CN111183288A - Screw compressor - Google Patents
Screw compressor Download PDFInfo
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- CN111183288A CN111183288A CN201880063296.8A CN201880063296A CN111183288A CN 111183288 A CN111183288 A CN 111183288A CN 201880063296 A CN201880063296 A CN 201880063296A CN 111183288 A CN111183288 A CN 111183288A
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- valve
- screw
- valve members
- pressure
- rotor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
- F04C18/48—Rotary-piston pumps with non-parallel axes of movement of co-operating members
- F04C18/50—Rotary-piston pumps with non-parallel axes of movement of co-operating members the axes being arranged at an angle of 90 degrees
- F04C18/52—Rotary-piston pumps with non-parallel axes of movement of co-operating members the axes being arranged at an angle of 90 degrees of intermeshing engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
- F04C28/10—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by changing the positions of the inlet or outlet openings with respect to the working chamber
- F04C28/12—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by changing the positions of the inlet or outlet openings with respect to the working chamber using sliding valves
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Applications Or Details Of Rotary Compressors (AREA)
Abstract
A screw compressor (1) is provided with a slide valve mechanism (50), the slide valve mechanism (50) adjusts the opening areas of cylinder openings (51A, 51B) formed in a cylinder portion (25) of a housing (10), and in the screw compressor (1), a plurality of valve members (52A, 52B) provided in the slide valve mechanism (50) are arranged for one compression chamber, and the opening areas of the cylinder openings (51A, 51B) are adjusted by the movement of the valve members in the axial direction of a screw rotor. A plurality of valve housing sections (53A, 53B) that house the valve members (52A, 52B) individually are provided in the housing (10).
Description
Technical Field
The invention relates to a screw compressor comprising a screw rotor, a gate rotor and a slide valve mechanism.
Background
Conventionally, a screw compressor has been used as a compressor for compressing a refrigerant or air. For example, patent document 1 discloses a screw compressor (single screw compressor) including one screw rotor and one gate rotor.
In the screw compressor, the screw rotor and the gate rotor are housed in a casing. The screw rotor is rotatably inserted into a cylinder portion provided at a central portion of the housing. A spiral screw groove is formed in the screw rotor, and a gate of the gate rotor engages with the screw groove to form a compression chamber. In the housing, a low pressure chamber and a high pressure chamber are formed. When the screw rotor rotates, the fluid in the low-pressure chamber is sucked into the compression chamber and compressed, and the fluid compressed in the compression chamber is discharged into the high-pressure chamber.
The screw compressor of patent document 1 is provided with a slide valve mechanism. The slide valve mechanism includes a valve member, and an inner surface (a surface located radially inside the housing) of the valve member is almost in contact with an outer peripheral surface of the screw rotor via an oil film. The cylinder portion is formed with a valve housing portion for housing the valve member so that the valve member can slide, and a slide groove (cylinder opening) is formed in a portion of the valve housing portion. The valve member is formed to have an arc-shaped cross section so as to be fitted into the valve housing, and a concave curved surface extending along the outer peripheral surface of the screw rotor is formed in a part of the valve member.
The slide valve mechanism is used to control the internal volume ratio of the compression mechanism or to control the operating capacity of the compressor. The position of the end surface of the valve member on the discharge side is changed in the axial direction of the screw rotor, whereby the size of the cylinder opening on the discharge side is adjusted, and the discharge timing is adjusted, whereby the internal volume ratio is controlled. Further, the operating capacity is controlled by adjusting the size of a bypass cylinder opening communicating with a bypass passage for returning the refrigerant during compression to the suction side of the compression chamber.
When the internal volume ratio is controlled, the valve member is moved in the axial direction, thereby adjusting the timing at which the refrigerant is discharged from the compression chamber to the high-pressure chamber of the housing through the discharge-side cylinder opening formed in the cylinder portion, and adjusting the ratio of the discharge volume to the suction volume. When the operation capacity is controlled, the valve member is moved in the axial direction, thereby adjusting the amount of return (the amount of discharge) of the refrigerant during compression to the low-pressure chamber of the casing through the cylinder opening for bypass formed in the cylinder portion.
Documents of the prior art
Patent document
Patent document 1: japanese laid-open patent publication No. Hei 6-042475
Disclosure of Invention
Technical problems to be solved by the invention
As described above, the cylinder opening formed on the discharge side of the valve member is an opening constituting the discharge port, and the pressure loss increases as the flow velocity of the discharged working fluid increases. Therefore, in order to reduce the pressure loss, it is desirable to increase the opening area of the ejection orifice to suppress the flow velocity. However, if the valve member 101 is enlarged to increase the opening area as shown in fig. 13, for example, the diameter of the valve member 101 becomes larger. As a result, the amount P of projection of the valve member 101 from the screw rotor 100 to the outside in the radial direction increases, and the valve housing portion housing the valve member 101 also increases, and therefore the housing of the screw compressor also increases in size.
The purpose of the present invention is to suppress the increase in size of a casing in a screw compressor provided with a slide valve.
Technical solution for solving technical problem
The invention in a first aspect relates to a screw compressor comprising: a screw rotor 30 having a spiral screw groove 31 formed therein; a gate rotor 40 having a gate 41 engaged with the screw groove 31; a housing 10 having a cylinder portion 25 therein, the screw rotor 30 being rotatably inserted into the cylinder portion 25; a compression chamber 23 formed by the screw rotor 30 and the gate rotor 40 engaging with each other inside the cylinder portion 25; and a slide valve mechanism 50 for adjusting the opening area of cylinder openings 51A, 51B formed in the cylinder portion 25 and communicating with the compression chamber 23,
the slide valve mechanism 50 of the screw compressor is characterized by comprising: a plurality of valve members 52A, 52B, the valve members 52A, 52B being disposed in relation to one compression chamber 23, each of the valve members 52A, 52B moving in the axial direction of the screw rotor 30 to adjust the opening area; and a plurality of valve housing portions 53A, 53B, the plurality of valve housing portions 53A, 53B being formed in the housing 10 and housing the respective valve members 52A, 52B individually.
In the first aspect of the invention, since the valve members 52A and 52B provided in the slide valve mechanism 50 are disposed in a single compressor in a plurality of divisions, the valve members 52A and 52B can be made smaller even if the opening area of the discharge port is increased. Therefore, the size increase of the casing 10 of the screw compressor can be suppressed.
In the second aspect of the present invention, in addition to the first aspect of the present invention, each of the valve housing portions 53A, 53B has a curved wall 54, the curved wall 54 protrudes from the cylinder portion 25 radially outward of the screw rotor 30 in an arc-shaped cross section and extends in the axial direction of the screw rotor 30, and the outer peripheral surface of each of the valve members 52A, 52B is formed by a curved surface in an arc-shaped cross section that is fitted into the curved wall 54 of the valve housing portion 53A, 53B. In this configuration, the "arc-shaped cross section" means that the cross section in the direction perpendicular to the axis is arc-shaped.
In the second aspect of the present invention, the portions where the valve members 52A, 52B are fitted to the valve housing portions 53A, 53B are formed in an arc-shaped cross section, and therefore the structure can be simplified. Further, since the fitting portion is formed into an arc-shaped cross section having no flat portion or the like, a decrease in strength of the housing 10 can be suppressed.
In the third aspect of the present invention, in addition to the first or second aspect of the present invention, the screw rotor 30 and the gate rotor 40 are provided in the housing 10 in a one-to-one relationship.
In the third aspect of the present invention, the casing 10 can be effectively downsized in a so-called single-gate rotor screw compressor.
A fourth aspect of the present invention is characterized in that, in any one of the first to third aspects of the present invention, the amounts of movement of the valve members 52A, 52B in the axial direction when the spool valve mechanism 50 is operated are different from each other. The axial movement amount of each valve member 52A, 52B is determined based on, for example, the movement amount by which the screw groove 31 changes its position at the position where each valve member 52A, 52B is provided.
In the fourth aspect of the present invention, since the amounts of movement of the valve members 52A, 52B in the axial direction are different from each other, the opening area of each of the valve members 52A, 52B can be optimized, the discharge port area can be effectively increased, and the pressure loss can be reduced.
In the fifth aspect of the present invention, in addition to any one of the first to fourth aspects of the present invention, each of the valve members 52A, 52B has a high-pressure-side end surface 57a, 57B, the high-pressure-side end surface 57a, 57B faces a flow path through which the high-pressure fluid compressed in the compression chamber 23 flows out to the discharge passage in the casing 10, and the inclination angles θ 1, θ 2 of the high-pressure-side end surfaces 57a, 57B of the valve members 52A, 52B are different from each other. The slopes (inclination angles θ 1, θ 2) of the high-pressure-side end surfaces 57a, 57B of the valve members 52A, 52B are determined based on, for example, the slope of the screw groove 31 at the position where the valve members 52A, 52B are provided.
In the fifth aspect of the present invention, since the slopes (the inclination angles θ 1, θ 2) of the high-pressure side end surfaces 57a, 57B of the valve members 52A, 52B are different from each other, the inclination angles θ 1, θ 2 of the valve members 52A, 52B can be optimized to effectively increase the discharge port area, and the pressure loss can be reduced.
The sixth aspect of the invention is characterized in that, in any one of the first to fifth aspects of the invention, the slide valve mechanism 50 includes: a drive mechanism 60 that moves at least one of the plurality of valve members 52A, 52B as a member to be driven; and an interlocking mechanism 70 for moving the other valve members 52A, 52B as driven members driven by the driving target member.
In the sixth aspect of the present invention, since the interlocking target member of the plurality of valve members 52A, 52B is driven by the driving target member, the amount of movement of each valve member 52A, 52B can be easily optimized for each valve member 52A, 52B. Therefore, the pressure loss can be reduced efficiently.
In the seventh aspect of the invention, in any one of the first to sixth aspects of the invention, the slide valve mechanism 50 is an operation capacity adjustment mechanism that returns a part of the intermediate pressure fluid during compression to the suction side of the compression chamber 23 through the bypass passages 59a, 59B of the housing 10, and each of the valve members 52A, 52B has a low pressure side end surface 58a, 58B that faces a flow passage through which the intermediate pressure fluid flows out from the compression chamber 23 to the bypass passages 59a, 59B, and the low pressure side end surfaces 58a, 58B of the valve members 52A, 52B are different from each other in position in the axial direction.
In the eighth aspect of the present invention, in the seventh aspect of the present invention, the opening areas on the side of the bypass passages 59a, 59B corresponding to the valve members 52A, 52B are determined to be substantially the same area. The axial position of the low-pressure side end surfaces 58a, 58B of the valve members 52A, 52B is determined based on the axial position of the screw groove 31 at the location where the valve members 52A, 52B are provided, for example.
In the seventh and eighth aspects of the invention, the positions of the low-pressure side end surfaces 58a, 58B of the valve members 52A, 52B in the axial direction are different, and particularly in the eighth aspect of the invention, the opening areas on the side of the bypass passages 59a, 59B corresponding to the valve members 52A, 52B are substantially the same area. Therefore, an appropriate amount of the refrigerant during compression can be returned to the low-pressure side of the compression mechanism for each valve member 52A, 52B, and therefore, the displacement control by unloading can be performed efficiently.
Drawings
Fig. 1 is a longitudinal sectional view (sectional view taken along line I-I of fig. 2) of the screw compressor of the embodiment.
Fig. 2 is a sectional view taken along line II-II of fig. 1.
Fig. 3 is a perspective view of the casing of the screw compressor of fig. 1 as viewed from the end surface on the discharge side.
Fig. 4 is an external view showing a state where the screw rotor and the gate rotor are engaged with each other.
Fig. 5 is a sectional view showing a meshed state of the screw rotor and the gate rotor.
Fig. 6 is a perspective view showing a state of engagement of the screw rotor with the gate rotor.
Fig. 7 is a development view showing a screw rotor in which the shape and arrangement of a valve member of a slide valve mechanism provided in the screw compressor of fig. 1 to 3 are shown.
Fig. 8 is a plan view of the slide valve mechanism.
Fig. 9 is a developed view of the screw rotor showing a state when the slide valve mechanism of modification 1 is fully loaded.
Fig. 10 is a development view of the screw rotor showing a state at the time of unloading of the slide valve mechanism of modification 1.
Fig. 11 is a side view showing a modification of the spool valve mechanism.
Fig. 12 is a top view of the slide valve mechanism of fig. 11.
Fig. 13 is a perspective view showing an example of a combination of a screw rotor and a slide valve in a conventional screw compressor.
Detailed Description
Hereinafter, embodiments will be described in detail with reference to the drawings.
The screw compressor 1 of the present embodiment shown in fig. 1 and 2 is used for a refrigeration air conditioner, and is provided in a refrigerant circuit that performs a refrigeration cycle and compresses a refrigerant. The screw compressor 1 includes a hollow casing 10 and a compression mechanism 20.
The casing 10 houses the compression mechanism 20 for compressing the low-pressure refrigerant at substantially the center thereof. Further, inside the housing 10, there are formed: a low-pressure chamber 11 into which a low-pressure gaseous refrigerant is introduced from an evaporator (not shown) of the refrigerant circuit and which guides the low-pressure gaseous refrigerant to the compression mechanism 20; and a high-pressure chamber 12, the high-pressure chamber 12 being located on the opposite side of the low-pressure chamber 11 with reference to the compression mechanism 20, and the high-pressure chamber 12 being supplied with a high-pressure gaseous refrigerant discharged from the compression mechanism 20.
A motor 15 having a rotor 15b rotating within a stator 15a is fixed within the housing 10, and the motor 15 and the compression mechanism 20 are coupled by a drive shaft 21 as a rotation shaft. A bearing holder 27 is provided in the housing 10. The end portion of the drive shaft 21 on the discharge side is supported by a bearing 26 attached to a bearing holder 27, and the intermediate portion of the drive shaft 21 is supported by a bearing 28.
The compression mechanism 20 includes: a cylinder portion 25 formed in the housing 10; a screw rotor 30 disposed in the cylinder portion 25; and a gate rotor 40 engaged with the screw rotor 30. The screw rotor 30 is attached to the drive shaft 21 and is locked with respect to the drive shaft 21 by a key groove (not shown). The screw compressor 1 of the present embodiment is a single screw compressor in which one screw rotor 30 and one gate rotor 40 are provided in a one-to-one relationship in the casing 10, respectively, so-called single gate rotors.
The cylinder portion 25 is formed in a central portion of the housing 10 with a predetermined thickness, and the screw rotor 30 is rotatably inserted into the cylinder portion 25. One surface side (right end in fig. 1) of the cylinder portion 25 faces the low pressure chamber 11, and the other surface side (left end in fig. 1) of the cylinder portion 25 faces the high pressure chamber 12. The cylinder portion 25 is not formed over the entire circumference of the screw rotor 30, and its end surface is inclined in accordance with the rotational direction of a screw groove 31 described later.
As shown in fig. 4 to 6, a plurality of (three in the present embodiment) helical screw grooves 31 are formed in the outer peripheral surface of the screw rotor 30. The screw rotor 30 is rotatably fitted to the cylinder portion 25, and the outer peripheral surface of the tooth tip thereof is surrounded by the cylinder portion 25.
On the other hand, each gate rotor 40 is formed in a disc shape having a plurality of (10 in the first embodiment) gates 41 arranged radially. The gate rotor 40 is disposed with its axial center on a plane orthogonal to the axial center of the screw rotor 30. The gate rotor 40 is configured such that the gate 41 penetrates a part of the cylinder portion 25 and meshes with the screw groove 31 of the screw rotor 30. In addition, the screw rotor 30 is made of metal, and the gate rotor 40 is made of synthetic resin.
The gate rotor 40 is disposed in a gate rotor chamber 14 defined in the housing 10. A driven shaft 45 as a rotation shaft is connected to the center of the gate rotor 40. The driven shaft 45 is rotatably supported by a bearing 46 provided in the gate rotor chamber 14. The bearing 46 is held by the housing 10 via a bearing housing.
An intake cover 16 is attached to an end surface of the casing 10 on the low pressure chamber 11 side, and an ejection cover 17 is attached to an end surface of the casing 10 on the high pressure chamber 12 side. In addition, the gate rotor chamber 14 of the housing 10 is covered by a gate rotor cover 18. A drive mechanism 60 for driving a spool valve mechanism 50, which will be described later, is mounted on the fixed plate 19 of the bearing holder 27 at a portion on the discharge side of the housing 10.
In the compression mechanism 20, a space surrounded by the inner peripheral surface of the cylinder portion 25, the screw groove 31 of the screw rotor 30, and the gate 41 of the gate rotor 40 serves as the compression chamber 23. In the screw rotor 30, the right end in fig. 1, 4, and 5 is the suction side, and the left end is the discharge side. Further, the outer peripheral portion of the suction side end portion 32 of the screw rotor 30 is formed in a tapered shape. The screw groove 31 of the screw rotor 30 is open to the low pressure chamber 11 at the suction side end 32, and this open portion serves as a suction port of the compression mechanism 20.
As the screw rotor 30 rotates, the gate 41 of the gate rotor 40 moves relative to the screw groove 31 of the screw rotor 30, and the compression mechanism 20 repeats the expansion and contraction operations of the compression chamber 23. Thereby, the suction stroke, the compression stroke, and the discharge stroke of the refrigerant are performed in this order.
As shown in fig. 3, the screw compressor 1 is provided with a slide valve mechanism 50, and the slide valve mechanism 50 is used to control an internal volume ratio (a ratio of a discharge volume to a suction volume of the compression mechanism 20) by adjusting a timing at which the compression chamber 23 communicates with the discharge port 24 (see fig. 7).
In the present embodiment, a plurality of spool valve mechanisms 50 are provided for one compression chamber 23 (in the present embodiment, two spool valve mechanisms 50 (a first spool valve mechanism 50A and a second spool valve mechanism 50B)) are provided. The spool valve mechanism 50 is a mechanism for adjusting the opening area of a cylinder opening 51 formed in the cylinder portion 25 so as to communicate with the compression chamber 23, and the compression chamber 23 is formed by engaging the gate 41 with the screw groove 31. As shown in fig. 3, the first spool valve mechanism 50A adjusts the opening area of the first cylinder opening 51A, and the second spool valve mechanism 50B adjusts the opening area of the second cylinder opening 51B.
The spool valve mechanism 50 includes two valve members 52 (a first valve member 52A and a second valve member 52B), and valve housing portions 53 (a first valve housing portion 53A and a second valve housing portion 53B) having the same number as the valve members 52A and 52B. In the present embodiment, as shown in fig. 7, the plurality of valve members 52A and 52B are provided so as to be movable in the axial direction of the screw rotor 30 with respect to one compression chamber 23. The valve housing portions 53A and 53B are formed in the cylinder portion 25 of the housing 10 along the axial direction. The valve housing portions 53A and 53B are portions that house the valve members 52A and 52B individually. The openings of the valve housing portions 53A, 53B on the screw rotor 30 side constitute cylinder openings 51A, 51B.
Each of the valve housing portions 53A and 53B has a curved wall 54, and the curved wall 54 protrudes from the cylinder portion 25 radially outward of the screw rotor 30 in an arc-shaped cross section and extends in the axial direction of the screw rotor 30. The outer peripheral surfaces of the valve members 52A and 52B are formed by curved surfaces 55 having an arc-shaped cross section and fitted into the curved walls 54 of the valve housing portions 53A and 53B. The "arc-shaped cross section" means that the cross section in the direction perpendicular to the axis is arc-shaped.
The amount of movement of the valve members 52A, 52B in the axial direction when the spool valve mechanism 50 is operated is determined based on the amount of movement of the screw groove 31 that changes in position in the axial direction at the locations where the valve members 52A, 52B are provided (points a, B in fig. 7). Further, since the displacement amounts of the screw grooves 31 that change their positions in the axial direction at the positions where the valve members 52A and 52B are provided are different from each other, the displacement amounts S1 and S2 of the valve members 52A and 52B in the axial direction are also determined to be different from each other as shown in fig. 8.
As shown in fig. 7, the valve members 52A and 52B have high-pressure-side end surfaces 57a and 57B, and the high-pressure-side end surfaces 57a and 57B face a flow path through which the high-pressure fluid compressed in the compression chamber 23 flows out to the discharge passage in the casing 10. The slopes (slope angles θ 1 and θ 2 in fig. 8) of the high-pressure-side end surfaces 57a and 57B of the valve members 52A and 52B are determined based on the slope of the screw groove 31 at the positions (points a and B in fig. 7) where the valve members 52A and 52B are provided. Further, since the inclination of the screw groove 31 changes continuously, the inclination of the screw groove 31 at the position where the valve members 52A, 52B are provided differs from each other, and therefore, the inclination angles θ 1, θ 2 of the high-pressure side end surfaces 57a, 57B of the valve members 52A, 52B differ from each other.
As shown in fig. 1, the spool valve mechanism 50 includes a drive mechanism 60, and the drive mechanism 60 moves one valve member 52A of the valve members 52A and 52B as a member to be driven. The drive mechanism 60 is coupled to the driven portions 56A, 56B of the valve members 52A, 52B shown in fig. 3 to drive the valve members 52A, 52B. Although a specific structure of the drive mechanism 60 is not illustrated, the drive mechanism 60 includes a cylinder portion provided on the discharge side of each of the valve members 52A and 52B in the housing 10, and a piston that advances and retracts in the axial direction of the screw rotor 30 in the cylinder portion.
The spool valve mechanism 50 includes an interlocking mechanism 70 (fig. 8), and the interlocking mechanism 70 moves one valve member 52B other than the drive target member among the valve members 52A and 52B as a driven target member driven by the drive target member.
In this embodiment, the interlocking mechanism 70 is constituted by a link mechanism. The link mechanism 70 is a mechanism in which link rods 71a and 71B provided on the suction-side end surfaces of the valve members 52A and 52B are coupled to a link arm 73 that can swing about a fulcrum pin 72. Since the distances (swing radii) from the fulcrum pins 72 to the connecting rods 71a and 71B are different, the amounts of movement (strokes S1 and S2) of the valve members 52A and 52B during the operation of the spool valve mechanism 50 are also different from each other. As described above, the movement amount of each valve member 52A, 52B is determined based on the movement amount by which the screw groove 31 changes its position in the axial direction at the position where each valve member 52A, 52B is provided (point a, point B in fig. 7).
The coupling portions between the links 71a and 71b and the link arm 73 are constituted by a pin 74a and a slit, the pin 74a is provided in the links 71a and 71b, and the slit is formed in the link arm 73 so as to engage with the pin 74 a.
In the case where three or more valve members 52 are provided, although not shown, the drive mechanism 60 may be configured to move at least one of the valve members 52 as a drive target member, and the interlocking mechanism 70 may be configured to move the remaining valve members 52 as driven target members that are driven by the drive target member.
When the positions of the valve members 52A and 52B of the slide valve mechanism 50 are adjusted, the positions of the high-pressure-side end surfaces 57a and 57B, which face the flow path through which the high-pressure refrigerant compressed in the compression chamber 23 flows out to the discharge passage in the housing 10, change, and therefore the opening area of the cylinder opening on the discharge side formed in the cylinder portion 25 of the housing 10 changes. Thereby, the timing at which the screw groove 31 communicates with the discharge port (not shown) during the rotation of the screw rotor 30 is changed, and therefore, the internal volume ratio of the compression mechanism 20 is adjusted.
-operation actions-
Next, the operation of the screw compressor 1 will be described.
When the motor is started in the screw compressor 1, the screw rotor 30 rotates as the drive shaft 21 rotates. As the screw rotor 30 rotates, the gate rotor 40 also rotates, and the compression mechanism 20 repeats an intake stroke, a compression stroke, and a discharge stroke.
In the compression mechanism 20, the screw rotor 30 rotates, and thereby the volume of the compression chamber 23 of the screw compressor 1 expands and then contracts with the relative movement of the screw groove 31 and the gate 41.
While the volume of the compression chamber 23 is expanded, the low-pressure gaseous refrigerant in the low-pressure chamber 11 is sucked into the compression chamber 23 through the suction port (suction stroke). When the rotation of the screw rotor 30 progresses, the compression chamber 23 is partitioned from the low pressure side by the gate 41 of the gate rotor 40, and at this time, the expansion operation of the volume of the compression chamber 23 is finished and the contraction operation is started. While the volume of the compression chamber 23 is reduced, the sucked refrigerant is compressed (compression stroke). The screw rotor 30 further rotates, whereby the compression chamber 23 continues to move, and finally, the discharge-side end portion communicates with the discharge port. When the discharge-side end of the compression chamber 23 is open and communicates with the discharge port, the high-pressure gas refrigerant is discharged from the compression chamber 23 to the high-pressure chamber 12 (discharge stroke).
Actuation of the slide valve mechanism
In the spool valve mechanism 50, the opening areas of the cylinder openings (openings communicating with the discharge port) 51A and 51B on the discharge side formed in the cylinder portion 25 of the housing 10 are changed by adjusting the positions of the valve members 52A and 52B, respectively. Then, the ratio of the discharge volume to the suction volume is changed by the change in the area, the internal volume ratio of the compression mechanism 20 is adjusted, and the timing at which the screw groove 31 communicates with the discharge port is changed during the rotation of the screw rotor 30.
In the present embodiment, the positions of the valve members 52A, 52B are changed by the amounts corresponding to the moving amounts S1, S2 of the screw groove 31 that are changed in position in the axial direction at the locations where the valve members 52A, 52B are provided (points a, B in fig. 7), and the respective moving amounts are different. Therefore, in the two valve members 52A and 52B, the communication between the screw groove 31 (compression chamber 23) passing through the high-pressure-side end surface 57a and the discharge port and the communication between the screw groove 31 (compression chamber 23) passing through the high-pressure-side end surface 57B and the discharge port are performed at the same timing, and the discharge opening area is enlarged as compared with the case where there is one valve member, and therefore, the flow velocity of the discharged gas is suppressed.
In the present embodiment, the slopes (the inclination angles θ 1, θ 2) of the high-pressure-side end surfaces 57a, 57B of the valve members 52A, 52B are determined based on the slope of the screw groove 31 at the positions (points a, B in fig. 7) where the valve members 52A, 52B are provided. Therefore, the discharge opening area is adjusted in a state where the positions and the inclination angles θ 1 and θ 2 of the high-pressure side end surfaces 57a and 57B of the valve members 52A and 52B are optimized. Therefore, the effect of reducing the pressure loss can be improved.
Effects of the embodiment
According to this embodiment, in a so-called single gate rotor screw compressor, since the valve members 52A and 52B provided in the slide valve mechanism 50 are divided into a plurality of (two) members and the plurality of (two) valve members 52A and 52B are arranged for one compressor, the respective valve members 52A and 52B can be made small even if the opening area of the discharge port is increased. Therefore, the size increase of the casing 10 of the screw compressor can be suppressed. In the present embodiment, since the valve housing portions 53A and 53B do not need to be enlarged, a decrease in rigidity of the casing 10 can be suppressed, and a deformation of the casing 10 at the time of pressure resistance is less likely to occur, and therefore, a decrease in dimensional accuracy due to the deformation can be suppressed.
In addition, in the present embodiment, since the portions where the valve members 52A and 52B are fitted to the valve housing portions 53A and 53B are formed in the shape of an arc in cross section, the structures of the valve members 52A and 52B and the valve housing portions 53A and 53B can be simplified, and the processing can be facilitated and the processing time can be shortened. Further, since the valve members 52A, 52B and the valve housing portions 53A, 53B have an arc-shaped cross section, a decrease in dimensional accuracy and a decrease in efficiency due to refrigerant leakage can also be suppressed. Further, since the fitting portions between the valve members 52A and 52B and the valve housing portions 53A and 53B are formed in an arc shape without providing flat portions, it is effective in suppressing a decrease in strength of the housing 10.
In the present embodiment, the amount of movement of the valve members 52A, 52B in the axial direction is determined by the amount of movement of the screw grooves 31 in the axial direction at the locations corresponding to the valve members 52A, 52B, and the slopes of the high-pressure-side end surfaces 57a, 57B of the valve members 52A, 52B are determined by the slopes of the screw grooves 31 at the locations corresponding to the valve members 52A, 52B, so that the discharge port area can be effectively increased, and the pressure loss can be efficiently reduced.
In the present embodiment, since the interlocking target member of the plurality of valve members 52A and 52B is driven by the driving target member, the amount of movement of each valve member 52A and 52B is appropriate and effective for the amount of movement in the axial direction of the screw groove 31 at the location where each valve member 52A and 52B is provided, and the effect of reducing the pressure loss can be enhanced.
Modification of embodiment
(modification 1)
Fig. 9 and 10 show a slide valve mechanism 50 according to modification 1.
The slide valve mechanism 50 is used as an operation capacity adjustment mechanism for performing an unloading operation in which a part of the intermediate-pressure gas refrigerant during compression is returned to the suction side of the compression chamber 23 through the bypass passages 59a and 59b of the casing 10. Fig. 9 shows the state of the valve members 52A, 52B when fully loaded without performing the unloading operation, and fig. 10 shows the state of the valve members 52A, 52B when unloaded.
In the slide valve mechanism 50 according to modification 1, the valve members 52A and 52B have low-pressure-side end surfaces 58a and 58B, and the low-pressure-side end surfaces 58a and 58B face a flow path through which a gas refrigerant of an intermediate pressure flows from the compression chamber 23 to the bypass passages 59a and 59B.
As shown in fig. 9 and 10, the positions of the low-pressure side end surfaces 58a and 58B of the valve members 52A and 52B in the axial direction are not on the same plane but are set at different positions from each other. The position in the axial direction of the low-pressure side end surfaces 58a, 58B of the valve members 52A, 52B is determined based on the position in the axial direction of the screw groove 23 at the location where the valve members 52A, 52B are provided (points C, D in fig. 9). The positions of the low-pressure side end surfaces 58a, 58B of the valve members 52A, 52B are determined as follows: in each of the valve members 52A and 52B, the passage areas of the bypass passages 59a and 59B formed to communicate with the screw groove 23 are substantially the same.
The other structures are the same as those of the above embodiment.
When the operation capacity of the screw compressor 1 is controlled, when the valve members 52A and 52B slide toward the high pressure side (the direction from fig. 9 to fig. 10), the opening areas of the cylinder openings 51A and 51B (the opening areas of the bypass passages 59a and 59B) located on the low pressure side end surfaces 58a and 58B of the valve members 52A and 52B increase. Therefore, the refrigerant returns from the cylinder openings 51A and 51B to the low-pressure chamber 11 of the casing 10 from the compression middle position of the compression chamber 23 through the bypass passages 59a and 59B.
In this case, the larger the opening area is, the larger the amount of returned intermediate-pressure refrigerant in the compression mechanism 20 is, and the smaller the operating capacity is. Conversely, when the valve members 52A and 52B slide toward the low pressure side (in the direction from fig. 10 to fig. 9), the opening area becomes smaller, and the amount of refrigerant returning to the low pressure chamber 11 becomes smaller. Therefore, the operating capacity becomes large. As described above, when the valve members 52A and 52B are slid and the opening areas of the cylinder openings 51A and 51B are changed, the flow rate of the refrigerant returning from the compression chamber 23 to the low-pressure side during compression changes, and therefore the capacity of the compression mechanism 20 changes.
In this modification, since the positions of the low-pressure side end surfaces 58a and 58B of the valve members 52A and 52B are determined such that the opening areas of the bypass passages 59a and 59B formed in the valve members 52A and 52B so as to communicate with the screw groove 23 are substantially the same, the amounts of refrigerant returned to the low-pressure side through the cylinder openings 51A and 51B formed in the low-pressure sides of the valve members 52A and 52B are substantially the same, and the amounts of refrigerant returned to the low-pressure chambers during compression are also uniform for each of the valve members 52A and 52B.
Conversely, for example, when the low-pressure side end surfaces 58a and 58B of the valve members 52A and 52B are not formed in the same positional relationship with respect to the screw groove 23, the amount of refrigerant returning to the low-pressure side in one valve member is reduced. Therefore, in this case, when compared with the slide valve mechanism 50 of modification 1, if the movement amounts of the valve members 52A and 52B are the same, the amount of refrigerant returning (the amount of unloading) decreases. Therefore, according to the slide valve mechanism 50 of modification 1, the return amounts of the refrigerant are substantially the same for each of the valve members 52A, 52B, and therefore the movement amounts of the valve members 52A, 52B can be reduced. Further, since an appropriate amount of the refrigerant during compression is returned to the low-pressure side of the compression mechanism for each valve member 52A, 52B, the capacity control by unloading can be efficiently performed.
In the screw compressor 1 using the slide valve mechanism 50 of modification 1, the plurality of valve members 52A and 52B are inserted into the plurality of valve housing portions 53A and 53B, and the shape thereof is formed in an arc-shaped cross section, similarly to the above-described embodiment. Therefore, the increase in size and the decrease in strength of the housing can be suppressed.
(modification 2)
Modification 2 shown in fig. 11 and 12 is an example in which the configuration of the interlocking mechanism 70 is different from that of the first embodiment shown in fig. 8.
The interlocking mechanism 70 of modification 2 is a mechanism using a rack and pinion. Specifically, the interlocking mechanism 70 is constituted by a first rack 75a fixed to the first valve member 52A, a first pinion 76a meshing with the first rack 75a, a second rack 75B fixed to the second valve member 52B, and a second pinion 76B meshing with the second rack 75B. The pinion gears 76a and 76b are fixed to a pinion shaft 76 c.
The slopes (inclination angles θ 1, θ 2) of the high-pressure side end surfaces 57a, 57B of the valve members 52A, 52B are different, as in the first embodiment. The strokes of the valve members 52A and 52B are also set to be different from each other as in the first embodiment. Therefore, pinions with different pitch circle diameters are used for the pinions 76a and 76 b.
The other structure is the same as that of the first embodiment.
The screw compressor 1 using the slide valve mechanism 50 of modification 2 is also configured in the same manner as in the above-described embodiment in that the plurality of valve members 52A, 52B are inserted into the plurality of valve housing portions 53A, 53B, and the shape thereof is formed in an arc-shaped cross section, as in the first embodiment. Therefore, the increase in size and the decrease in strength of the housing can be suppressed.
Other embodiments
The above embodiment may have the following configuration.
For example, in the above-described embodiment, the fitting surfaces of the valve members 52A, 52B and the valve housing portions 53A, 53B are formed as curved surfaces having an arc-shaped cross section, but may not necessarily be curved surfaces having an arc-shaped cross section, and if a plurality of (not limited to two) valve members 52A, 52B are provided for each compression chamber and the plurality of valve members 52A, 52B are housed in the valve housing portions 53A, 53B individually, even if the shape of the fitting surfaces is changed, it is possible to suppress an increase in size and a decrease in strength of the housing 10 as compared with a case where one large spool valve is used.
In addition, the above embodiment exemplifies the screw compressor 1 in which only one gate rotor 40 is provided for one screw rotor 30, but a screw compressor in which a plurality of gate rotors are provided may be employed.
In the above embodiment, the amount of movement of the valve members 52A, 52B in the axial direction and the inclination angles θ 1, θ 2 of the high-pressure-side end surfaces 57a, 57B of the valve members 52A, 52B are different from each other, but may be configured to be different from each other, and even if the amount of movement and the inclination angle of the valve members 52A, 52B are the same, the size reduction can be achieved.
In the above embodiment, when two valve members 52A and 52B are provided, one of the valve members is driven by the driving mechanism 60, and the other valve member is driven by the interlocking mechanism 70, but the configuration may be such that: the two valve members are driven by a drive mechanism 60, and the movement amounts thereof are adjusted by an interlocking mechanism 70.
The above embodiments are essentially preferred examples, and are not intended to limit the scope of the present invention, its application objects, or its uses.
Industrial applicability-
As described above, the present invention is useful for a screw compressor provided with a slide valve mechanism.
-description of symbols-
1 screw compressor
10 casing
20 compression mechanism
23 compression chamber
25 cylinder part
30 screw rotor
31 screw groove
40-gate rotor
41 gate
50 slide valve mechanism
51 cylinder opening
51A first Cylinder opening
51B second Cylinder opening
52 valve member
52A first valve part
52B second valve component
53 valve housing part
53A first valve housing
53B second valve housing
54 curved wall
55 curved surface
57a high-pressure side end face
57b high-pressure side end face
58a low pressure side end face
58b low pressure side end face
60 drive mechanism
70 interlocking mechanism.
Claims (8)
1. A screw compressor comprising:
a screw rotor (30) in which a helical screw groove (31) is formed;
a gate rotor (40) having a gate (41) engaged with the screw groove (31);
a housing (10) having a cylinder portion (25) therein, the screw rotor (30) being rotatably inserted into the cylinder portion (25);
a compression chamber (23) formed by the screw rotor (30) and the gate rotor (40) meshing with each other inside the cylinder portion (25); and
a slide valve mechanism (50) for adjusting the opening area of cylinder openings (51A, 51B) formed in the cylinder part (25) and communicating with the compression chamber (23),
the screw compressor described above is characterized in that,
the spool valve mechanism (50) includes:
a plurality of valve members (52A, 52B), the valve members (52A, 52B) being disposed with respect to one compression chamber (23), each of the valve members (52A, 52B) moving in the axial direction of the screw rotor (30) to adjust the opening area; and
and a plurality of valve housing sections (53A, 53B), wherein the plurality of valve housing sections (53A, 53B) are formed in the housing (10) and individually house the valve members (52A, 52B).
2. Screw compressor according to claim 1,
each of the valve housing sections (53A, 53B) has a curved wall (54), the curved wall (54) projecting from the cylinder section (25) radially outward of the screw rotor (30) in an arc-shaped cross section and extending in the axial direction of the screw rotor (30),
the outer peripheral surface of each valve member (52A, 52B) is formed by a curved surface having an arc-shaped cross section that is fitted to the curved wall (54) of the valve housing section (53A, 53B).
3. Screw compressor according to claim 1 or 2,
the screw rotor (30) and the gate rotor (40) are disposed in the housing (10) in a one-to-one relationship.
4. -screw compressor according to any one of the claims 1 to 3,
the amounts of movement of the valve members (52A, 52B) in the axial direction when the spool valve mechanism (50) is operated are different from each other.
5. The screw compressor according to any one of claims 1 to 4,
each valve member (52A, 52B) has a high-pressure-side end surface (57a, 57B), the high-pressure-side end surface (57a, 57B) faces a flow path through which high-pressure fluid compressed in the compression chamber (23) flows out to a discharge passage in the housing (10),
the inclination angles (theta 1, theta 2) of the high-pressure side end surfaces (57a, 57B) of the valve members (52A, 52B) are different from each other.
6. The screw compressor according to any one of claims 1 to 5,
the spool valve mechanism (50) includes:
a drive mechanism (60) that moves at least one of the plurality of valve members (52A, 52B) as a member to be driven; and
and an interlocking mechanism (70) for moving the other valve members (52A, 52B) as driven members driven by the driving target member.
7. The screw compressor according to any one of claims 1 to 6,
the slide valve mechanism (50) is an operating capacity adjusting mechanism that returns a part of the intermediate-pressure fluid during compression to the suction side of the compression chamber (23) via bypass passages (59a, 59b) of the housing (10),
each valve member (52A, 52B) has a low-pressure-side end surface (58a, 58B), the low-pressure-side end surface (58a, 58B) faces a flow path through which the intermediate-pressure fluid flows from the compression chamber (23) to the bypass path (59a, 59B),
the positions of the low-pressure side end surfaces (58a, 58B) of the valve members (52A, 52B) in the axial direction are different from each other.
8. Screw compressor according to claim 7,
the opening areas on the side of the bypass passages (59a, 59B) corresponding to the valve members (52A, 52B) are determined to be substantially the same area.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017208828A JP6500964B1 (en) | 2017-10-30 | 2017-10-30 | Screw compressor |
| JP2017-208828 | 2017-10-30 | ||
| PCT/JP2018/038630 WO2019087785A1 (en) | 2017-10-30 | 2018-10-17 | Screw compressor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111183288A true CN111183288A (en) | 2020-05-19 |
| CN111183288B CN111183288B (en) | 2021-03-26 |
Family
ID=66166731
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201880063296.8A Active CN111183288B (en) | 2017-10-30 | 2018-10-17 | Screw compressor |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP3683445B1 (en) |
| JP (1) | JP6500964B1 (en) |
| CN (1) | CN111183288B (en) |
| WO (1) | WO2019087785A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7128426B1 (en) * | 2021-03-31 | 2022-08-31 | ダイキン工業株式会社 | compressor |
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| US4704069A (en) * | 1986-09-16 | 1987-11-03 | Vilter Manufacturing Corporation | Method for operating dual slide valve rotary gas compressor |
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| CN102459906A (en) * | 2009-06-15 | 2012-05-16 | 大金工业株式会社 | Screw compressor |
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| JPH0780135B2 (en) | 1990-04-18 | 1995-08-30 | コクヨ株式会社 | Staple remover |
| JP4911260B1 (en) * | 2010-09-30 | 2012-04-04 | ダイキン工業株式会社 | Screw compressor |
| JP2012197734A (en) * | 2011-03-22 | 2012-10-18 | Daikin Industries Ltd | Screw compressor |
| JP2014029133A (en) * | 2012-07-31 | 2014-02-13 | Mitsubishi Electric Corp | Screw compressor |
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| WO2017094057A1 (en) * | 2015-11-30 | 2017-06-08 | 三菱電機株式会社 | Single-screw compressor and refrigeration cycle device |
| WO2017175298A1 (en) * | 2016-04-05 | 2017-10-12 | 三菱電機株式会社 | Screw compressor and refrigeration cycle device |
| RU2713784C1 (en) * | 2016-04-06 | 2020-02-07 | Битцер Кюльмашиненбау Гмбх | Screw compressor (versions) |
-
2017
- 2017-10-30 JP JP2017208828A patent/JP6500964B1/en active Active
-
2018
- 2018-10-17 EP EP18874619.2A patent/EP3683445B1/en active Active
- 2018-10-17 WO PCT/JP2018/038630 patent/WO2019087785A1/en unknown
- 2018-10-17 CN CN201880063296.8A patent/CN111183288B/en active Active
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|---|---|---|---|---|
| JPS61277885A (en) * | 1985-06-03 | 1986-12-08 | ヴイルタ−・マニユフアクチヤリング・コ−ポレ−シヨン | Rotary screw type gas compressor with double slide valve |
| US4704069A (en) * | 1986-09-16 | 1987-11-03 | Vilter Manufacturing Corporation | Method for operating dual slide valve rotary gas compressor |
| CN101657641A (en) * | 2007-02-22 | 2010-02-24 | 维尔特制造有限责任公司 | Compressor with dual slide valve assembly |
| JP2009002257A (en) * | 2007-06-22 | 2009-01-08 | Daikin Ind Ltd | Single screw compressor and its assembling method |
| CN102459906A (en) * | 2009-06-15 | 2012-05-16 | 大金工业株式会社 | Screw compressor |
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Also Published As
| Publication number | Publication date |
|---|---|
| EP3683445B1 (en) | 2023-11-08 |
| WO2019087785A1 (en) | 2019-05-09 |
| JP2019082123A (en) | 2019-05-30 |
| EP3683445A1 (en) | 2020-07-22 |
| CN111183288B (en) | 2021-03-26 |
| JP6500964B1 (en) | 2019-04-17 |
| EP3683445A4 (en) | 2020-12-09 |
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