TW202022233A - Screw compressor - Google Patents

Abstract

Provided is a screw compressor that can reduce a pressure loss of a suction passage. A casing 12 of the screw compressor comprises: a bore 21 that accommodates a tooth part 13A of a male rotor 11A and a tooth part 13B of a female rotor 11B to form function chambers in spaces of the tooth parts 13A and 13B; a suction port 22 that is positioned on an outside in a rotor radial direction; and a suction passage 23 that communicates with the function chambers undergoing a suction process in a rotor axial direction. The suction passage 23 has a male rotor side suction passage 26A that is positioned on a male rotor 11A side and on a downstream side of a virtual plane C, and has a female rotor side suction passage 26B that is positioned on a female rotor 11B side and on the downstream side of the virtual plane C. The male rotor side suction passage 26A is formed so that, in at least a range half an axial pitch P1 of the tooth part 13A from the suction side end of the tooth part 13A of the male rotor 11A in the rotor axial direction, a passage wall 27A on the outside in the rotor radial direction is at the same position as a wall of the bore 21 when seen from the rotor axial direction.

Description

Screw compressor

The present invention relates to a screw compressor having a suction port located on the radially outer side of the rotor and a suction flow path communicating with the working chamber along the axial direction of the rotor.

The screw compressor described in Patent Document 1 includes a male rotor having teeth, a female rotor having teeth meshing with the teeth of the male rotor, and a housing accommodating the male rotor and the female rotor.

The casing has an inner cavity for accommodating the teeth of the male rotor and the teeth of the female rotor, and forming the working chamber on the male rotor side and the working chamber on the female rotor side in the tooth grooves of them. In addition, the housing has a suction port located on the outer side of the rotor radial direction than the tooth portion of the male rotor and the tooth portion of the female rotor, and a suction flow path formed to connect the suction port and the operating chamber of the suction stroke. In addition, the housing has an ejection port located on the outer side of the rotor radial direction than the tooth portion of the male rotor and the tooth portion of the female rotor, and an ejection flow path formed by connecting the ejection port and the operating chamber of the ejection stroke.

The actuating chamber moves from one side of the rotor shaft to the other side, and its volume changes. Thereby, the actuating chamber sequentially performs a suction stroke of sucking gas from the suction port through the suction flow path, a compression stroke of compressing the gas, and a discharge stroke of spraying compressed gas to the discharge port through the discharge flow path.

The suction flow path communicates with the working chamber of the suction stroke along the axial direction of the rotor. In addition, the suction flow path has a suction flow path on the male rotor side that is located on the male rotor side and is on the downstream side (in other words, the side opposite to the suction port) than the virtual plane passing through the central axis of the male rotor and the central axis of the female rotor, and The female rotor side suction flow path on the female rotor side and downstream of the aforementioned imaginary plane. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2012-041910 (for example, refer to FIGS. 8 and 9)

[Problems to be solved by the invention]

In Patent Document 1, the flow path wall outside the rotor radial direction of the suction flow path on the male rotor side (except for the part used to seal the gas into the operating chamber) is located on the outside of the rotor radial direction than the wall of the inner cavity. Therefore, as a component of the flow direction of the gas from the male rotor side suction flow path to the male rotor side working chamber, a component in the radial direction of the rotor is generated, which becomes a factor of increase in pressure loss.

Similarly, the flow path wall of the suction flow path on the female rotor side in the radial direction outside the rotor (except for the wall part used to seal the gas into the working chamber) is located on the radial outside of the rotor than the wall of the inner cavity. Therefore, as a component of the flow direction of the gas from the female rotor side suction flow path to the female rotor side working chamber, a component in the radial direction of the rotor is generated, which becomes a factor of increase in pressure loss.

The present invention was completed in view of the above-mentioned circumstances, and one of its problems is to reduce the pressure loss of the suction flow path. [Technical means to solve the problem]

In order to solve the above-mentioned problems, the composition described in the scope of patent application is applied. The present invention includes a plurality of technical means to solve the above-mentioned problems, but if one example is cited, it is a screw compressor which has a male rotor with teeth, a female rotor with teeth that mesh with the teeth of the male rotor, And a housing for accommodating the male rotor and the female rotor, and the housing has: an inner cavity that houses the teeth of the male rotor and the teeth of the female rotor, and forms an operating chamber on the male rotor side in the tooth grooves of them And the working chamber on the female rotor side; the suction port, which is located on the outer side of the rotor radial direction than the teeth of the male rotor and the tooth of the female rotor; and the suction flow path, which connects the suction port and the suction stroke The working chamber is formed in a manner that communicates with the working chamber of the suction stroke in the axial direction of the rotor; and the suction flow path has an imaginary that is located on the side of the male rotor and passes through the central axis of the male rotor and the central axis of the female rotor. The male rotor side suction flow path on the downstream side of the plane, and the female rotor side suction flow path on the female rotor side and further downstream than the virtual plane. The male rotor side suction flow path is formed as follows: , At least in the rotor axial direction from the suction side end surface of the tooth portion of the male rotor to one-half of the axial pitch of the tooth portion, the flow path wall on the radially outer side of the rotor becomes the same as the above The wall of the inner cavity is at the same position. [Effect of invention]

According to the present invention, the pressure loss of the suction flow path can be reduced.

In addition, the problems, constitution, and effects other than the above are clarified by the following description.

An embodiment of the present invention will be described with reference to FIGS. 1 to 5.

The screw compressor of this embodiment includes a motor 1, a compressor body that is driven by the motor 1 to compress air (gas), and a gas-liquid that separates the compressed air ejected from the compressor body 2 from the oil (liquid) contained in it The separator 3 and the oil pipe 4 that supplies the oil separated by the gas-liquid separator 3 to the compressor body 2 (in detail, the operating chamber, the suction side bearing, and the discharge side bearing described below). The oil pipe 4 is provided with an oil cooler 5 to cool the oil, or an oil filter 6 to remove impurities in the oil.

The compressor body 2 includes a male rotor 11A and a female rotor 11B as spiral rotors, and a housing 12 that houses the male rotor 11A and the female rotor 11B.

The male rotor 11A has a tooth portion 13A with a plurality of (4 in this embodiment) teeth extending in a spiral shape, and a suction side connected to the axial side of the tooth portion 13A (the left side in FIGS. 2 and 3) The shaft portion 14A and the ejection side shaft portion 15A connected to the other axial side of the tooth portion 13A (the right side in FIGS. 2 and 3). The suction side shaft portion 14A of the male rotor 11A is rotatably supported by the suction side bearing 16A, and the discharge side shaft portion 15A of the male rotor 11A is rotatably supported by the discharge side bearing 17A.

Similarly, the female rotor 11B has a tooth portion 13B having a plurality of (six in this embodiment) teeth extending in a spiral shape, and an axial side connected to the tooth portion 13B (left side in FIGS. 2 and 3) The suction side shaft portion 14B, and the discharge side shaft portion 15B connected to the other axial side of the tooth portion 13B (the right side in FIGS. 2 and 3). The suction side shaft portion 14B of the female rotor 11B is rotatably supported by the suction side bearing 16B, and the discharge side shaft portion 15B of the female rotor 11B is rotatably supported by the discharge side bearing 17B.

The suction side shaft portion 14A of the male rotor 11A penetrates the housing 12 and is connected to the rotating shaft of the motor 1. Moreover, the male rotor 11A is driven by the motor 1 to rotate, and the female rotor 11B is also rotated by the meshing of the teeth 13A of the male rotor 11A and the teeth 13B of the female rotor 11B.

The housing 12 includes a main housing 18, a suction side housing 19 connected to one axial side of the main housing 18 (the left side in FIGS. 2 and 3), and an axial other side connected to the main housing 18 (FIG. 2 and 3 The right side of) the ejection side shell 20.

The housing 12 has a tooth portion 13A of the male rotor 11A and a tooth portion 13B of the female rotor 11B, and an inner cavity 21 is formed in the tooth slots of the male rotor side working chamber and the female rotor side working chamber. The inner cavity 21 is configured by partially accommodating the teeth 13A of the male rotor 11A and the teeth 13B of the female rotor 11B by partially overlapping two cylindrical holes (see FIG. 5).

The housing 12 has a suction port 22 located on the outer side (upper side of FIG. 2) in the radial direction of the rotor than the tooth portion 13A of the male rotor 11A and the tooth portion 13B of the female rotor 11B, and an operating chamber connecting the suction port 22 and the suction stroke The way to form the suction flow path 23. The inner cavity 21, the suction port 22, and the suction flow path 23 are formed in the main housing 18.

The housing 12 has an ejection port 24 located on the outer side of the rotor radial direction (the lower side of FIG. 2) than the tooth portion 13A of the male rotor 11A and the tooth portion 13B of the female rotor 11B, and a working chamber connecting the ejection port and the ejection stroke The ejection flow path 25 is formed in a way. The discharge port 24 is formed in the discharge side housing 20, and the discharge flow path 25 is formed in the discharge side housing 20 and the main housing 18.

The actuating chamber moves from one side of the rotor shaft to the other side, and its volume changes on one side. Thereby, the actuating chamber sequentially performs a suction stroke of sucking gas from the suction port 22 through the suction flow path 23, a compression stroke of compressing the gas, and a discharge stroke of blowing compressed gas to the discharge port 24 through the discharge flow path 25.

The suction flow path 23 communicates with the actuation chamber of the suction stroke along the rotor axial direction. In addition, the suction flow path 23 has a male rotor 11A located on the side of the male rotor 11A and further downstream (in other words, the side opposite to the suction port 22) than a virtual plane C passing through the central axis O1 of the male rotor 11A and the central axis O2 of the female rotor 11B. The rotor side suction flow path 26A, and the female rotor side suction flow path 26B located on the female rotor 11B side and downstream of the virtual plane C (refer to FIGS. 3 and 4).

Here, as a major feature of the present embodiment, the flow path wall 27A (except for the part 28 used to seal the gas in the operating chamber) on the rotor radially outer side of the male rotor side suction flow path 26A is as follows It is formed, that is, within the range from the suction side end surface of the tooth 13A of the male rotor 11A to the tooth 13A in the axial pitch P1 (refer to FIG. 3) at least in the rotor axial direction (as a specific example, in FIG. 3) It is in the range of P1×0.8=R1, and in Fig. 6 below, it is in the range of P1×0.5=R1), it becomes the same position as the wall of the cavity 21 when viewed from the rotor axial direction. Furthermore, the axial pitch of the teeth refers to the distance between the tooth tips in the axial direction of the rotor. In addition, since processing errors and the like are taken into consideration, the position where the flow path wall 27A is the same as the wall of the cavity 21 when viewed from the rotor axial direction refers to the radial direction of the flow path wall 27A based on the central axis O1 of the male rotor 11A The position is in the range of 95%-105% of the radial position of the wall of the inner cavity 21.

In addition, the flow path wall 27B (except for the part 28 used to seal the gas in the operating chamber) of the female rotor side suction flow path 26B on the radially outer side of the rotor is formed in such a way that at least the rotor axial direction is free from The suction side end surface of the tooth portion 13B of the female rotor 11B to the axial pitch P2 of the tooth portion 13B (where P1=P2; refer to Fig. 3) is within one half of the range (as a specific example, in Fig. 3, at P2× 0.8=R2 range, in the following Fig. 6, in P2×0.5=R2 range), it becomes the same position as the wall of the cavity 21 when viewed from the rotor axial direction. In addition, due to processing errors, etc., the position where the flow path wall 27B is the same as the wall of the cavity 21 when viewed from the rotor axial direction refers to the radius of the flow path wall 27B based on the central axis O2 of the female rotor 11B The directional position is within the range of 95%-105% of the radial position of the wall of the inner cavity 21.

In this embodiment, as the component of the flow direction of the gas from the male rotor side suction flow path 26A toward the male rotor side operating chamber, it is difficult to generate a component in the radial direction of the rotor, so that the pressure loss can be reduced. In addition, as the component of the flow direction of the gas from the female rotor side suction flow path 26B toward the female rotor side operating chamber, it is difficult to generate a component in the radial direction of the rotor, so that the pressure loss can be reduced. As a result, it is possible to increase the intake air flow rate or decrease the power.

In addition, compared with the case where the flow path walls 27A and 27B are located on the outer side in the rotor radial direction than the wall of the inner cavity 21, it is possible to prevent oil from accumulating in the male rotor side suction flow path 26A and the female rotor side when the compressor body 2 is stopped. The lower part of the suction flow path 26B. Therefore, it is also possible to suppress the pressure loss due to the influence of the oil accumulated in the lower portion of the male rotor side suction flow path 26A and the female rotor side suction flow path 26B.

As the range where the flow path walls 27A and 27B are at the same position as the wall of the cavity 21 when viewed from the rotor axial direction, it is set at least in the rotor axial direction from the suction side end surface of the rotor tooth to the axial section of the tooth Supplement the reason for the one-half distance. From the viewpoint of volumetric efficiency of the screw compressor, it is necessary to consider the size of the suction flow path 26A on the male rotor side relative to the area of the rotor axial section of the male rotor side operating chamber (in other words, the section extending in the rotor axial direction) The area of the rotor axial section or the area of the rotor axial section of the female rotor side suction flow path 26B relative to the area of the rotor axial section of the female rotor side operating chamber. The area of the rotor axial section of the working chamber on the male rotor side is represented by, for example, (the difference between the outer diameter of the teeth of the male rotor and the outer diameter of the shaft) × the axial pitch ÷ 2. Therefore, the suction flow path 26A on the male rotor side The area of the axial section of the rotor should be at least (the difference between the outer diameter of the teeth of the male rotor and the outer diameter of the shaft)×axial pitch ÷ 2. Similarly, the area of the rotor axial section of the working chamber on the female rotor side is represented by (the difference between the outer diameter of the teeth of the female rotor and the outer diameter of the shaft) × axial pitch ÷ 2, therefore, the suction flow on the female rotor side The area of the axial section of the rotor of road 26B should be at least (the difference between the outer diameter of the tooth of the female rotor and the outer diameter of the shaft)×axial pitch ÷ 2. From this point of view, if it is not at least within the range from the suction side end surface of the tooth portion of the rotor to half of the axial pitch of the tooth portion in the rotor axial direction, the male rotor side suction flow path 26A and the female rotor side suction The flow path 26B has a characteristic, and its effect cannot be sufficiently obtained.

Furthermore, in the above-mentioned embodiment, the male rotor side suction flow path 26A is formed in such a way that the axial section of the rotor is cut along each radial direction of the male rotor 11A, that is, the area of each flow path section V1 (refer to Fig. 3) is larger than the area S1 (refer to Fig. 5) of the rotor radial cross section (in other words, the cross section extending in the rotor radial direction) of each working chamber on the male rotor side, and the female rotor side suction flow path 26B is as follows It is formed that the axial section of the rotor cut along each radial direction of the female rotor 11B, that is, the area V2 of each flow path section (refer to FIG. 3) is larger than the area of the radial section of the rotor of each working chamber on the female rotor side S2 (refer to FIG. 5) shows this situation as an example, but it is not limited to this. A modification example of the present invention will be explained using FIG. 6. Figure 6 is a horizontal cross-sectional view showing the structure of the compressor body in this modification.

In this modified example, the male rotor side suction flow path 26A is formed in such a way that at least the rotation direction pitch of the male rotor 11A from the imaginary plane C to the tooth 13A of the male rotor 11A (at Within the range of 90 degrees in this embodiment), the axial section of the rotor obtained by cutting along the radial direction of the male rotor 11A, that is, the area V1 of each flow path section (refer to Fig. 6) and the actions on the side of the male rotor The cross-sectional area S1 (refer to FIG. 5) in the radial direction of the rotor of the chamber is the same. Furthermore, the pitch of the rotation direction of the teeth refers to the angle between adjacent tooth tips in the rotation direction of the rotor. In addition, due to the consideration of processing errors, etc., the area V1 and the area S1 are the same means that the area V1 is within the range of 95% to 105% of the area S1.

In addition, the female rotor side suction flow path 26B is formed in such a way that at least the rotation direction pitch of the female rotor 11B from the imaginary plane C to the tooth 13B of the female rotor 11B (in this embodiment Within the range of 45 degrees), the axial section of the rotor obtained by cutting along the radial direction of the female rotor 11B, that is, the area V2 of each flow path section (refer to Figure 6) and the rotor diameter of each working chamber on the female rotor side The area S2 (refer to FIG. 5) of the cross section is the same. Furthermore, due to the consideration of processing errors, etc., the area V2 and the area S2 being the same means that the area V2 is within the range of 95%-105% of the area S2.

In this modified example, it is possible to suppress the change of the flow velocity in the male rotor side suction flow path 26A, or the change of the flow velocity from the male rotor side suction flow path 26A to the male rotor side working chamber, thereby further reducing the pressure loss. In addition, it is possible to suppress the change of the flow velocity in the female rotor side suction flow path 26B or the change of the flow velocity from the female rotor side suction flow path 26B to the female rotor side operating chamber, thereby further reducing the pressure loss.

Furthermore, in the above-mentioned embodiment, both the male rotor-side suction flow path 26A and the female rotor-side suction flow path 26B have the first feature (specifically, at least the suction from the teeth in the rotor axial direction In the range from the side end surface to half of the axial pitch of the tooth, the flow path wall on the radial outer side of the rotor is formed in the same position as the wall of the cavity 21 when viewed from the rotor axial direction. It is explained, but it is not limited to this. That is, only one of the male rotor side suction flow path 26A and the female rotor side suction flow path 26B may have the first feature.

In addition, in the above-mentioned modification, both the male rotor side suction flow path 26A and the female rotor side suction flow path 26B have the first feature and the second feature (in detail, at least in the rotor rotation direction The axial section of the rotor cut from the imaginary plane C to the pitch of the tooth in the direction of rotation, cut along each radial direction of the rotor, that is, the area of each flow path section is the same as the area of the radial section of the rotor of each operating chamber The method of forming the feature) is described as an example, but it is not limited to this. That is, for example, only one of the male rotor side suction flow path 26A and the female rotor side suction flow path 26B may have the first feature and the second feature. Also, for example, both the male rotor side suction flow path 26A and the female rotor side suction flow path 26B may have the first feature, and only one of the male rotor side suction flow path 26A and the female rotor side suction flow path 26B may have The second feature.

In addition, as an application target of the present invention, an oil-supply type (in particular, oil is supplied to the operating chamber) screw compressor is described as an example, but it is not limited to this, and may be a water-supply type (in detail, A screw compressor that supplies water to the operating chamber or a non-liquid type (specifically, a screw compressor that does not supply liquid such as oil or water to the operating chamber).

1: motor 2: Compressor body 3: Gas-liquid separator 4: Oil piping 5: Oil cooler 6: oil filter 11A: male rotor 11B: Female rotor 12: Shell 13A: Teeth 13B: Teeth 14A: The suction side shaft of the male rotor 14B: The suction side shaft of the female rotor 15A: Shaft on the ejection side of the male rotor 15B: Shaft of the discharge side of the female rotor 16A: Suction side bearing 16B: Suction side bearing 17A: Discharge side bearing 17B: Discharge side bearing 18: main shell 19: Suction side housing 20: Outlet side shell 21: Internal cavity 22: suction port 23: Suction flow path 24: spout 25: Jet flow path 26A: suction flow path on the male rotor side 26B: suction flow path on the female rotor side 27A: The flow path wall outside the rotor radial direction of the suction flow path on the male rotor side 27B: The flow path wall outside the rotor radial direction of the suction flow path on the female rotor side

Fig. 1 is a schematic diagram showing the structure of an oil-supply screw compressor in an embodiment of the present invention. Fig. 2 is a vertical sectional view showing the structure of a compressor body in an embodiment of the present invention. Fig. 3 is a horizontal sectional view of section III-III of Fig. 2; Fig. 4 is a vertical sectional view of the section IV-IV of Fig. 2; Fig. 5 is a vertical sectional view of the section V-V of Fig. 2; Fig. 6 is a horizontal sectional view showing the structure of the compressor body in a modification of the present invention.

2: Compressor body

11A: male rotor

11B: Female rotor

12: Shell

13A: Teeth

13B: Teeth

14A: The suction side shaft of the male rotor

14B: The suction side shaft of the female rotor

15A: Shaft on the ejection side of the male rotor

15B: Shaft of the discharge side of the female rotor

16A: Suction side bearing

16B: Suction side bearing

17A: Discharge side bearing

17B: Discharge side bearing

18: main shell

19: Suction side housing

20: Outlet side shell

21: Internal cavity

26A: suction flow path on the male rotor side

26B: suction flow path on the female rotor side

27A: The flow path wall outside the rotor radial direction of the suction flow path on the male rotor side

27B: The flow path wall outside the rotor radial direction of the suction flow path on the female rotor side

Claims (6)

A screw compressor is provided with a male rotor having teeth, a female rotor having teeth meshing with the teeth of the male rotor, and a housing accommodating the male rotor and the female rotor, and The housing has: an inner cavity which accommodates the teeth of the male rotor and the teeth of the female rotor, and forms an operating chamber on the male rotor side and an operating chamber on the female rotor side in their cogging slots; a suction port, which is located The tooth part of the male rotor and the tooth part of the female rotor are more on the outer side of the rotor radial direction; and the suction flow path is formed by connecting the suction port and the working chamber of the suction stroke, and is related to the suction stroke The actuating chamber communicates along the axial direction of the rotor; and The suction flow path has a suction flow path on the male rotor side that is located on the male rotor side and is more downstream than the imaginary plane passing through the central axis of the male rotor and the central axis of the female rotor, and is located on the female rotor side and is more downstream than the above The imaginary plane is closer to the suction flow path on the downstream side of the female rotor; its characteristics are: The suction flow path on the male rotor side is formed in such a way that at least in the rotor axial direction from the suction side end surface of the tooth portion of the male rotor to half of the axial pitch of the tooth portion, the rotor radial direction The outer flow path wall becomes the same position as the wall of the inner cavity when viewed from the rotor axial direction. Such as the screw compressor of claim 1, where The suction flow path on the male rotor side is formed in such a way that at least in the rotation direction of the male rotor from the imaginary plane to the rotation direction pitch of the teeth of the male rotor, along the male rotor The area of the axial cross section of the rotor obtained by cutting in each radial direction, that is, the cross section of each flow path, is the same as the area of the radial cross section of the rotor of each working chamber on the male rotor side. Such as the screw compressor of claim 1 or 2, where The female rotor side suction flow path is formed in such a way that at least in the rotor axial direction from the suction side end surface of the female rotor tooth portion to half of the axial pitch of the tooth portion, the rotor radial direction The outer flow path wall becomes the same position as the wall of the inner cavity when viewed from the rotor axial direction. Such as the screw compressor of claim 3, where The suction flow path on the female rotor side is formed in such a way that at least in the rotation direction of the female rotor from the imaginary plane to the rotation direction pitch of the teeth of the female rotor, along the female rotor The area of the axial section of the rotor obtained by cutting in each radial direction, that is, the area of each flow path section is the same as the area of the radial section of the rotor of each working chamber on the female rotor side. A screw compressor is provided with a male rotor having teeth, a female rotor having teeth meshing with the teeth of the male rotor, and a housing accommodating the male rotor and the female rotor, and The housing has: an inner cavity which accommodates the teeth of the male rotor and the teeth of the female rotor, and forms an operating chamber on the male rotor side and an operating chamber on the female rotor side in their cogging slots; a suction port, which is located The tooth part of the male rotor and the tooth part of the female rotor are more on the outer side of the rotor radial direction; and the suction flow path is formed by connecting the suction port and the working chamber of the suction stroke, and is related to the suction stroke The actuating chamber communicates along the axial direction of the rotor; and The suction flow path has a suction flow path on the male rotor side that is located on the male rotor side and is more downstream than the imaginary plane passing through the central axis of the male rotor and the central axis of the female rotor, and is located on the female rotor side and is more downstream than the above The imaginary plane is closer to the suction flow path on the downstream side of the female rotor; its characteristics are: The female rotor side suction flow path is formed in such a way that at least in the rotor axial direction from the suction side end surface of the female rotor tooth portion to half of the axial pitch of the tooth portion, the rotor radial direction The outer flow path wall becomes the same position as the wall of the inner cavity when viewed from the rotor axial direction. Such as the screw compressor of claim 5, where The suction flow path on the female rotor side is formed in such a way that at least in the rotation direction of the female rotor from the imaginary plane to the rotation direction pitch of the teeth of the female rotor, along the female rotor The area of the axial section of the rotor obtained by cutting in each radial direction, that is, the area of each flow path section is the same as the area of the radial section of the rotor of each working chamber on the female rotor side.

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