JP2014070567A - Single screw compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the slide resistance of a gate rotor compared to conventional arts to improve the operation efficiency of a single screw compressor.SOLUTION: In an inner surface 2 of a through hole 3 in a cylindrical wall 30 of a single screw compressor 1, a non-slide contact surface 2a brought into non-slide contact with an end surface 52 of a gate rotor 50, and a flat surface 2b brought into slide contact with the end surface 52 of the gate rotor 50 are formed. A boundary C between the non-slide contact surface 2a and the flat surface 2b is positioned so as to be opposite to a rear edge 51a of a gate 51 forming a compression chamber 23 right after closing. The non-slide contact surface 2a is arranged on the rear side of the boundary C, and the flat surface 2b is arranged on the front side thereof.

Description

    The present invention relates to a single screw compressor, and particularly relates to measures for reducing sliding loss of a gate rotor.

    2. Description of the Related Art Conventionally, there is known a single screw compressor that includes one screw rotor and two gate rotors housed in a casing, and compresses fluid in a compression chamber formed by meshing a spiral groove of the screw rotor and a gate of the gate rotor. (For example, see Patent Document 1).

    This single screw compressor has a cylindrical wall formed in its casing. A screw rotor is rotatably accommodated inside the cylindrical wall. The inner surface of the cylindrical wall of the casing and the outer surface of the screw rotor are configured to be slidable, and a spiral groove is formed on the outer surface of the screw rotor. A through hole is formed in the cylindrical wall of the casing. A gate rotor accommodating chamber communicates with the outside of the through hole, and the gate rotor is disposed in the gate rotor accommodating chamber. This gate rotor has a plurality of gates provided radially. The gate of the gate rotor is engaged with the spiral groove of the screw rotor through the through hole of the cylindrical wall of the casing, and a compression chamber is formed between the spiral groove, the gate, and the inner surface of the cylindrical wall.

    Here, the end surface of the gate of the gate rotor and the inner surface of the through hole of the cylindrical wall of the casing are brought into sliding contact with each other, and the end surface of the gate rotor of the gate rotor and the inner surface of the through hole of the cylindrical wall of the casing The gap is sealed so that fluid does not leak from the compression chamber.

JP 2009-2326 A

    However, in the case of the conventional single screw compressor, before the gate of the gate rotor reaches the closed position of the compression chamber, the end surface of the gate of the gate rotor and the inner surface of the through hole of the cylindrical wall of the casing are slid. The gap between the end face of the gate of the gate rotor and the inner surface of the through hole of the cylindrical wall of the casing is sealed. For this reason, there existed a problem that the sliding resistance of the said gate rotor will increase.

    This invention is made | formed in view of this point, The objective is to reduce the sliding resistance of a gate rotor than before, and to improve the operating efficiency of a single screw compressor.

    According to a first aspect of the present invention, there is provided a casing (10) having a cylindrical wall (30) formed therein, and a screw rotor accommodated in the cylindrical wall (30) of the casing (10) and having a plurality of spiral grooves (41) ( 40) and a gate rotor (50) in which a plurality of gates (51) that engage with the spiral groove (41) through a through hole (3) formed in the cylindrical wall (30) of the casing (10) are radially formed. A single screw compressor that compresses fluid in a compression chamber (23) formed by meshing a spiral groove (41) of the screw rotor (40) and a gate (51) of the gate rotor (50). . And the inner surface (2) of the through-hole (3) of the cylindrical wall (30) is located at a position facing the rear edge (51a) of the gate (51) that forms the compression chamber (23) immediately after closing ( C), the non-sliding contact surface (2a) that is non-sliding contact with the end surface (52) of the gate (51) on the rear side of the rear edge (51a) of the gate (51), and the boundary (C) In addition, a flat surface (2b) that is in sliding contact with the end surface (52) of the gate is provided on the front side of the rear edge (51a) of the gate (51).

    In the first invention, the gate rotor (50) rotates with the rotation of the screw rotor (40), and the front edge (51b) of the gate (51) of the gate rotor (50) is the boundary (C) of the inner surface. The end surface (52) of the gate (51) and the inner surface (2) of the through hole (3) of the cylindrical wall (30) are not slidably contacted by the non-sliding surface (2a). Then, when the rotation of the gate rotor (50) advances and the front edge (51b) of the gate (51) of the gate rotor (50) reaches the boundary (C) of the inner surface (2), the gate (51 ) And the flat surface (2b) of the inner surface (2) begin to slidably contact each other. When the rotation of the gate rotor (50) further proceeds, the end surface (52) of the gate (51) gradually comes into sliding contact with the flat surface (2b) from the front edge (51b) toward the rear edge (51a), Finally, when the rear edge (51a) of the gate (51) reaches the boundary (C), the entire end surface (52) of the gate (51) is formed on the inner surface (2) of the through hole (3). The flat surface (2b) is slidably contacted, and the compression chamber (23) is closed.

    According to a second invention, in the first invention, the non-sliding contact surface (2a) of the inner surface (2) is formed so that the non-sliding contact surface (2a) and the gate (51) ) Is inclined so that the gap with the end surface (52) is small.

    In the second invention, as the gate rotor (50) rotates, the gate (51) of the gate rotor (50) gradually approaches the inner surface (2) of the through hole (3) of the cylindrical wall (30). . Thereby, the impact when the end surface (52) of the gate (51) and the inner surface (2) of the through hole (3) contact at the boundary (C) is alleviated.

    According to a third aspect, in the first aspect, the non-sliding contact surface (2a) of the inner surface (2) is formed so that the non-sliding contact surface (2a) and the gate (51) ) Is formed of a stepped surface formed so that the gap with the end surface (52) is gradually reduced.

    In the third invention, as the gate rotor (50) rotates, the gate (51) of the gate rotor (50) is stepped on the inner surface (2) of the through hole (3) of the cylindrical wall (30). Get closer. Thereby, the impact when the end surface (52) of the gate (51) and the inner surface (2) of the through hole (3) come into contact with each other is reduced.

    According to the present invention, since the non-sliding contact surface (2a) is formed on the inner surface (2) of the through hole (3) of the cylindrical wall (30) of the casing (10), the gate of the gate rotor (50) Until the front edge (51b) of (51) reaches the boundary (C) of the inner surface (2), the end surface (52) of the gate (51) and the through hole (3) of the cylindrical wall (30) There is no sliding contact with the inner surface (2). In this case, until the front edge (51b) of the gate (51) reaches the boundary (C) of the inner surface (2), the end surface (52) of the gate (51) and the cylindrical wall (30) penetrate. Although a gap is formed between the hole (3) and the inner surface (2), the compression chamber (23) is not in a closed state, and therefore it is not necessary to seal this gap.

    As a result, the end surface (52) of the gate (51) and the inner surface (2) of the through hole (3) of the cylindrical wall (30) are prevented from being slid in vain. The sliding loss of the gate rotor (50) can be reduced, and the operating efficiency of the single screw compressor can be improved.

    According to the second aspect of the invention, the gate rotor (50) gate (51) gradually approaches the inner surface (2) of the through hole (3) of the cylindrical wall (30) so that the gate rotor The impact when the gate (51) of (50) and the inner surface (2) of the through hole (3) of the cylindrical wall (30) contact at the boundary (C) was reduced. Thereby, abrasion and breakage of the gate (51) of the gate rotor (50) can be suppressed.

    According to the third aspect of the invention, the gate (51) of the gate rotor (50) approaches the inner surface (2) of the through hole (3) of the cylindrical wall (30) in a stepwise manner. The impact was mitigated when the gate (51) of the rotor (50) and the inner surface (2) of the through hole (3) of the cylindrical wall (30) contacted at the boundary (C). Thereby, abrasion and breakage of the gate (51) of the gate rotor (50) can be suppressed.

Drawing 1 is a schematic diagram of a single screw compressor concerning an embodiment. FIG. 2 is a cross-sectional view of the single screw compressor according to the embodiment. FIG. 3 is a perspective view showing the screw rotor and the gate rotor. FIG. 4 is a perspective view showing an essential part of the single screw compressor. FIG. 5 is a longitudinal sectional view showing the inner surface of the through hole of the cylindrical wall and the gate of the gate rotor. 6A and 6B are diagrams showing the operation of the compression mechanism, where FIG. 6A shows the suction stroke, FIG. 6B shows the compression stroke, and FIG. 6C shows the discharge stroke. FIG. 7 is a diagram illustrating the operation of the compression mechanism. FIG. 8 is a perspective view showing a state of the screw rotor and the gate rotor before the compression chamber is completely closed. FIG. 9 is a perspective view showing a state of the screw rotor and the gate rotor immediately after the compression chamber is completely closed. FIG. 10 is a longitudinal sectional view showing the shape of the inner surface of the through hole of the cylindrical wall according to another embodiment. FIG. 11 is a longitudinal sectional view showing the shape of the inner surface of the through hole of the cylindrical wall according to another embodiment.

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

    The single screw compressor (1) of the present embodiment (hereinafter simply referred to as a screw compressor) is provided in a refrigerant circuit (not shown) that performs a refrigeration cycle, for example, and compresses the refrigerant in the refrigerant circuit. It is.

    As shown in FIG. 1, the screw compressor (1) includes a compression mechanism (20) and an electric motor (15) for driving the compression mechanism (20) in one casing (10). The compression mechanism (20) is connected to the electric motor (15) via the drive shaft (21). In the casing (10), low-pressure gas refrigerant is introduced from the evaporator of the refrigerant circuit, and the low-pressure space (S1) for guiding the low-pressure gas to the compression mechanism (20), and the compression mechanism (20) A high-pressure space (S2) into which the discharged high-pressure gas refrigerant flows is partitioned.

    As shown in FIG. 2, the single screw compressor (1) includes a cylindrical wall (30) formed in the casing (10), one screw rotor (40), and two gate rotors (50). ing.

    The screw rotor (40) is a metal member formed in a substantially cylindrical shape. The screw rotor (40) is rotatably accommodated inside the cylindrical wall (30) of the casing (10). The outer diameter of the screw rotor (40) is set slightly smaller than the inner diameter of the cylindrical wall (30) of the casing (10), and the outer peripheral surface of the screw rotor (40) is the cylindrical wall (30) of the casing (10). It is comprised so that it may slidably contact with the inner peripheral surface.

    A plurality of spiral grooves (41) extending spirally from one axial end to the other end of the screw rotor (40) are formed on the outer periphery of the screw rotor (40). Each of the plurality of spiral grooves (41) has a symmetrical shape around the axis of the cylindrical screw rotor (40) (that is, in the cross section of the screw rotor (40), Each has a point-symmetric shape with respect to the center of the screw rotor (40).) A drive shaft (21) is inserted through the center of the screw rotor (40).

    Two through holes (3) formed in the cylindrical wall (30) are formed in the casing (10). The gate rotor accommodating chamber (60) communicates with the outside of these through holes (3). The gate rotor accommodating chamber (60) communicates with the low pressure space (S1) and accommodates the gate rotor (50) and the gate rotor support member (55).

    Each gate rotor (50) is a resin member provided with a plurality of gates (51) formed in a rectangular plate shape radially. The compression chamber (23) is formed between the gate (51), the spiral groove (41), and the inner peripheral surface of the cylindrical wall (30) by meshing each gate rotor (50) with the screw rotor (40). Is done. Each gate rotor (50) is symmetrically disposed on the outside of the cylindrical wall (30) with the screw rotor (40) interposed therebetween, and the axis is perpendicular to the axis of the screw rotor (40).

    As shown in FIG. 3, the gate rotor support member (55) includes a base portion (56), an arm portion (57), and a shaft portion (58). The base (56) is formed in a slightly thick disk shape. The same number of arms (57) as the gates (51) of the gate rotor (50) are provided and extend radially outward from the outer peripheral surface of the base (56). The shaft portion (58) is formed in a rod shape and is erected on the base portion (56). The central axis of the shaft portion (58) coincides with the central axis of the base portion (56). The gate rotor (50) is attached to a surface of the base portion (56) and the arm portion (57) opposite to the shaft portion (58). Each arm part (57) is in contact with the back surface of the gate (51).

    The gate rotor support member (55) disposed on the right side of the screw rotor (40) in FIG. 2 is installed in such a posture that the gate rotor (50) is on the lower end side. On the other hand, the gate rotor support member (55) disposed on the left side of the screw rotor (40) in the figure is installed in such a posture that the gate rotor (50) is on the upper end side.

    As shown in FIG. 4, the end surface (52) of the gate (51) of the gate rotor (50) faces the inner surface (2) of the through hole (3) of the cylindrical wall (30). The inner surface (2) of the through hole (3) extends along the axial direction of the screw rotor (40). The inner surface (2) has a flat surface (2b) and an inclined surface (as shown in FIG. 5). 2a) is provided. This inclined surface (2a) constitutes the non-sliding contact surface (2a) of the present invention. The inclination angle of the inclined surface (2a) is set in the range of 5 ° to 40 °. The length of the inclined surface (2a) is set to the length indicated by A in FIG.

-Driving action-
The operation of the screw compressor (1) will be described.

    When the electric motor (15) is started in the screw compressor (1), the screw rotor (40) rotates with the rotation of the drive shaft (21). As the screw rotor (40) rotates, the gate rotor (50) also rotates, and the compression mechanism (20) repeats the suction stroke, the compression stroke, and the discharge stroke. Description will be made by paying attention to the compression chamber (23) shaded in FIG.

    In FIG. 6 (A), the compression chamber (23) with shading communicates with the low-pressure space (S1). Further, the spiral groove (41) forming the compression chamber (23) meshes with the gate (51) of the gate rotor (50) located on the lower side of the figure. When the screw rotor (40) rotates, the gate (51) relatively moves from the start end side to the end end side of the spiral groove (41), and the volume of the compression chamber (23) increases accordingly. As a result, the low-pressure gas refrigerant in the low-pressure space (S1) is sucked into the compression chamber (23) through the suction port (24).

    When the screw rotor (40) further rotates, the state shown in FIG. In the figure, the compression chamber (23) with shading is completely closed. That is, the spiral groove (41) forming the compression chamber (23) is engaged with the gate (51) of the gate rotor (50) located on the upper side of the drawing, and the low pressure space (S1) is formed by the gate (51). Partitioned from. Then, when the gate (51) relatively moves from the start end side to the end end side of the spiral groove (41) with the rotation of the screw rotor (40), the volume of the compression chamber (23) is gradually reduced. As a result, the gas refrigerant in the compression chamber (23) is compressed.

    When the screw rotor (40) further rotates, the state shown in FIG. In the figure, the shaded compression chamber (23) is in communication with the high-pressure space (S2) via a discharge port (not shown). When the gate (51) moves toward the end of the spiral groove (41) as the screw rotor (40) rotates, the compressed refrigerant gas is pushed out from the compression chamber (23) to the high-pressure space (S2). Go.

    As described above, the flat surface (2b) and the inclined surface (2a) are provided on the inner surface (2) of the through hole (3) of the cylindrical wall (30). Here, the boundary (C) between the flat surface (2b) and the inclined surface (2a) is at a position facing the rear edge (51a) of the gate (51) forming the compression chamber (23) immediately after closing. The front side of the boundary (C) including the boundary (C) (the front side of the rear edge (51a) of the gate (51)) is a flat surface (2b), and the rear side of the boundary (C) is an inclined surface. (2a). The inclined surface (2a) is inclined so that the gap with the end surface (52) of the gate (51) gradually decreases as the gate (51) of the gate rotor (50) advances.

    FIG. 7 shows a sliding contact state between the end surface (52) of the gate (51) of the gate rotor (50) and the inner surface (2) of the through hole (3) of the cylindrical wall (30). In the following, the shaded portion of the inner surface (2) shown in FIG. 7 indicates the inclined surface (2a), and the non-shaded portion of the inner surface (2) indicates the flat surface (2b). Yes.

    7A, the gate (51) of the gate rotor (50) (the hatched gate (51) in FIG. 7) has not entered the spiral groove (41) of the screw rotor (40). It is. In this state, the end surface (52) of the gate (51) of the gate rotor (50) faces the inclined surface (2a) of the inner surface (2), and they are not in contact with each other.

    When the rotation of the gate rotor (50) advances and the state shown in FIG. 7B is reached, the gate (51) of the gate rotor (50) begins to enter the spiral groove (41) of the screw rotor (40). At this time, the end surface (52) of the gate (51) of the gate rotor (50) has its front edge (51b) reaching the boundary (C) of the inner surface (2), and the flat surface (2b) of the inner surface (2). ).

    When the rotation of the gate rotor (50) further progresses to the state shown in FIG. 7C, the side surface on the front edge side of the gate (51) of the gate rotor (50) is the spiral groove ( In contact with the inner wall of 41), the gate (51) and the spiral groove (41) begin to mesh. A perspective view of this state is shown in FIG. In this state, the compression chamber (23) is not completely closed. A part of the end surface (52) of the gate (51) of the gate rotor (50) is in sliding contact with the flat surface (2b) of the inner surface (2). The end surface (52) of the gate (51) of the gate rotor (50) is in a non-sliding contact with the inner surface (2) of the through hole (3) of the cylindrical wall (30).

    When the rotation of the gate rotor (50) further proceeds to the state of FIG. 7D, the rear edge of the gate (51) of the gate rotor (50) is more than the inner surface (2) than the state of FIG. ) Approaches the boundary (C). Even in this state, similarly to the state of FIG. 7C, the compression chamber (23) is not completely closed.

    When the rotation of the gate rotor (50) further progresses to the state of FIG. 7 (E), the gate (51) of the gate rotor (50) has its front side, rear end side, and front end side each having the above screw side. The state comes into contact with the inner wall of the spiral groove (41) of the rotor (40) and immediately after the compression chamber (23) is closed. A perspective view of this state is shown in FIG. At this time, the gate (51) of the gate rotor (50) has its rear edge reaching the boundary (C) of the inner surface (2), and the entire end surface (52) of the gate (51) is the same as the inner surface (2). Touch the flat surface (2b). As a result, the gap between the end surface (52) of the gate (51) of the gate rotor (50) and the inner surface (2) of the through hole (3) of the cylindrical wall (30) is sealed, and the compression chamber (23) Fluid will not leak outside.

    Further, as can be seen from FIGS. 7E and 9, the boundary line of the boundary (C) of the inner surface (2) is inclined from the inner side to the outer side of the inner surface (2). In the plan view, the boundary line and the rear edge of the gate (51) that closes the compression chamber (23) overlap each other. Thereby, the closing timing of the compression chamber (23), the end surface (52) of the gate (51) of the gate rotor (50), and the inner surface (2) of the through hole (3) of the casing (10) The timing for completely sealing the gap is matched.

    When the rotation of the gate rotor (50) further progresses to become FIG. 7 (F), the volume of the compression chamber (23) begins to contract and the fluid is compressed. Thereafter, the rotation of the gate rotor (50) further proceeds, and the state shown in FIG. 7 (A) is obtained again, and the state shown in FIGS. 7 (A) to 7 (F) is repeated.

-Effect of the embodiment-
According to this embodiment, since the non-sliding contact surface (2a) is formed on the inner surface (2) of the through hole (3) of the casing (10), the front of the gate (51) of the gate rotor (50) Until the edge (51b) reaches the boundary (C) of the inner surface (2), the end surface (52) of the gate (51) and the inner surface (2) of the through hole (3) of the cylindrical wall (30) Does not slide. In this case, until the front edge (51b) of the gate (51) reaches the boundary (C) of the inner surface (2), the end surface (52) of the gate (51) and the cylindrical wall (30) penetrate. Although a gap is formed between the hole (3) and the inner surface (2), the compression chamber (23) is not in a closed state, and therefore it is not necessary to seal this gap.

    As a result, the end surface (52) of the gate (51) and the inner surface (2) of the through hole (3) of the cylindrical wall (30) are prevented from being slid in vain. The sliding loss of the gate rotor (50) can be reduced, and the operating efficiency of the single screw compressor can be improved.

    Further, according to the present embodiment, the end surface (52) of the gate (51) of the gate rotor (50) is gradually approached to the inner surface (2) of the through hole (3) of the cylindrical wall (30), Mitigates impact when the end surface (52) of the gate (51) of the gate rotor (50) and the inner surface (2) of the through hole (3) of the cylindrical wall (30) contact at the boundary (C). I did it. Thereby, abrasion and breakage of the gate (51) of the gate rotor (50) can be suppressed.

<< Other Embodiments >>
About the said embodiment, it is good also as the following structures.

    In the above embodiment, the inclined surface (2a) is formed as the non-contact surface on the inner surface (2) of the through hole (3) of the cylindrical wall (30). However, the present invention is not limited to this. You may comprise by the level | step difference surface (2a) as shown in FIG. The number of steps on the step surface (2a) may be one as shown in FIG. 10, two may be combined as shown in FIG. 11, or three or more. In this way, the non-sliding surface of the inner surface (2) of the through hole (3) is made to be a stepped surface (2a), so that the non-sliding surface can be made easier than when the inclined surface (2a) is formed. Can be formed.

    In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention relates to a single screw compressor, and is particularly useful for measures for reducing the sliding loss of the gate rotor.

1 Single screw compressor
2 Inside
2a Inclined surface (non-sliding surface)
2b Flat surface
3 Through hole
10 Casing
20 Compression mechanism
30 cylindrical wall
40 screw rotor
50 Gate rotor

Claims (3)

A casing (10) formed with a cylindrical wall (30), a screw rotor (40) accommodated in the cylindrical wall (30) of the casing (10) and formed with a plurality of spiral grooves (41), and the casing A gate rotor (50) in which a plurality of gates (51) engaged with the spiral groove (41) through a through hole (3) formed in the cylindrical wall (30) of (10) are radially formed,
A single screw compressor that compresses fluid in a compression chamber (23) formed by meshing a spiral groove (41) of the screw rotor (40) and a gate (51) of the gate rotor (50),
The inner surface (2) of the through hole (3) of the cylindrical wall (30) is located at the position facing the rear edge (51a) of the gate (51) that forms the compression chamber (23) immediately after closing (C) And a non-sliding contact surface (2a) that is non-sliding contact with the end surface (52) of the gate (51) on the rear side of the rear edge (51a) of the gate (51) and the boundary (C). A single screw compressor, comprising: a flat surface (2b) slidably contacting the end surface (52) of the gate on the front side of the rear edge (51a) of the gate (51). In claim 1,
The non-sliding contact surface (2a) of the inner surface (2) has a smaller clearance between the non-sliding contact surface (2a) and the end surface (52) of the gate (51) as the gate (51) advances. A single screw compressor characterized in that it is composed of an inclined surface that is inclined as described above. In claim 1,
The non-sliding contact surface (2a) of the inner surface (2) has a stepped gap between the non-sliding contact surface (2a) and the end surface (52) of the gate (51) as the gate (51) advances. A single screw compressor characterized by comprising a stepped surface formed to be small.

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