JP2011074852A - Screw compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screw compressor capable of enhancing compression performance by reducing a pressure loss at the suction of a refrigerant. <P>SOLUTION: The single screw compressor 1 includes a cylindrical-shaped screw rotor 40, a casing 30, and a gate rotor 50. The screw rotor 40 has a spiral-shaped groove 41 on an outer peripheral surface. The groove 41 has a first groove 42 located at the suction side of the refrigerant including a suction side end 41a of the groove 41. The first groove 42 is constituted of a first suction side groove 44 including the suction side end 41a, and a second suction side groove 45 located at a discharge side of the refrigerant than the first suction side groove 44. The first groove 42 is formed so that a cross-sectional area of the first suction side groove 44 is larger than a cross-sectional area of the second suction side groove 45 in the proximity of a boundary between the first suction side groove 44 and the second suction side groove 45. The boundary between the first suction side groove 44 and the second suction side groove 45 is located within a region from a suction close-out position P1 of a compression chamber to the suction side end 41a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a screw compressor.

  2. Description of the Related Art Conventionally, a screw compressor including a screw rotor having a spiral groove on an outer peripheral surface and a gate rotor configured to mesh with the screw rotor is known as a compressor used in a refrigerator.

  For example, a screw compressor disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-324601) includes a compression mechanism and a casing that houses the compression mechanism. The compression mechanism includes a screw rotor having a plurality of tooth grooves (corresponding to groove portions), a cylindrical wall that can accommodate the screw rotor, and a gate rotor having a plurality of teeth. A low-pressure refrigerant is introduced into the casing, and a low-pressure space that guides the low-pressure refrigerant to the compression mechanism and a high-pressure space into which the high-pressure refrigerant discharged from the compression mechanism flows are partitioned.

  In this screw compressor, a compression chamber is formed by the space surrounded by the inner peripheral surface of the cylindrical wall, the tooth groove of the screw rotor, and the teeth of the gate rotor. One end of the tooth groove of the screw rotor is opened to the low pressure space, and the refrigerant is sucked into the compression chamber from the opened portion.

  Furthermore, in this screw compressor, the teeth of the gate rotor move along the tooth grooves of the screw rotor as the screw rotor rotates, so that the volume of the compression chamber is expanded or reduced. Then, the refrigerant is sucked into the compression chamber from the low pressure space when the volume of the compression chamber is enlarged, and is compressed and discharged to the high pressure space by reducing the volume of the compression chamber. In this way, the screw compressor compresses the refrigerant.

  By the way, in order to improve the compression performance of the screw compressor, it is desired to reduce the pressure loss when the refrigerant is sucked.

  Then, the subject of this invention is providing the screw compressor which can improve compression performance by reducing the pressure loss at the time of the suction | inhalation of a refrigerant | coolant.

  The screw compressor which concerns on 1st invention is provided with the cylindrical screw rotor, the casing, and the gate rotor. The screw rotor has a spiral groove on the outer peripheral surface. The casing houses the screw rotor. The gate rotor meshes with the screw rotor. Further, the groove portion has a suction side groove portion. The suction side groove includes the end of the groove and is located on the refrigerant suction side. In addition, the suction side groove portion includes a first suction side groove portion including an end portion, and a second suction side groove portion positioned on the refrigerant discharge side with respect to the first suction side groove portion. Further, the suction-side groove is formed so that the cross-sectional area of the first suction-side groove is larger than the cross-sectional area of the second suction-side groove near the boundary between the first suction-side groove and the second suction-side groove. ing. In addition, the boundary between the first suction side groove and the second suction side groove is located in the region from the suction closed position to the end of the compression chamber.

  In the screw compressor according to the first aspect of the invention, the suction side groove is formed such that the cross-sectional area near the boundary of the first suction side groove is larger than the cross-sectional area near the boundary of the second suction side groove. For this reason, for example, compared with the case where the groove is formed so that the cross-sectional area of the first suction-side groove is smaller than the cross-sectional area of the second suction-side groove, the pressure loss during the suction of the refrigerant is reduced. be able to.

  Thereby, the compression performance can be improved by reducing the pressure loss during the suction of the refrigerant.

  A screw compressor according to a second invention is the screw compressor of the first invention, wherein the groove width of the first suction side groove is larger than the groove width of the second suction side groove. For this reason, for example, compared with the case where the groove width of the 1st suction side groove part is smaller than the groove width of the 2nd suction side groove part, the pressure loss at the time of the suction | inhalation of a refrigerant | coolant can be reduced.

  A screw compressor according to a third invention is the screw compressor of the first invention or the second invention, wherein the groove depth of the first suction side groove portion is larger than the groove depth of the second suction side groove portion. For this reason, for example, compared with the case where the groove depth of the 1st suction side groove part is smaller than the groove depth of the 2nd suction side groove part, the pressure loss at the time of the suction | inhalation of a refrigerant | coolant can be reduced.

  Here, the groove depth of the first suction side groove portion and the groove depth of the second suction side groove portion are the average groove depths calculated based on the respective groove depths.

  A screw compressor according to a fourth invention is the screw compressor according to any one of the first to third inventions, wherein the suction side groove depth of the first suction side groove portion is the discharge side of the first suction side groove portion. Greater than the groove depth. For this reason, for example, the pressure loss during the suction of the refrigerant can be reduced as compared with the case where the suction side groove depth in the first suction side groove portion is smaller than the discharge side groove depth in the first suction side groove portion. it can.

  A screw compressor according to a fifth aspect is the screw compressor according to any one of the first to fourth aspects, wherein the cross-sectional area of the first suction side groove portion decreases from the suction side toward the discharge side. For this reason, in this screw compressor, the pressure loss at the time of suction | inhalation of a refrigerant | coolant can be reduced.

  A screw compressor according to a sixth aspect of the present invention is the screw compressor according to any one of the first to third aspects, wherein the cross-sectional area of the first suction side groove is constant. For this reason, for example, the groove portion can be easily formed as compared with the case where the cross-sectional area changes between the suction side and the discharge side of the first suction side groove portion.

  A screw compressor according to a seventh aspect is the screw compressor according to any one of the first to sixth aspects, wherein the screw rotor is driven by a motor controlled by an inverter. For this reason, in this screw compressor, the rotational speed of the screw rotor can be adjusted.

  A screw compressor according to an eighth aspect of the present invention is the screw compressor according to any one of the first to seventh aspects, wherein the boundary between the first suction side groove and the second suction side groove is the suction closing of the compression chamber. In position. For this reason, in the groove part, a compression chamber can be formed from the boundary between the first suction side groove part and the second suction side groove part.

  In the screw compressor according to the first aspect of the present invention, the compression performance can be improved by reducing the pressure loss during the suction of the refrigerant.

  In the screw compressor according to the second aspect of the present invention, it is possible to reduce the pressure loss when the refrigerant is sucked.

  In the screw compressor according to the third aspect of the invention, it is possible to reduce the pressure loss during the suction of the refrigerant.

  In the screw compressor according to the fourth aspect of the invention, it is possible to reduce the pressure loss during the suction of the refrigerant.

  In the screw compressor according to the fifth aspect of the present invention, it is possible to reduce the pressure loss when the refrigerant is sucked.

  In the screw compressor according to the sixth aspect of the invention, the groove can be easily formed.

  In the screw compressor according to the seventh aspect of the invention, the rotational speed of the screw rotor can be adjusted.

  In the screw compressor according to the eighth aspect of the invention, the compression chamber can be formed at the groove portion from the boundary between the first suction side groove portion and the second suction side groove portion.

A sectional view of a single screw compressor concerning one embodiment of the present invention. The external appearance perspective view of the conventional screw rotor. The schematic side view of the conventional compression mechanism (a casing is abbreviate | omitted). The external appearance perspective view of the screw rotor with which the single screw compressor which concerns on one Embodiment of this invention is provided. A simplified development view of a screw rotor. In the compression mechanism, (a) a partial schematic diagram showing a state in which a conventional screw rotor and a gate rotor are meshed with each other (a casing is omitted), and (b) a screw rotor and a gate rotor of the compression mechanism according to the embodiment of the present invention. The partial schematic diagram which shows the state which has meshed | engaged (a casing is abbreviate | omitted). The external appearance perspective view of the screw rotor in a modification (A). In a compression mechanism, (a) Simplified development view of conventional screw rotor, (b) Simplified development view of screw rotor of modification (A). The external appearance perspective view of the screw rotor in a modification (A). The external appearance perspective view of the screw rotor in a modification (B).

  FIG. 1 is a cross-sectional view of a single screw compressor according to an embodiment of the screw compressor of the present invention. The single screw compressor is a compressor for refrigeration compression used in a refrigerator or the like, and is provided in a refrigerant circuit that performs a refrigeration cycle and has a function of compressing a refrigerant.

<Configuration of single screw compressor>
The single screw compressor 1 includes a compressor casing 25 and a compression mechanism 20 accommodated in the compressor casing 25.

  As shown in FIG. 1, the compressor casing 25 mainly includes a substantially cylindrical main body casing portion 26 and cover portions 27 a and 27 b fixed to both ends of the main body casing portion 26. The compressor casing 25 includes a compressor inlet 21 that sucks low-pressure gas refrigerant into the compressor casing 25, and a compressor outlet 22 that discharges high-pressure gas refrigerant compressed by the compression mechanism 20. Is provided. In the compressor casing 25, a low-pressure space S1 that guides the low-pressure gas refrigerant from the compressor suction port 21 to the compression mechanism 20 and a high-pressure space S2 into which the high-pressure gas refrigerant compressed in the compression mechanism 20 flows. It is partitioned.

  Next, before explaining the compression mechanism 20 included in the single screw compressor 1 according to the embodiment of the present invention, a conventional compression mechanism 120 before the present invention is made will be described.

<Configuration of conventional compression mechanism>
FIG. 2 is an external perspective view of the screw rotor 140 provided in the conventional compression mechanism 120. FIG. 3 is a schematic side view of the compression mechanism 120 with the casing omitted in the conventional compression mechanism 120.

  The conventional compression mechanism 120 mainly includes a casing, a screw rotor 140, and a gate rotor 150.

  The casing is a substantially cylindrical member and accommodates the screw rotor 140 and the rotating shaft 119 in a rotatable manner.

  The screw rotor 140 is disposed inside the casing. The screw rotor 140 has a rotation shaft 119, and rotates about the rotation shaft 119 by driving of a drive motor. Further, as shown in FIG. 2, a plurality of spiral grooves 141 are provided on the outer peripheral surface of the screw rotor 140. The groove portion 141 includes a first groove portion 142 including an end portion close to the suction side in the groove portion 141 (hereinafter referred to as suction side end portion 141a) and an end portion close to the discharge side in the groove portion 141 (hereinafter referred to as discharge portion). And a second groove portion 143 including a side end portion 141b). Further, the width of the groove portion 141 of the screw rotor is formed substantially the same as the width of the tooth portion 151 of the gate rotor 150.

  Further, the groove depth of the groove portion 141 of the screw rotor 140 changes along the outer peripheral surface. Specifically, the groove depth of the groove portion 141 is such that the tip end surface of the tooth portion 151 of the gate rotor 150 is always in contact with the vicinity of the suction side end portion 141a of the first groove portion 142 and the discharge side end portion of the second groove portion 143. 141b vicinity is the smallest, it becomes large as it goes to a center from both ends, and the center part is the largest. Further, the groove depth at the central portion of the groove portion 141 is formed substantially the same as the tooth height of the tooth portion 151 of the gate rotor 150. For this reason, the cross-sectional area of the screw rotor 140 increases from the suction side end portion 141 a of the first groove portion 142 toward the central portion of the groove portion 141. Therefore, the cross-sectional area of the first groove 142 near the suction side end 141a is smaller than the cross-sectional area of the first groove 142 near the suction side than the vicinity of the suction side end 141a.

  Further, the first groove 142 is provided with a suction cut portion 142a formed by cutting out the suction side end portion 141a. The suction cut portion 142a is open to a low pressure space in the compressor casing, and serves as a suction port for sucking low pressure gas refrigerant.

  The gate rotor 150 has a disk shape and is made of synthetic resin. In addition, as shown in FIG. 3, a plurality (11 in this embodiment) of tooth portions 151 are provided radially on the outer peripheral surface of the gate rotor 150. Further, two gate rotors 150 are arranged with the screw rotor 140 interposed therebetween so as to be orthogonal to the rotation shaft 119 of the screw rotor 140. Specifically, the gate rotor 150 is disposed symmetrically with respect to the rotating shaft 119 of the screw rotor 140. Further, the gate rotor 150 is disposed so that the tooth portion 151 penetrates a part of the casing and engages with the groove portion 141 of the screw rotor 140. Furthermore, a driven shaft (not shown), which is a rotating shaft, is coupled to the center of the gate rotor 150, and the gate rotor 150 rotates about the driven shaft by the drive motor. For this reason, when the screw rotor 140 rotates, the plurality of tooth portions 151 of the gate rotor 150 can sequentially mesh with the plurality of groove portions 141.

  With such a configuration, in the compression mechanism 120, a space surrounded by the inner peripheral surface of the casing, the groove portion 141 of the screw rotor 140, and the tooth portion 151 of the gate rotor 150 becomes a compression chamber. When the screw rotor 140 rotates about the rotation axis in the direction of arrow R1 shown in FIG. 3 and the gate rotor 150 rotates in the direction of arrow R2 shown in FIG. When the part 151 moves in the groove part 141 of the screw rotor 140, the gas refrigerant in the compression chamber is compressed.

  Thus, by rotating the screw rotor 140 and the gate rotor 150, the gas refrigerant in the low pressure space is sucked into the compression chamber from the suction port, and the sucked low pressure gas refrigerant is compressed and compressed in the compression chamber. A high-pressure gas refrigerant is discharged into the high-pressure space.

  Next, the compression function 20 with which the single screw compressor 1 which concerns on embodiment of this invention is provided is demonstrated.

<Configuration of compression mechanism of this embodiment>
FIG. 4 is an external perspective view of the screw rotor 40 included in the compression mechanism 20 included in the single screw compressor 1 according to the embodiment of the present invention. FIG. 5 is a simplified development view of the screw rotor 40. FIG. 6A is a schematic diagram illustrating a state where the conventional screw rotor 140 and the gate rotor 150 are engaged with each other. FIG. 6B is a schematic diagram illustrating a state where the screw rotor 40 and the gate rotor 50 included in the compression mechanism 20 included in the single screw compressor 1 according to the embodiment of the present invention are engaged with each other.

  The compression mechanism 20 mainly includes a casing 30, a screw rotor 40, and a gate rotor 50. In the compression mechanism 20, the configuration other than the screw rotor 40 is the same as that of the conventional compression mechanism 120 described above, and thus the description thereof is omitted.

  The screw rotor 40 has a substantially cylindrical shape and is accommodated in the casing 30. Further, as shown in FIG. 4, a plurality of (six in this embodiment) spiral groove portions 41 are provided on the outer peripheral surface of the screw rotor 40. Further, the screw rotor 40 is provided with a suction cut portion 42a formed by cutting out one end portion thereof, and one end (suction side end portion 41a) of the groove portion 41 includes the suction cut portion 42a. The suction cut portion 42a is opened to the low pressure space S1 in the compressor casing 25, and serves as a suction port for sucking low pressure gas refrigerant in the compression mechanism 20.

  As shown in FIGS. 4 and 5, the groove portion 41 of the screw rotor 40 is positioned on the refrigerant suction side and includes a first groove portion 42 including a suction side end portion 41a in which a suction cut portion 42a is formed. And a second groove portion 43 that is located on the refrigerant discharge side with respect to the first groove portion 42 and includes the discharge side end portion 41b. Further, the first groove portion 42 includes a first suction side groove portion 44 including the suction side end portion 41 a and a second suction side groove portion 45 located on the refrigerant discharge side with respect to the first suction side groove portion 44. Further, the first suction side groove portion 44 and the second suction side groove portion 45 are continuously arranged, and the boundary between the first suction side groove portion 44 and the second suction side groove portion 45 is the suction closing position of the compression chamber S3. It is in position P1. For this reason, the compression chamber S <b> 3 is formed in the second suction side groove 45 and the second groove 43 of the first groove 42.

  The suction closed position is a position at which the refrigerant suction process is completed and the compression process is started. Specifically, the tooth bottom 51 and the tooth side surface of the gate rotor 50 have a groove 41. It is the position where it begins to contact the inner surface of the. Further, in detail, the tooth bottom and the tooth side surface of the tooth portion 51 of the gate rotor 50 are in contact with the inner surface of the groove portion 41 through the refrigerant.

  Furthermore, in the present embodiment, the boundary between the first suction side groove 44 and the second suction side groove 45 is at the suction closing position P1 of the compression chamber S3, but is not limited thereto, and the first suction side groove and The boundary with the second suction side groove may be located in the region from the suction closing position of the compression chamber to the suction side end. The boundary position is preferably in the vicinity of the suction closed position of the compression chamber in the region.

  Further, the groove 41 has a cross-sectional area in the vicinity of the boundary in the first suction side groove 44 where the boundary between the first suction side groove 44 and the second suction side groove 45 is a reference position. It is comprised so that it may become larger than the cross-sectional area of. For this reason, as shown in FIG. 5, the first groove portion 42 is first with respect to the suction closing position P1 of the compression chamber S3 that is the boundary position between the first suction side groove portion 44 and the second suction side groove portion 45. The cross-sectional area of the first suction-side groove 44 at the position P1a near the boundary with respect to the suction-side groove 44 is larger than the cross-sectional area of the second suction-side groove 45 at the position P1b near the boundary with respect to the second suction-side groove 45. ing.

  Specifically, the groove depth W1 of the first suction side groove portion 44 is formed to be larger than the groove depth of the second suction side groove portion 45 (see FIGS. 4 and 6B). More specifically, the average value of the groove depth of the first suction side groove portion 44 calculated based on the groove depth W1 of the first suction side groove portion 44 is based on the groove depth of the second suction side groove portion 45. It is formed so as to be larger than the average value of the groove depth of the second suction side groove 45 calculated in the above. Further, the groove depth of the first suction side groove portion 44 becomes smaller from the suction side toward the discharge side. In other words, the bottom surface of the groove constituting the first suction side groove portion 44 is smoothly inclined. For this reason, the cross-sectional area of the predetermined portion in the first suction side groove 44 is larger than the cross-sectional area of the portion of the first suction side groove 44 located on the discharge side from the predetermined portion. Further, when compared with the groove depth W2 of the portion corresponding to the first suction side groove portion in the groove portion 141 of the conventional screw rotor 140, the first suction side groove portion 44 has a groove depth W1 as shown in FIG. Is getting bigger. In the present embodiment, the second suction side groove portion 45 is formed to have a groove depth similar to that of the portion corresponding to the second suction side groove portion in the groove portion 141 of the conventional screw rotor 140. Further, the groove width of the first groove portion 42 is formed to be substantially the same as the width of the tooth portion 51 of the gate rotor 50, similarly to the conventional screw rotor 140. Therefore, the cross-sectional area of the first suction side groove 44 is larger than the cross-sectional area of the portion corresponding to the first suction side groove in the conventional conventional screw rotor 140, and the cross-sectional area of the second suction side groove 45 is In the conventional screw rotor 140, the sectional area of the portion corresponding to the second suction side groove is substantially the same.

  In the present embodiment, the bottom surface of the groove constituting the first suction side groove 44 has a smooth slope so that the groove depth W1 of the first suction side groove 44 decreases from the suction side toward the discharge side. ing. However, the shape of the bottom surface of the groove constituting the first suction side groove 44 is not limited to this, and the first suction so that the suction side groove depth is larger than the discharge side groove depth in the first suction side groove portion. The side groove part should just be formed. For example, the bottom surface of the groove constituting the first suction side groove may be formed in a step shape so that the groove depth of the first suction side groove is greater than the groove depth of the second suction side groove.

  The configuration of the second groove 43 is the same as that of the portion corresponding to the second groove 143 in the groove 141 of the conventional screw rotor 140. Specifically, the groove width of the second groove portion 43 is formed substantially the same as the width of the tooth portion 51 of the gate rotor 50. That is, the groove width of the first groove portion 42 and the groove width of the second groove portion 43 have substantially the same size. Further, the groove depth of the second groove portion 43 is the smallest at the discharge side end of the second groove portion 43 so that the tip surface of the tooth portion 51 of the gate rotor 50 is always in contact, that is, the central portion of the groove portion 41, that is, It is the largest in the middle of the second groove 43. Further, the groove depth of the portion where the groove depth is the largest in the second groove portion 43 is formed to be substantially the same as the tooth height of the tooth portion 51 of the gate rotor 50. Further, the second groove portion 43 is configured such that the cross-sectional area of the portion having the largest groove depth in the second groove portion 43 is larger than the cross-sectional area of the first suction side groove portion 44.

  In the present embodiment, the rotational speed of the drive motor 65 is controlled by an inverter. For this reason, the single screw compressor 1 of this embodiment can vary the operating capacity by inverter control.

<Operation description of single screw compressor>
When the rotary shaft 19 is rotationally driven by the drive motor 65 outside the casing 30, the screw rotor 40 rotates in the direction of the arrow R1 shown in FIG. At this time, the driven shaft is rotationally driven by the drive motor, so that the tooth portion 51 of the gate rotor 50 that meshes with the spiral groove portion 41 of the screw rotor 40 also rotates. At this time, the volume of the compression chamber S3 formed by being partitioned by the inner surface of the casing 30, the groove portion 41 of the screw rotor 40, and the tooth portion 51 of the gate rotor 50 is reduced.

  By utilizing the decrease in the volume of the compression chamber S3, the refrigerant before compression introduced from the low pressure space S1 is guided to the compression chamber S3 immediately before the groove portion 41 and the tooth portion 51 are engaged with each other, and is then guided to the compression chamber S3. The refrigerant is compressed by reducing the volume of the compression chamber S3 while the groove portion 41 and the tooth portion 51 are engaged with each other, and the compressed refrigerant is compressed into the high-pressure space immediately after the groove portion 41 and the tooth portion 51 are disengaged. Discharged to S2.

  In this way, the gas refrigerant is compressed in the single screw compressor 1.

<Features>
(1)
In the above embodiment, the groove portion 41 is configured such that the cross-sectional area of the first suction side groove portion 44 is larger than the cross-sectional area of the second suction side groove portion 45. That is, in the vicinity of the boundary between the first suction side groove 44 and the second suction side groove 45, the sectional area of the first suction side groove 44 at the position P1a is larger than the sectional area of the second suction side groove 45 at the position P1b. The 1st groove part 42 is comprised so that it may become. For this reason, for example, compared with the case where the conventional screw rotor 140 in which the cross-sectional area of the first suction side groove portion is smaller than the cross-sectional area of the second suction side groove portion is employed, the pressure loss during refrigerant suction is reduced. can do.

  Thereby, the compression performance can be improved.

  Further, since the groove portion 41 may be formed so that the cross-sectional area of the first suction side groove portion 44 is larger than the cross-sectional area of the second suction side groove portion 45, a conventional processing machine (for example, a 5-axis processing machine) is used. Can be processed.

(2)
In the above embodiment, the groove depth W1 of the first suction side groove 44 is formed to be greater than the groove depth of the second suction side groove 45. For this reason, the cross-sectional area of the first suction side groove 44 can be made larger than the cross-sectional area of the second suction side groove 45.

  Thereby, the pressure loss at the time of suction | inhalation of a refrigerant | coolant can be reduced.

(3)
In the above-described embodiment, the groove depth of the first suction side groove portion 44 becomes smaller from the suction side toward the discharge side. For this reason, for example, the pressure loss during the suction of the refrigerant can be reduced as compared with the case where the groove depth on the suction side of the first suction side groove is smaller than the groove depth on the discharge side of the first suction side groove. it can.

(4)
In the above embodiment, the rotational speed of the drive motor 65 is controlled by the inverter. For this reason, the rotational speed of the screw rotor 40 can be adjusted by inverter control.

  Further, since the cross-sectional area of the first suction side groove 44 is larger than that of the conventional screw rotor 140, for example, even when the rotational speed of the screw rotor 40 is increased by inverter control, the suction of the refrigerant accompanying the increase in speed. The pressure loss at the time can be reduced.

(5)
In the above embodiment, the boundary between the first suction side groove 44 and the second suction side groove 45 is the suction closing position P1 of the compression chamber S3. For this reason, the compression chamber S <b> 3 can be formed in the second suction side groove 45 and the second groove 43 of the first groove 42.

<Modification>
(A)
In the above embodiment, the first suction side groove portion 44 is formed so that the groove depth W1 of the first suction side groove portion 44 is larger than the groove depth of the second suction side groove portion 45, so that the cross-sectional area of the first suction side groove portion 44 is the second. It is configured to be larger than the cross-sectional area of the suction side groove 45.

  Instead, the first suction side groove is formed so that the groove width of the first suction side groove is larger than the groove width of the second suction side groove. You may be comprised so that it may become larger than an area.

  Further, in the groove portion of the screw rotor, the groove width and the groove depth of the first suction side groove portion may be configured to be larger than the groove width and the groove depth of the second suction side groove portion. When such a screw rotor is employed in the compression mechanism, pressure loss during refrigerant suction can be reduced as compared with a compression mechanism employing a conventional screw rotor.

  Thereby, compression performance can be improved.

  As shown in FIGS. 7 and 8, the width of the suction cut portion 242a of the first suction side groove portion 244, that is, the suction portion groove width W3 of the first suction side groove portion 244 is the suction cut of the conventional screw rotor 140. It may be formed to be larger than the suction portion groove width W4 of the portion 142a. Hereinafter, the screw rotor 240 formed so that the suction portion groove width W3 of the first suction side groove portion 244 is larger than the suction portion groove width W4 of the suction cut portion 142a of the conventional screw rotor 140 will be described.

  The groove portion 241 of the screw rotor 240 includes a first groove portion 242 that is located on the refrigerant suction side and includes a suction cut portion 242a, and a second groove portion 243 that is located on the refrigerant discharge side with respect to the first groove portion 242. Yes.

  The first groove part 242 includes a first suction side groove part 244 and a second suction side groove part 245 located on the refrigerant discharge side with respect to the first suction side groove part 244. The first groove portion 242 is configured such that the cross-sectional area at a predetermined position of the first suction side groove portion 244 is larger than the cross-sectional area at a predetermined position of the second suction side groove portion 245. Specifically, the suction portion groove width W3 of the first suction side groove portion 244 is formed to be larger than the suction portion groove width W4 of the suction cut portion 142a of the conventional screw rotor 140 (see FIGS. 7 and 7). 8). In the first suction side groove 244, the width of the first suction side groove 244 in the direction parallel to the direction of the suction portion groove width W3 decreases from the suction side toward the discharge side, and the first suction side groove 244 and the second suction side groove 244 In the vicinity of the boundary with the suction-side groove 245, a portion corresponding to the first suction-side groove of the conventional screw rotor 140 (a portion indicated by reference numeral 144 in FIG. 8A) and a second suction-side groove (FIG. 8A). , The width in the vicinity of the boundary with the portion corresponding to 145). Therefore, the first suction side groove 244 has a larger width as shown in FIG. 8 when compared with the portion corresponding to the first suction side groove in the first groove 142 of the groove 141 of the conventional screw rotor 140. It has become. In this modification, the groove depth of the first groove portion 242 is formed so that the tip surface of the tooth portion of the gate rotor is always in contact with the screw groove 140 as in the conventional screw rotor 140. Further, the groove width of the second suction side groove portion 245 is formed to be substantially the same as the width of the tooth portion of the gate rotor, like the conventional screw rotor 140. Therefore, the cross-sectional area of the first suction side groove 244 is larger than the cross-sectional area of the portion corresponding to the first suction side groove in the first groove 142 of the groove 141 of the conventional screw rotor 140, and the second suction side groove 245. The cross-sectional area is substantially the same as the cross-sectional area of the portion corresponding to the second suction side groove in the conventional screw rotor 140 of the related art.

  The configuration of the second groove 243 is the same as that of the second groove 143 of the conventional screw rotor 140. Specifically, the groove width of the second groove portion 243 is formed substantially the same as the width of the tooth portion of the gate rotor. Further, the groove depth of the second groove portion 243 is the smallest at the discharge side end of the second groove portion 243 so that the front end surface of the tooth portion of the gate rotor is always in contact with the central portion of the groove portion 241, that is, the second portion. It is the largest in the middle of the groove 243. In addition, the groove depth of the portion having the largest groove depth in the second groove portion 243 is formed to be substantially the same as the tooth height of the tooth portion of the gate rotor.

  With this configuration, in the screw rotor 240, the groove portion 241 is configured such that the cross-sectional area of the first suction side groove portion 244 is larger than the cross-sectional area of the second suction side groove portion 245. For this reason, compared with the conventional screw rotor 140, the pressure loss at the time of the suction | inhalation of a refrigerant | coolant can be reduced.

  Thereby, compression performance can be improved.

  Further, in the groove portion 341 of the screw rotor 340, as shown in FIG. 9, the groove depth of the first suction side groove portion 344 is configured to be larger than the groove depth of the second suction side groove portion 345, and The suction part groove width of the first suction side groove part 344 may be configured to be larger than the suction part groove width of the conventional screw rotor. When such a screw rotor 340 is employed in the compression mechanism, pressure loss during refrigerant suction can be reduced as compared with a compression mechanism in which the conventional screw rotor 140 is employed.

  Thereby, compression performance can be improved.

  In FIG. 9, reference numeral 341 indicates a groove, reference numeral 342 indicates a first groove, and reference numeral 343 indicates a second groove.

(B)
In the above embodiment, the screw rotor 40 is formed with the suction cut portion 42a, and the first suction side groove portion 44 includes the suction cut portion 42a.

  Instead of this, the suction cut portion may not be formed.

  For example, as shown in FIG. 10, in the screw rotor 440 in which the suction cut portion is not formed, the groove width and groove depth of the first suction side groove portion 444 are larger than the groove width and groove depth of the second suction side groove portion 445. By forming the groove 441 to be larger, the cross-sectional area of the first suction side groove 444 can be made larger than the cross-sectional area of the second suction side groove 445. For this reason, for example, when the groove width and groove depth of the second suction side groove 445 have the same configuration as the portion corresponding to the second suction side groove in the first groove 144 of the conventional screw rotor 140, Compared to the screw rotor 140, the cross-sectional area of the first suction side groove 444 can be increased. Therefore, even in the screw rotor 440 in which the suction cut portion is not formed, the pressure loss during the suction of the refrigerant can be reduced.

  Thereby, compression performance can be improved.

  In addition, in FIG. 10, the code | symbol 442 has shown the 1st groove part and the code | symbol 443 has shown the 2nd groove part.

(C)
In the above embodiment, the groove depth of the first suction side groove portion 44 decreases as it goes from the suction side to the discharge side. For this reason, in the first suction side groove portion 44, the sectional area on the suction side is larger than the sectional area on the discharge side.

  Alternatively, as long as the cross-sectional area of the first suction side groove is larger than the cross-sectional area of the second suction side groove, the cross-sectional area of the first suction side groove may be constant. For example, when the groove depth of the first suction side groove portion is configured to maintain a predetermined groove depth, and the groove width of the first suction side groove portion is configured to maintain a predetermined groove width. The cross-sectional area of the first suction side groove can be made constant. Thus, when the cross-sectional area of the first suction side groove is constant, for example, the groove is easier than the case where the bottom surface of the first suction side groove is formed to change stepwise. Can be formed.

(D)
In the above embodiment, the rotational speed of the screw rotor 40 in which the groove 41 is formed so that the cross-sectional area of the first suction-side groove 44 is larger than the cross-sectional area of the second suction-side groove 45 is controlled by the inverter. Although applied to a screw compressor, it can also be applied to a non-inverter screw compressor whose rotation speed is not controlled by an inverter.

  Since the present invention can improve the compression performance by reducing the pressure loss at the time of sucking the refrigerant, the application to the screw compressor is effective.

1 Single screw compressor (screw compressor)
30 Casing 40 Screw rotor 41 Groove 41a Suction side end (end)
42 1st groove part (suction side groove part)
44 First suction side groove 45 Second suction side groove 50 Gate rotor

JP 2004-324601 A

Claims (8)

A cylindrical screw rotor (40) having a spiral groove (41) on the outer peripheral surface;
A casing (30) for housing the screw rotor;
A gate rotor (50) meshing with the screw rotor,
The groove portion includes an inlet side groove portion (42) that is located on the refrigerant suction side including the end portion (42a) of the groove portion,
The suction side groove is
A first suction side groove portion (44) including the end portion, and a second suction side groove portion (45) located closer to the refrigerant discharge side than the first suction side groove portion,
In the vicinity of the boundary between the first suction side groove and the second suction side groove, the cross section of the first suction side groove is larger than the cross section of the second suction side groove,
The boundary is located in a region from the suction closing position of the compression chamber (S3) to the end of the suction side groove,
Screw compressor (1). The groove width of the first suction side groove is larger than the groove width of the second suction side groove.
The screw compressor according to claim 1. The groove depth of the first suction side groove is greater than the groove depth of the second suction side groove.
The screw compressor according to claim 1 or 2. A groove depth on the suction side of the first suction side groove portion is larger than a groove depth on the discharge side of the first suction side groove portion;
The screw compressor according to any one of claims 1 to 3. The cross-sectional area of the first suction side groove is reduced from the suction side toward the discharge side.
The screw compressor according to any one of claims 1 to 4. A cross-sectional area of the first suction side groove is constant;
The screw compressor according to any one of claims 1 to 3. The screw rotor is driven by a motor controlled by an inverter.
The screw compressor according to any one of claims 1 to 6. The boundary is at the suction closed position (P1).
The screw compressor according to any one of claims 1 to 7.

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