JP2014234775A - Slide component, and gas compressor and analysis equipment using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slide component suppressing abrasion of a PTFE slide material, and provide a gas compressor and an analysis device which have the slide component.SOLUTION: To avoid direct contact of a PTFE slide material with metal of the other material, a resin component easier to form a transfer film than PTFE is arranged near the PTFE slide material desired for reducing abrasion.

Description

  The present invention relates to a sliding component and a gas compressor or an analytical instrument using the sliding component.

  Compressed gas such as air is used in factories of various industries, and in recent years, the demand for clean compressed gas that does not contain inert compressed nitrogen gas or oil mist is increasing.

Compressed gas is generally created using a compressor with a reciprocating piston and cylinder. The compressed gas is generated by putting the gas before being compressed into a compression chamber in the cylinder and compressing it with a piston. Generally, a piston is provided with a piston ring.
A so-called oil-free compressor piston ring uses a self-lubricating resin material, and a PTFE composite material mainly composed of PTFE (polytetrafluoroethylene) having a lower coefficient of friction than so-called resin materials such as polyethylene and nylon is often used. Is called. PTFE has a characteristic that the coefficient of friction is low, but also has a characteristic that the amount of wear is large. Therefore, in order to use PTFE or PTFE composite material, it is necessary to reduce the amount of wear while utilizing the low coefficient of friction of PTFE.

  On the other hand, there is a problem that the wear amount of the piston ring is greater in the case of nitrogen gas than in the case of air when compressing air with a gas compressor and when compressing nitrogen gas. In order to solve this problem, the PTFE or PTFE composite material is hardened by adding copper oxide to improve the wear resistance of the PTFE or PTFE composite material (see Patent Document 1).

  In addition, in reducing the wear of PTFE or PTFE composite material, it is known that when the PTFE transfer film formed on the surface of the counterpart material is successfully formed when they slide, it is effective in reducing the wear. (See Non-Patent Document 1).

JP 2009-85051 A

Akitoshi Takeuchi et al., Journal name: Tribologist, Vol. 43, No. 3, 1998, pp. 258-261

  Although Patent Document 1 has a certain effect on reducing the wear amount of the piston ring when compressing nitrogen gas, the replacement period is extended by further reducing the wear amount, thereby reducing the operating cost. It was necessary to plan.

  An object of the present invention is to provide a structure that reduces the wear of the PTFE sliding material.

In order to solve the above-described problems, a sliding component made of a resin that is more easily transferred to metal than PTFE is disposed near the PTFE sliding material.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is nitrogen gas and dry air, the sliding component which can reduce the abrasion of a PTFE sliding material and can extend the replacement period, and a gas compressor or analysis instrument using the same can be provided. .

It is a figure for demonstrating the relationship between the presence or absence of a transfer film, and an abrasion powder. It is sectional drawing of the sliding part explaining Example 1 of this invention. It is an enlarged view of the sliding part of FIG. It is a figure which shows the flow of the test for investigating the relationship between a transfer film and abrasion. It is a figure which shows the test result of the relationship between a transfer film and abrasion. It is sectional drawing of the sliding part explaining Example 2 of this invention. It is sectional drawing of the sliding part explaining Example 3 of this invention. It is sectional drawing of the sliding part explaining Example 4 of this invention. It is sectional drawing of the sliding part explaining Example 5 of this invention. It is sectional drawing of the sliding part explaining Example 6 of this invention. It is sectional drawing of the sliding part explaining the modification of Example 6 of this invention. It is sectional drawing of the sliding part explaining Example 7 of this invention. It is sectional drawing of the sliding part explaining Example 8 of this invention. It is a structure sectional drawing of the analytical instrument explaining Example 9 of this invention. It is sectional drawing of a common oil free gas compressor. 15 is an enlarged view of the sliding portion.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 15 is a cross-sectional view of a general oil-free gas compressor. The gas compressor mainly includes a cylinder 40, a piston 1, a suction valve, a discharge valve (compressed gas side), a connecting rod, a pulley, a motor, and a casing that constitute the compression chamber 3. To generate compressed gas, the power of the motor is transmitted to the piston through the belt, pulley, and connecting rod, the piston is moved up and down, and the gas is compressed into the compression chamber through the intake valve. The compressed gas is discharged to a compressed gas pipe through a discharge valve. At this time, the piston ring slides and wears with the inner surface of the cylinder 40, and the amount thereof increases as the number of sliding operations increases. The rider ring 30 is provided to adjust the posture of the piston with respect to the cylinder 40.

  FIG. 16 is an enlarged view of a sliding portion in which the piston ring of FIG. 15 slides on the inner surface of the cylinder 40, and is a view for explaining the transfer film. In the enlarged view, a state in which the piston ring 20 of the PTFE composite slides on the cylinder inner surface 41 and a part of the piston ring 20 forms the transfer film 28 on the cylinder inner surface 41 is shown. The piston ring 20 contacts the cylinder 40 or the cylinder inner surface 41 via the transfer film 28. As a result, the piston ring 20 slides without directly touching the irregularities of the cylinder inner surface 41, so that wear can be reduced.

  If the transfer layer 28 is not formed, the piston ring 20 comes into direct contact with the cylinder inner surface 41, and the convex portion of the cylinder inner surface 41 scrapes the piston ring 20 so that wear of the piston ring 20 is promoted. Become.

FIG. 1 is a diagram for explaining how abrasion powder is generated depending on the presence or absence of a transfer film on a metal surface when a resin (PTFE resin material) slides on the metal.
FIG. 1A shows a case where a transfer film can be formed on the current microcontact surface, in which a metal and a resin slide through the transfer film. On the other hand, FIG. 1B shows a case where a transfer film cannot be formed on the current microcontact surface, and the metal and the resin are in direct contact. Therefore, the surface of the resin material is always scraped by the metal surface during sliding, and the amount of wear powder increases as compared with the case where there is a transfer film.

  FIG. 1C is a view for explaining the principle of the present invention and shows a micro contact surface of the present invention. In FIG. 1 (c), a material that promotes transfer or forms a reinforced transfer film is disposed near the PTFE resin material. A state in which a transfer film made of a resin material that promotes transfer is formed on a metal surface by a resin material that promotes transfer more than the PTFE resin material is shown. With this structure, as a result, the transfer film can be formed in a stable manner, corresponding to the case where the transfer film can be formed as described in FIG. 1A. Therefore, the resin (PTFE resin material) and the metal material can be directly used. Contact can be avoided and generation of wear powder can be suppressed, that is, the amount of wear can be reduced.

  FIG. 2 is a view showing a cross section of the sliding portion of the present embodiment. In this embodiment, as shown in FIG. 2, the piston ring 20 is composed of two piston rings 20 and 21, one of which is a PTFE composite material, and the other is a transfer film formed more than the PTFE composite material. It is comprised with the piston ring 21 which consists of resin which is easy to do.

  In the present embodiment, unless otherwise specified, the resin refers to a resin material including a single resin material such as PTFE, polyethylene, nylon, or a composite material composed of the resin material and another material.

  Examples of the resin whose transfer is promoted more than PTFE include carboxylic acid, PPS (polyphenylene sulfide), and a polymer containing an ether chain. Moreover, it is desirable that heat resistance is equivalent to PTFE. The reason why it is desirable to have heat resistance is that the piston ring is exposed to a temperature environment of 100 degrees to 200 degrees due to frictional heat due to sliding and heat generated when compressing the gas. The reason why it is desirable to be a polymer containing an ether chain is that it has the effect of increasing the adhesive force between the metal and the resin. Desirable examples of such resins include PFA (perfluoroalkoxide), PAI (polyamideimide), PBT (polybutylene phthalate), PEI (polyetherimide), PEEK (polyetherketone), and resins. Moreover, the resin containing at least 1 or more types of any of those is mentioned. Since the resin mentioned here has an ether chain, it forms a transfer film on the counterpart material more easily than PTFE even in a gas composed of nonpolar molecules such as nitrogen molecules or in dry air.

  FIG. 3 shows a partially enlarged view of FIG. In the enlarged view, a state in which the transfer film 28 is formed on the sliding surface 41 by sliding the piston ring 21 made of a resin that is easier to form the transfer film than the PTFE composite material on the cylinder inner surface 41. Show. Due to the transfer film 28, the piston ring 20 comes into contact with the cylinder inner surface 41 through the transfer film 28. As a result, even if the piston ring 20 is in a gas composed of nonpolar molecules such as nitrogen molecules or in dry air, the piston ring 20 is slid without directly touching the unevenness of the cylinder inner surface 41 and the piston ring 20 is prevented from being worn. be able to.

  The sliding member made of a polymer containing an ether chain forms a thicker transfer film than the transfer film formed by the PTFE sliding material. Alternatively, even in a harsh environment where the PTFE sliding material hardly forms a transfer film, the sliding member made of a polymer containing an ether chain is more easily transferred to the sliding metal surface than PTFE. Form. The PTFE sliding material can be prevented from coming into direct contact with the metal surface by a transfer film formed by a sliding component made of a sliding material that forms a transfer film on the metal surface separately from itself. As a result, even if the PTFE sliding material loses its ability to form a transfer film depending on the environment, the PTFE sliding material can slide without being affected and without increasing wear.

  4 and 5 are test results showing the influence of the transfer film of PTFE and PFA on the wear phenomenon of the PTFE composite material. FIG. 4 shows the test flow. Here, press riding is a process of attaching a resin to be transferred to the surface of a metal material. In press riding, PTFE and PFA were slid in the atmosphere for 20 minutes, and two types of metal materials with either PTFE or PFA were prepared. In the PTFE composite material wear test, two kinds of metal materials prepared by press riding were each slid for 60 minutes with a new PTFE composite material, and then the wear amount of the PTFE was measured. FIG. 5 is a test result showing the amount of wear of each PTFE composite material slid with a metal material prepared by press riding. From FIG. 5, it can be seen that the wear amount of the PTFE composite varies depending on the type of transfer film on the metal surface, and that the transfer film of PFA has a greater effect of reducing the wear amount of the PTFE composite than the transfer film of PTFE. I understand. By analogy with this result, when the PTFE composite material and the PFA are slid simultaneously and when the PTFE composite material and the PTFE are slid simultaneously, the former PFA is slid simultaneously. It was found that the amount of wear of the composite material can be reduced.

  FIG. 6 is a diagram illustrating a cross section of the sliding portion in the second embodiment. 6 differs from FIG. 2 in the position of a piston ring 20 made of PTFE composite material and a piston ring 21 made of a resin that is easier to form a transfer film than PTFE composite material. The difference is that it is on the upper side (or top dead center) side of the cylinder from the ring 20. The advantage of this configuration is that in the case of FIG. 2, since the piston ring 21 is below the piston ring 20, there is a place where no transfer film is generated by the piston ring 21 near the top dead center of the piston. The piston ring 20 slides in a place where no transfer film is generated. On the other hand, in the case of FIG. 6, since the piston ring 21 is above the piston ring 20, the piston ring 20 slides on the transfer film generated by the piston ring 21 even near the top dead center of the piston. It is possible to move, and there is a specific effect that wear of the piston ring 20 can be further suppressed. When the piston comes to the bottom of the cylinder, the piston ring 20 slides in a place where the piston ring 21 does not slide, but the compression chamber in the space above the piston is made of nitrogen gas. Even in this case, since the space under the piston is in the atmosphere, it is easy to generate a transfer film even with the PTFE composite material. Therefore, wear can be suppressed by forming the transfer film with the piston ring 20 itself.

  FIG. 7 is a diagram illustrating a cross section of the sliding portion in the third embodiment. The configuration shown in FIG. 7 differs from FIGS. 2 and 6 in that two piston rings 21 made of a resin that is easier to form a transfer film than the PTFE composite material are arranged above and below the PTFE composite material. . The advantage of this configuration is that when the piston ring 20 reciprocates up and down the cylinder inner surface, the upper part of the cylinder inner surface is above the transfer film generated by the piston ring 21 at the upper part of the piston ring 20 and the lower part is the piston ring. 20 slides on the transfer membrane produced by the lower piston ring 21. Therefore, the piston ring 20 can always slide on the transfer film generated by the upper and lower piston rings 21. As a result, the piston ring 20 has a specific effect that wear can be further suppressed.

  In the configuration of the piston ring shown in FIGS. 2, 6, and 7 of the first to third embodiments, the piston ring 20 is in close contact with the inner surface of the cylinder so as not to leak the compressed gas from the gap between the cylinder and the piston. It is desirable to do so. The piston ring 21 is preferably made of a material such as PFA, which has a higher coefficient of friction than the PTFE composite material. It is better to make it smaller than that of the ring 20.

  FIG. 8 is a diagram illustrating a cross section of the sliding portion in the fourth embodiment. The configuration shown in FIG. 8 is obtained by embedding a resin material 22b that promotes formation of a transfer film in a conventional piston ring of a PTFE composite material. In this configuration, as in the configurations described in the first to third embodiments, the resin material 22b that promotes transfer film formation generates the transfer film 28 on the cylinder inner surface 41. As a result, the resin material 22b transfers to the PTFE composite material 22a. Wear of the piston ring 22 made of the resin material 22b that promotes film formation is reduced.

  FIG. 9 is a diagram illustrating a cross section of the sliding portion in the fifth embodiment. The configuration shown in FIG. 9 is obtained by replacing the PTFE composite material 22a of FIG. 8 with the resin material 22b that promotes transfer film formation. In the configuration of FIG. 8, when the piston is at the top dead center and the bottom dead center, the transfer film is not formed by the resin material 22b that promotes the transfer film formation. The PTFE composite material 22a wears when it is at the bottom dead center. However, in FIG. 9, even when the piston is at the top dead center and the bottom dead center, the resin transfer film is always formed on the cylinder surface by the resin material 22b that promotes transfer film formation. Wear of the piston ring 23 made of the PTFE composite material 22a and the resin material 22b that promotes transfer film formation is avoided.

  10 and 11 are diagrams showing a cross section of the sliding portion in the sixth embodiment. 10 and FIG. 11, the PTFE composite material 22a and the resin material 22b for promoting transfer film formation are stacked one above the other. The effect is almost the same as the effect obtained by the configurations of FIGS. 10 and FIG. 11 is that the PTFE composite material 22a does not need to be embedded with a resin material 22b that promotes formation of a transfer film, as compared with FIGS. Further, compared with the configuration of FIGS. 2 and 6, since the number of grooves in which the piston ring can be accommodated can be reduced, there is a specific effect that the time required for the groove processing can be reduced when the piston is manufactured.

  FIG. 12 is a diagram illustrating a cross section of the sliding portion in the seventh embodiment. The structure shown in FIG. 12 includes a PTFE composite piston ring 20 and a resin rider ring 31 that is easier to form a transfer film than the PTFE composite. The role of the rider ring 31 is to adjust the posture with respect to the cylinder 40 and to form a transfer film on the cylinder inner surface 41 to suppress wear of the piston ring 20. As a result, the piston ring 20 slides on the transfer film generated by the rider ring 31 even in a gas composed of nonpolar molecules such as nitrogen molecules or in dry air. It is possible to prevent the piston ring 20 from being worn by sliding without directly touching.

  FIG. 13 is a diagram illustrating a cross section of the sliding portion in the eighth embodiment. The configuration shown in FIG. 13 is that a resin film 32 that promotes transfer film formation is formed directly on the piston 1 instead of the rider ring 31 of FIG. As a film forming method, when the PFA is used as the resin film 32 for promoting the transfer film formation, it is desirable to cast the cylinder 1 in the PFA that is heated to be liquid. In the case of PEEK or epoxy resin, the organic solvent in which they are dissolved is dissolved, and then the organic solvent in which they are dissolved is applied to the piston surface to form a film.

  The gas compressor described above can suppress wear of the piston ring 20 even when compressing a gas composed of nonpolar molecules such as nitrogen molecules or dry air.

FIG. 14 is a diagram illustrating an analytical instrument according to the ninth embodiment.
An analytical instrument is a general term for an apparatus that measures and analyzes physical characteristics and composition of a sample. For example, a length measuring SEM that is a scanning electron microscope that measures the dimensions of a fine circuit pattern on a semiconductor wafer. (Scanning Electron Microscope). These analytical instruments need to be moved in order to measure a sample (sample), and therefore a sliding member is necessary. Analytical instruments must avoid the use of lubricating oil for sliding members because of their fine structure and the nature of detecting components. In addition, since the wear powder at the sliding portion may affect the detection result, the apparatus dislikes the discharge of the wear powder.

FIG. 14 shows a configuration in which the present invention is applied to a general analytical instrument, in which a sample stage 53, a detection device 52, a sample 55, and the like are arranged in a chamber 50 and a chamber interior 51. In this analytical instrument, the sample is fixed on the sample stage 53 and moved on the guide rail 54 so that the sample can be analyzed by the detection device. When the sample stage is moved, a PTFE composite material 56 and a material 57 for promoting transfer film formation are provided between the sample stage and the guide rail so that the sample stage can move smoothly on the guide rail. The PTFE composite material and the material that promotes transfer film formation are fixed to the sample stage and slide with the guide rail. In the analytical instrument to which the present invention is applied, the resin transfer film is formed of a material for forming the transfer film on the surface of the guide rail. Therefore, the PTFE composite material is prevented from contacting the guide rail directly, and as a result, the wear of the PTFE composite material is reduced. Moreover, since discharge | emission of abrasion powder is suppressed, a suitable analytical instrument is realizable.
In FIG. 14, the sliding portion is composed of the PTFE composite material 56 and the material 57 that promotes the formation of the transfer film, but may be integrally formed.

  Although the embodiments have been described above, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is also possible to add, delete, and replace other configurations for a part of the configuration of each embodiment. For example, the piston ring 21 in FIG. 6 and the rider ring 31 in FIG. 12 may be combined.

3 Compression Chamber 5 Connecting Rod 20, 21, 22, 23, 24, 25 Piston Ring 22a PTFE Composite Material 22b Resin Material Promoting Transfer Film Formation 28 Transfer Film 30, 31 Rider Ring 32 Promoting Transfer Film Formation Resin film 40 Cylinder 41 Cylinder inner surface

Claims (16)

Gas compression that generates a compressed gas by compressing a gas in a compression chamber provided in the cylinder with a piston, and a cylinder formed mainly of metal, a piston, and a piston ring molded mainly of PTFE resin. In the machine
A sliding portion that slides with the cylinder is provided in the vicinity of the piston ring, and the sliding portion is made of a resin that is more easily transferred to the cylinder than the PTFE resin. A gas compressor, wherein the piston ring slides. The gas compressor according to claim 1,
The gas compressor according to claim 1, wherein the sliding portion is made of a polymer containing an ether chain. A gas compressor according to claim 2, wherein
The gas compressor according to claim 1, wherein the polymer including an ether chain is a resin including at least one of PAI resin, PBT resin, PEI resin, PGT resin, PEEK resin, and epoxy resin. A gas compressor according to any one of claims 1 to 3,
The gas compressor according to claim 1, wherein the sliding portion is a second piston ring. A gas compressor according to any one of claims 1 to 3,
The gas compressor according to claim 1, wherein the sliding portion is a rider ring. A gas compressor according to any one of claims 1 to 3,
The gas compressor according to claim 1, wherein the sliding portion is formed integrally with the piston ring. In an analysis apparatus that has a detection device, a sample stage, and a guide rail, and analyzes the sample on the sample stage by moving the sample stage on the guide rail,
A first sliding portion mainly composed of PTFE resin is provided in a portion that slides with the guide rail of the sample stage, and a second sliding that slides with the guide rail in the vicinity of the first sliding portion. The second sliding portion is made of a resin that is more easily transferred to the guide rail than the PTFE resin, and the first sliding portion is moved on the guide rail on which the second sliding portion has slid. An analytical instrument characterized in that the moving part slides. The analytical instrument according to claim 7, wherein
The second sliding portion is made of a polymer containing an ether chain. The analytical instrument according to claim 8, wherein
The analytical instrument characterized in that the polymer containing an ether chain is a resin containing at least one kind of PAI resin, PBT resin, PEI resin, PGT resin, PEEK resin, and epoxy resin. The analytical instrument according to any one of claims 7 to 9,
The analytical instrument, wherein the second sliding part is integrally formed with the first sliding part. A sliding component used together with a PTFE composite material mainly composed of PTFE resin,
The sliding component is made of a resin that is more easily transferred to a counterpart material that slides than the PTFE resin. The sliding component according to claim 11,
The sliding component is made of a polymer containing an ether chain. The sliding component according to claim 12,
The sliding component, wherein the polymer containing an ether chain is a resin containing at least one kind of PAI resin, PBT resin, PEI resin, PGT resin, PEEK resin, and epoxy resin. The sliding component according to any one of claims 11 to 13,
The sliding component is a piston ring. The sliding component according to any one of claims 11 to 13,
The sliding component is a rider ring. The sliding component according to any one of claims 11 to 13,
The sliding component, wherein the sliding component is integrally formed with the PTFE composite material.

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