Screw Compressor

Abstract

To provide a screw compressor capable of reducing acceleration loss of a working medium and compressing the working medium with high energy efficiency.SOLUTION: A screw compressor compresses a working medium sucked in from a suction opening and discharges the working medium from a discharge opening. The screw compressor is provided with: a male rotor and a female rotor, which rotate while meshing with each other; a casing in which the male rotor and the female rotor are received and which is provided with a bore for forming a working chamber for compressing the working medium together with the male rotor and the female rotor; a drive unit that rotationally drives at least one of the male rotor and the female rotor; a working chamber closing part that forms a suction port for sucking the working medium into the working chamber and closes the working chamber when the working chamber becomes a predetermined capacity; and a suction space that provides communication between the suction opening and the suction port. An open space for providing communication between the suction opening and the suction port is provided between a shaft portion of the male rotor and a shaft portion of the female rotor, which are on the opposite side from the male rotor and the female rotor with respect to the suction port.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention is suitable for application to various screw compressors, such as injection-type screw compressors in which a cooling medium such as oil or water is injected during compression operation, as well as dry-type screw compressors in which no cooling medium is injected. [Background technology]

[0002] A known invention relating to a screw compressor is the screw compressor disclosed in Patent Document 1. This screw compressor is configured so that a connecting portion is provided to connect a rotor casing and a main body casing, an intake port is located on the side of the main body casing, and an intake port is an axial intake port located at the end of the rotor casing in the axial direction of the screw rotor.

[0003] With this configuration, since the connecting portion is disposed in the suction space to connect the rotor casing and the main casing, it is possible to prevent the rotor casing from vibrating significantly during operation of the screw compressor without significantly increasing manufacturing costs. In other words, it is possible to reduce vibration during operation of the screw compressor, thereby preventing performance degradation and damage, and it is also possible to eliminate the need to increase the thickness of the main casing as a vibration countermeasure.

[0004] As a result, with this screw compressor, it is possible to eliminate the need to increase the rigidity of the main casing by adding parts, thereby reducing vibration during operation of the screw compressor and preventing performance degradation and damage without significantly increasing manufacturing costs. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-8509 Summary of the Invention [Problem to be solved by the invention]

[0006] Screw compressors are widely used as air compressors and compressors for refrigeration and air conditioning. Accordingly, there is a strong demand for energy-saving screw compressors, and high energy efficiency and large air volume (high capacity) are becoming increasingly important. In this case, in order to achieve downsizing for cost reduction in injection-type screw compressors, it is unavoidable to increase the speed at which the working medium is sucked into the working chamber.

[0007] On the other hand, dry screw compressors cannot expect any sealing effect from the cooling medium inside the working chamber, so they operate at high speeds of over 10,000 revolutions per minute to reduce leakage loss of the working medium inside the working chamber.In other words, from the perspective of high energy efficiency, the higher the operating speed, the more rapidly the working medium flowing into the working chamber is accelerated, so if the working medium cannot be sucked into the working chamber smoothly, there is a problem that acceleration loss of the working medium increases.

[0008] The present invention has been made in consideration of the above points, and aims to propose a screw compressor that can reduce the acceleration loss of the working medium and compress the working medium with high energy efficiency. [Means for solving the problem]

[0009] In order to solve this problem, the present invention provides a screw compressor that compresses a working medium sucked from a suction port and discharges the compressed working medium from a discharge port, in which the working medium is intermeshed with the screw shafts. A shaft portion connected to the tooth portion is provided.The compressor comprises a male rotor and a female rotor, a casing provided with a bore that houses the male rotor and the female rotor and forms a working chamber for compressing the working medium together with the male rotor and the female rotor, a working chamber closing part that forms a suction port for drawing the working medium into the working chamber and closes the working chamber when the working chamber reaches a predetermined volume, and a suction space that communicates between the suction port and the suction port, and an open space that communicates between the suction space and the suction port is provided between the shaft part of the male rotor and the shaft part of the female rotor on the opposite side of the male rotor and the female rotor with respect to the suction port. The working chamber closing portion is provided between the shaft portion of the male rotor and the shaft portion of the female rotor, and separates the open space into the male rotor side and the female rotor side. A first recess in an arc shape having a diameter larger than that of the shaft portion is formed at a portion of the male rotor facing the shaft portion, and a second recess in an arc shape coaxial with the female rotor and having a diameter larger than that of the shaft portion is formed at a portion of the female rotor facing the shaft portion. , At least one of the first and second recesses is formed so that its curvature increases in the direction of rotation of the shaft portion of the opposing male rotor or the shaft portion of the opposing female rotor. I did so.

[0010] According to the screw compressor of the present invention, the flow resistance of the working medium sucked in through the suction port is small, allowing the working medium to be sucked smoothly into the working chambers. As a result, when the male rotor and the female rotor are rotating at high speed, the working medium is not decelerated when it flows into the working chambers, so the energy required to accelerate the working medium is reduced, thereby improving the energy efficiency of the screw compressor. On the other hand, when the male rotor and the female rotor are rotating at low speed, the flow rate of the working medium can be increased due to the reduced suction resistance of the working medium. [Effects of the Invention]

[0011] In order to solve the above problem, the present invention provides a screw compressor that compresses a working medium sucked in through a suction port and discharges the compressed working medium from a discharge port, the screw compressor comprising: a male rotor and a female rotor having teeth that mesh with each other and a shaft connected to the teeth; a casing that houses the male rotor and the female rotor and that has a bore that forms a working chamber for compressing the working medium together with the male rotor and the female rotor; and a suction port that sucks the working medium into the working chamber. and a surface formed on the suction port and facing an end surface on one axial end side of the male rotor and the female rotor. a working chamber closing member, and a suction space communicating between the suction port and the suction port; 、 and the suction port And, before The shaft of the male rotor and the shaft of the female rotor with An open space communicating between the suction space and the suction port is provided between the working chamber closing portion and the working chamber closing portion. Material is provided between the shaft portion of the male rotor and the shaft portion of the female rotor, and separates the open space into the male rotor side and the female rotor side, and is provided at a portion of the male rotor facing the shaft portion from the shaft portion. Also large A first recess having an arc shape and a large diameter is formed. 、 The female rotor has a portion facing the shaft portion. Current From the shaft Also large and a second recess having an arcuate shape and a large diameter is formed in the male rotor, and at least one of the first and second recesses is formed in the male rotor. The aforementioned The shaft portion or the shaft portion of the female rotor is formed so that the curvature increases in the direction of rotation. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing the configuration of a screw compressor according to a first embodiment. [Figure 2] 1 is a cross-sectional view (view taken along the arrow AA in FIG. 1) showing the configuration of a screw compressor according to a first embodiment. [Figure 3] 1 is a cross-sectional view (view taken along arrow BB in FIG. 1) illustrating the configuration of a screw compressor according to a first embodiment. [Figure 4] 1 is a cross-sectional view (view taken along arrow CC in FIG. 1) illustrating the configuration of a screw compressor according to a first embodiment. [Figure 5] FIG. 1 is a cross-sectional view showing an example of the configuration of a conventional screw compressor. [Figure 6] FIG. 3 is a cross-sectional view showing the configuration of a conventional screw compressor corresponding to FIG. 2. [Figure 7] 1. FIG. 3 is a cross-sectional view showing the configuration of a screw compressor according to a second embodiment, corresponding to a view taken along the CC arrow in FIG. [Figure 8] 1. FIG. 4 is a cross-sectional view showing the configuration of a screw compressor according to a third embodiment, corresponding to a view taken along the CC arrow in FIG. [Figure 9] 1. FIG. 4 is a cross-sectional view showing the configuration of a screw compressor according to a fourth embodiment, corresponding to a view taken along the CC arrow in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the present invention will be described in detail below with reference to the drawings.

[0014] (1) First embodiment Figures 1 to 4 show a screw compressor according to a first embodiment. Figure 1 is a view taken along the arrow DD in Figure 2, Figure 2 is a view taken along the arrow AA in Figure 1, Figure 3 is a view taken along the arrow BB in Figures 1 and 2, and Figure 4 is a view taken along the arrow CC in Figures 1 and 2.

[0015] As shown in FIGS. 1 and 2, a screw compressor 1 of this embodiment is configured to include a male rotor 2 and a female rotor 3 which are screw rotors, and a casing 4 that houses the male rotor 2 and the female rotor 3.

[0016] The male rotor 2 is configured with a toothed portion 2A provided with a plurality of (four in this embodiment) spirally extending teeth 2AA (FIGS. 3 and 4), a suction-side shaft portion 2B connected to one axial end of the toothed portion 2A (left side in FIGS. 1 and 2), and a discharge-side shaft portion 2C connected to the other axial end of the toothed portion 2A (right side in FIGS. 1 and 2). The suction-side shaft portion 2B of the male rotor 2 is rotatably supported by a suction-side bearing 5, and the discharge-side shaft portion 2C of the male rotor 2 is rotatably supported by a discharge-side bearing 7.

[0017] Similarly, the female rotor 3 is configured with a toothed portion 3A provided with a plurality of (six in this embodiment) spirally extending teeth 3AA (FIGS. 3 and 4), a suction-side shaft portion 3B connected to one axial end of the toothed portion 3A, and a discharge-side shaft portion 3C connected to the other axial end of the toothed portion 3A. The suction-side shaft portion 3B of the female rotor 3 is rotatably supported by a suction-side bearing 6, and the discharge-side shaft portion 3C of the female rotor 3 is rotatably supported by a discharge-side bearing 8.

[0018] The suction-side shaft 2B of the male rotor 2 is connected to the rotary shaft 9B of a motor 9A that penetrates the casing 4 and constitutes the drive unit 9. As a result, by driving the motor 9A, the male rotor 2 can be rotated integrally with the rotary shaft 9B of the motor 9A, and further, the engagement of the teeth 2A of the male rotor 2 with the teeth 3A of the female rotor 3 can also rotate integrally with the male rotor 2. However, when driving the screw compressor 1, either the male rotor 2 or the female rotor 3 may be driven. Alternatively, the male rotor 2 and the female rotor 3 may be synchronized and both driven by the motor.

[0019] The casing 4 is composed of a main casing 10 and a D casing 11 connected to the other end of the main casing 10 in the rotor shaft direction (the right side in Figures 1 and 2). The D casing 11 is formed with a discharge port 11A located radially outward (lower side in Figure 1) of the tooth portion 2A of the male rotor 2 and the tooth portion 3A of the female rotor 3, and a discharge path 11B formed to connect the discharge port 11A and a working chamber described below.

[0020] 3, the main casing 10 is formed with a bore 10A that houses the teeth 2A of the male rotor 2 and the teeth 3A of the female rotor 3. The bore 10A is a space having a shape in which two cylindrical holes partially overlap each other, and that houses the teeth 2A of the male rotor 2 and the teeth 3A of the female rotor 3 in an intermeshed state.

[0021] A working chamber is formed by the inner wall surface of the bore 10A, the tooth grooves 2AB (FIGS. 3 and 4) of the male rotor 2, and the tooth grooves 3AB (FIGS. 3 and 4) of the female rotor 3. The working chamber is formed so that its volume gradually decreases from one side (the left side in FIG. 1 and FIG. 2) to the other side (the right side in FIG. 1 and FIG. 2) in the rotor axial direction. As a result, a working medium such as air sucked in through the suction port 12 is gradually compressed in the working chamber and discharged from the discharge port 11A via the discharge path 11B.

[0022] The suction port 12 is formed in the main casing 10 radially outward of the tooth portion 2A of the male rotor 2 and the tooth portion 3A of the female rotor 3 (upper side in Figure 1). As shown in Figures 1 and 2, the suction port 12 communicates with the suction port via the suction space 13, and the working medium sucked through the suction port 12 is sucked into the working chamber via the suction space 13 and the suction port in that order. The suction port is a port provided on a plane perpendicular to the axial direction of the male rotor 2 and the female rotor 3, and includes an end face on one end of the tooth portion 2A of the male rotor 2 in the bore 10A in the rotor axial direction and an end face on one end of the tooth portion 3A of the female rotor 3 in the rotor axial direction.

[0023] A plate-shaped working chamber closing member 14 is arranged in the suction port so as to close the end face on one end of the tooth portion 2A of the male rotor 2 and the end face on one end of the tooth portion 3A of the female rotor 3 (to close the working chamber) when the working chamber reaches its maximum capacity. In practice, the working chamber closing member 14 is arranged between the suction side shaft portion 2B of the male rotor 2 and the suction side shaft portion 3B of the female rotor 3 so that one face 14A (hereinafter referred to as the rotor facing face) that faces the end face on one end of the rotor axial direction of the tooth portion 2A of the male rotor 2 and the end face on one end of the rotor axial direction of the tooth portion 3A of the female rotor 3 is positioned on the suction port.

[0024] Furthermore, on the opposite side of the suction port from the male rotor 2 and female rotor 3, at a portion of the working chamber closing member 14 facing the suction side shaft 2B of the male rotor 2, there is formed an arc-shaped recess 14C that is coaxial with the suction side shaft 2B (centered at the center of the rotor shaft of the male rotor 2) and has a diameter (radius) that is somewhat larger than that of the suction side shaft 2B. This forms a space 15A of a certain size (hereinafter referred to as the male rotor side open space) between the suction side shaft 2B of the male rotor 2 and the recess 14C of the working chamber closing member 14.

[0025] Similarly, an arc-shaped recess 14D is formed in the working-chamber closing member 14 at a location facing the suction-side shaft 3B of the female rotor 3. The arc-shaped recess 14D is coaxial with the suction-side shaft 3B (centered on the center of the rotor shaft of the female rotor 3) and has a diameter that is somewhat larger than that of the suction-side shaft 3B. This forms a space 15B of a certain size (hereinafter referred to as the female rotor-side open space) between the suction-side shaft 3B of the female rotor 3 and the recess 14D of the working-chamber closing member 14.

[0026] In this case, the diameters of the recesses 14C and 14D of the working chamber closing member 14 are set to the same as those of the male rotor 2 and the female rotor 3 so as to be able to close the working chambers. The root is the radius of the tooth base The radius is selected to be smaller than the radius of the suction side shaft portion 2B of the male rotor 2 and the suction side shaft portion 3B of the female rotor 3.

[0027] Furthermore, on the other side 14B (hereinafter referred to as the anti-rotor facing side) of the working chamber closing member 14 opposite the rotor facing side 14A, there is provided an open space 15C (hereinafter referred to as the motor side open space) which is located between the suction side shaft portion 2B of the male rotor 2 and the suction side shaft portion 3B of the female rotor 3 and which is connected to both the suction space 13 and the male rotor side open space 15A and the female rotor side open space 15B.

[0028] In the following description, this motor-side open space 15C, the male rotor-side open space 15A, and the female rotor-side open space 15B will be collectively referred to as the open space 15. This open space 15 is a section that connects the suction space 13 located outside the suction-side shaft portion 2B of the male rotor 2 and the suction space 13 located outside the suction-side shaft portion 3B of the female rotor 3 with the suction port.

[0029] 5 and 6, in which parts corresponding to those in FIGS. 2 and 4 are indicated by the same reference numerals with a prime ('), show the structure of parts corresponding to those in FIGS. 2 and 4 in a conventional screw compressor 1'. As is clear from FIGS. 5 and 6, in the conventional screw compressor 1', the working chamber closing portion 16 corresponding to the working chamber closing member 14 of this embodiment is provided on the opposite side of the rotor facing surface 16A. Motor sideThere is no space similar to the open space 15C, Motor side An operating chamber closing portion 16 is formed integrally with the main casing 10' so as to completely fill the portion corresponding to the open space 15C.

[0030] In addition, in the conventional screw compressor 1', an arc-shaped recess 16B is formed coaxially with the suction side shaft portion 2B' of the male rotor 2' at a position facing the suction side shaft portion 2B' of the working chamber closing portion 16, but the diameter of this recess 16B is ´ The clearance 16 is selected so as not to interfere with the rotation of the suction-side shaft portion 2B' of the male rotor 2'. Therefore, only a minute gap is formed between the working chamber closing portion 16 and the suction-side shaft portion 2B' of the male rotor 2', and no space like the male rotor-side open space 15A (FIG. 4) of the screw compressor 1 of this embodiment exists.

[0031] Similarly, in the conventional screw compressor 1', the female rotor 3 in the working chamber closing portion 16 ´ Suction side shaft 3B ´ Although an arc-shaped recess 16C is formed coaxially with the suction-side shaft portion 3B' at a location facing the working chamber closing portion 16, the diameter of this recess 16C is selected so as not to interfere with the rotation of the suction-side shaft portion 3B' of the female rotor 3'. Therefore, only a minute gap is formed between the working chamber closing portion 16 and the suction-side shaft portion 3B' of the female rotor 3', and no space like the female rotor-side open space 15B (FIG. 4) of the screw compressor 1 of this embodiment exists.

[0032] In a conventional screw compressor 1' having such a configuration, the working medium sucked in through the suction port flows into the screw compressor 1' via suction spaces 13' located outside the suction-side shaft portion 2B' of the male rotor 2' and suction spaces 13' located outside the suction-side shaft portion 3B' of the female rotor 3'. However, the flow of the working medium flowing through these suction spaces 13' is blocked by the working chamber closing portion 16, which increases the flow resistance within the suction spaces 13' and inhibits the working medium from being sucked into the working chambers.

[0033] On the other hand, in the screw compressor 1 of this embodiment, as in the conventional screw compressor 1′, the working medium sucked in from the suction port 12 flows into the screw compressor 1 via a spatial portion of the suction space 13 that is located outside the suction-side shaft portion 2B of the male rotor 2 and a spatial portion that is located outside the suction-side shaft portion 3B of the female rotor 3. In this case, the working medium flowing through these spatial portions of the suction space 13 flows into the open space 15 consisting of the male rotor-side open space 15A, the female rotor-side open space 15B, and the motor-side open space 15C. Therefore, the flow of the working medium that flows into the screw compressor 1 via the spatial portion of the suction space 13 that is located outside the suction-side shaft portion 2B of the male rotor 2 and the spatial portion of the suction space 13 that is located outside the suction-side shaft portion 3B of the female rotor 3 is not blocked by the working chamber closing member 14.

[0034] Then, part of the working medium that has flowed through the space portion of the suction space 13 that is located outside the suction side shaft portion 2B of the male rotor 2 collides with the side surface of the working chamber closing member 14 facing the male rotor 2, and then passes through the male rotor side open space 15A between the recess 14C of the working chamber closing member 14 and the suction side shaft portion 2B of the male rotor 2, flows through the suction space 13 and the open space 15 so as to rotate around the suction side shaft portion 2B of the male rotor 2 in the same direction as the rotational direction of the suction side shaft portion 2B (the rotational direction indicated by arrow a in Figure 4), and is eventually sucked into the working chamber through the suction port.

[0035] The remaining working medium collides in the motor side open space 15C with the working medium that has flowed through the space portion of the suction space 13 located outside the suction side shaft portion 3B of the female rotor 3, and then flows through the suction space 13 and the open space 15 so as to rotate around the suction side shaft portion 2B of the male rotor 2 in the same direction as the rotational direction of the suction side shaft portion 2B, and is eventually sucked into the working chamber through the suction port.

[0036] Similarly, a portion of the working medium that has flowed through the space portion of the suction space 13 located outside the suction side shaft 3B of the female rotor 3 collides with the side surface of the working chamber closing member 14 on the female rotor 3 side, and then passes through the female rotor side open space 15B between the recess 14D of the working chamber closing member 14 and the suction side shaft 3B of the female rotor 3, and flows through the suction space 13 and open space 15 so as to rotate around the suction side shaft 3B of the female rotor 3 in the same direction as the rotation direction of the suction side shaft 3B (the direction indicated by arrow b in Figure 4), and is eventually sucked into the working chamber through the suction port.

[0037] The remaining working medium collides in the motor side open space 15C with the working medium that has flowed through the space portion of the suction space 13 located outside the suction side shaft portion 2B of the male rotor 2, and then flows through the suction space 13 and the open space 15 so as to rotate around the suction side shaft portion 3B of the female rotor 3 in the same direction as the rotational direction of the suction side shaft portion 3B, and is eventually sucked into the working chamber through the suction port.

[0038] Therefore, according to the screw compressor 1 of this embodiment, the open space 15 consisting of the male rotor side open space 15A, the female rotor side open space 15B, and the motor side open space 15C is provided, so that the flow resistance of the working medium sucked in from the suction port 12 is less than that of the conventional screw compressor 1', and the working medium can be sucked into the working chamber more smoothly.

[0039] As a result, when the male rotor 2 and the female rotor 3 are rotating at high speeds, the working medium is not decelerated even when it flows into the working chambers, so the energy required to accelerate the working medium is reduced, improving the energy efficiency of the screw compressor, while even when the male rotor 2 and the female rotor 3 are rotating at low speeds, the flow rate of the working medium can be increased as the suction resistance of the working medium is reduced. Therefore, with this screw compressor 1, the acceleration loss of the working medium is reduced and the working medium can be compressed with high energy efficiency.

[0040] (2) Second embodiment Figure 7, in which parts corresponding to those in Figure 4 are indicated by the same reference numerals or the same reference numerals with the suffix "X", shows the configuration of part of a screw compressor according to a second embodiment and corresponds to a view seen from the arrow CC in Figure 1. The screw compressor of this embodiment is configured similarly to the screw compressor 1 of the first embodiment, except that instead of the working chamber closing member 14 (Figures 1, 2, and 4) of the first embodiment, a working chamber closing portion 20 having the same size as the conventional working chamber closing portion 16 described above with reference to Figure 6 is formed integrally with the main casing 10X at the same position as the working chamber closing portion 16.

[0041] In this case, the working chamber closing section 20 of the screw compressor of this embodiment is formed with a male rotor-side recess 20A and a female rotor-side recess 20B by cutting the side facing the male rotor 2 and the side facing the female rotor 3, respectively, from one end on the motor 9A (FIG. 1) side in the rotor axial direction to the vicinity of the rotor-opposing surfaces (the surfaces facing the ends of the tooth portions 2A of the male rotor 2 and the tooth portions 3A of the female rotor 3). Furthermore, the male rotor-side recess 20A and the female rotor-side recess 20B are formed in a curved shape that smoothly joins with the inner wall surface of the bore 10AX when viewed from the rotor axial direction of the male rotor 2 and the female rotor 3, respectively.

[0042] By forming the male rotor side recess 20A and the female rotor side recess 20B in this manner in the working chamber closing portion 20, a first male rotor side open space 21A having the same shape as the male rotor side recess 20A is formed between the isolation wall 20C of the working chamber closing portion 20 that isolates the male rotor side recess 20A and the female rotor side recess 20B and the suction side shaft portion 2B of the male rotor 2, and a first female rotor side open space 22A having the same shape as the female rotor side recess 20B is formed between the isolation wall 20C and the suction side shaft portion 3B of the female rotor 3.

[0043] Furthermore, an arc-shaped recess 20D is formed in the working chamber closing portion 20 at a position on the rotor-opposing surface facing the suction-side shaft 2B of the male rotor 2. The arc-shaped recess 20D is coaxial with the suction-side shaft 2B of the male rotor 2 and has a diameter that is somewhat larger than the suction-side shaft 2B. This forms a second male rotor side open space 21B of a certain size between the suction-side shaft 2B of the male rotor 2 and the working chamber closing portion 20, which communicates with the first male rotor side open space 21A and constitutes the first open space 21 together with the first male rotor side open space 21A.

[0044] Similarly, the working chamber closing portion 20 has an arc-shaped recess 20E formed on the rotor-opposing surface at a position facing the suction side shaft 3B of the female rotor 3. The arc-shaped recess 20E is coaxial with the suction side shaft 3B of the female rotor 3 and has a diameter that is somewhat larger than that of the suction side shaft 3B. This provides a second gap between the suction side shaft 3B of the female rotor 3 and the working chamber closing portion 20. 1 A second female rotor side open space 22B of a certain size is formed which communicates with the first female rotor side open space 22A and constitutes the second open space 22 together with the first female rotor side open space 22A.

[0045] In this case, the diameters of the recesses 20D, 20E of the working chamber closing portion 20 are set to be equal to the diameters of the teeth of the male rotor 2 and the female rotor 3 so as to be able to close the working chamber. bottom The radius is selected to be smaller than the radius of the suction side shaft portion 2B of the male rotor 2 and the suction side shaft portion 3B of the female rotor 3.

[0046] In the screw compressor of this embodiment having the above-mentioned configuration, the working medium that has flowed through the space portion of the suction space 13 (FIGS. 1 and 2) that is located outside the suction side shaft portion 2B of the male rotor 2 flows along the wall surface of the male rotor side recess 20A of the working chamber closing portion 20, flows through the suction space 13 and the first open space 21 so as to rotate around the suction side shaft portion 2B of the male rotor 2 in the same direction as the rotation direction of the suction side shaft portion 2B (the rotation direction indicated by arrow a), and is eventually sucked into the working chamber through the suction port.

[0047] Furthermore, a portion of the working medium that has flowed into the space portion of the suction space 13 located outside the suction side shaft portion 2B of the male rotor 2 collides with the side wall on the rotor-facing side of the working chamber closing portion 20, but then passes through the second male rotor side open space 21B of the working chamber closing portion 20, flows through the suction space 13 and the first open space 21 so as to rotate around the suction side shaft portion 2B of the male rotor 2 in the same direction as the rotational direction of the suction side shaft portion 2B, and is eventually sucked into the working chamber through the suction port.

[0048] Similarly, in this screw compressor, the working medium that has flowed through the space portion of the suction space 13 (Figures 1 and 2) that is located outside the suction side shaft portion 3B of the female rotor 3 flows along the wall surface of the female rotor side recess 20B of the working chamber closing portion 20, flows through the suction space 13 and the second open space 22 so as to rotate around the suction side shaft portion 3B of the female rotor 3 in the same direction as the rotation direction of the suction side shaft portion 3B (the rotation direction indicated by arrow b), and is eventually sucked into the working chamber through the suction port.

[0049] In addition, a portion of the working medium that flows into the space portion of the suction space 13 located outside the suction side shaft portion 3B of the female rotor 3 collides with the side wall on the rotor-facing side of the working chamber closing portion 20, but then passes through the second female rotor side open space 22B of the working chamber closing portion 20, flows through the suction space 13 and the second open space 22 so as to rotate around the suction side shaft portion 3B of the female rotor 3 in the same direction as the rotational direction of the suction side shaft portion 3B, and is eventually sucked into the working chamber through the suction port.

[0050] As described above, the screw compressor of this embodiment has a configuration in which the first open space 21 and the second open space 22 are separated, which has the effect of rectifying the flow of the working medium flowing in the suction space 13 and the like as the male rotor 2 and the female rotor 3 rotate. This rectifying effect is particularly effective when the male rotor 2 and the female rotor 3 rotate at high speeds, and is effective in reducing suction resistance in screw compressors with a low low-speed operation ratio. Furthermore, in this screw compressor, the male rotor-side recess 20A and the female rotor-side recess 20B of the working chamber closing portion 20 are each formed in a curved shape that smoothly joins with the inner wall surface of the bore 10AX, which has the effect of further preventing disturbance of the flow of the working medium flowing in the suction space 13 and the like.

[0051] Therefore, according to the screw compressor of this embodiment, the flow resistance of the working medium sucked in from the suction port 12 (FIG. 1) is less than in conventional screw compressors, and the working medium is sucked into the working chambers more smoothly. As a result, when the male rotor 2 and the female rotor 3 are rotating at high speed, the working medium is not decelerated even when flowing into the working chambers, so the energy required to accelerate the working medium is reduced, thereby improving the energy efficiency of the screw compressor, and even when the male rotor 2 and the female rotor 3 are rotating at low speed, the flow rate of the working medium can be increased as the suction resistance of the working medium is reduced.

[0052] (3) Third embodiment Figure 8, in which parts corresponding to those in Figure 4 are indicated by the same reference numerals or the same reference numerals with the suffix "Y", shows the configuration of part of a screw compressor according to a third embodiment and corresponds to the view seen from the CC arrow in Figure 1. The screw compressor of this embodiment has the same configuration as the screw compressor of the second embodiment, except that the configuration of the working chamber closing section 30 is different.

[0053] In practice, in the screw compressor of this embodiment, an operating chamber closing portion 30 of the same size as the operating chamber closing portion 16 is formed integrally with the main casing 10Y at the same position as the conventional operating chamber closing portion 16 described above with reference to Figure 6.

[0054] In this working chamber closing section 30, a male rotor side recess 30A and a female rotor side recess 30B are formed on the side facing the male rotor 2 and the side facing the female rotor 3, respectively, so as to extend from the end on the motor 9A (Figure 1) side in the rotor axial direction to the vicinity of the rotor opposing surface (the surface opposing the end of the tooth portion 2A of the male rotor 2 and the tooth portion 3A of the female rotor 3).

[0055] By forming the male rotor side recess 30A and the female rotor side recess 30B in this manner in the working chamber closing portion 30, a first male rotor side open space 31A having the same shape as the male rotor side recess 30A is formed between the isolation wall 30C of the working chamber closing portion 30, which isolates the male rotor side recess 30A and the female rotor side recess 30B, and the suction side shaft portion 2B of the male rotor 2, and a first female rotor side open space 32A having the same shape as the female rotor side recess 30B is formed between the isolation wall 30C and the suction side shaft portion 3B of the female rotor 3.

[0056] In this case, the male rotor side recess 30A has a side formed in an arc shape whose curvature increases as the working medium flows from the inlet side to the outlet side of the first male rotor side open space 31A, as will be described later, and is designed so that the curvature of the first male rotor side open space 31A increases as the working medium flows in the rotational direction of the suction side shaft portion 2B of the male rotor 2.

[0057] Similarly, the side of the female rotor side recess 30B is formed in an arc shape whose curvature increases as the working medium flowing into the first female rotor side open space 32A moves from the inlet side to the outlet side of the first female rotor side open space 32A, as described below, and is designed so that the curvature of the first female rotor side open space 32A increases as it moves in the rotational direction of the suction side shaft portion 3B of the female rotor 3.

[0058] Furthermore, an arc-shaped recess 30D is formed in the working chamber closing portion 30 at a position on the rotor-opposing surface facing the suction-side shaft 2B of the male rotor 2. The recess 30D is coaxial with the suction-side shaft 2B of the male rotor 2 and has a diameter that is somewhat larger than the suction-side shaft 2B. This forms a second male rotor side open space 31B of a certain size between the suction-side shaft 2B of the male rotor 2 and the working chamber closing portion 30, which communicates with the first male rotor side open space 31A and constitutes the first open space 31 together with the first male rotor side open space 31A.

[0059] Similarly, the working chamber closing part 30 has an arc-shaped recess 30E formed on the rotor-opposing surface at a position facing the suction side shaft 3B of the female rotor 3. The arc-shaped recess 30E is coaxial with the suction side shaft 3B of the female rotor 3 and has a diameter that is somewhat larger than the suction side shaft 3B. This provides a second gap between the suction side shaft 3B of the female rotor 3 and the working chamber closing part 30. 1 A second female rotor side open space 32B of a certain size is formed which communicates with the first female rotor side open space 32A and constitutes the second open space 32 together with the first female rotor side open space 32A.

[0060] The diameters of the recesses 30D, 30E of the working chamber closing portion 30 are set to the same as the teeth of the male rotor 2 and the female rotor 3 so as to be able to close the working chamber. bottom The radius is selected to be smaller than the radius of the suction side shaft portion 2B of the male rotor 2 and the suction side shaft portion 3B of the female rotor 3.

[0061] In the screw compressor of this embodiment having the above-mentioned configuration, the working medium that has flowed through the space portion of the suction space 13 (FIGS. 1 and 2) that is located outside the suction side shaft portion 2B of the male rotor 2 flows along the wall surface of the male rotor side recess 30A of the working chamber closing portion 30, flows through the suction space 13 and the first open space 31 so as to rotate around the suction side shaft portion 2B of the male rotor 2 in the same direction as the rotation direction of the suction side shaft portion 2B (the rotation direction indicated by arrow a), and is eventually sucked into the working chamber through the suction port.

[0062] Furthermore, a portion of the working medium that has flowed through the suction space 13 located outside the suction side shaft portion 2B of the male rotor 2 collides with the rotor-facing side of the working chamber closing portion 30, but then passes through the second male rotor side open space 31B of the working chamber closing portion 30, flows through the suction space 13 and the first male rotor side open space 31A so as to rotate around the suction side shaft portion 2B of the male rotor 2 in the same direction as the rotational direction of the suction side shaft portion 2B, and is eventually sucked into the working chamber through the suction port.

[0063] Similarly, in this screw compressor, the working medium that has flowed through the space portion of the suction space 13 (FIGS. 1 and 2) located outside the suction side shaft portion 3B of the female rotor 3 flows along the wall surface of the female rotor side recess 30B of the working chamber closing portion 30, flows through the suction space 13 and the second open space 32 so as to rotate around the suction side shaft portion 3B of the female rotor 3 in the same direction as the rotation direction of the suction side shaft portion 3B (the rotation direction indicated by arrow b), and is eventually sucked into the working chamber through the suction port.

[0064] In addition, a portion of the working medium that flows into the space portion of the suction space 13 located outside the suction side shaft portion 3B of the female rotor 3 collides with the side wall on the rotor-facing side of the working chamber closing portion 30, but then passes through the second female rotor side open space 32B of the working chamber closing portion 30, flows through the suction space 13 and the second open space 32 so as to rotate around the suction side shaft portion 3B of the female rotor 3 in the same direction as the rotation of the suction side shaft portion 3B, and is eventually sucked into the working chamber through the suction port.

[0065] As described above, the screw compressor of this embodiment is configured such that the first open space 31 and the second open space 32 are separated, and therefore, similar to the screw compressor of the second embodiment, it has the effect of rectifying the flow of the working medium that flows within the suction space 13, etc., as the male rotor 2 and the female rotor 3 rotate.

[0066] Therefore, according to the screw compressor of this embodiment, as with the screw compressor of the second embodiment, the flow resistance of the working medium sucked in from the suction port 12 (FIG. 1) is less than in conventional screw compressors, and the working medium is sucked into the working chambers more smoothly. As a result, when the male rotor 2 and the female rotor 3 are rotating at high speeds, the working medium is not decelerated when it flows into the working chambers, so the energy required to accelerate the working medium is reduced, improving the energy efficiency of the screw compressor. Also, when the male rotor 2 and the female rotor 3 are rotating at low speeds, the flow rate of the working medium can be increased as the suction resistance of the working medium is reduced.

[0067] In addition, in this screw compressor, the outlet sides of the first male rotor side open space 31A and the first female rotor side open space 32A are formed into an arc shape with a larger curvature than the inlets, so the flow path area of ​​the working medium flowing in the first male rotor side open space 31A and the first female rotor side open space 31B is narrowed on the outlet side, thereby making it possible to increase the speed of the working medium flowing out from the outlet sides of the first male rotor side open space 31A and the first female rotor side open space 31B, and reducing acceleration loss of the working medium.

[0068] Furthermore, in the present screw compressor, the side shapes of the male rotor side recess 30A and the female rotor side recess 30B are substantially cylindrical, which makes it easy to process the working chamber closing portion 30, thereby improving the manufacturing efficiency of the screw compressor and reducing the manufacturing costs.

[0069] (4) Fourth embodiment Figure 9, in which parts corresponding to those in Figure 4 are indicated by the same reference numerals or the same reference numerals with the suffix "Z", shows the configuration of part of a screw compressor according to a fourth embodiment and corresponds to the view seen from the CC arrow in Figure 1. The screw compressor of this embodiment has the same configuration as the screw compressor of the third embodiment, except that the configuration of the working chamber closing section 40 is different.

[0070] In practice, in the screw compressor of this embodiment, a working chamber closing section 40 having the same length in the rotor axial direction as the working chamber closing section 16 is formed integrally with the main casing 10Z at the same position as the conventional working chamber closing section 16 described above with reference to Figure 6.

[0071] The working chamber closing portion 40 has a pair of rotors on the side of the male rotor 2 and the side of the female rotor 3, extending from the end of the rotor axial direction on the motor 9A (FIG. 1) side to the rotor opposing surface. depression 40A and depression 40B is formed.

[0072] In this way, the working chamber closing portion 40 depression 40A and depression By forming 40B, depression A male rotor side open space 41A is formed between the suction side shaft portion 2B of the male rotor 2 and the suction side shaft portion 2B of the male rotor 2. depression A female rotor side open space 41B is formed between 40B and the suction side shaft portion 3B of the female rotor 3.

[0073] In this case, the working chamber closing portion 40 depression 40A and depression The diameter of 40B is set to the same as that of the teeth of the male rotor 2 and the female rotor 3 so as to close the working chamber. bottom The radius is selected to be smaller than the radius of the suction side shaft portion 2B of the male rotor 2 and the suction side shaft portion 3B of the female rotor 3.

[0074] Also, the working chamber closing portion 40 depression As will be described later, the side surface of 40A is formed in an arc shape whose curvature increases as the working medium flows from the inlet side to the outlet side of the male rotor side open space 41A, and is designed so that the curvature of the male rotor side open space 41A increases as the working medium flows in the direction of rotation of the suction side shaft portion 2B of the male rotor 2.

[0075] Similarly, the working chamber closing portion 40 depressionThe side of 40B is formed in an arc shape whose curvature increases as the working medium flows from the inlet side to the outlet side of the female rotor side open space 41B as described below, and is designed so that the curvature of the female rotor side open space 41B increases as the working medium flows in the direction of rotation of the suction side shaft portion 3B of the female rotor 3.

[0076] In the screw compressor of this embodiment having the above-mentioned configuration, the working medium that has flowed through the space portion of the suction space 13 (FIGS. 1 and 2) that is located outside the suction side shaft portion 2B of the male rotor 2 collides with the side surface of the working chamber closing portion 40, then flows through the male rotor side open space 41A, within the suction space 13 and the male rotor side open space 41A, so as to rotate around the suction side shaft portion 2B of the male rotor 2 in the same direction as the rotation direction of the suction side shaft portion 2B (the rotation direction indicated by arrow a), and is eventually sucked into the working chamber through the suction port.

[0077] Similarly, in this screw compressor, the working medium that has flowed through the space portion of the suction space 13 located outside the suction side shaft portion 3B of the female rotor 3 collides with the side of the working chamber closing portion 40, then passes through the female rotor side open space 41B, flows through the suction space 13 and the female rotor side open space 41B so as to rotate around the suction side shaft portion 3B of the female rotor 3 in the same direction as the rotation direction of the suction side shaft portion 3B (the rotation direction indicated by arrow b), and is eventually sucked into the working chamber through the suction port.

[0078] As described above, in the screw compressor of this embodiment, similarly to the screw compressors of the second and third embodiments, the male rotor side open space 41A and the female rotor side open space 41B are configured to be separated, and therefore, the effect of rectifying the flow of the working medium that flows within the suction space 13, etc., as the male rotor 2 and the female rotor 3 rotate is exhibited.

[0079] Therefore, according to the screw compressor of this embodiment, the flow resistance of the working medium sucked in from the suction port 12 (FIG. 1) is less than in conventional screw compressors, and the working medium is sucked into the working chambers more smoothly. As a result, when the male rotor 2 and the female rotor 3 are rotating at high speed, the working medium is not decelerated even when flowing into the working chambers, so the energy required to accelerate the working medium is reduced, thereby improving the energy efficiency of the screw compressor, and even when the male rotor 2 and the female rotor 3 are rotating at low speed, the flow rate of the working medium can be increased as the suction resistance of the working medium is reduced.

[0080] In addition, in this screw compressor, as in the third embodiment, the working chamber closing portion 40 depression The side shape of 40A depression Since the side shape of 40B is cylindrical with a larger curvature on the outlet side of the male rotor side open space 41A and the female rotor side open space 41B than on the inlet side, it is possible to increase the speed of the working medium flowing out from the outlet side of the male rotor side open space 41A and the female rotor side open space 41B to the suction space 13, etc., and to reduce acceleration loss of the working medium.

[0081] In addition, in this screw compressor, the working chamber closing portion 40 depression The side shape of 40A depression Since the side shape of 40B is substantially cylindrical, the working chamber closing portion 40 can be easily machined, which can improve the manufacturing efficiency of the screw compressor and reduce the manufacturing cost.

[0082] (5) Other embodiments In the above-described first to fourth embodiments, the present invention has been described as being applied to a screw compressor 1 in which the toothed portion 2A of the male rotor 2 has four teeth and the toothed portion 3A of the female rotor 3 has six teeth, but the present invention is not limited to this and can be widely applied to screw compressors of various other configurations.

[0083] Furthermore, in the above-described first to fourth embodiments, the recesses 14C, 14D, 20D, 20E, 30D, 30E, 40A, 40B of the working chamber closing member 14 and the working chamber closing portions 20, 30, 40 are described as being formed in an arc shape that is coaxial with the male rotor 2 and the female rotor 3, but the present invention is not limited to this, and the recesses 14C, 14D, 20D, 20E, 30D, 30E, 40A, 40B may be arc-shaped and not coaxial with the male rotor 2 and the female rotor 3, or may have a shape other than an arc shape.

[0084] Furthermore, in the first embodiment described above, a motor side open space 15C is provided on the motor 9A side of the working chamber closing member 14, and a male rotor side open space 15A and a female rotor side open space 15B are provided on the side of the working chamber closing member 14. In the second and third embodiments, first and second male rotor side open spaces 21A and 21B are provided on the male rotor 2 side of the working chamber closing parts 20 and 30. ,31A,31B and first and second female rotor side open spaces 22A, 22B are provided on the female rotor 3 side of the working chamber closing portions 20, 30. ,32A,32B However, the present invention is not limited to this. For example, in the first embodiment, the motor side open space 15C and male In the second and third embodiments, only one of the male rotor side open space 15A and the female rotor side open space 15B is provided, and in the second and third embodiments, the first male rotor side open space 21A ,31A and the first female rotor side open space 22A ,32A In the second and third embodiments, the second male rotor side open space 21B may be provided. ,31B and the second female rotor side open space 22B ,32B The fourth embodiment is one in which only the above-mentioned is provided. [Industrial Applicability]

[0085] The present invention can be widely applied to screw compressors of various configurations. [Explanation of symbols]

[0086] 1...Screw compressor, 2...Male rotor, 2A, 3A...Tooth portion, 2B, 3B...Suction side shaft portion, 2C, 3C...Discharge side shaft portion, 3...Female rotor, 4...Casing, 9...Drive portion, 9A...Motor, 10, 10X to 10Z...Main casing, 10A, 10AX to 10AZ...Bore, 12...Suction port, 13...Suction space, 14...Working chamber closing member, 14C, 14D, 20D, 20E, 30D, 30 E, 40A, 40B...recesses, 15, 21, 22, 31, 32...open spaces, 15A, 21A, 21B, 31A, 31B, 41A...male rotor side open spaces, 15B, 22A, 22B, 32A, 32B, 41B...female rotor side open spaces, 15C...motor side open spaces, 20, 30, 40...operating chamber closing portions, 20A, 30A...male rotor side recesses, 20B, 30B...female rotor side recesses, 20C...isolation wall.

Claims

1. In a screw compressor that compresses a working medium sucked in from a suction port and discharges it from a discharge port, a male rotor and a female rotor having teeth that mesh with each other and a shaft connected to the teeth; a casing having a bore in which the male rotor and the female rotor are housed and which defines a working chamber for compressing the working medium together with the male rotor and the female rotor; an intake port for drawing the working medium into the working chamber; a working chamber closing member formed on the suction port and having one surface facing one axial end surface of the male rotor and the female rotor; a suction space communicating between the suction port and the suction port; Equipped with an open space communicating between the suction space and the suction port is provided between the suction port and the shaft portion of the male rotor and the shaft portion of the female rotor; the working chamber closing member is provided between the shaft portion of the male rotor and the shaft portion of the female rotor, and separates the open space into the male rotor side and the female rotor side; a first recess having an arc shape and a diameter larger than that of the shaft portion is formed in a portion of the male rotor facing the shaft portion, a second recess having an arc shape and a diameter larger than that of the shaft portion is formed in a portion of the female rotor facing the shaft portion; At least one of the first and second recesses is The shaft portion of the opposing male rotor or the shaft portion of the opposing female rotor is formed so that the curvature increases as it advances in the direction of rotation. A screw compressor characterized by:

2. The suction port is The suction port is opened at a plane including an end face of the tooth portion of the male rotor on the suction port side via the male rotor and the female rotor in the axial direction of the male rotor and the female rotor.

2. The screw compressor according to claim 1.

3. The suction port, a space outside the shaft portion of the male rotor, a space outside the shaft portion of the female rotor, and the open space are in communication with each other.

2. The screw compressor according to claim 1.

4. The space outside the shaft portion of the male rotor communicates with the open space on the female rotor side, and the space outside the shaft portion of the female rotor communicates with the open space on the male rotor side.

2. The screw compressor according to claim 1.

5. the arcuate portion of the first recess and the rotor shaft of the male rotor are coaxial; The arcuate portion of the second recess and the rotor shaft of the female rotor are coaxial.

2. The screw compressor according to claim 1.

6. The radii of the first and second recesses are: a radius of the tooth bottom of the male rotor and the female rotor that is selected to be smaller than the radius of the tooth bottom of the male rotor and the female rotor, and larger than the radius of the shaft portion of the male rotor and the female rotor; 2. The screw compressor according to claim 1.

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