickness between sliding surfaces of a mechanical seal, (a) is a film thickness at rest, (b) is a film thickness distribution during rotation at 100 rpm, and (c) is 1000 rpm. (D) is a binarization result of the film thickness distribution at 100 rpm, and (e) is an explanatory diagram showing the binarization result of the film thickness distribution at 1000 rpm.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base | substrate 2 Housing 3 End surface sealing member 3a, 4a Sliding surface 4 Opposing member 5 Bearing 6 Rotating shaft 7 Rotation drive source 8 Fluid 9 Laser light source 10 Laser beam (excitation light)
DESCRIPTION OF SYMBOLS 11 Optical axis adjustment mechanism 12, 13 Aperture 14 Optical filter holder 15 Line formation mechanism 16 Optical microscope 17 Fluorescent image 18 Objective lens 19 Beam splitter 20 Optical filter 21 Imaging device 22 Irradiated part 23 Housing rotation control means 24 Servo motor

Claims (2)

An apparatus for measuring a fluid film thickness on a sliding surface of an end face seal member,
A housing which is rotatably connected to the base and holds an end face seal member which is a specimen, and a mating member which is disposed so as to be able to contact the end face seal member held in the housing and has light transmittance; , A fluid containing a fluorescent dye housed in the housing and sealed by contact between the end face seal member and the counterpart member, a light source for irradiating excitation light, an optical axis adjustment mechanism for excitation light, and optical axis adjustment For the aperture, an optical filter holder, a line-forming mechanism for diffusing the irradiation shape of the excitation light from a dot shape to a line shape, and the end face seal member and the counterpart member that are the measurement target region of the excitation light from the light source An optical microscope that guides to a contact portion, expands a fluorescent image emitted from a fluid existing in the contact portion through an objective lens, and guides it to a beam splitter; and a wavelength of the excitation light An optical filter that removes light, an imaging device that captures a fluorescent image obtained by the optical filter, and a rotational drive source that rotates the mating member to realize a sliding state of the contact portions of the end face seal member and the mating member And having
The excitation light diffused in a line shape is irradiated at one place on the circumference of the sliding surface of the end face seal member and extending along the radial direction of the sliding surface. Fluid film thickness measuring device. The fluid film thickness measuring device according to claim 1,
The fluid film thickness is characterized in that a housing rotation control means is provided for rotating and stopping the housing at a constant pitch so as to position the irradiation position of the excitation light on the end face seal member held in the housing on the circumference. measuring device.

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