JP2005030360A - Screw compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screw compressor enabling an increase in performance by preventing a fluid from leaking in the peripheral direction of a screw rotor. <P>SOLUTION: The facing surface 10 of a screw rotor 1 and the facing surface 20 of a stationary member 2 are smoothly finished. Also, a covering member 3 is installed on an end face 11 and a peripheral surface 12 forming the facing surface 10 of the screw rotor 1 to prevent the fluid from leaking in the peripheral direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a screw compressor used for refrigerant compression of a refrigerator, for example.

  In general, as shown in FIG. 7, the screw compressor includes a casing 40, a screw rotor 41 disposed in the casing 40, and a bearing that supports a journal 46 on one end side of the screw rotor 41 via a bearing 44. A holder 45.

  The screw rotor 41 has a plurality of screw grooves 41a, and a pair of gate rotors 42 and 42 arranged so as to sandwich the screw rotor 41 in the radial direction of the screw rotor 41 mesh with the screw groove 41a. ing. The shaft portion 43 on the other end side of the screw rotor 41 is connected to a motor (not shown). When the motor is driven, the screw rotor 41 is rotated around the axis and the gate rotor 42 is moved to the axis. Rotate around the axis perpendicular to

  As the screw rotor 41 rotates, the low-pressure fluid (refrigerant gas) sucked from the shaft portion 43 side is sent along the screw groove 41a to the journal 46 side and discharged. At this time, the casing 40, the screw groove 41a, and the pair of gate rotors 42 and 42 form an upper compression chamber 31 formed of a screw groove and a lower compression chamber 32 formed of a screw groove.

  In the screw compressor, the high-pressure fluid in the compression chambers 31 and 32 formed of the screw groove leaks to the low-pressure bearing 44 side through the space between the screw rotor 41 and the bearing holder 45. In order to prevent this, as shown in FIG. 8, an annular labyrinth groove 50 that is continuous with a cylindrical surface that is the facing surface of the bearing holder 45 facing the screw rotor 41 is provided (Japanese Patent Laid-Open No. 6-101672: Patent Document 1).

However, in the conventional screw compressor, since the labyrinth groove 50 has a continuous annular shape, the high-pressure fluid in the compression chambers 31 and 32 passes through the annular continuous labyrinth groove 50, and FIG. As indicated by the arrows B and C in the middle, the compression chambers 31 and 32 leaked into the low-pressure screw groove. In short, the continuous annular labyrinth groove 50 serves as a bypass passage in the circumferential direction, leading to an increase in fluid leakage from the high-pressure screw groove to the low-pressure screw groove. The leakage in the circumferential direction caused a large performance drop compared to the leakage toward the bearing 44.
JP-A-6-101672 (paragraph number [0002])

  Then, the subject of this invention is providing the screw compressor which can aim at the improvement of performance by preventing that a fluid leaks to the circumferential direction of a screw rotor.

In order to solve the above problems, a screw compressor according to the present invention is a screw compressor including a screw rotor and a stationary member disposed to face the discharge side in the axial direction of the screw rotor,
The opposed surface of the screw rotor and the opposed surface of the stationary member are opposed to each other,
The opposing surfaces are smooth, and a covering member is provided on at least one of the opposing surfaces.

  According to this invention, since the opposing surface of the screw rotor and the opposing surface of the stationary member are smooth, there is no conventional continuous annular labyrinth groove (that is, a bypass passage in the circumferential direction), and the fluid is Leakage in the circumferential direction of the opposing surface can be prevented, and performance can be improved. In addition, since the covering member is provided on at least one of the opposing surfaces, even if the screw rotor approaches the stationary member, the covering member is worn and seizure can be avoided.

  Moreover, in the screw compressor of one Embodiment, the said coating | coated member is contacting the said both opposing surfaces.

  According to the screw compressor of this embodiment, the gap between the opposing surfaces can be eliminated by the covering member, and fluid leakage can be more reliably prevented.

  In the screw compressor of one embodiment, the opposed surface has an end surface perpendicular to the axis of the screw rotor, and a peripheral surface coaxial with the axis, and the end surface and the peripheral surface The covering member is provided on at least one of them.

  According to the screw compressor of this embodiment, since the facing surface has an end surface and a peripheral surface, the facing surface forms a stepped structure and ensures that the fluid leaks to the low pressure side. Can be prevented. Specifically, fluid leakage in the radial direction and circumferential direction of the screw rotor is prevented at the end face, and fluid leakage in the axial direction and circumferential direction of the screw rotor is prevented at the circumferential face. prevent.

Further, the screw compressor of the present invention is a screw compressor including a screw rotor and a stationary member disposed opposite to the axial direction discharge side of the screw rotor,
The opposed surface of the screw rotor and the opposed surface of the stationary member are opposed to each other,
A labyrinth groove is provided on at least one of the opposing surfaces, and the labyrinth groove is composed of a plurality of groove portions separated in the circumferential direction.

  According to this invention, since the labyrinth groove is composed of a plurality of groove portions separated in the circumferential direction, the labyrinth groove has a structure in which a continuous annular labyrinth groove is intermittently separated in the circumferential direction to divide the passage. The fluid can be prevented from leaking through the groove portion in the circumferential direction of the facing surface, and the performance can be improved. Moreover, since the labyrinth groove is provided, fluid leakage to the axial center side of the screw rotor and seizure due to contact between the screw rotor and the stationary member can be avoided.

  In the screw compressor of one embodiment, the opposed surface has an end surface perpendicular to the axis of the screw rotor, and a peripheral surface coaxial with the axis, and the end surface and the peripheral surface The labyrinth groove is provided in at least one of the above.

  According to the screw compressor of this embodiment, since the facing surface has an end surface and a peripheral surface, the facing surface forms a stepped structure and ensures that the fluid leaks to the low pressure side. Can be prevented. Specifically, fluid leakage in the radial direction and circumferential direction of the screw rotor is prevented at the end face, and fluid leakage in the axial direction and circumferential direction of the screw rotor is prevented at the circumferential face. prevent.

  In one embodiment of the screw compressor, the end face has at least one groove in any radial direction of the end face.

  According to the screw compressor of this embodiment, the labyrinth effect is obtained in all radial directions of the end face. If the flat portion where the groove does not exist is continuous in the radial direction, the labyrinth effect cannot be obtained at that location, and fluid leakage increases.

  Moreover, in the screw compressor of one Embodiment, it has at least 1 said groove part in all the bus-line directions of the said surrounding surface in the said surrounding surface.

  According to the screw compressor of this embodiment, the labyrinth effect can be obtained in any bus direction of the peripheral surface. If the flat portion where the groove does not exist is continuous in the generatrix direction, the labyrinth effect cannot be obtained at that location, and fluid leakage increases.

  According to the screw compressor of the present invention, since the opposed surface of the screw rotor and the opposed surface of the stationary member are smooth, there is no conventional circumferential bypass passage, and fluid flows in the circumferential direction of the opposed surface. Leakage can be prevented and performance can be improved. In addition, since the covering member is provided on at least one of the opposing surfaces, even if the screw rotor approaches the stationary member, the covering member is worn and seizure can be avoided.

  Further, according to the screw compressor of one embodiment, since the covering member is in contact with the opposing surfaces, the clearance between the opposing surfaces can be eliminated by the covering member, and fluid leakage Can be more reliably prevented.

  Further, according to the screw compressor of one embodiment, since the facing surface has an end surface and a peripheral surface, the facing surface forms a stepped structure and leaks fluid to the low pressure side. It can be surely prevented.

  Further, according to the screw compressor of the present invention, the labyrinth groove is composed of a plurality of groove portions separated in the circumferential direction, so that fluid is prevented from leaking through the groove portion in the circumferential direction of the facing surface. And the performance can be improved. Moreover, since the labyrinth groove is provided, fluid leakage to the axial center side of the screw rotor and seizure due to contact between the screw rotor and the stationary member can be avoided.

  Further, according to the screw compressor of one embodiment, since the facing surface has an end surface and a peripheral surface, the facing surface forms a stepped structure and leaks fluid to the low pressure side. It can be surely prevented.

  Moreover, according to the screw compressor of one embodiment, since the end face has at least one groove portion in any radial direction of the end face, a labyrinth effect can be obtained in any radial direction of the end face.

  Moreover, according to the screw compressor of one embodiment, since the circumferential surface has at least one groove portion in every bus line direction of the circumferential surface, a labyrinth effect can be obtained in every bus line direction of the circumferential surface.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1: has shown the principal part expanded sectional view which is one Embodiment of the screw compressor of this invention. The screw compressor includes a screw rotor 1 and a stationary member 2 disposed to face the discharge side in the axial direction of the screw rotor 1.

  Since this screw compressor has the same configuration as the conventional screw compressor of FIG. 7 except for the structure between the screw rotor 1 and the stationary member 2, the description thereof will be omitted. Also, the same reference numerals as those in FIG. 7 have the same configuration as in FIG. Moreover, in FIG. 1, the clearance gap between the said screw rotor 1 and the said stationary member 2 is drawn larger than actual.

  The screw rotor 1 has a screw groove 1a, and a compression chamber 31 is formed by the screw groove 1a and a casing and a gate rotor (not shown). The stationary member 2 is a bearing holder.

  The facing surface 10 of the screw rotor 1 and the facing surface 20 of the stationary member 2 face each other.

  The opposing surface 10 of the screw rotor 1 is smooth, and is sequentially connected to the end surface 11 from the outer peripheral surface of the screw rotor 1 and a radial end surface 11 perpendicular to the axis of the screw rotor 1. It has the (outer) peripheral surface 12 coaxial with the said axial center. Similarly, the opposing surface 20 of the stationary member 2 is smooth and has an end surface 21 and an (inner) peripheral surface 22 connected to the end surface 21. In short, the screw rotor 1 has a stepped protrusion that forms the facing surface 10, and the stationary member 2 has a stepped recess that forms the facing surface 20.

  The covering member 3 is provided on the end surface 11 and the peripheral surface 12 which are the opposed surfaces 10 of the screw rotor 1. The covering member 3 is made of a material softer than the screw rotor 1 and the stationary member 2 such as a fluororesin film such as polytetrafluoroethylene (PTFE).

  According to the screw compressor having the above-described configuration, since the facing surface 10 of the screw rotor 1 and the facing surface 20 of the stationary member 2 are smooth, the fluid (refrigerant gas) is prevented from leaking in the circumferential direction. And the performance can be improved. Of course, fluid leakage to the axial center side of the screw rotor 1 can be prevented. In addition, since the covering member 3 is disposed on the opposing surface 10 of the screw rotor 1, even if the screw rotor 1 approaches the stationary member 2, the covering member 3 is worn to avoid seizure. it can.

  Further, since the end faces 11 and 21 are provided, leakage of fluid in the radial direction and the circumferential direction of the screw rotor 1 is prevented, and since the peripheral faces 12 and 22 are provided, the axial center direction and the circumferential direction of the screw rotor 1 are provided. Prevent fluid leakage into the.

  Although not shown, the covering member 3 may be provided only on the facing surface 20 of the stationary member 2 or on both the facing surface 10 of the screw rotor 1 and the facing surface 20 of the stationary member 2. Good. The covering member 3 may be provided only on one of the end surfaces 11 and 21 or the peripheral surfaces 12 and 22.

(Second Embodiment)
FIG. 2 shows another embodiment of the screw compressor of the present invention. In this screw compressor, a plurality of concentric labyrinth grooves 4 arranged at equal intervals are provided on the end surface 11 and the peripheral surface 12 which are opposing surfaces 10 of the screw rotor 1. Since other structures are the same as those of the first embodiment, description thereof is omitted.

  Specifically, the labyrinth groove 4 of the end face 11 is composed of a plurality of groove portions 4a separated at equal intervals in the circumferential direction, as shown in FIG. In other words, the labyrinth groove 4 has a structure in which a continuous annular labyrinth groove is intermittently provided in the circumferential direction to divide the passage. Moreover, in the said labyrinth groove | channel 4, the flat part 4b in which this groove part 4a does not exist is provided between the said groove parts 4a and 4a adjacent to the circumferential direction. The flat portion 4b is connected in a substantially straight line in the radial direction of the end face 11.

  Similarly, the labyrinth groove 4 of the peripheral surface 12 is formed from a plurality of groove portions 4a separated at equal intervals in the circumferential direction, as shown in the plan view of FIG. 4A and the cross-sectional view of FIG. Become. In one labyrinth groove 4, a flat portion 4b is provided between the groove portions 4a and 4a adjacent in the circumferential direction. The flat portion 4b is connected in a substantially straight line in the generatrix direction of the peripheral surface 12.

  According to the screw compressor having the above-described configuration, the labyrinth groove 4 includes a plurality of groove portions 4a separated in the circumferential direction, so that fluid can be prevented from leaking in the circumferential direction, and performance can be improved. be able to. Further, since the labyrinth groove 4 is provided, fluid leakage to the axial center side of the screw rotor 1 and seizure due to contact between the screw rotor 1 and the stationary member 2 can be avoided. Since other effects are the same as those in the first embodiment, description thereof is omitted.

  Although not shown, the labyrinth groove 4 may be provided only on the facing surface 20 of the stationary member 2. The labyrinth groove 4 may be provided only on one of the end surfaces 11 and 21 or the peripheral surfaces 12 and 22.

(Third embodiment)
5 and 6 show another embodiment of the screw compressor of the present invention. In this screw compressor, as shown in FIG. 5, the end face 11 of the screw rotor 1 has at least one groove 4a in every radial direction of the end face 11, and further, as shown in FIG. In addition, the peripheral surface 12 of the screw rotor 1 has at least one groove portion 4a in any generatrix direction of the peripheral surface 12. Since other structures are the same as those in the first and second embodiments, description thereof is omitted.

  Specifically, in the labyrinth groove 4 of the end surface 11, the flat portions 4 b are alternately provided in the radial direction of the end surface 11 as shown in FIG. 5. In other words, the groove 4b is provided in a staggered manner in the radial direction of the end face 11.

  Similarly, in the labyrinth groove 4 of the peripheral surface 12, the flat portions 4 b are alternately provided in the generatrix direction of the peripheral surface 12 as shown in FIG. 6. In other words, the grooves 4b are provided in a staggered manner in the direction of the generatrix of the peripheral surface 12.

  According to the screw compressor configured as described above, a labyrinth effect can be obtained in all radial directions of the end surface 11. Moreover, the labyrinth effect is acquired in all the bus line directions of the said surrounding surface 12. FIG. Since other effects are the same as those of the first and second embodiments, description thereof is omitted.

  The present invention is not limited to the above-described embodiment, and the design can be changed without departing from the gist of the present invention. For example, the opposing surfaces 10 and 20 may be only the end surfaces 11 and 21 or only the peripheral surfaces 12 and 22.

  Moreover, the said stationary member 2 says a casing or a spacer other than a bearing holder, for example. In addition to the fluororesin film such as PTFE, the covering member 3 is, for example, a resin film containing molybdenum disulfide, or a eutectoid particle of a fluorine compound such as PTFE in a metal matrix such as Ni-P (nickel-phosphorus). It consists of a composite plating film in which is dispersed. The discharge side of the screw rotor 1 refers to one end side (journal side) of the screw rotor 1 and is the side from which fluid (refrigerant gas) sucked from the other end side of the screw rotor 1 is discharged. The axial direction is defined with reference to the screw rotor 1.

  Further, on the peripheral surfaces 12 and 22 of the facing surfaces 10 and 20, the screw rotor 1 is an outer peripheral surface and the stationary member 2 is an inner peripheral surface, and the screw rotor 1 is an inner peripheral surface and the stationary surface. The member 2 may be an outer peripheral surface.

  The covering member 2 (or the labyrinth groove 4) may be provided on the end surface 11 of the screw rotor 1 and the peripheral surface 22 of the stationary member 2, or the covering member 2 (or the labyrinth groove 4). ) May be provided on the peripheral surface 12 of the screw rotor 1 and the end surface 21 of the stationary member 2.

  Moreover, it is preferable to provide the labyrinth groove 4 on either one of the opposing surfaces 10 and 20, so that the leakage of fluid in the circumferential direction can be more reliably prevented. Specifically, the labyrinth groove 4 is provided on either one of both end faces 11 and 21 (or both peripheral faces 12 and 22).

It is a principal part expanded sectional view which shows one Embodiment of the screw compressor of this invention. It is a principal part expanded sectional view which shows other embodiment of the screw compressor of this invention. It is a front view which shows a screw rotor. It is composition explanatory drawing which shows a screw rotor. It is a front view which shows another embodiment of the screw compressor of this invention, and shows a screw rotor. It is a top view which shows a screw rotor. It is a partial cross section side view which shows the conventional screw compressor. It is an expanded sectional view of the A section of FIG. It is action explanatory drawing seen from the front side of the conventional screw compressor.

Explanation of symbols

1 Screw rotor 2 Stationary member (bearing holder)
DESCRIPTION OF SYMBOLS 3 Cover member 4 Labyrinth groove 4a Groove part 10 Opposing surface 11 End surface 12 Peripheral surface 20 Opposing surface 21 End surface 22

Claims (7)

A screw compressor comprising a screw rotor (1) and a stationary member (2) arranged opposite to the axial direction discharge side of the screw rotor (1),
The opposed surface (10) of the screw rotor (1) and the opposed surface (20) of the stationary member (2) are opposed to each other,
Both the opposing surfaces (10, 20) are smooth, and a screw compressor is characterized in that a covering member (3) is provided on at least one of the opposing surfaces (10, 20). The screw compressor according to claim 1,
The screw compressor, wherein the covering member (3) is in contact with the opposing surfaces (10, 20). The screw compressor according to claim 1 or 2,
The opposed surfaces (10, 20) have end faces (11, 21) perpendicular to the axis of the screw rotor (1) and peripheral surfaces (12, 22) coaxial with the axis. The screw compressor, wherein the covering member (3) is provided on at least one of the end surfaces (11, 21) and the peripheral surfaces (12, 22). A screw compressor comprising a screw rotor (1) and a stationary member (2) arranged opposite to the axial direction discharge side of the screw rotor (1),
The opposed surface (10) of the screw rotor (1) and the opposed surface (20) of the stationary member (2) are opposed to each other,
A labyrinth groove (4) is provided in at least one of the opposing surfaces (10, 20), and the labyrinth groove (4) is composed of a plurality of groove portions (4a) separated in the circumferential direction. Screw compressor to do. The screw compressor according to claim 4, wherein
The opposed surfaces (10, 20) have end faces (11, 21) perpendicular to the axis of the screw rotor (1) and peripheral surfaces (12, 22) coaxial with the axis. The screw compressor, wherein the labyrinth groove (4) is provided in at least one of the end surfaces (11, 21) and the peripheral surfaces (12, 22). The screw compressor according to claim 5,
The screw compressor characterized in that the end face (11, 21) has at least one groove (4a) in any radial direction of the end face (11, 21). The screw compressor according to claim 5,
The screw compressor characterized in that the peripheral surface (12, 22) has at least one groove (4a) in any bus line direction of the peripheral surface (12, 22).

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