JP2006258000A - Helical fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a helical fluid machine with good performance, for suppressing leakage of fluid from a clearance between a roller and a cylinder. <P>SOLUTION: In this helical fluid machine, a coating s produced by closely holding a self-lubricating solid lubricant on a sliding surface of a metallic base member with using resin material as a binder is formed in a blade groove 22a of a roller 22. The blade 24 is formed of a member containing a 50 wt% or more of fluororesin. The coating s is formed to only a part of the blade groove 22a or part of the coating is formed to be thinner than the other part of the coating. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a helical fluid machine, and more particularly to a helical fluid machine in which a sliding portion between a blade groove and a blade provided in a roller is improved.

  Conventionally, in the parts used for the sliding parts of helical fluid machines such as compressors and vacuum pumps, as relatively high reliability, a resin containing fluororesin and a metal or metal with a hard surface treatment Or a combination with a high-hardness ceramic.

  In such a configuration in which the resin and the metal (or a hard surface equal to or more than the metal) slide directly, a high local contact surface pressure is generated particularly in the initial stage of the compression operation, and the metal scrapes the resin. As a result, the resin-side member may be greatly worn locally. When the sliding part wears, there is an increase in the amount of backlash and there is a problem that abnormal vibration or abnormal noise occurs during operation of the device. In addition, in the case of a movable seal part that seals at the same time as it slides, if even part of it wears, it will lead to fluid leakage and it will not be able to perform its function. There was a problem of lowering the performance.

  Accordingly, the present inventors have provided a coating in which a sliding portion provided between a fixed member and a movable member uses a resin material as a binder and holds a self-lubricating solid lubricant in close contact with the sliding surface of a metal substrate. This is a combination of one side member formed with the other side member containing 50% by weight or more of fluororesin, and has a long life and high reliability, and the frequency of sliding member replacement is reduced or no running cost is required. A fluid machine that can be significantly reduced has been proposed (Patent Document 1).

  When the solid lubricant film described in Patent Document 1 is applied to a helical fluid machine, the solid lubricant film is formed on the roller sliding portion. Go around the outer surface and make the outer surface bulge. This swell causes abnormal noise due to contact between this part and the cylinder and increases input, so avoiding abnormal noise and increasing input, and taking a large clearance between the roller and cylinder, in this case, it causes performance degradation due to leakage. There is a fear and there is room for improvement.

  When a solid lubricating coating is formed as in the prior art, the portion changes in size by the film thickness. However, as shown in FIGS. 9 and 10, the coating s is placed in a roller 22 and a blade groove 22a which is a blade sliding portion. It is difficult in terms of manufacturing technology to limit the film formation only to the inside of the blade groove 22a and not to protrude from the outer peripheral surface of the roller. When the coating protrudes from the roller outer sliding surface, only the coating portion is partially raised on the outer peripheral surface, resulting in a shape with poor shape accuracy. In such a situation, if the clearance between the roller and the cylinder is too small, abnormal noise will be generated due to contact with the raised part and input will increase. Conversely, if it is set too large, the gap in the not raised part will become too large and leakage will occur. This causes a performance drop and makes it difficult to achieve high performance.

  Although it is conceivable to use oil to seal the clearance, the presence of a large amount of seal oil leads to an increase in input, so even in this case, the clearance must be kept to a minimum in order to minimize the amount of seal oil used. There is no change in certain circumstances.

  Further, in order to avoid the bulge of the outer peripheral surface, as shown in FIG. 11, a method of keeping the clearance between the roller and the cylinder small by forming a coating on the entire outer peripheral surface other than the blade groove and increasing the overall film thickness. However, in this case, the film forming area becomes very large, and it is necessary to manage the film thickness variation in all of the vast outer peripheral surface abdomen, which causes a problem in manufacturability. For example, when a coating is formed by coating, it is very difficult to prevent swell due to dripping in this portion when the coating is applied to a large outer peripheral surface.

Further, it was found that the solid lubricant film was worn and consumed together with the blade during sliding of the solid lubricant film and the blade. The consumption of this solid lubricating film is also more when the load on the blade is larger. Further, when the entire amount of the solid lubricant film is consumed due to abrasion, the sliding material combination is changed to a combination of a blade and a roller base material, and the wear progresses faster.
JP 2004-190605 A

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a helical fluid machine that reduces fluid leakage from the clearance between a roller and a cylinder and has good performance.

  In order to achieve the above-described object, a helical fluid machine according to the present invention includes a cylinder, a roller made of a metal material eccentrically disposed in the cylinder, and a spiral blade groove formed on the outer peripheral surface of the roller. In a helical fluid machine having a helical blade that is slidably fitted and forms a plurality of working chambers, a resin lubricant is used as a binder in the blade groove of the roller, and a self-lubricating solid lubricant is closely held. The blade is formed of a member containing 50% by weight or more of a fluororesin, and the coating is formed only on a part of the blade groove, or a part of the film thickness is the film thickness of the other part. It is characterized by being formed thinner.

  According to the helical fluid machine according to the present invention, it is possible to provide a helical fluid machine with good performance by reducing fluid leakage from the clearance between the roller and the cylinder.

  Hereinafter, an embodiment of a helical fluid machine according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a longitudinal sectional view of a horizontal helical compressor as an embodiment of a helical fluid machine according to the present invention.

  As shown in FIG. 1, the helical compressor 1 is a casingless compressor, and includes a helical compression mechanism portion 2 as a helical mechanism portion, a drive portion 3 that drives the helical compression mechanism portion 2, and this drive Rotation prevention for preventing rotation of the crankshaft 4 provided between the part 3 and the helical compression mechanism part 2 and transmitting the power of the drive part 3 to the helical compression mechanism part 2 and the roller 22 of the helical compression mechanism part 2 It has an Oldham ring 5 constituting the mechanism.

  The helical compression mechanism 2 has an annular roller 22 as a movable member that is eccentrically disposed in a cylinder 21 as a fixed member so as to be pivotable (revolved), and a volume gradually increases in the axial direction between the roller 22 and the cylinder 21. And blades 24 of unequal pitch that define the compression chambers 23 to be smaller. A blade groove 22a having a predetermined size is formed on the outer peripheral surface of the roller 22 so that the pitch gradually decreases from the left end of the suction port 21a side in FIG. 1 toward the right end of the discharge port 21b. A spiral blade 24 having elasticity is fitted into the groove 22a so as to appear and slide.

  As shown in FIGS. 2 and 3, the helical compressor 1 has a roller 22 and a helical blade 24 combined to form a sliding portion, and forms a movable seal portion that seals while sliding against each other. ing. 2 shows the fitting state of the blade groove 22a and the blade 24 coated with the coating s, and FIG. 3 shows the fitting state of the blade groove 22a and the blade 24 in the non-coating portion a.

  Further, the non-coating portion a is preferably, for example, a portion in the vicinity of the end portion of the blade 24 and excluding the vicinity of the maximum spiral inclination portion of the blade 24.

  As shown in FIG. 4, the roller 22 is made of, for example, a hollow cylindrical aluminum alloy roller base material, and a coating s is formed in the blade groove 22a by using a resin as a binder and holding and holding a self-lubricating solid lubricant. Has been.

  The coating s is formed only on a part of the blade groove 22a, and the non-coating portion where the coating is not coated or the thin film portion a having a thickness smaller than that of the coating s is at least part of one turn on the discharge side of the blade 24. This is good to include. As a result, a sufficient solid lubricating film is formed in a place where the load on the blade is large, and a film is consumed slowly in a place where the load is light. Extend the life of helical fluid machinery.

  In addition to forming on the discharge side of the blade as described above, or as shown in FIG. 5, a thin film portion having a smaller film thickness than the non-coating portion or the coating a is formed only on the suction side 1 roll. You may do it. Thereby, the same effect as the case where it provides in the discharge side is acquired.

  Also, the vicinity of the first roll on the discharge side is usually close to the adjacent groove in the helical spiral design, and when the solid lubricant film is formed by spray coating, the outer periphery wrap portion is applied twice, as shown in FIG. In particular, the bulge on the outer peripheral surface is likely to increase, but if this part is not coated or if the film thickness is reduced, the bulge on the outer periphery of the roller will be reduced at the largest part, and the gap between the roller and cylinder will be reduced. It is possible to achieve high performance while keeping the clearance small and ensuring the service life.

  Further, the non-coating portion not coated with the coating or the thin film portion a having a thickness smaller than that of the coating s is provided on the portion excluding the vicinity of the maximum spiral inclination portion of the blade 24, that is, on the discharge side or suction side of the blade groove 22a. It is done.

  In addition, since the metal base material of the roller is an aluminum alloy, the weight of the device is reduced and the heat conductivity of the base material is high. Severe wear due to heat generation can be prevented more effectively and reliability can be improved. The metal substrate has a hardness of HRB (Rockwell hardness) 60 or more. As a result, the strength of the base material is maintained, and it is possible to prevent the occurrence of abnormal vibration and abnormal sound, or leakage of the seal.

  The resin material as the binder is preferably an epoxy resin or a polyamideimide resin. As a result, the binder resin has excellent adhesion to any substrate and is not easily peeled off, has excellent heat resistance, little deterioration due to frictional heat, and excellent mechanical strength of the material itself. Since it has wear, a highly reliable sliding part can be realized.

  Further, the solid lubricant is preferably selected from one or more of graphite, molybdenum disulfide, boron nitride, antimony oxide, and mica. As a result, the solid lubrication effect has a layered crystal structure, and the sliding effect between the layers shows a lubrication effect. It is suitable for constituting the part.

  Further, the member forming the blade 24 preferably contains a fibrous reinforcing material or other fillers in addition to containing 50% by weight or more of a fluororesin. This prevents deformation of the blade, improves leakage resistance, improves thermal conductivity, lowers the sliding part temperature, reduces wear, and improves wear resistance by providing lubrication. As a result, a sliding portion with higher reliability and longer life can be realized.

  Next, the compression action of the helical compressor of this embodiment will be described.

  The roller 3 is eccentrically rotated (revolved) through the crankshaft 4 by energizing the drive unit 3 of the helical compressor 1 as shown in FIG. Due to the eccentric rotation of the roller 22, the roller 22 slides and revolves while being in contact with the inner peripheral surface of the cylinder 21. The eccentric rotation of the roller 22 causes each compression chamber 23 formed by the blade 24 between the cylinder 21 and the roller 22 to change in volume so that the volume gradually decreases while moving in a helical shape in the cylinder axis direction. In each compression chamber 23, the refrigerant sucked through the suction pipe 21a due to the volume change is sequentially compressed and increased in pressure, and discharged through the discharge pipe 21b.

  In such a compression stroke, the roller 22 has a mechanism that moves circularly with a certain amount of eccentricity with respect to the cylinder 21, so in order to achieve high performance, the roundness of the roller outer periphery and the cylinder inner surface, It is important to maintain good part shape accuracy such as cylindricity and to keep the clearance between the roller 22 and the cylinder 21 small with high accuracy.

  In this embodiment, in the non-coating portion or the thin film portion a, the outer peripheral bulge of a part of the roller is reduced and the shape accuracy of the outer peripheral surface of the roller is improved, so that the clearance between the roller and the cylinder can be kept small. This reduces the leakage of fluid from the clearance between the roller and cylinder, and exhibits high performance.

  Further, in the compression stroke, the load applied to the blade 24 includes a load due to the pressure difference between the compression chambers 22a partitioned by the blade, a load due to the blade 24 hitting the groove when the blade 24 protrudes into and out of the blade groove 22a, and the like. Of these loads, when considering the former load, the blade discharge side 1 volume is divided by the discharge pressure space and the pressure of the compression chamber in front of it. Even so, at least one part of the one discharge side winding is a part where the former load is lighter than the other parts (see FIG. 7).

  Therefore, the film forming part is minimized by not forming the film at the lightly loaded part or by making the film thickness thinner than the others while maintaining the film thickness at the high load where the blade is easily worn. , While avoiding the problems associated with a wide range of conventional film formation, a lubrication film is reliably formed on areas where lubrication is required, improving manufacturability (easiness of film thickness management, speeding up the process), and the amount of raw materials used The cost can be reduced by reducing the cost.

  Further, in the compression stroke, the latter load, that is, the load caused when the blade 24 hits and enters the blade groove 22a depends on the inclination of the blade spiral (see FIG. 8). This is because, for geometrical reasons, the greater the slope of the helix, the greater the distance that the blade 24 slides with the cylinder when the blade 24 enters and exits, and thus, when the blade 24 moves into and out of the blade groove, This is because the load generated when the blade is pressed against the roller because the blade moves against the friction with the cylinder increases as the spiral inclination increases. A part having the largest load, that is, a part in the vicinity of the maximum part of the spiral inclination of the blade is formed with a film having a specified thickness, thereby extending the life.

  According to the above embodiment, in the non-coating portion or the thin film portion, the peripheral bulge of a part of the roller is reduced, and as a result, the shape accuracy of the roller outer peripheral surface is improved, so the clearance between the roller and the cylinder can be kept small. This reduces the leakage of fluid from the clearance and realizes a helical fluid machine with good performance.

  In the above embodiment, the horizontal helical compressor has been described as an example. However, the present invention is not limited to this, and the helical fluid compressor according to the present invention can be applied to other compressors, vacuum pumps, and the like.

1 is a longitudinal sectional view of a horizontal helical compressor according to an embodiment of a helical fluid machine of the present invention. The longitudinal cross-sectional view of the sliding part of the horizontal type helical compressor which concerns on one Embodiment of the helical fluid machine of this invention. The longitudinal cross-sectional view of the sliding part of the horizontal type helical compressor which concerns on one Embodiment of the helical fluid machine of this invention. The perspective view of the roller used for the horizontal type helical compressor which concerns on one Embodiment of the helical fluid machine of this invention. The perspective view of other embodiment of the roller used for the horizontal type helical compressor which concerns on one Embodiment of the helical fluid machine of this invention. The conceptual diagram which shows the blade groove | channel and film which are used for a general horizontal type | mold helical fluid machine. The diagram which shows the relationship between the helical rotation angle of a general helical fluid machine, and the pressure difference between compression chambers. The diagram which shows the helical rotation angle of a general helical fluid machine, and the axial displacement of a helix. The perspective view of the roller used for the conventional horizontal type helical compressor. The perspective view of the roller used for the conventional horizontal type helical compressor. The perspective view of the roller used for the conventional horizontal type helical compressor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Helical type compressor, 2 ... Helical compression mechanism part, 3 ... Drive part, 21 ... Cylinder, 21a ... Suction port, 21b ... Discharge port, 22 ... Roller, 22a ... Blade groove, 23 ... Compression chamber, 24 ... Blade

Claims (3)

A cylinder, a roller made of a metallic material eccentrically disposed in the cylinder, and a helical blade that is slidably fitted in a helical blade groove formed on the outer peripheral surface of the roller and forms a plurality of working chambers In the helical fluid machine having the above structure, a film is formed in the blade groove of the roller by using a resin as a binder to hold and hold a self-lubricating solid lubricant, and the blade includes a member containing 50% by weight or more of a fluororesin The helical fluid machine is characterized in that the coating is formed only on a part of the blade groove, or a part of the film is formed thinner than the other part. The portion where the coating film is not formed or the portion where the film thickness is formed thinner than other portions includes at least a part of one turn on the discharge side or suction side of the blade. A helical fluid machine according to claim 1. 2. The helical portion according to claim 1, wherein the portion where the coating film is not formed or the portion where the film thickness of the coating film is formed thinner than other portions is a portion excluding the vicinity of the maximum spiral inclination portion of the blade. Fluid machine.

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