JPH0412190A - Compressor - Google Patents

Abstract

PURPOSE:To improve durability and sealing property by fitting a cylindrical piston provided with a spiral blade of which the outer circumference is contacted with the inner circumferential face of a cylinder on the outer circumferential face into a cylinder, and forming the blade out of fluororesin. CONSTITUTION:When a rotor 6 is rotated by supplying current to a motor part 3 and a cylinder 7 in one body with the rotor is also rotated, a piston 11 is swingingly rotated around the center axis B of the cylinder 7, while contacting a part of the outer circumferential face with the inner circumferential face of the cylinder. Consequently, a spiral blade 21 on the outer circumference of the piston 11 is pushed in a groove 19 as the piston 11 is approached to the contact part with the cylinder 7, and drawn from the groove 19 as it is separated from the contact part, refrigerant gas is transferred in order in confined condition in a crescent-shaped working chamber 22, and compressed. In such compressor, the blade 21 is formed out of fluororesin. Further, fluoro coating film is formed on the groove 19 of the outer circumferential face of the piston 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a compressor for compressing a medium to be compressed, such as refrigerant gas in a refrigeration cycle.

(Prior art) Compressors used in refrigeration cycles, such as air conditioners and refrigerators, generally use a reciprocating type that uses a reciprocating piston, or a rotary type that rotates a disk-shaped piston eccentrically within a cylinder. There is.

However, all of these types of compressors have the disadvantage that the structure of the drive section, such as the crankshaft that transmits rotational force to the compressor, and the compressor section are complex, and the number of parts is large.

Therefore, recently, a compressor called a helical blade type has been proposed. The compressor section is constructed by combining a cylindrical cylinder with one end on the suction side and the other end on the discharge side, and a cylindrical piston with a spiral blade on its outer circumferential surface. It is something.

Specifically, the compressor was as shown in FIGS. 6 to 15. Here, we will explain this helical blade type compressor.

That is, 1 in FIG. 6 indicates a hermetic compressor for refrigerant gas used in the refrigeration cycle. The compressor 1 includes a closed case 2, and a motor section 3 and a compressor section 4 disposed within the closed case 2. The electric motor section 3 includes a substantially annular stator 5 fixed to the inner surface of the sealed case 2 and an annular rotor 6 provided inside the stator 5.

The compressor section 4 has a cylindrical cylinder 7. The rotor 6 is coaxially fixed to the outer peripheral surface of the cylinder 7. Further, both ends of the cylinder 7 are rotatably fitted into bearings 8 and 9 fixed to the inner surface of the end portion of the closed case 2.

Thereby, both ends of the cylinder 7 are hermetically closed and rotatably supported.

A cylindrical piston 11 having an outer diameter smaller than the inner diameter of the cylinder 7 is disposed inside the cylinder 7 along the axial direction of the cylinder 7 . This piston 11 is arranged such that its central axis A is eccentrically downward in FIG. 6 by a distance e with respect to the central axis B of the cylinder 7. With this arrangement, a part of the outer peripheral surface of the piston 11 is brought into contact with the inner peripheral surface of the cylinder 7.

Further, support shaft portions 12a and 12b are provided at both axial ends of the piston 1, respectively. These support shaft portions 12a and 12b are rotatably inserted and supported in bearing holes 8c and 9c formed in the bearings 8 and 9, respectively, so that the piston 11 can be pivoted relative to the cylinder 7.

A prismatic portion 13 having a square cross section is formed on one support shaft portion 12 a of the piston 11 . As shown in FIG. 9, this prismatic portion 13 is provided with an Oldham ring 15 in which a rectangular long hole 14 is bored. That is, the prismatic portion 1
3, an Oldham ring 15 is fitted into the elongated hole 14 so as to be slidable along the longitudinal direction thereof. Further, on the outer circumferential surface of the Oldham ring 15, as shown in FIG.
6 are implanted so as to be slidable.

The other ends of these bins 16 are fitted and fixed into fitting holes 17 formed in the peripheral wall of the cylinder 7, and the piston 11 is connected to the cylinder 7 so as to be eccentric with respect to the radial direction of the cylinder 7. are doing. By this Oldham coupling, when the electric motor section 3 is energized and the cylinder 7 is rotated together with the rotor 6, the rotational force of the cylinder 7 is transmitted to the piston 11 via the Oldham ring 15. That is, the piston 11 internally rotates (turns while rotating) within the cylinder 7 with a portion of the piston 11 in contact with the inner surface of the cylinder 7 . Note that the fitting hole 17 is hermetically closed by a cover member 18.

Further, the outer peripheral surface of the piston 11 has a spiral groove 1 along the axial direction of the piston 11, as shown in FIGS. 6 to 8.
9 is formed. The pitch of the grooves 19 is gradually reduced from the right side to the left side in these drawings, that is, from the suction side to the discharge side of the cylinder 7.

A spiral blade 21 is fitted into this groove 19 as shown in FIGS. 7 and 8. The thickness dimension of this blade 21 almost matches the width dimension of the spiral groove 19, and each part of the blade 21 can freely move forward and backward with respect to the groove 19 along the radial direction of the piston 11. ing. As a result, the blade 21 can be attached to the cylinder 7 with its outer circumferential surface in close contact with the inner circumferential surface of the cylinder 7.
It is designed to slide on the inner peripheral surface of.

The blade 21 partitions the space between the inner circumferential surface of the cylinder 7 and the outer circumferential surface of the piston 11 into a plurality of working chambers 22 . That is, each working chamber 22 is formed between two adjacent windings of the blade 21. In addition,
Its shape is approximately crescent-shaped, extending along the blade 21 from one contact point between the piston 11 and the inner peripheral surface of the cylinder 7 to the next contact point. And this blade 2
With a pitch of 1, the volume of the working chamber 22 is equal to that of the cylinder 7.
It gradually becomes smaller from the suction side to the discharge side.

On the other hand, a suction hole 23 penetrates in the axial direction inside the bearing 8 located on the suction side of the cylinder 7.

One end of this suction hole 23 opens into the inside of the cylinder 7. A suction pipe 24 of a refrigeration cycle (not shown) is connected to the other end of the suction hole 23. Further, the other bearing 9 is provided with a discharge hole 25 . This discharge hole 2
One end of 5 communicates with the discharge end side inside the cylinder 7.

Further, the other end of the discharge hole 25 opens into the inside of the sealed case 2, so that the compressed gas is discharged into the sealed case 2.

On the other hand, an oil introduction passage 26 is bored inside the piston 11 along its central axis A, as shown in FIG.

One end of this oil introduction path 26 communicates with the bottom of the spiral groove 19 on the discharge side. The other end opens into an oil reservoir 2a at the bottom of the sealed case 2 via a through hole 27 formed in one of the bearings 8 and an introduction pipe 28. As a result, when the pressure inside the sealed case 2 increases, the lubricating oil 29 stored in the oil reservoir 2a passes through the introduction pipe 28, the through hole 27, and the oil introduction path 26, and connects the bottom of the groove 19 and the blade 21. It is now being introduced into the space between.

Note that 31 is a suction groove, and 32 is a discharge pipe for discharging compressed gas from inside the sealed case 2 to the refrigeration cycle circuit.

In such a compressor, when the rotor 6 rotates due to energization of the electric motor section 3, the cylinder 7 also rotates together with the rotor 6. The piston 11 rotates while turning around the central axis B of the cylinder 7, with a part of its outer circumferential surface contacting the inner circumferential surface of the cylinder 7. Note that such relative rotational movement between the piston 11 and the cylinder 7 is ensured by the Oldham ring 15.

On the other hand, the blade 21 rotating together with the piston 11 rotates with its outer circumferential surface in contact with the inner circumferential surface of the cylinder 7. Then, each part of the blade 21 is pushed into the groove 19 as it approaches the contact area between the outer peripheral surface of the piston 11 and the inner peripheral surface of the cylinder 7, and exits from the groove 19 as it moves away from the contact area. As a result, the suction pipe 24
The refrigerant gas sucked into the cylinder 7 through the suction hole 23 remains confined in the crescent-shaped working chamber 22 as shown in FIGS. 10 to 14 as the piston 11 rotates. It is sequentially transferred to the working chamber 22 on the discharge side and compressed. Then, this compressed refrigerant gas passes through the discharge hole 25 formed in the bearing 9 on the discharge side, the inside of the sealed case 2, and the discharge pipe 32, and is discharged into the refrigeration cycle circuit.

Note that the blade 21 is constantly pressed toward the inner circumferential surface of the cylinder 7 by oil 29 introduced between the groove 19 and the blade 21 to prevent gas leakage from the working chamber 22.

(Problem to be Solved by the Invention) By the way, the blades 21 of such a compressor have various performances necessary for compressing the refrigerant, such as not deteriorating in properties even when exposed to the refrigerant, and performance that allows them to be easily fitted into the grooves 19 (elasticity). The performance required to screw into the groove 19 while being deformed (low rigidity) is required.

Therefore, it has been considered to use a fluororesin for the blade 21, which has properties such as a small coefficient of friction, resistance to coolant, low heat resistance, and low modulus of elasticity in bending. Specifically, tetrafluoroethylene resin (hereinafter referred to as PTFE) and tetrafluoroethylene/perfluoroalkoxyethylene copolymer resin (hereinafter referred to as PFA) are considered.

However, PTFE, PFA, etc. have the drawback of high wear.

Therefore, in order to improve this drawback, inorganic fillers such as glass fiber, carbon fiber, molybdenum disulfide, graphite bronze, etc., or polyether ether ketone resin, polyimide resin, polyester resin, polyphenylene sulfide resin, etc. are generally used. Abrasion resistance is improved by adding microparticles and fibrous fillers.

Even if the blade 21 is made of such a fluororesin, the blade 21 is subject to wear as shown in FIG. 16 due to the compression action unique to the helical blade type.

That is, in the helical blade type compressor, as described above, the refrigerant gas remains confined in the working chamber 22 and is sequentially transferred to the discharge side according to the rotation of the piston 11 and compressed. In this state, as shown in FIG. 16, while being pressed against the suction side side of the groove 19 due to the pressure difference generated in the working chamber 22,
It is repeatedly pushed in and out of the groove 19 by the relative rotational movement between the cylinder 7 and the piston 11. In other words, the blade 21 and the groove 19 will rub against each other under a considerable load,
The side surface of the blade 21 on the suction side is worn out.

Incidentally, the amount of wear varies depending on the type of filler added to the fluororesin.

For example, the piston 11 is made of carbon steel, and the blade 21 is made of PTFE resin and glass fiber (13μ).

A material filled with "15% by weight" of PT
2, a material made of FE resin filled with ``15% by weight'' of carbon fiber.
The seeds were used as parts of the helical blade compressor shown in Figure 6 to create a ``100
The amount of wear (displacement of the depression) and surface roughness of the blade 21 during operation for 1 hour are investigated. As a result, as shown in Figure 17, blade 21 filled with carbon fiber had less wear than blade 21 filled with glass fiber, and the surface roughness was as shown in Figure 18. Although the blade 21 filled with glass fibers had a large score of "8-", the blade 21 filled with carbon fibers shown in FIG. 19 had a smooth score of "2-". However, the surface roughness of the groove 19 is "4 degrees" at maximum.

In other words, the blade 21 filled with glass fiber damages the surface of the groove 19 with the glass fiber, increases the surface roughness, and increases the load (contact surface pressure is large) due to the reduction of the contact area. A smooth fluororesin coating called a transition film is formed in the grooves 19 of the fibers, and the wear of the blade 21 is reduced.

Considering these things, the sliding properties of PTFE resin etc.
When asking questions about friction and wear, it can be seen that the presence or absence of the formation of the above-mentioned transition film has a large influence.

Although it is believed that the quality of the transfer film depends on the quality of the chemical bond (compatibility), which is determined by the combination of the material and physical conditions such as surface roughness and sliding conditions (pressure, speed, temperature).
The mechanism is still not clear, but as a phenomenon, the formation of a transfer film causes the fluororesins to slide against each other, and the lubricity unique to fluororesin acts, reducing the coefficient of friction and causing wear. It is only known that it can also become smaller.

A typical example is a material in which PTFE resin is filled with carbon fiber, so if you look at the characteristics from the displacement, the change in the amount of wear will be "1 to 1".
It can be seen that a large amount of wear occurs after 2 hours, and approximately linear wear occurs between 2 and 100 hours.

Here, the wear for "1 to 2 hours" is the wear during the process of forming the transfer film, that is, initial wear, and the wear for "2 to 100 hours" is the wear after the formation of the transfer film, that is, steady wear. The condition is called the wear coefficient (amount of wear per unit time)
It is indicated by. In other words, since the wear coefficient varies depending on the composition of the material, it is possible to reduce it.

However, since initial wear is a process that leads to steady wear, it is difficult to reduce this initial wear.

Moreover, the wear coefficient becomes smaller, so the blade 2
The ratio of initial wear to the total wear of No. 1 also increases. In particular, compressors generally require reliability for 10 years or more, but if the above initial wear cannot be improved, the sealing performance will be impaired and the refrigerant will not be able to be compressed efficiently, resulting in a loss of compression performance as a compressor. .

Therefore, in order to reduce the initial wear, it is conceivable to use fluororesin as the material of the piston 11 to have the same effect as the transfer film.

However, considering the differential pressure in the working chamber 22 and the high-speed rotational movement, rigidity was required to withstand such pressure, and fluororesin, which had low rigidity, was insufficient in terms of strength and was not a fundamental solution. .

This invention was made with attention to these circumstances,
The aim is to provide a compressor with excellent durability and sealing properties.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the compressor of the present invention has blades made of fluororesin, and a spiral groove provided on the outer circumferential surface of the piston that is made of fluorine. The reason lies in the formation of a system film.

(Function) According to the compressor of the present invention, from the beginning, the piston and the blades slide against each other to perform compression operation.

This makes it possible to reduce the wear during the transfer film formation process, which has been a problem, that is, the initial wear, while maintaining the rigidity of the piston.

However, it is possible to improve the sealing performance and durability required for helical blade compressors.
The desired compressor performance can be maintained for a long period of time.

(Example) The present invention will be described below based on an example shown in FIGS. 1 to 3.

Here, since the configuration of each component of the helical blade type compressor is the same as that shown in FIGS. 6 to 16, the explanation of that part will be omitted, and in this section, the main part, the blade 21, will be explained.

In this embodiment, the blades 21 of the helical blade type compressor described in the "Prior Art" section are made of fluorocarbon resin. Further, a fluorine-based coating film is formed on the groove 19 provided on the outer circumferential surface of the piston 11, which is made of a rigid body.

In this embodiment, the coating layer 35 is provided on the wall surface of the groove 19 using, for example, dispersion processing as a fluorine-based coating method.

Here, to explain disversion processing, for example, PTFE disversion is an aqueous colloidal suspension containing fine PTFE resin powder at a concentration of 35 to 60% by weight, and if it is applied to the workpiece and baked, It is something that will be glued. Furthermore, by mixing an inorganic filler, it has the property of improving the abrasion resistance of the coating.

In this embodiment, grooves 19 having three types of coatings formed by such dispersion processing are used in Example 1 and Example 2. This is listed as Example 3.

Specifically, Example 1. Example 2. In Example 3, the blade 21 has a density of 2.15 g/c!113, for example.
A material obtained by mixing ``15% by weight'' of carbon fiber (diameter 10μ, length 100μ) with tetrafluoroethylene resin was used. In addition, the coating was coated on the groove 19 of the piston 11 with a mixture of PTFE dispersion (resin concentration 50% by weight), glass powder, molybdenum disulfide, and graphite each in an amount of 5% by weight. Three types of PTFE dispersion coatings fired and fused at 400'' CJ were used.

As a result of applying such a piston 10 and blade 21 to a helical blade type compressor shown in FIG. 6, it was confirmed that initial wear of the blade 21 was reduced and high sealing performance and durability were obtained.

Here, to explain the content of the experiment, "Freon 12" was used as the refrigerant gas in the compressor, and the cylinder 7 and piston 11 were heated to R300 by energizing the electric motor section 3.
Rotate at a speed of 0rpIIJ. Then, the suction side refrigerant pressure r0. 5kg/c4J, discharge side refrigerant pressure rlOk
g / cj
An attempt was made to measure the refrigerating capacity (unit: kcaN: calculated from the refrigerant discharge flow rate) and the amount of wear of the blade 21 when a piston 10 not subjected to FE disversion processing is combined. The measurement time is 10
It was set as 0 hours.

The results are shown in FIGS. 2 and 3.

That is, looking at FIG. 2, the comparative example in which the piston 19 is not coated has a refrigerating capacity of 65 kcag/h.
The refrigerating capacity increases only up to J, and the refrigerating capacity further decreases from 70 to 100 hours. In contrast, Examples 1 to 3
The refrigerating capacity of all the samples coated with the above coating was higher than that of the comparative example. Specifically, the one using the coating mixed with the glass powder of Example 1 is r68 keai)
/hJ, and r6 at “70 to 100 hours”
It only decreases to 5kca#/hJ. Also, Example 2
Those using a coating mixed with molybdenum disulfide of
r 70 kcaIl/hJ, Example 3
The one using a coating mixed with graphite is "73
kcafI/hJ, and no decrease in refrigeration capacity was observed even after 100 hours had elapsed.

Also, looking at FIG. 3, the piston rod 1 of the comparative example that is not coated has considerably large initial wear after 1 to 2 hours, and the wear after 100 hours is also large. On the other hand, those coated with the coatings of Examples 1 to 3 all showed smaller wear than the comparative example.Specifically, the coats coated with glass powder had less initial wear. In addition, in Examples 2 and 3, which used coatings containing molybdenum disulfide and graphite, no initial wear was observed, and 100%
There is also less wear over time.

To put this into perspective, if no treatment is applied to the grooves 19, the fluororesin blade 21 will wear out significantly and the sealing performance will deteriorate significantly, but in the case where the grooves 19 are coated with a dispersion process, It can be seen that since the piston 11 and the blade 21 slide against each other from the fluororesin from the beginning of the compression operation, the initial wear of the blade 21 is small and high sealing performance is maintained. That is, blade 2
1 and groove 19 are established.

Therefore, it is possible to improve the sealing performance and durability of the helical blade compressor, and the performance of the compressor can be maintained over a long period of time. Moreover, as shown in FIGS. 2 and 3, a coating containing the same type of filler as the filler of the blade 21 can reduce the wear (including initial wear) of the blade 21. By providing a coating, the performance of the compressor can be improved.

Further, in the above embodiment, the coating was provided in the groove 19 by dispersion processing, but the coating is not limited to this, and the coating may be provided in the groove 19 using other methods, such as enamel coating processing.

To explain this enamel coating film as another example, the difference between the enamel coating process and the above-mentioned dispersion process is that the enamel coating process uses the above-mentioned dispersion process with adhesion aids and pigments added. Baking is a coating that has high smoothness and adhesion to the base material. Therefore, even if a film formed by enamel coating is used, the same effect as in the above embodiment can be obtained.

We will now prove the point of this effect.

That is, the groove 19 having three types of coatings formed by enamel coating was formed in Example 5. This was listed as Example 6 and Example 7.

For details, see Example 5. Example 6. In Example 7, PTFE
To the enamel coating agent (resin concentration 40% by weight), for the purpose of improving wear resistance as in Examples 1 to 3 above,
A mixture of 5% by weight each of glass powder, molybdenum disulfide, and graphite was used, and this was mixed into groove 1.
9 and baked at 370℃ to 400℃.
Three types of enamel coatings were used. In addition, in all of Examples 5 to 7, the blade 21 was made of carbon fiber (diameter 10 μm) made of tetrafluoroethylene resin with a density of 2.15 g/co+3, as described above.

The material used is a mixture of 15% by weight of 100 μm in length.

Then, the piston 10 and blade 21 are
Applying the helical blade type compressor shown in the figure, the refrigerating capacity and blade 2
As a result of measuring the amount of wear of the blade 21, it was confirmed that the characteristics of the refrigerating capacity and the amount of wear of the blade 21 had the same tendency as shown in FIGS. 3 and 4. Furthermore, the enamel coating film had a larger refrigerating capacity of 1 to 2 kcaN/hJ than the above-mentioned dispersion film, and the amount of wear on the blade 21 tended to be smaller. This is because the adhesion becomes stronger.

[Effects of the Invention] As explained above, according to the present invention, since the piston and the blade are compressed from the beginning by sliding the fluororesin together, the rigidity of the piston is maintained and the wear during the transfer film formation process is reduced. can be reduced.

Therefore, a compressor with excellent durability and sealing performance can be provided.

[Brief explanation of the drawing]

Figures 1 to 3 show one embodiment of the present invention.
The figure is an enlarged sectional view of the area around the working chamber, Figure 2 is a diagram showing the refrigerating capacity when a dispersion coating is formed on the groove, along with the refrigerating capacity when the same coating is not applied, and Figure 3 is a diagram showing the refrigerating capacity when the groove is not coated. A diagram showing the amount of blade wear when a dispersion coating is formed on the grooves, along with the amount of blade wear when the same coating is not applied, and FIG. Figure 5 shows the amount of blade wear when an enamel coating is formed on the grooves, along with the amount of blade wear when the same coating is not applied. Fig. 6 is a sectional view showing a helical blade compressor, Fig. 7 is an exploded perspective view of the compressor section, Fig. 8 is a perspective view showing a piston with blades attached, and Fig. 9 is a cross-sectional view showing a helical blade type compressor. A cross-sectional view showing the Oldham mechanism that connects the cylinder, Figures 10 to 14 are cross-sectional views sequentially showing the refrigerant gas compression process, Figure 15 is a side view of the compressor, and Figure 16 shows blade wear. Figure 17 is a cross-sectional view showing the condition, Figure 17 is a diagram showing the amount of wear on a blade made of tetrafluoroethylene resin mixed with a filler, Figure 18 is a graph showing the surface roughness of a blade when glass fiber is used as a filler. FIG. 19 is a diagram showing the surface roughness of a blade when carbon fiber is used as a filler. 7... Cylinder, 8.9... Bearing, 11... Piston, 15... Oldham ring, 19... Spiral groove, 21... Blade, 35... Film layer. Figure 1 Applicant's agent Patent attorney Takehiko Suzue Daimachi T/1 (Hr) Figure 2 Bar (Hr) Ritt'+ 2b Monthly (Hr) Figure 4 (H") Figure 1 Figure 1゜Figure Figure Figure Figure Figure Figure

Claims (1)

[Claims] a cylindrical cylinder having a suction end side and a discharge end side;
A cylindrical piston is inserted eccentrically into this cylinder so that a portion of its outer circumferential surface is in contact with the inner circumferential surface of the cylinder, and a cylindrical piston is provided on the outer circumferential surface of this piston and becomes smaller as it goes from the suction side to the discharge side. a spiral groove formed with a pitch of 1, a spiral blade that can freely move in and out of the groove and is fitted so as to be in contact with the inner circumferential surface of the cylinder; In the compressor, the blade is made of a fluororesin, and the groove is coated with a fluorine-based coating. A compressor characterized by forming.