JPH0739837B2 - Oilless compressor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rotary type oilless compressor, and more particularly to measures against leakage of high pressure fluid.

(Prior Art) Generally, a refrigerator is configured so that a refrigerant gas compressed by a compressor is liquefied by a condenser, expanded by an expansion mechanism, vaporized by an evaporator, and returned to the compressor again. ing.

As shown in FIG. 4, the compressor has a structure in which an electric motor (b) and a compressor body (c) linked to the motor (b) are housed in a closed casing (a). In the compressor body (c), a rotary piston (e) is eccentrically provided in a cylinder (d), and front and rear plates (f) and (g) are provided on both upper and lower end surfaces of the cylinder (d). A blade (not shown) is attached to the cylinder (d) so as to be retractable in the cylinder (d) and pressed against the rotary piston (e) to form a fixed blade shape. The suction port (h) of the compressor body (c) is connected to the suction pipe (i) penetrating the closed casing (a), and the discharge port (j) is connected to the casing through the discharge valve (k). It is designed to be opened in (a). Further, a discharge pipe (1) connected to a condenser is connected to the casing (a).

Therefore, in this compressor, the refrigerant gas vaporized in the evaporator is introduced into the cylinder (d) from the suction port (h) through the suction pipe (i), and the refrigerant gas is compressed by the rotation of the rotary piston (e). After that, it is discharged into the casing (a) through the discharge port (j). Then, the high pressure refrigerant gas in the casing (a) is sent to the condenser through the discharge pipe (1). In this way, the internal space of the casing has a high pressure over the entire region when the compressor is driven (called a high-pressure dome type).

In the rotary compressor configured as described above, a compressor using lubricating oil has been widely used. A rotary compressor using this lubricating oil causes the lubricating oil to enter the clearance formed between the front and rear plates (f) and (g) and the rotary piston (e) to close the clearance. The shaft hole (A) of the motor shaft (see FIG. 5) formed in the rotary piston (e) and the compression chamber (B) in the cylinder (d) are sealed. Therefore, in the cylinder (d), the leakage of the refrigerant gas from the high pressure shaft hole (A) of the rotary piston (e) to the low pressure compression chamber (B) is effectively prevented by the oil. The volume efficiency is secured.

On the other hand, in recent years, an oilless compressor that does not use the lubricating oil has been proposed, and if the conventional rotary compressor is directly applied as an oilless compressor, no oil is present in each of the clearances described above. Therefore, the sealing is not performed and the clearance still remains. Therefore, in order to close the clearance, a tip seal (m) is applied to the outer peripheral edge of the end face of the rotary piston (e) as shown in FIG. 6, and the rotary piston (e) and each plate (f), (g) are applied. The gap between and is sealed.
The tip seal (m) is formed of a ring member that is freely fitted into the rotary piston (e) and the recessed groove (n) provided along the entire circumference of the outer peripheral edge of the end face. The shaft holes (high pressure side) (A) of the rotary piston (e) and the compression chambers (low pressure side) (B) are isolated by abutting on the plates (f) and (g).

(Problems to be Solved by the Invention) However, in such a structure, as shown in the arrow in FIG. 6, since the pressure in the shaft hole (A) of the rotary piston is high when the compressor is driven. In the space formed between the tip seal (m) and the concave groove (n), the pressure strongly presses the tip seal (m) toward the plate (g) side, and friction loss of the abutting portion. However, the electric power consumption of the electric motor is increased, and the tip seal (m) is greatly worn. Further, it is difficult to completely prevent the refrigerant gas from leaking by the tip seal (m), and in particular, the compression chamber (B) is contracted by the rotation of the rotary piston (e) (direction of arrow C in FIG. 5). The refrigerant gas is then compressed, and as this compression proceeds, the boundary between the low pressure compression chamber and the shaft hole (A) of the high pressure side rotary piston (e) increases, that is, the refrigerant leakage area increases. As a result, the amount of refrigerant leakage increases and the compression efficiency decreases.

Therefore, an object of the present invention is to reduce the pressure applied to the tip seal by reducing the internal pressure of the rotary piston to reduce the leakage loss of the refrigerant gas.

(Means for Solving the Problems) Means taken by the present invention to achieve the above object are as follows.

In the invention according to claim (1), as shown in FIG. 1, the fluid compression operation is performed in the casing (2) to which the fluid suction pipe (19) and the fluid discharge pipe (20) are connected. The compression means (4) and the drive means (3) connected to the compression means (4) are housed. The compression means (4) connects the inner space of the casing (2) to the first space (9) on the drive means installation side to which the fluid suction pipe (19) is connected and the fluid suction pipe (19). Second space (10) on the side where drive means is not installed
In addition to partitioning the compression means (4) into a cylinder (5) and a rotary piston (6) in the cylinder (5), the front plate (7) is provided on the end face of the cylinder (5) on the side of the first space (9). Between the inner peripheral surface (5d) of the cylinder (5) and the outer peripheral surface (6a) of the rotary piston (6) by disposing the rear plate (8) on the end surface on the second space (10) side. It is formed by forming a compression chamber (15). Further, while forming a through hole (7a) corresponding to the shaft hole (6b) formed in the central portion of the rotary piston (6) in the front plate (7),
The rear plate (8) closes the second space (10) side of the shaft hole (6b) of the rotary piston (6). Further, an eccentric portion (3c) formed in the shaft hole (6b) of the rotary piston (6) by eccentricity in a predetermined direction from the shaft center of the drive shaft (3b) of the drive means (3) is provided on the front plate (7). Through the through hole (7a), the rotary piston (6) is eccentric with respect to the cylinder (5), and a part of its outer peripheral surface is brought into contact with the inner peripheral surface (5d) of the cylinder (5). . Further, a blade (14) which can be retracted into and from the compression chamber (15) is arranged in the cylinder (5), and the tip of the blade (14) is brought into contact with the outer peripheral surface of the rotary piston (6). The compression chamber (15) is divided into a high pressure chamber (15a) and a low pressure chamber (15b).
In addition, the end faces (6d) and (6e) of the rotary piston (6) facing the plates (7) and (8) are provided with recessed grooves (6c) over the entire circumference thereof. (6c) is provided with a tip seal (T) that closes the space between the end faces (6d) and (6e) of the rotary piston (6) and the plates (7) and (8). The suction passage (5f) communicating with the first space (9) is connected to the low pressure chamber (15b), and the discharge passage (5g) communicating with the second space (10) is connected to the high pressure chamber (15a). The rotary piston (6) is rotated in the cylinder (5) in accordance with the driving of the driving means (3), and the fluid introduced from the fluid suction pipe (19) into the first space (9) is sucked into the suction passage (5f). From the high pressure chamber (15a) after inhaling into the low pressure chamber (15b)
In the second embodiment, the fluid is discharged from the discharge passage (5g) into the second space (10) and then discharged to the outside of the casing (2) through the fluid discharge pipe (20).

The invention according to claim (2) is the oilless compressor according to claim (1), in which the blade (14) is provided in a guide groove (5e) formed in the cylinder (5), and the guide groove (5) is provided.
e) is communicated with the second space (10) so that the blade (14)
The high-pressure fluid is applied to the outer end surface (14c) of the.

The invention according to claim (3) is the oilless compressor according to claim (1) or (2), in which the tip seal (T) includes two seal rings (1) having a small diameter and a large diameter.
6) and (17).

(Operation) The operation of the present invention having the above-described configuration is as follows.

First, in the invention according to claim (1), the rotary piston (6) rotates in the cylinder (5) in accordance with the driving of the driving means (3), and the rotary piston (6) moves from the fluid suction pipe (19) to the first space (9). ) Is introduced into the low pressure chamber (15b) of the compression chamber (15) from the suction passage (5f), and then the high pressure chamber (15a).
Is compressed in the discharge passage (5g), then discharged into the second space (10) and led out of the casing (2) by the fluid discharge pipe (20). The rear plate (8) is the second space (10) of the shaft hole (6b) of the rotary piston (6).
Since it is provided so as to close the side, the side of the front plate (7) in the casing (2) is formed in the low pressure space (9) into which the low pressure fluid flows, and the shaft hole of the rotary piston (6) is formed. (6b) The inside is communicated with the low pressure space (9), while the rear plate (8) side is located in the compression chamber (15).
Is formed in the high-pressure space (10) from which the high-pressure fluid is discharged. Therefore, since the pressure inside the shaft hole (6b) is low, the tip seal (T) is attached to each plate (7), (8).
The fluid pressure to strongly pressurize is not generated, the friction loss and the wear of the tip seal are reduced, and the refrigerant leakage area becomes smaller as the compression operation of the rotary piston (6) proceeds, so the leakage amount is reduced and the volume is reduced. The efficiency can be improved.

Further, in the invention described in claim (2), since the high pressure fluid acts on the outer end surface (14c) of the blade (14), the pressing force of the blade (14) on the rotary piston (6) is increased. The effect of claim (1) can be obtained without reducing

Further, in the invention according to claim (3), the seal effect is further improved by applying the seal rings (16) and (17) having two small diameters and two large diameters to the rotary piston (6).

(Example) Next, an example of the present invention will be described with reference to the drawings.

As shown in FIG. 1, an oilless compressor (1) according to the present invention comprises a drive means (3) inside a hermetic casing (2).
And a compressor body (4) as a compression means connected to the electric motor (3a) of the drive means (3) via a crankshaft (3b) as a drive shaft. The compressor body (4) has a fixed vane shape, and a rotary piston (6) is provided in the cylinder (5). The outer peripheral surface (5a) of the cylinder (5) is fixedly supported on the inner peripheral surface (2a) of the closed casing (2), and the cylinder (5)
The front plate (7) is attached to the upper end surface (5b) of the and the rear plate (8) is attached to the lower end surface (5c) of the cylinder (5) by both plates (7) and (8). Between the rotary piston (6) and the compression chamber (1
5) has been formed. The rotary piston (6) is provided at the lower end of the crankshaft (3b) with a cam (3
c) and the needle bearing (11) to be eccentrically provided with respect to the cylinder (5), and the crankshaft (3)
b) is directly connected to the electric motor (3a), and the front and rear plates (7) and (8) respectively have bearings (1
It is rotatably supported via 2) and (13). The rotary piston (6) is provided so that a part of the peripheral surface (6a) contacts the inner surface (5d) of the cylinder (5). More specifically, the rotary piston (6) is a cylindrical member as shown in FIG. 2, and the upper and lower end surfaces (6d) and (6e) of the rotary piston (6) have an annular groove (6c) all around. Has been set up across. In addition, the recessed groove (6c) has two self-lubricating seal rings (16) each having inner and outer sides made of PTFE (polytetrafluoroethylene) or the like having high self-lubricity and excellent wear resistance.
The tip seal (T) composed of (17) is fitted. In addition, the groove (6c) and the seal rings (16), (1
A spring (18) as a pressing means is contractedly provided between the seal ring (16) and each of the seal rings (16) and (17) by the spring (18) and the front and rear plates (7) and (8). Is pressed toward (see Fig. 3),
The clearance between the plates (7) and (8) and the rotary piston (6) is closed.

A guide groove (5e) is formed in the cylinder (5), and a blade (14) is formed in the guide groove (5e) (see FIG. 2).
Are provided in the cylinder (5) so as to be retractable.
A flat plate-shaped sealing material (not shown) is interposed between the upper surface (14a) of the blade (14) and the front plate (7) to prevent refrigerant gas from leaking out. The tip of the blade (14) is pressed against the peripheral surface (6a) of the rotary piston (6) by the spring and the urging force of a high-pressure refrigerant gas described later, and the blade (14) and the rotary piston (6). ) Inside the cylinder (5), the high pressure chamber (15a) on the discharge passage (5g) side and the low pressure chamber (1) on the suction passage (5f) side
5b) and a compression chamber (15) is formed.

Further, as a feature of the present invention, in the front plate (7), the outer peripheral surface (7b) is the inner surface (2) of the casing (2).
It is attached to the upper end surface (5b) of the cylinder (5) in close contact with (a), and a through hole (7a) for the crankshaft (3b) is formed in the center. Then, the through hole (7a) is connected to the crankshaft (3b) via the bearing (12) as described above.
Is inserted into and is communicated with the shaft hole (6b) of the rotary piston (6). On the other hand, the rear plate (8) has a disk-shaped central portion formed with a recess (8a) protruding downward, and the rear plate (8) has an outer diameter larger than the inner diameter of the cylinder (5) and a casing ( 2)
It is formed smaller than the above and is attached to the lower end surface (5c) of the cylinder (5). Further, as described above, the lower end of the crankshaft (3b) is fitted into the bearing (1) in the recess (8a).
3) is fitted through the rear plate (8)
Is provided so as to close the lower part of the compression chamber (15) and the lower part of the shaft hole (6b). And the cylinder (5)
In the casing (2), the front plate (7) side serves as the first space and the low pressure space (9) serves as the first space, and the rear plate (8) side serves as the second space. The high pressure space (10) is formed, and the inside of the shaft hole (6b) of the rotary piston (6) communicates with the low pressure space (9) through the through hole (7a) of the front plate (7). Is configured to be maintained in a low pressure state. Further, the high-pressure space (10) communicates with the guide groove (5e), and the pressure of the high-pressure refrigerant acts on the outer end surface (14c) of the blade (14) inserted in the guide groove (5e). It is supposed to do.

A suction pipe (19) communicating with the low pressure space (9) and a discharge pipe (20) communicating with the high pressure space (10) are connected to the closed casing (1), while the compression chamber ( 15)
Between the low pressure chamber (15b) and the low pressure space (9) by the suction passage (5f), and between the high pressure chamber (15a) of the compression chamber (15) and the high pressure space (10) is the discharge passage (5g). ) Are communicated with each other. A reed valve (not shown) is provided at the outlet of the discharge passage (5g).

Next, the operation of the oilless compressor (1) will be described.

First, when the rotary piston (6) rotates with the driving of the electric motor (3a), the low pressure space (9) flows from the suction pipe (19).
The refrigerant gas introduced into the low pressure space (9) is sucked into the low pressure chamber (15b) through the suction passage (5f), and is compressed in the high pressure chamber (15a) as the rotary piston (6) rotates. After that, it is discharged from the discharge path (5g) into the high pressure space (10), and then discharged from the high pressure space (10) to the outside of the hermetic casing (2) through the discharge pipe (20).

Further, as a characteristic action of the present invention at the time of compression, since the shaft hole (6b) which is the internal space of the rotary piston (6) communicates with the low pressure space (9) and has a low pressure, the tip seal High pressure does not act on (T), and therefore friction loss and wear of the tip seal as in the conventional case are suppressed. Furthermore, the rotary piston (6)
As the compression due to rotation (arrow C in FIG. 2) progresses, the peripheral area of the rotary piston on the high pressure chamber (15a) side becomes smaller, so the pressure differential boundary portion with the low pressure shaft hole (6b) becomes smaller, The leakage amount of the high-pressure refrigerant is reduced, and the volumetric efficiency of the compressor (1) is improved. Further, in FIG. 3, the tip seal (T) is provided with two seal rings (16),
With the configuration of (17), the seal ring (16) and (17) enter the concave groove (6c) from the high pressure chamber (15a) side and the outer surface (6f) and the inner surface of the concave groove (6c). Pressing to (6g) improves its sealing property. This pressure also acts on each plate side, but changes as the rotary piston (6) rotates, so that high pressure does not always act, so friction loss and the seal rings (16), (17)
Wear will be significantly reduced compared to the conventional one.

(Effects of the Invention) As described above, according to the present invention, the following effects are exhibited.

In the invention according to claim (1), at the time of compression accompanying the rotation of the rotary piston, the inside of the shaft hole formed in the rotary piston is communicated with the low pressure space in the casing to have a low pressure, so Since the force that strongly presses the tip seal against each plate is suppressed, friction loss and wear of the tip seal are reduced, and the refrigerant leakage area becomes smaller as the compression progresses, so the amount of leakage is reduced. The volume efficiency is good and the performance of the compressor is improved.

In the invention according to claim (2), since the high pressure fluid acts on the outer end surface of the blade, the effect according to claim (1) can be achieved without reducing the pressing force of the blade on the rotary piston. It becomes possible to obtain.

In the invention according to claim (3), since a seal ring having two small diameters and two large diameters is applied to the rotary piston, high pressure penetrates into the groove to strongly press each seal ring to the side surface of the groove. Therefore, the sealing effect between the inside and the outside of the rotary piston is further improved.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a longitudinal sectional view showing the internal structure of a compressor, FIG. 2 is a transverse sectional view of a compressor body, and FIG. 3 is a rotary piston. FIG. 6 is a vertical cross-sectional view showing a state in which the tip seal is fitted in the concave groove of FIG. 4 to 6
The drawing shows a conventional example, FIG. 4 is a drawing corresponding to FIG. 1, FIG. 5 is a drawing corresponding to FIG. 2, and FIG. 6 is a drawing corresponding to FIG. (1) ... oilless compressor, (2) ... hermetic casing, (3) ... drive means, (3b) ... crankshaft (drive shaft), (3c) ... cam (eccentric part), ( 4) ...... Compressor body (compression means), (5) ...... Cylinder, (5d) ...... Inner surface, (5e) ...... Guide groove, (5f) …… Suction path, (5g) ……
Discharge path, (6) …… Rotary piston, (6a) …… Peripheral surface, (6b) …… Shaft hole, (6c) …… Concave groove, (6d), (6e)
…… End face, (7) …… Front plate, (7a) …… Through hole, (8) …… Rear plate, (9) …… Low pressure space (first space), (10) …… High pressure space (first 2 spaces), (1
4) ... Blade, (14c) ... Outer end surface, (15) ... Compression chamber, (15a) ... High pressure chamber, (15b) ... Low pressure chamber, (T) ...
… Chip seal, (16) …… Small diameter seal ring, (17)
…… Large-diameter seal ring, (19) …… Suction pipe.

Claims (3)

[Claims] 1. A casing (2) in which a fluid suction pipe (19) and a fluid discharge pipe (20) are connected to each other, and a compression means (4) for performing a compression operation of a fluid and a communication means with the compression means (4). The drive means (3) is housed therein, and the compression means (4) has a space inside the casing (2) in which the fluid suction pipe (19) is connected to the drive means arranged side first space (9). And the fluid discharge pipe (20) are connected to the second space (10) on the side where the driving means is not disposed, the rotary piston (6) is housed in the cylinder (5), and the cylinder ( The front plate (7) is arranged on the end surface of the first space (9) side of 5) and the rear plate (8) is arranged on the second space (10) side end surface of the cylinder (5). 5d)
A compression chamber (15) is formed between the rotary piston (6) and the outer peripheral surface (6a) of the rotary piston (6). The front plate (7) is formed at the center of the rotary piston (6). The through hole (7a) corresponding to the shaft hole (6b) is formed, while the rear plate (8) is formed.
Seals the second space (10) side of the shaft hole (6b) of the rotary piston (6). The shaft hole (6b) of the rotary piston (6) has the drive shaft of the drive means (3). An eccentric part (3c) formed eccentrically in a predetermined direction from the axis of (3b) is inserted through the through hole (7a) of the front plate (7), and the rotary piston (6) is inserted in the cylinder (5). It is eccentric with respect to the outer peripheral surface (6a) of which part is in contact with the inner peripheral surface (5d) of the cylinder (5), and the cylinder (5) can be retracted into the compression chamber (15). A blade (14) is provided, and the blade (14)
The tip of the abutting contact with the outer peripheral surface of the rotary piston (6), the compression chamber (15) is divided into a high pressure chamber (15a) and a low pressure chamber (15b), and each of the plates (7) and (8) is A concave groove (6c) is formed on the end faces (6d) and (6e) of the opposing rotary piston (6) over the entire circumference thereof, and the rotary piston (6) is formed in the concave groove (6c). Is provided with a tip seal (T) that closes the space between the end faces (6d) and (6e) of the plate and the plates (7) and (8), and the low pressure chamber (15b) has the first space ( A suction passage (5f) communicating with 9) and a discharge passage (5g) communicating with the second space (10) are connected to the high pressure chamber (15a), respectively, and are driven by the driving means (3). The rotary piston (6) rotates in the cylinder (5), and the fluid introduced from the fluid suction pipe (19) into the first space (9) is sucked from the suction passage (5f) into the low pressure chamber (15).
After being sucked into b), it is compressed in the high pressure chamber (15a), then discharged from the discharge passage (5g) into the second space (10) and discharged to the outside of the casing (2) through the fluid discharge pipe (20). An oilless compressor characterized by being 2. The oilless compressor according to claim 1, wherein the blade (14) is provided in a guide groove (5e) formed in the cylinder (5), and the guide groove (5e) is a second groove. The outer end surface (14c) of the blade (14) communicating with the space (10)
An oilless compressor characterized in that a high-pressure fluid acts on the compressor. 3. The oilless compressor according to claim 1 or 2, wherein the tip seal (T) comprises two seal rings (16) and (17) having a small diameter and a large diameter. An oilless compressor that is characterized by