JPH0476295A - Fluid compressor - Google Patents

Abstract

PURPOSE:To hold lubricating oil in iron oxide coat for maintaining excellent wear and abrasion resistance by forming iron oxide coat made of mainly Fe3O4 on the sliding surface of at least one of sliding members, composed of iron metallic base material, opposing to each other in a compression mechanism. CONSTITUTION:When a motor section 3 is energized, a rotor 6 is rotated, and a cylinder 7 is rotated integrally with the rotor 6, and a piston 11 is rotated in the cylinder 7. In addition, a blade 21 is rotated following the rotation of the cylinder 7 and enters and comes out a spiral groove 19. When a compression section 4 is actuated, refrigerant gas is sucked into the cylinder 7, moved to an operation room 22, and compressed. In this case, the sliding surface of at least one of sliding parts of a compression mechanism, for example, a cylinder, bearing and others, at least two metallic members of which are arranged so as to slide to each other as sliding parts, is coated with iron oxide made of mainly Fe3O4(iron tetroxide).

Description

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

(Prior Art) Conventionally, fluid compressors used in refrigeration cycles of air conditioners, refrigerators, etc. generally include the Renpro type using a reciprocating piston, the Rokuri type in which a disc-shaped piston rotates eccentrically within a cylinder, etc. is used.

However, all of these types of fluid compressors have the disadvantage that the structure of the drive section such as a crankshaft that transmits rotational force to the compressor and the compressor section is complicated, and there are many parts.

Therefore, recently, a compression mechanism has been constructed by combining a cylindrical cylinder with one end on the absorption side and the other end on the discharge side, and a cylindrical piston with a spiral plate on the outer circumferential surface. A fluid compressor called a helical blade type has been proposed and put into practical use.

This type of fluid compressor includes a cylinder and a piston that is eccentrically disposed within the cylinder and is pivotable relative to the cylinder.

A spiral groove is formed on the outer peripheral surface of the piston over substantially the entire length of the piston, and a synthetic resin spiral blade is fitted into this groove.

Further, the outer circumferential surface of the plate is in close contact with the inner circumferential surface of the cylinder, and as the piston rotates relative to the cylinder, the blade slides within the spiral groove in the radial direction of the piston.

The space between the piston and the cylinder is divided into multiple spaces by blades, and the pitch of the grooves gradually decreases from one end of the piston to the other.
The volumes of the plurality of spaces also gradually become smaller from one end of the rod to the other end.

The ends of the piston and cylinder are supported at one end so as to be rotatable around the axis, and at the other end are supported by a bearing that is rotatable relative to the support means, and the axis support side of the support means. It is supported by a transmission means such as an Oldham ring that rotates and, in accordance with this rotation, rotates the support side of the rotation relative to each other without rotating.

Therefore, the fluid sucked into the space from one end of the piston is conveyed to the other end of the piston while being confined in the space, and during this time, the fluid is gradually compressed and finally reaches the piston. It is discharged from the other end.

The helical blade type fluid compressor with this configuration not only has a small number of parts and is easy to downsize due to its simple structure, but also does not require a check valve in the compression mechanism and has a small mass imbalance. It has the advantage of reducing noise and vibration during operation.

(Problem to be Solved by the Invention) However, in the compression mechanism of the conventional fluid compressor configured as described above, most of the parts except the blades are made of metal, so the cylinder and bearing, the piston and bearing, and the transmission Wear between the pin and piston in the device is a major problem.

In other words, between the cylinder and the bearing, and between the piston and the bearing, the overall length of the bearing is large and it is difficult to supply lubricating oil to the sliding surfaces, so the lubricating oil film sometimes ruptures, causing damage to the inner peripheral surface of the cylinder. Wear occurs between the outer circumferential surface of the bearing and between the outer circumferential surface of the bearing portion of the piston and the inner circumferential surface of the bearing.

Furthermore, since the sliding motion between the piston and the pin in the transmission means is a reciprocating motion while receiving the rotational torque of the piston, the sliding speed becomes zero at both ends of this reciprocating motion under large load conditions. The lubricating oil disappears from the sliding surfaces, resulting in wear of the sliding surfaces between both ends of the piston and the pin.

Therefore, in the above-mentioned helical blade type fluid compressor, when using high hardness materials such as ordinary hardened steel or high speed steel as the material for the compression mechanism, depending on the structure and sliding form of the compression mechanism, lubricating oil When fracture occurs, the amount of wear increases dramatically, especially the wear of the mating material that comes into contact with the above-mentioned high-hardness materials, which not only reduces the durability of the fluid compressor but also reduces its operating efficiency. There was a problem of being blocked.

The present invention has been made in view of the above points, and its purpose is to provide a fluid compressor that is highly durable and has a long lifespan.

[Structure of the invention] (Means for solving the problem) In order to achieve the above object, the fluid compressor of the present invention has the following features:
A cylindrical cylinder with one end on the suction side and the other end on the discharge side, and a part of the cylinder is inserted eccentrically so that the outer circumferential surface or the inner circumferential surface of the cylinder is in contact with the cylinder, and the cylinder moves relative to the above cylinder. a spiral groove formed on the outer circumferential surface of the piston with a pitch that gradually decreases from the suction side to the discharge side of the cylinder; a spiral blade fitted so as to be in contact with the circumferential surface; and support means for supporting the ends of the piston and cylinder so as to be rotatable about the axis, and for supporting the ends of the piston and the cylinder so as to be rotatable relative to the other end; and a transmission means that rotates the axis support side of the support means and relatively rotates the pivot support side while rotating on its own axis in accordance with this rotation, and the compression mechanism includes a compression mechanism that rotates the axis support side of the support means and relatively rotates the rotation support side while rotating on its axis, A helical blade fluid compressor configured to compress the fluid taken in between the blades and transfer it to the side where the pitch becomes smaller, wherein the slides made of opposing iron-based metal base materials in the compression mechanism It is characterized in that an iron oxide film containing Fe, 04 as a main component is formed on at least one sliding surface of the moving member.

(Function) In the fluid compressor of the present invention, Fe50. Even if the lubricating oil breaks, the iron oxide film retains the lubricating oil within the film and prevents abnormal wear between two opposing sliding members. It is possible to maintain excellent abrasion resistance without causing any damage.

Therefore, the fluid compressor of the present invention has excellent durability and
This is designed to extend the life of the device, allowing it to maintain excellent performance such as high operating efficiency over a long period of time.

(Example) Hereinafter, an example of the fluid compressor of the present invention will be described in detail according to the drawings.

1 to 10 show an embodiment of the fluid compressor of the present invention, FIG. 1 is a sectional view showing the entire compressor, FIG. 2 is a side view showing the compression mechanism exploded, and FIG. The figure is a perspective view of the piston and the blade, Figure 4 is a sectional view taken along the line X-X in Figure 1, and Figures 5 to 9 show the relative positions of the cylinder, piston, and blade during the compression stroke. 10 is a side view of the compression mechanism, FIGS. 11 to 14 show test modes and evaluation results in test examples of the present invention, and FIG. 11 is a cross-sectional view of the sliding member used in this test example. Figure 1-
Figure 2 is a photoelectron spectrum diagram showing the structure of the surface of the sliding member, Figure 13 is a sectional view of the friction and wear tester, and Figure 14 is a graph showing the results of the friction and wear test.

1 to 10 show an embodiment in which the present invention is applied to a hermetic compressor for compressing refrigerant gas in a refrigerant cycle.

In the drawings, a compressor 1 includes a closed case 2, an electric motor section 3 and a compressor section 4 disposed within the case.

The electric motor section 3 includes a substantially annular stator 5 fixed to the inner surface of the case 2 and an annular rotor 6 provided inside the stator.

The compressor section 4 has a cylindrical cylinder 7, and the rotor 6 is coaxially fixed to the outer peripheral surface of this cylinder.

Further, both ends of the cylinder 7 are rotatably fitted into bearings 8 and 9 as supporting means fixed to the inner surface of the end portions of the case 2, thereby airtightly closing the cylinder 7.

The right end of the cylinder 7, that is, the suction side end, is rotatably supported by a bearing 8, and the left end of the cylinder, that is, the discharge side end, is rotatably supported by a bearing 9.

Here, the bearings 8 and 9 have boss parts 8a and 9a rotatably inserted into the end of the cylinder 7, and boss parts 8a and 9a, respectively.
9a, the base 8 has a larger diameter and is fixed to the inner surface of the case 2.
b and 9b, respectively.

Therefore, the cylinder 7 and the rotor 6 fixed thereto are supported coaxially with the stator 5 by the bearings 8 and 9.

Inside the cylinder 7, a cylindrical piston 1 having a smaller diameter than the inner diameter of the cylinder is arranged along the axial direction of the cylinder 7.

This piston 1] is usually made of metal such as iron, and its central axis A is located eccentrically by a distance e with respect to the central axis B of the cylinder 7, and its outer circumferential surface is A portion is in line contact with the inner peripheral surface of the cylinder 7.

Further, a support shaft 1.2 is provided at both axial ends of the piston 1].
a and 12b, respectively, and these support shafts 12a and 12b are inserted into bearing holes 8c formed in the bearings 8 and 9.
, 9c and is rotatably inserted and supported.

As shown in FIGS. 1 to 4, one support shaft 12a of the piston 1 is formed with a prismatic portion 3 having a square cross section, and this prismatic portion 13 is provided with a rectangular long hole 14. [Oldham ring as a transmission means] 5 (see especially FIGS. 2 and 3) is installed.

That is, the Oldham ring [5] or its elongated hole [4] is fitted into the prismatic portion 13 so as to be slidable along the longitudinal direction thereof.

As shown in FIG. 2, on the outer circumferential surface of the Oldham ring 15, in the radial direction perpendicular to the long direction of the elongated hole 4,
Also, one end of a pair of pins 16 as a transmission means is implanted in a slidable manner, and these pins 16
The other end is fitted and fixed into a fitting hole 17 formed in the peripheral wall of the cylinder 7, and the piston 11 is eccentrically connected to the cylinder 7 in the radial direction.

In addition, as shown in FIG. 4, the outer end of each fitting hole]7 is
It is hermetically closed by a cap 18.

Therefore, when the electric motor section 3 is energized to rotate the cylinder 7 integrally with the rotor 6, the rotational force of the cylinder 7 is transmitted to the rotating piston 11 via the Oldham ring 5. .

Moreover, as shown in FIGS. 1 to 3, the piston 1
A spiral groove 19 is formed on the outer peripheral surface of the piston 11 and extends between both ends of the piston 11 along the axial direction.

The groove portions 19 are formed such that the pitch thereof gradually decreases from the right end to the left end of the cylinder 7 in the drawings, that is, from the suction side to the discharge side of the cylinder.

Further, the total length of the groove 19 is larger than the total length of the blade 2, which will be described later, and when the piston 11 is assembled into the cylinder 7, there is a gap between the end of the groove 19 and the end of the blade 21, as shown in FIG. 3, for example. As shown, it is desirable that a gap G be provided.

A spiral blade 21 shown in FIGS. 2 and 3 is fitted into the groove 9 of the piston 1.

The blade 21 is usually made of an elastic material such as synthetic resin, and is inserted into the groove 19 by being pushed into the groove 19 by utilizing its elasticity.

As shown in FIG. 1, the space between the inner circumferential surface of the cylinder 7 and the outer circumferential surface of the piston 11 is partitioned into a plurality of working chambers 22 by the blades 21.

In other words, each working chamber 22 is formed between two adjacent windings of the blade 2], and its shape extends from the contact point between the piston 11 and the inner peripheral surface of the cylinder 7 along the blade 21 to the next contact point. It is almost crescent-shaped, extending up to the top.

Due to the pitch of the blades 21, the volume of the working chamber 22 gradually decreases from the suction side to the discharge side of the cylinder 7.

On the other hand, a suction hole 23 extending in the axial direction of the cylinder 7 is formed through the bearing 8 that supports the suction side end of the cylinder 7. One end of this suction hole 23 is connected to the suction side end of the cylinder 7. The other end is connected to a suction pipe 24 of a freezing cycle (not shown).

Further, a discharge hole 25 is bored in the bearing 9 that supported the discharge side end of the cylinder 7. One end of this discharge hole 25 communicates with the discharge side end of the cylinder 7, and the other end is connected to the case 2.
It is open to the inside and allows compressed gas to be discharged into the case 2.

On the other hand, as shown in FIG. 1, inside the piston 1, an oil introduction passage 26 extending from the right end to approximately the middle is bored along the central axis A of the piston 1. One end of the oil introduction passage 26 opens into the oil reservoir 2a at the bottom of the case 2 through a through hole 27 formed in the bearing 8 and an introduction pipe 28, and the other end opens into a groove formed in the piston. It communicates with the basolateral part.

As a result, when the pressure inside the case 2 increases, the lubricating oil 29 stored in the oil reservoir 2a is transferred to the inlet pipe 28 and the through hole 2.
7 and the oil introduction path 26, and is introduced into the space between the bottom of the groove [9] and the blade [2].

Further, a suction groove 31 is formed on the outer circumferential surface of the suction side end of the piston 11, and this suction groove 31 extends in the axial direction of the piston 1 and is formed deeper than the spiral bay part 19. one end of which is the large diameter part 1 of the piston]1. ] The suction pipe 24 is opened at the end surface of the cylinder a, and the other end extends to a position where the inside of the working chamber 22 is also communicated with the first working chamber 22 located at the suction side end of the cylinder 7.
The refrigerant gas sucked into the cylinder 7 from the cylinder 7 is reliably introduced into the first working chamber 22 through the suction groove 31 without interruption.

Note that reference numeral 32 in the drawings indicates a discharge pipe communicating with the inside of the case 2.

Next, the operation of the fluid compressor configured as above will be explained.

First, when the electric motor section 3 is energized, the rotor 6 rotates,
As the cylinder 7 rotates integrally with the rotor 6, a relative speed difference is generated between the outer circumferential surface of the piston 11 and the inner circumferential surface of the cylinder 7 facing the piston 11 via the Oldham ring 15. The piston]] rotates within the cylinder 7, with one rotation of the cylinder 7 being one cycle.

That is, the piston 11 positioned by each of the support shafts 12a and 12b rotates and rotates at a position an eccentric distance e away from the center of the cylinder 7 and the center of the piston. In other words, the piston 11 rotates relative to the cylinder 7.

On the other hand, the blade 21 is fitted into a groove 19 spirally formed along the axial direction on the outer peripheral surface of the piston 11.
It rotates following the rotation of the cylinder 7, and rotates at substantially the same angle as the cylinder 7. Therefore, relative positional rubbing with the cylinder 7 does not substantially occur.

Therefore, as shown in FIG. 10, each point of the blade 21 moves in and out of the spiral groove 19 during one rotation.

In this way, when the compression section 4 is activated, the suction pipe 24
Refrigerant gas is sucked into the cylinder 7 through the suction hole 23, and the sucked gas passes through the introduction groove 31, and then enters the first working chamber 2 located on the most suction side of the cylinder 7.
Trapped within 2.

As shown in FIGS. 5 to 9, the sucked gas is confined in the crescent-shaped working chamber 22, and as the piston rotates, the discharge side is sequentially activated. It is transferred to the chamber 22 and compressed.

The refrigerant gas compressed in this manner is discharged into the case 2 from the discharge hole 25 formed in the bearing 9, and further discharged into the refrigeration cycle circuit through the discharge pipe 32.

When the pressure inside the case 2 increases due to the discharged refrigerant gas, the lubricating oil 29 stored inside the case is pressurized and passes through the oil introduction path 26 to the bottom of the groove 19 and the blade 2.
Since the blade 2 is introduced into the space between the working chambers 22 and 1, the blade 2 is constantly pressed in the direction in which it pops out from the groove 19 by hydraulic pressure, that is, toward the inner circumferential surface of the cylinder 7, which prevents gas leakage between the working chambers 22. can be reliably prevented.

In the fluid compressor configured as described above, the present invention provides at least two metal members such as sliding parts in the compression mechanism, such as a combination of a cylinder and a bearing, a piston and a bearing, and a combination of a pin and a piston in a transmission means. As a sliding part between which these parts are arranged so that they can slide together, an iron oxide film containing Fe3O4 (iron tetroxide) as a main component is formed on at least one sliding surface. .

That is, in the present invention, the sliding member is made of cast iron, carbon steel,
At least one sliding surface of a sliding member made of a sintered alloy steel, stainless steel, etc. or an opposing iron-based metal substrate is coated with Fe, 0. It is important to form an iron oxide film containing iron oxide as the main component.

This iron oxide film has a high hardness with an HV hardness of 1,000 or more, and has minute pores in its film structure, and has a large lubricating oil retention capacity, so it can be used under certain conditions without lubricating oil. It also exhibits excellent wear resistance without adhesion to the Fe-based metal of the mating stone.

Methods for forming such an iron oxide film include high-temperature oxidation method and steam contact method, but in order to minimize thermal deformation of the processed material of compression mechanism parts that are precisely machined with high dimensional accuracy, For this purpose, a steam contact method is preferable since it is possible to produce dense Fe, Q at a lower temperature.

The thickness of the iron oxide film mainly composed of Fe3O4 in compression mechanism parts is usually 0.001 to 10 microns,
In particular, a range of 0.004 to 1 micron is suitable.

As mentioned above, by forming an iron oxide film mainly composed of Fe5o4 on the sliding surface of at least one of the sliding members of the compression mechanism, even if the lubricating oil film is temporarily ruptured, the opposing member Abnormal wear does not occur during the process, and excellent wear resistance can be maintained.

The effects of the fluid compressor of the present invention will be further explained below with reference to test examples. For example, it can be applied not only to a compressor combined with a refrigeration cycle but also to other compressors.

In addition, the refrigerant gases that can be used are chlorofluorocane,
Needless to say, there are a wide variety of examples including hydrochlorofluorocarbon type and hydrofluorocarbon type.

(Test Example) As shown in FIG. 11, on the surface of the Fe-based metal base material 31,
A bearing 8.9 made of metal paulownia wood on which an iron oxide film 32 containing Fe3O4 as a main component was formed was prepared.

That is, by cutting spheroidized graphite cast iron FCD 45 into a predetermined bearing shape, heating this base material 31 to 350 to 450°C, and after the base material temperature stabilizes at 350 to 450°C, water vapor is sprayed onto this. An iron oxide film 32 containing Fe3O4 as a main component was formed on the surface thereof.

A part of this bearing was cut out and XPS (X
As a result of analyzing the element distribution on the surface by line photoelectron spectroscopy, it was confirmed that an iron oxide film containing Fe3O4 as the main component was formed, as shown in FIG.

Next, using a friction and wear tester as shown in FIG. 13, the seizure resistance and dynamic friction coefficient of the bearing portion +4 obtained above were evaluated.

That is, in this friction and wear tester, the shaft portion 41 is sandwiched between the bear link portions 42, 42, and the shaft portion 4 is
This device measures the load value that causes seizure and examines changes in the coefficient of dynamic friction by changing the load due to the tightening of the bearing parts 42 while rotating the bearing part 1.

Then, the above-mentioned iron oxide film was formed on the bearing, and the cast iron FC2
0 as the shaft part and bearing part, respectively,
The rotation speed of the shaft part is 29Orpm.

Assuming the load rising speed is 22.5kgf/3m1n, 25
The load was increased to 0 kg f, and the relationship between the load and the coefficient of dynamic friction and the seizure load value were investigated.

As shown by the solid line in Figure 14, this result shows that even in high load areas where the lubricating oil film breaks, the coefficient of dynamic friction can be suppressed to a low level, and in the range of loads up to 250 kgf, seizure can occur. No occurrence of this was observed.

Furthermore, as a result of a wear test under a constant load using the same equipment as above, the combination of the above members showed good wear resistance.

Moreover, in the fluid compressor shown in FIGS. 1 to 10,
Assemble the bearing with the iron oxide film formed on it as the bearing 8.9, and cast iron FC20 as the cylinder 7,
When we conducted an actual test using ``U Freon 12'' as the refrigerant gas and rotating the cylinder 7 and piston 11 at 3,000 rpm, no abnormal wear occurred even after continuous operation for over 4,000 hours. , and was able to continue operating smoothly.

On the other hand, for comparison, a bearing made of cast iron (FCD55) and
A cylinder made of cast iron (FC20) was combined as a sliding member, and the same friction and wear tester as above was used to measure the load value that causes seizure and examine changes in the coefficient of dynamic friction. As a result, the dotted line in Figure 14 As shown, the load is 140 kg
Seizing occurred at f.

In addition, when we conducted an actual machine test on a fluid compressor similar to the one above using this combination of sliding members, abnormal wear occurred between the cylinder and bearing, and sufficient operational reliability could not be obtained. Ta.

From the above results, it is clear that the fluid compressor of the present invention has high durability and reliability as a helical plate type fluid compressor.

[Effects of the Invention] As explained above, the fluid compressor of the present invention has an oxidized material containing Fe3O4 as a main component on at least one sliding surface of the sliding members made of opposing iron-based metal base materials in the compression mechanism. Because the iron coating is formed, even if the lubricating oil breaks, the iron oxide coating or lubricating oil will be retained within the film, and no abnormal wear will occur between the two opposing sliding members. , and can maintain excellent abrasion resistance.

Therefore, the fluid compressor of the present invention has excellent durability and
This is designed to extend the lifespan of the device, allowing it to maintain excellent performance such as high operating efficiency over a long period of time.

[Brief explanation of the drawing]

1 to 10 show an embodiment of the fluid compressor of the present invention, FIG. 1 is a cross-sectional view showing the entire compressor, FIG. 2 is an exploded side view of the compression mechanism, and FIG. 3 is an exploded side view of the compressor. is a perspective view of the piston and the blade, FIG. 4 is a sectional view taken along the line X-X in FIG. 1, and FIGS. 5 to 9 show the relative positions of the cylinder, piston, and blade during the compression stroke, respectively. 10 is a side view of the compression mechanism, FIGS. 11 to 14 show test modes and evaluation results in test examples of the present invention, and FIG. 11 is a sectional view of the sliding member used in this test example. , 12th
The figure is a photoelectron spectrum diagram showing the structure of the surface of the sliding member, Figure 13 is a sectional view of the friction and wear tester, and Figure 14 is a graph showing the results of the friction and wear test. 1... Fluid compressor 3... Electric motor part 4... Compression mechanism 7... Cylinder 8... Bearing 9... Bearing 11... Piston 15... Oldham ring 19... Groove part 21...Blade 22...Working chamber 31...Iron-based metal base material 32...Iron oxide film

Claims (1)

[Claims] A cylindrical cylinder with one end on the suction side and the other end on the discharge side, and a part of the outer circumferential surface of the cylinder is inserted eccentrically so that it touches the inner circumferential surface of the cylinder, and moves relative to the cylinder. a spiral groove formed on the outer circumferential surface of the piston with a pitch that gradually decreases from the suction side to the discharge side of the cylinder; A spiral blade fitted and inserted so as to be in contact with the circumferential surface, and a support means for supporting the ends of the piston and cylinder so as to be rotatable about the axis on one side and rotatably relative to the other end. and a transmission means that rotates the axis support side of the support means and relatively rotates the pivot support side while rotating on its own axis in accordance with this rotation, and the compression mechanism includes a compression mechanism that rotates the axis support side of the support means and relatively rotates the rotation support side while rotating on its axis, A helical blade type fluid compressor configured to compress the fluid taken between the blades and transfer it to the side where the pitch becomes smaller, wherein the sliding member made of an opposing ferrous metal base material in the compression mechanism A fluid compressor characterized in that an iron oxide film containing Fe_3O_4 as a main component is formed on at least one sliding surface of a moving member.