JPS60249689A - Screw compressor - Google Patents

Abstract

PURPOSE:To prevent thrust force from occurring as well as to make high-speed rotation performable in an easy manner, by making the transfer directions of gas to be transferred by two-paired screws with each other. CONSTITUTION:A sense of movement of gas to be led into a compression chamber P1 from a suction port 42 and a sense of movement of gas to be led into another compression chamber P2 from a suction port 43 are made into the sense opposed with each other. Therefore, the pressure inside both compression chambers P1 and P2 is symmetrically set up with each other in consequence so that thrust force to produced in both paired screws is offset with each other so that generation of the thrust force is prevented. Therefore, high-speed rotation is thus attainable without complicating a structure of bearings and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a screw compressor capable of improving mechanical efficiency.

[Technical background of the invention and its problems]

BACKGROUND OF THE INVENTION Various types of rotary compressors have been known in the past, but screw compressors among them have the advantage of having extremely little vibration because there is no pulsation in the discharged gas.

Typically, a screw compressor is configured as shown in FIG.

That is, in FIG. 2, 1 is a case in which a compression shaft P is formed inside, and inside this case 1, there are first and second rotors, which are arranged with their central axes parallel to each other. =
, β- are accommodated. The first rotor? - consists of a first rotating shaft 6 whose both ends are rotatably supported by a bearing 4°5 fixed to the case 1, and a first screw 7 fixed to this rotating shaft 6. There is. The screw 7 has, for example, a left-handed spiral groove 7a formed on its circumferential surface, and its outer circumferential portion is dimensioned to substantially contact the inner surface of the case 1. On the other hand, the second rotor β- has bearings 8 and 9 on one end side,
Further, it is composed of a second rotating shaft 11 whose other end is rotatably supported by a bearing 10, and a second screw 12 fixed to this rotating shaft 11. The second screw 12 is provided with a helical protrusion 12a on its circumferential surface that meshes with the helical groove 78 of the first screw 7, for example, progressing in a right-handed direction, and its outer circumference The portion is dimensioned to substantially contact the inner surface of the case 1.

The one end side of the second rotating shaft 11 extends outside the case 1, and its tip is connected to the rotor of a motor 13 for rotationally driving the rotating shaft 11.

The case 1 is provided with an inlet 14 for the compressed gas G1 at one end of the pair of screws, and an outlet 15 for the compressed gas G2 at the other end.

The screw compressor configured in this manner operates as follows. That is, the motor 13 is operated to rotate the rotating shaft 1.
1 is rotated, the screw 7 meshed with the screw 12 also rotates in the opposite direction to the direction of rotation of the rotating shaft 11.

It is now assumed that the rotating shaft 6 is rotating such that the spiral groove 78 formed on the circumferential surface of the screw 7 moves in a direction from the suction port 14 toward the discharge port 15 side. In this state, the compressed gas G flows from the suction port 14 into the compression port P.
1, this gas G1 flows into the groove 7 of the screw 7.
Since it moves along the direction a, it is transferred from the suction port 14 side to the discharge port 15 side as the groove 7a moves in the axial direction.

At this time, since the gas transfer speed is high, the gas is sufficiently compressed during this transfer process. Therefore, the high pressure gas G2 can be discharged from the discharge port 15.

However, in a conventional screw compressor of this type, the pressure at one end of the screws 7 and 12 is sufficiently higher than the pressure at the other end, so a thrust is generated in the rotating shafts 6 and 11 from the high pressure side to the low pressure side. There was a problem in that a force was generated, and a decrease in mechanical efficiency due to this thrust load could not be ignored. Due to these problems, conventional screw compressors have the disadvantage of being unable to rotate at high speeds.

[Purpose of the invention]

The present invention has been made based on the above-mentioned problems, and an object thereof is to provide a screw compressor that can improve mechanical efficiency and thereby enable high-speed rotation.

[Summary of the invention]

The present invention has two pairs of screws, each of which is coaxially arranged on a first rotor and a second rotor arranged in parallel. The two coaxial screws are provided with grooves or protrusions that run in opposite directions. The gas is transported in directions opposite to each other by the two pairs of screws.

〔Effect of the invention〕

According to the present invention, the directions of gas transferred by the two screw pairs are opposite to each other, so the direction of the thrust force generated by one pair of screws is different from the thrust force generated by the other pair of screws. are always in an opposite relationship. Therefore, both thrust forces will cancel out and the overall thrust load will disappear.

Therefore, according to the present invention, it is possible to improve mechanical efficiency,
A screw compressor capable of high-speed rotation can be provided. As a result, the compression ratio can be improved.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a typical configuration example of the present invention.
Reference numeral 1 denotes a case whose interior is hermetically sealed and is formed horizontally in the left-right direction in the figure. Inside this case 21, two compression holes Pt and P2 are formed in the axial direction due to the presence of a partition wall 22 provided at the center. Inside the case 21, first and second rotor lice and fins are accommodated.

The first rotor technique connects both ends to bearings 25, 26 fixed to both ends of the case 21 and the partition wall 22.
a first rotating shaft 28 whose center portion is rotatably supported by a bearing 27 fixed to the rotating shaft 2;
8, which is fixed to a portion located on the compression chamber Pl side
screw 31 and the compression WP2 of the rotating shaft 28.
A second screw 32 is fixed to the side portion. The first screw 31 is provided with a so-called left-handed spiral groove 31a on its circumferential surface, and is formed in a dimension relationship such that its outer circumference substantially slides on the inner surface of the case 21. In addition, the second screw 32
is formed with a spiral groove 32a having a so-called right-handed thread direction, which is opposite to that of the first screw, on its circumferential surface, and is also formed in a dimensional relationship such that its outer circumference substantially slides into contact with the inner surface of the case 21. There is.

On the other hand, the second rotor is rotatably supported at one end by bearings 33 and 34 fixed to the case 21 and at the other end by the same bearing 35, and further fixed to the partition wall 22. A second rotating shaft 37 whose central portion is rotatably supported by a bearing 36, a third screw 38 fixed to a portion of this rotating shaft 37 located on the compression chamber Pl side, and the rotating shaft 37 A fourth screw 3 fixed to a portion located on the compression chamber P2 side of
It consists of 9. The third screw 38 is provided with a spiral protrusion 38a having a right-handed thread direction and meshing with the helical groove 31a of the first screw 31 on its peripheral surface, and its outer periphery is connected to the case 21. It is formed in a dimensional relationship that substantially contacts the inner surface of the. In addition, the fourth screw 39
has the helical groove 3 of the second screw 32 on its peripheral surface.
A spiral protrusion 39a with a left-hand thread direction is provided to mesh with the case 2a, and the outer periphery thereof is also formed in a dimensional relationship such that it substantially contacts the inner surface of the case 21. In this way, the first and third screws 31.38 form one screw pair Q1, and the second and fourth screws 32.39 form another screw pair Q2. .

The one end side of the second rotating shaft 37 extends outside the case 21, and its tip is connected to a rotor (not shown) of a motor 41 for rotationally driving the rotating shaft 37.

The gas to be compressed G1 is stored in compression chambers Pt at both ends of the case 21, that is, at the left end side of the pair of screws Q1 in the figure and at the right end side of the pair of screws Q2 in the figure.

Inlets 42, 43 are provided for introducing into P2. Also, the central part of the case 21, that is, both screws Q1. Compression chamber PL is on the connection side of Q2.

Discharge port 4 for discharging compressed gas G2 from P2 to the outside
4 is provided. Note that the partition wall 22 is provided with holes 45 for eliminating the pressure difference on both sides of the partition wall 22.

Next, the operation of the screw compressor according to this embodiment configured as described above will be explained.

A compressor configured in this manner is placed, for example, between an evaporator and a condenser of a refrigeration cycle. in this case,
The inlets 42, 43 are connected to the evaporator outlet, and the outlet 44 is connected to the condenser inlet.

It is now assumed that the rotating shaft 37 is being rotated by the motor 41 in the direction of arrow A in the figure. When the rotary shaft 37 rotates in this direction, the rotary shaft 28, to which this rotation is transmitted via the pair of screws Q1 and Q2, rotates in the direction shown by arrow B in the figure. When the rotating shaft 28 rotates in this manner, the spiral groove 31a provided in the screw 31 opens the suction port 4.
2 toward the discharge port 44. On the other hand, the spiral groove 32a provided in the screw 32 moves in the direction from the suction port 43 toward the discharge port 44. Therefore, the compressed dregs Gl introduced from the suction port 42 is compressed and transferred in a direction from the suction port 42 toward the discharge port 44, and is discharged from the discharge port 44 as compressed gas G2. Further, the compressed gas G1 introduced from the suction port 43 is compressed and transferred in a direction from the suction port 43 toward the discharge port 44, and is discharged from the discharge port 44 as compressed gas G2.

In this way, according to this embodiment, the direction of movement of the gas introduced into the compression chamber P1 from the suction port 42 and the direction of movement of the gas introduced into the compression chamber P2 from the suction port 43 are opposite to each other. It is facing the direction. Therefore, the pressure in the compression chamber Pt is low on the left side of the figure and high on the right side, and the pressure in the compression chamber Pt is
The pressure inside 2 is high on the left side of the figure and low on the right side. As a result, the direction of the thrust force received by the pair of screws Ql and the direction of the thrust force received by the pair of screws Q2 are opposite to each other, and as a result, these thrust forces cancel each other out. Therefore, according to this example:
The above-mentioned effects can be achieved.

Note that the present invention is not limited to the above embodiments. For example, the first to fourth screws 31, 32.3
8.39 may be formed in a right-handed thread, a left-handed thread, a left-handed thread, and a right-handed thread, respectively.

In short, it is only necessary to satisfy the condition that the helical directions of the two coaxially arranged screws are opposite to each other. Alternatively, the rotating directions of the rotating shafts 28 and 37 in the above embodiment may be reversed, and the gas may be introduced into the case 21 from the center of the case and discharged from both ends of the case 21. In short, the present invention can be implemented with various modifications without departing from the gist thereof.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a screw compressor according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a conventional screw compressor. 1.21...Case 1, 2-1 inhibition...First rotor, support. 24... Second rotor, 6.28... First rotating shaft, 7°12, 31.32.38.39... Screw, 11.37... Second rotating shaft, 13 .41...
Motor, 14.42.43... Suction port, 15, 44.
...Discharge port, P, Pt, P2...Compression chamber, Q. Qr, G2...pair of screws, G1...gas to be compressed, G2...compressed gas. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] A first rotor is provided with a screw having a helical groove formed on its circumferential surface, and the first rotor and its rotation axis are arranged parallel to each other, and the circumferential surface is provided with a screw that meshes with the helical groove of the screw. a second rotor having a screw formed with a spiral protrusion; a pair of screws in toothed engagement with each other of the first and second rotors; In the screw compressor, gas sucked from one end side of the pair of screws as the rotor rotates is compressed and transferred in the direction of the rotation axis of the pair of screws, and is discharged from the other end side of the pair of screws. 1
The rotor and the second rotor are each configured by coaxially arranging two screws constituting the two pairs of screws, and the two screws in a coaxial relationship are provided with grooves or protrusions that advance in opposite directions to each other. . A screw compressor, wherein the directions of gas transferred by the two pairs of screws are opposite to each other.