JPH0476294A - Fluid compressor - Google Patents

Abstract

PURPOSE:To maintain excellent wear and abrasion resistance by constituting the sliding parts of a compressing mechanism in such a way that the first member at least whose surface is made of Fe compound having a specific hardness and the second member made of Fe metal are slidably combined. 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 to the cylinder 7, moved to an operation room 22, and compressed. In this case, sliding parts of a compressing mechanism, for example, a cylinder and bearing are constituted in such a way that the first member at least whose surface is made of Fe compound having hardness of Hv 400 and the second member made of Fe metal are slidably combined.

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 a reciprocating type that uses a reciprocating piston, a rotary type that rotates a disk-shaped piston eccentrically within a cylinder, etc. is used.

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

Therefore, recently, compression mechanisms have 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 blade on its 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 blade 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 grooves gradually become smaller from one end of the piston to the other, so the volume of the multiple spaces is The diameter also gradually decreases 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, which rotates and, in accordance with this rotation, rotates the swing support side relative to each other while rotating on its own axis.

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 other than the other end of the piston. It is discharged from the end.

The helical blade type fluid compressor with this configuration not only has a small number of parts and a simple structure that makes it easy to downsize, but also eliminates the need for a check valve in the compression mechanism, has a small mass imbalance, and is easy to operate. This 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 bottle and the 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 bottle in the transmission means is a reciprocating motion while receiving the piston's rotational torque, the sliding speed at both ends of this reciprocating motion is zero under large load conditions. As a result, the lubricating oil disappears from the sliding surfaces, resulting in wear of the sliding surfaces between both ends of the piston and the bottle.

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 high-hardness materials mentioned above, 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 was 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.

[Configuration 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 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 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 rotates the pivot support side relative to the axis of the piston in response to this rotation, and In the helical blade type fluid compressor configured to compress the fluid taken in between the blades by a movement of the blades and transfer it to the side where the pitch becomes smaller, at least the surface of the fluid is compressed as a sliding part in the compression mechanism. A first member made of an Fe-based compound having an Hv hardness of 400 or more, and a second member made of an Fe-based metal.
The present invention is characterized in that the first member and the second member are combined so as to be slidable.

(Function) The fluid compressor of the present invention includes, as sliding parts in a compression mechanism, a first member whose surface is made of an Fe-based compound having an Hv hardness of 400 or more, and a second member made of an Fe-based metal.
Since the first member and the second member are combined so that they slide, even if the lubricating oil breaks, abnormal wear will occur between the two members. Excellent wear resistance can be maintained without any problems.

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, 12th
The figure is a profile diagram showing the element distribution by XMA analysis on 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 89 as supporting means fixed to the inner surface of the end portions of the case 2, and are airtightly closed thereby.

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 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.
A base 8b having a larger diameter than 9a and fixed to the inner surface of the case 2
, 9b, respectively.

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

Inside the cylinder 7, a cylindrical piston 11 having a smaller diameter than the inner diameter of the cylinder is disposed along the axial direction of the cylinder 7.

This piston 11 is usually made of metal such as iron, and its central axis A is eccentrically located by a distance e with respect to the central axis B of the cylinder 7. The portion is in line contact with the inner peripheral surface of the cylinder 7.

Further, support shafts 1.2 are provided at both axial ends of the piston 11.
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 11 is formed with a prismatic portion 13 having a square cross section, and this prismatic portion 13 has a rectangular long hole 14. An Oldham ring 15 (see especially FIGS. 2 and 3) is attached as a transmission means.

That is, the Oldham ring 15 is fitted into the square column part 13 so as to be slidable along the longitudinal direction of the elongated hole 14 .

As shown in FIG. 2, on the outer circumferential surface of the Oldham ring 15, there are
This also has one end of the pair of bottles 16 as a transmission means.
Each pin is installed so that it can slide freely, and these pins 1
The other end of the piston 6 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 17 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 rotary piston 11 via the Oldham ring 15.

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 21, 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, for example, as shown in FIG. It is desirable that a gap G be provided as shown in FIG.

A spiral blade 21 shown in FIGS. 2 and 3 is fitted into the groove 19 of the piston 11. As shown in FIGS.

This blade 21 is usually made of an elastic material such as synthetic resin, and is installed in the groove 19 by screwing into the groove 19 by utilizing its elasticity. The space between the surface and the outer peripheral surface of the piston 11 is partitioned into a plurality of working chambers 22.

In other words, each working chamber 22 is formed between two adjacent windings of the blade 21, 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 shaped like an elongated crescent.

Depending on 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 refrigeration 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, inside the piston 11, as shown in FIG. One end of the passage 26 opens to 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 to the bottom of the discharge side of the groove 19 formed in the piston 11. It's communicating.

As a result, when the pressure inside the case 2 increases, the two lubricating oils stored in the oil reservoir 2a are 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 19 and the blade 21.

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 groove 19. One end thereof opens at the end face of the large diameter portion 11H of the piston 11, and the other end extends to a position where the inside of the working chamber 22 also communicates with the first working chamber 22 located at the suction side end of the cylinder 7. Therefore, the refrigerant gas sucked into the cylinder 7 from the suction pipe 24 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 starts rotating.
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 opposing thereto via the Oldham ring 15, and the cylinder 7 The piston 11 rotates within the cylinder 7 while changing with one rotation as one period.

That is, the piston 11 positioned by each support shaft 12a, 12'b is moved from the center of the cylinder 7 to the piston 11.
It rotates at a position an eccentric distance e away from the center of the axis, and rotates on its own axis. 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. Because of this, 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 first 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 1 rotates, the gas is sequentially moved to the working chamber 22 on the discharge side. It is transferred to 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 flows through the oil introduction path 26 between the bottom of the groove 19 and the blade 21. Since the blade 21 is introduced into the space, the blade 21 is constantly pressed by hydraulic pressure in the direction in which it pops out from one groove, that is, toward the inner peripheral surface of the cylinder 7.
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. A first member whose surface is made of an Fe-based compound having an Hv hardness of 400 or more, and a second member made of an Fe-based metal are used as sliding parts arranged so that these members slide together.
The present invention is characterized in that the first member and the second member are combined so as to be slidable.

In the present invention, examples of the Fe-based metal material for the second member include cast iron, carbon steel, sintered alloy steel, stainless steel, etc., which are used as sliding parts of ordinary fluid compressors. These can be used without restriction.

However, as the first member, at least the surface thereof has a high hardness made of a Fe-based compound having an Hv hardness of 400 or more;
It is important to use a material with a high melting point and low surface energy.

As the material of the first member having the above characteristics, at least one of Fe-based compounds consisting of Fe and B or N, such as Fe, 3N and Fe, epsilon iron nitride and iron boride represented by -2B, etc. It is desirable that these Fe-based compounds have low chemical activity on the surface, and - even in the absence of lubricating oil, the Fe-based compounds of the mating material can be
Since it does not adhere to e-type metals, it can exhibit excellent wear resistance.

Methods for forming such a Fe-based compound as the first member include gasification method, molten salt method, 1. Examples include electrolytic methods and powder methods, but in order to minimize thermal deformation of the processed material of compression mechanism parts that are precisely machined with high dimensional accuracy, Fe
Electrolytic methods are suitable for B-based compounds, and low-temperature electrolysis and plasma electrolysis methods are suitable for FeN-based compounds.

The thickness of the Fe-based compound layer in the compression mechanism component is usually in the range of 1 to 50 microns, particularly 2 to 20 microns, and the Fe-based compound has some toughness in the above thickness range. This can cover the brittleness of the system compound itself.

As mentioned above, by combining the sliding members of the compression mechanism with at least two members, even if the lubricating oil film is temporarily ruptured, there will be no abnormal wear between the opposing members, resulting in an excellent Abrasion resistance can be maintained.

The effects of the fluid compressor of the present invention will be further explained below with reference to test examples. However, the present invention is not limited to the above-mentioned embodiments and the test examples described below, and various modifications may be made within the scope of the present invention. For example, it can be applied not only to a compressor combined with a refrigeration cycle but also to other compressors.

Furthermore, it goes without saying that the refrigerant gas used in the 1% range is wide-ranging, such as chlorofluorocane, hydrochlorofluorocarbon, and hydrofluorocarbon.

(Test Example) As shown in FIG. 11, on the surface of the Fe-based metal base material 31,
A bearing 8.9 made of a metal material on which a boriding layer 32 mainly composed of a FeB-based compound was formed by an electrolytic method was prepared.

That is, spheroidized graphite cast iron FCD45 is cut into a predetermined bearing shape, degreased and dried with acetone, and then Na
20 SK 20, 650℃ with B2O3 as the main component
A bearing with a boriding layer formed on the surface was prepared by immersing the bearing in a molten salt of 100% and electrolyzing it for 1 hour at a current density of 0.2 A/c- relative to the surface area of the bearing.

A part of this bearing was cut out and the element distribution on the surface was analyzed by XMA analysis. As a result, the formation of a boriding layer was confirmed as shown in FIG. 12.

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

That is, in this friction and wear tester, the shaft portion 41 is sandwiched between the bearing 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, a bearing formed with the above-mentioned boriding treatment layer and a cast iron FC
20 as a shaft part and a bearing part, respectively, the rotation speed of the shaft part is 290 rpm, and the load rising speed is 22°5 kgf/3 m1n, 250 kg f.
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 FIG. 14, the results show that the dynamic friction coefficient can be kept low even when the load is high, and no seizure was observed in the range of loads up to 250 kg f.

Furthermore, the results of an abrasion test under a constant load using the same equipment as above also showed that the combination of the above members had good abrasion resistance.

Moreover, in the fluid compressor shown in FIGS. 1 to 10,
Bearing 8.9 is a bearing on which the above-mentioned boriding layer is formed,
In addition, cast iron FC20 was applied and assembled as the cylinder 7, and an actual machine test was conducted in which the cylinder 7 and piston 11 were rotated at 3.00 rpm using Freon 12 as the refrigerant gas, and the continuous operation exceeded 4,000 hours. Until then, it was possible to continue operating smoothly without any abnormal wear.

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

[Effects of the Invention] As explained above, the fluid compressor of the present invention includes, as a sliding component in the compression mechanism, a first member whose surface is made of an Fe-based compound having an Hv hardness of 400 or more;
Since the second member made of e-based metal is used and the first member and second member are combined so as to slide, even if the lubricating oil breaks, there will be no interference between the two members. No abnormal wear occurs, and excellent wear resistance can be maintained.

Therefore, the fluid compressor of the present invention has excellent durability and
It is designed to extend the life of the device, and can 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 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, 12th
The figure is a profile diagram showing the element distribution by XMA analysis on 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... Compressor■ 7... Cylinder 8... Bearing 9... Bearing 1... Piston 5... Oldham ring 9... Groove portion 1...Blade 2...Working chamber 1...Iron-based metal base material 2...Boriding layer Rokushinjin Patent Attorney Hidekazu Miyoshi 4 Figure 5 Figure 6 Figure 8 Figure 2 ] Figure 9 Figure 10 Figure 11 B Depth (μm) Figure 13 o0 Load (kgD

Claims (3)

[Claims] (1) 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 inserted into the cylinder in an eccentric state so as to be in contact with the inner circumferential surface of the cylinder. a piston that moves relative to the piston; a spiral groove formed on the outer peripheral surface of the piston with a pitch that gradually decreases from the suction side to the discharge side of the cylinder; A spiral blade inserted so as to be in contact with the inner peripheral surface of the cylinder,
Supporting means for supporting the ends of the piston and cylinder so as to be rotatable about the shaft center on one side and rotatably relative to the other end portions; It is equipped with a compression mechanism consisting of a transmission means that relatively rotates the swing support side while rotating on its own axis as the piston rotates, and compresses the fluid taken between the blades by the relative movement of the piston, while adjusting the pitch. In a helical blade type fluid compressor configured to transfer fluid to a smaller side, the sliding parts in the compression mechanism include a first member whose surface is made of an Fe-based compound having an Hv hardness of 400 or more, and an Fe-based metal. A fluid compressor characterized in that the first member and the second member are combined so as to be slidable. (2) The fluid compressor according to claim 1, wherein the first member contains at least one Fe-based compound consisting of Fe and B or N as a main component. (3) The fluid compressor according to claim 1, wherein the second member is made of at least one Fe-based metal selected from the group of cast iron, steel, and sintered alloy.