WO2023090148A1

WO2023090148A1 - Compressor

Info

Publication number: WO2023090148A1
Application number: PCT/JP2022/040825
Authority: WO
Inventors: 政和石飛; 寛之小林; 善彰宮本; 隆史渡辺; 秀作後藤
Original assignee: 三菱重工サーマルシステムズ株式会社
Priority date: 2021-11-22
Filing date: 2022-10-31
Publication date: 2023-05-25
Also published as: JP2023076187A

Abstract

Provided is a compressor capable of introducing as little oil as possible to a higher-side compressing mechanism. A compressor (1) comprises: a rotary compressing mechanism (12) connected to a lower end of a rotation shaft (15), and which compresses and ejects a refrigerant into a housing (11); a scroll compressing mechanism (13) connected to an upper end of the rotation shaft (15), and which takes in and compresses the refrigerant ejected into the housing (11); and a cover (45) having, at a lower end thereof, an intake opening (45a) through which the refrigerant ejected from the scroll compressing mechanism (13) is taken in from around the rotation shaft (15), and partitioning a space inside the housing (11) so as to guide the refrigerant to an intake side of the scroll compressing mechanism (13). The intake opening (45a) of the cover (45) is provided inside an upper coil end (39b) of an electric motor (14) and below an upper end of the upper coil end (39b).

Description

compressor

The present disclosure relates to a compressor, and more specifically to a two-stage compressor having a low-stage compression mechanism and a high-stage compression mechanism.

A two-stage compressor having a rotary compression mechanism and a scroll compression mechanism in a housing is known. In the two-stage compressor disclosed in Patent Document 1, refrigerant compressed by a low-stage rotary compression mechanism is discharged into a housing, and the discharged refrigerant is further compressed by a high-stage scroll compressor. there is An oil reservoir that stores lubricating oil is provided in the housing. There is a risk that the oil that accumulates in this oil reservoir will accompany the refrigerant discharged from the rotary compression mechanism and be led to the scroll compression mechanism. If oil is led to the scroll compression mechanism, performance will deteriorate, so in Patent Document 1, a conical inflow restricting plate (see reference numeral 81 and FIG. 4 of Patent Document 1) is provided to reduce the amount of refrigerant that is led to the scroll compression mechanism. designed to restrict flow.

Japanese Patent Application Laid-Open No. 2017-190732 (Fig. 4, etc.)

However, in the inflow restricting plate of Patent Document 1, since the position of the lower end, which is the suction opening, is above the coil end of the electric motor, there is a risk that the refrigerant that accompanies the oil will be sucked.

The present disclosure has been made in view of such circumstances, and an object thereof is to provide a compressor capable of reducing the amount of oil introduced to the high-stage compression mechanism as much as possible.

In order to solve the above problems, the compressor of the present disclosure includes a housing having an oil reservoir below;
a rotating shaft housed in the housing and rotating around a longitudinal axis; an electric motor provided in the center of the rotating shaft in the direction of the longitudinal axis to rotationally drive the rotating shaft; a low-stage compression mechanism connected to a lower end for compressing and discharging refrigerant into the housing; A high-stage compression mechanism for sucking and compressing, and a suction opening for sucking the refrigerant discharged from the low-stage compression mechanism from around the rotating shaft portion at the lower end, the suction side of the high-stage compression mechanism. a cover that partitions the space in the housing so as to guide the coolant to the inside of the housing, wherein the suction opening of the cover is provided inside the coil end of the electric motor and below the upper end of the coil end. .

The amount of oil introduced to the high-stage compression mechanism can be reduced as much as possible.

1 is a vertical cross-sectional view showing a compressor according to an embodiment of the present disclosure; FIG. FIG. 2 is a vertical cross-sectional view showing a main part of the compressor of FIG. 1; 3 is a cross-sectional view taken along line III--III in FIG. 2; FIG. It is the longitudinal cross-sectional view which expanded and showed the compressor in the height position of the lower end of an oil return pipe. FIG. 4 is a vertical cross-sectional view showing the flow of coolant through a cover; FIG. 6 is a longitudinal sectional view showing a modification of FIG. 5;

Embodiments according to the present disclosure will be described below with reference to the drawings.
As shown in FIG. 1, a compressor 1 is used in an air conditioner, and performs two-stage compression of a refrigerant R, which is gas such as carbon dioxide. Compressor 1 is fixed to installation surface FL via legs 3 . The compressor 1 includes a housing 11, a rotary compression mechanism (low-stage compression mechanism) 12 provided inside the housing 11, a scroll compression mechanism (high-stage compression mechanism) 13, an electric motor 14, and a rotating shaft ( and a rotating shaft portion) 15 .

The housing 11 includes a cylindrical body portion 21 and upper and

lower lid portions

22 and 23 that close the upper and lower openings of the body portion 21 . The inside of the housing 11 forms a closed space.

The rotating shaft 15 is provided to extend vertically along the axis X inside the housing 11 . An upper end (one end) of the rotating shaft 15 is rotatably supported by an upper bearing 31 . A lower end (other end) side of the rotating shaft 15 is rotatably supported by a lower bearing 32 .

The electric motor 14 is arranged in the center in the longitudinal direction of the rotating shaft 15 and on the outer peripheral side of the rotating shaft 15, and rotates the rotating shaft 15 around the axis X. The electric motor 14 has a rotor 38 fixed to the outer peripheral surface of the rotary shaft 15 , and is radially opposed to the rotor 38 with a gap therebetween, and is shrink-fitted to the inner wall of the main body portion 21 of the housing 11 . and a stator 39 fixed by

The rotor 38 is provided with rotor passages 38a provided at predetermined intervals in the circumferential direction. Each rotor passage 38a penetrates the rotor 38 in the vertical direction (axis X direction). The refrigerant discharged from the rotary compression mechanism 12 flows upward through these rotor passages 38a. An oil separation plate (baffle plate) 38 b is fixed to the upper portion of the rotor 38 . The oil separation plate 38b is disc-shaped and arranged to extend in the horizontal direction. The oil separation plate 38b rotates around the axis X together with the rotor 38. As shown in FIG.

A plurality of stator passages 39a are formed on the outer periphery of the stator 39 at predetermined angular intervals in the circumferential direction (specifically described later with reference to FIG. 3).
As shown in FIG. 1, an upper coil end 39b with a folded winding is positioned above the stator 39, and a lower coil end 39c with a folded winding is positioned below the stator 39. As shown in FIG. The electric motor 14 is connected to a power source via an inverter (not shown), and rotates the rotary shaft 15 with a variable frequency.

The rotary compression mechanism 12 is provided inside the housing 11 on the lower end (other end) side of the rotating shaft 15 . The rotary compression mechanism 12 has two cylinders in this embodiment. It has a rotor 42 that is eccentric and rotates in the compression chamber C1, and a cylinder 44 in which the compression chamber C1 is formed.

Refrigerant R is supplied from the suction pipe 33 to the compression chamber C1 formed in the cylinder 44 . The refrigerant compressed in the compression chamber C<b>1 is discharged from the rotary discharge pipe 43 through the lower bearing 32 to a region below the electric motor 14 within the housing 11 .

The cylinder 44 is fixed from below with bolts 48 to the lower bearing 32 . An oil pump 49 fixed together with the cylinder 44 by bolts 48 is provided below the cylinder 44 . The oil pump 49 sucks the oil from the oil reservoir O1 at the bottom of the housing 11, passes through the oil supply hole 15a extending along the axis X of the rotating shaft 15, and guides it to the upper bearing 31 side.

The scroll compression mechanism 13 is arranged above the electric motor 14 inside the housing 11 . The scroll compression mechanism 13 includes a fixed scroll 51 fixed to the upper bearing 31 and an orbiting scroll 57 arranged below the fixed scroll 51 so as to face the fixed scroll 51 .

The fixed scroll 51 has an end plate 52 fixed to the upper surface of the upper bearing 31 and a fixed wrap 53 projecting downward from the end plate 52 . A discharge hole 52a penetrating vertically is formed in the central portion (near the axis X) of the end plate 52 .

The orbiting scroll 57 is arranged so as to be sandwiched between the upper bearing 31 and the fixed scroll 51 . The orbiting scroll 57 has an end plate 58 connected to the upper end side of the rotating shaft 15 and an orbiting wrap 59 projecting upward from the end plate 58 .

The end plate 58 is fixed via a bush 55 to an eccentric shaft portion 56 provided at the upper end of the rotating shaft 15 and rotates eccentrically with respect to the axis X as the rotating shaft 15 rotates.

The orbiting wrap 59 meshes with the fixed wrap 53 to form a compression chamber C2 for compressing the refrigerant R between itself and the fixed wrap 53 .

A balance weight chamber 63 is formed between the recess on the central side of the upper bearing 31 and the bottom of the orbiting scroll 57 . Inside the balance weight chamber 63 , the balance weight 54 rotates together with the rotating shaft 15 .

The refrigerant R compressed by the rotary compression mechanism 12 and discharged into the housing 11 is sucked into the compression chamber C2 from the outer peripheral side of the scroll compression mechanism 13 and compressed toward the center. The compressed refrigerant R is discharged from the discharge pipe 34 to the outside of the housing 11 through the discharge hole 52 a of the fixed scroll 51 .

A cover 45 is provided below the upper bearing 31 so as to cover the upper bearing 31 . The cover 45 is formed by sheet metal processing, and has a substantially conical shape that expands in diameter from bottom to top. An outer peripheral upper end of the cover 45 is fixed to the upper bearing 31 by a bolt 45b (see FIG. 2).

A suction opening 45 a is provided at the lower end of the cover 45 . That is, the intake opening 45 a is an annular region that faces downward and is formed between the cover 45 and the rotating shaft 15 . A space below the housing 11 and a space on the side of the upper bearing 31 are partitioned by the cover 45 so that only the refrigerant sucked from the suction opening 45 a is guided to the scroll compression mechanism 13 .

An oil level tank 60 is provided outside and below the housing 11 . The oil level tank 60 is a hollow container and communicates with the inside of the housing 11 via a lower pipe 61 and an upper pressure equalizing pipe 62 . The oil level tank 60 measures the oil level of the oil reservoir O1 by introducing oil from the oil reservoir O1 in the housing 11 through the lower pipe 61 .

A downstream end of an oil separator oil return pipe 65 is connected to the lower side portion of the housing 11 . An upstream end of the oil separator oil return pipe 65 is connected to an oil separator (not shown). The oil separated from the refrigerant discharged from the compressor 1 by the oil separator is returned to the oil reservoir O<b>1 inside the housing 11 via the oil separator oil return pipe 65 . The height position where the downstream end of the oil separator oil return pipe 65 is connected to the housing 11 is below the lower bearing 32 .

An oil return pipe 67 is provided in the housing 11 and extends vertically while contacting the inner wall of the housing 11 . As shown in FIG. 2, the oil return pipe 67 is provided so that its upper end (one end) is fixed to the upper bearing 31 via a boss 68 and its lower end (the other end) is positioned in the oil reservoir O1 at the bottom of the housing 11. It is A lower end of the oil return pipe 67 is fixed to the inner wall of the housing 11 via a rod-like member 70 .

The oil return pipe 67 is provided so as to pass through the space formed between the stator 39 and the housing 11 . Specifically, as shown in FIG. 3, notches are provided in the outer circumference of the stator 39 at predetermined angular intervals in the circumferential direction, thereby forming a plurality of stator passages 39a in the circumferential direction between the stator 39 and the inner wall of the housing 11. ing. Refrigerant and oil flow through these stator passages 39a. Two oil return pipes 67 are inserted through one or more of these stator passages 39a.

As can be seen from FIG. 3, the rotor passages 38a are provided at predetermined intervals in the circumferential direction. The refrigerant discharged from the rotary compression mechanism 12 flows upward through these rotor passages 38a.

A stabilizing plate 75 is fixed to the lower surface of the lower bearing 32 as shown in FIG. The stabilizing plate 75 is fixed to the lower bearing 32 (specifically, the radially protruding leg of the lower bearing 32) with bolts 76. As shown in FIG. The stabilizing plate 75 is a disc with an opening in the center. The stabilizing plate 75 stabilizes the oil surface by covering above the oil surface of the oil reservoir O1.

Details of the cover 45 will be described with reference to FIG. A suction opening 45a provided at the lower end of the cover 45 faces downward and is positioned inside (on the axis X side) of the upper coil end 39b. Furthermore, the height position of the intake opening 45a is positioned below the upper end of the upper coil end 39b. An oil separation plate 38b is provided at a position facing the suction opening 45a downward.
The cover 45 is shaped to have a plurality of stepped portions whose diameter changes stepwise upward from the intake opening 45a. The cover 45 having such a shape forms a channel through which the coolant flows along the shape of the lower surface of the upper bearing 31 .

The compressor 1 configured as described above operates as follows.
Refrigerant evaporated by an evaporator (not shown) is sucked into the compressor 1 through a suction pipe 33 and compressed by the rotary compression mechanism 12 . The refrigerant compressed by the rotary compression mechanism 12 is discharged from the rotary discharge pipe 43 into the housing 11 .
Refrigerant discharged into the housing 11 is sucked from the suction opening 45a of the cover 45, passes through the flow path in the cover 45, is guided to the scroll compression mechanism 13, and is compressed. The refrigerant compressed by the scroll compression mechanism 13 passes through the discharge hole 52a of the fixed scroll 51 and is discharged from the discharge pipe 34 to an external gas cooler or condenser.

Oil is separated from the refrigerant discharged from the discharge pipe 34 by an oil separator (not shown). The separated oil passes through the oil separator oil return pipe 65, is returned into the housing 11, and is stored in the oil reservoir O1.

The oil stored in the oil reservoir O1 is sucked up by the oil pump 49 and guided to the scroll compression mechanism 13 side through the oil supply hole 15a formed in the rotary shaft 15. The oil guided to the scroll compression mechanism 13 side lubricates sliding portions such as the bearing portion of the upper bearing 31 and the bush 55, and then is returned to the oil reservoir O1 below. Of the lubricated oil, the oil guided to the balance weight chamber 63 is guided to the oil return pipe 67 through the oil return hole 31 a and the vertical hole 31 b (see FIG. 2) formed in the upper bearing 31 .

The oil guided to the oil return pipe 67 passes through the internal flow path, is discharged from the lower end, and is returned to the oil reservoir O1.

FIG. 5 schematically shows the refrigerant and oil flows formed by the cover 45 . In the figure, white arrows indicate the flow of refrigerant, and black arrows indicate the flow of oil.
The refrigerant compressed by the rotary compression mechanism 12 and discharged into the housing 11 first passes through a rotor passage 38a formed in the rotor 38 and is guided from below the rotor 38 to above. At this time, oil is accompanied with the refrigerant.
The refrigerant and oil exiting the rotor passage 38a collide with the oil separation plate 38b and are guided radially about the axis X by centrifugal force. The oil, which has a higher specific gravity than the refrigerant, collides with the inner wall of the housing 11 and flows downward due to gravity. However, some of the oil flows upward together with the refrigerant through the space between the inner wall of the housing 11 and the upper coil end 39b.
A portion of the oil that has risen together with the coolant collides with the upper end of the outer periphery of the cover 45 and then drops downward due to gravity.
The coolant flows from the inner wall side of the housing 11 to the inner circumference, flows through the upper end of the upper coil end 39b, flows into the space between the inner circumference side of the upper coil end 39b and the outer circumference side of the cover 45, and flows downward. change. After colliding with the upper end of the oil separation plate 38b, the oil turns inward and turns upward, and then flows into the flow path in the cover 45 through the suction opening 45a.

According to this embodiment, the following effects are achieved.

Refrigerant discharged from the rotary compression mechanism 12 is discharged into the housing 11 and is led to the scroll compression mechanism 13 through the intake opening 45 a of the cover 45 . Since the cover 45 partitions the interior of the housing 11 , only the refrigerant that has passed through the intake opening 45 a of the cover 45 is guided to the scroll compression mechanism 13 .
The intake opening 45a of the cover 45 is provided inside the upper coil end 39b of the electric motor 14 and below the upper end of the upper coil end 39b. As a result, the refrigerant guided from the outer circumference to the inner circumference of the upper coil end 39 b flows downward, turns over, and then flows into the suction opening 45 a at the lower end of the cover 45 . Since the refrigerant is guided into the cover 45 after the direction of the flow of the refrigerant is repeatedly deflected in this way, the oil entrained in the refrigerant can be separated as much as possible.

An oil separation plate 38b is provided below the suction opening 45a to block the flow of refrigerant toward the suction opening 45a. As a result, it is possible to prevent the oil guided from the oil reservoir below the housing 11 from being led to the suction opening 45a together with the refrigerant.

The cover 45 is provided with a stepped portion whose diameter changes stepwise. Thereby, the direction of the refrigerant flowing along the cover 45 can be changed, and the oil accompanying the refrigerant can be separated.

In the above-described embodiment, the shape of the cover 45 has a stepped portion, but the present invention is not limited to this. It is good also as the cover 45' which was closed.

The compressors described in the embodiments described above are understood, for example, as follows.

A compressor according to an aspect of the present disclosure includes a housing (11) having an oil reservoir below it, a rotary shaft (15) housed in the housing and rotating around a longitudinal axis, and the an electric motor (14) provided in the center in the direction of the longitudinal axis to rotationally drive the rotating shaft; a mechanism (12), a high-stage compression mechanism (13) connected to the upper end of the rotating shaft portion for sucking and compressing refrigerant discharged from the low-stage compression mechanism into the housing, and the low-stage compression mechanism. A suction opening (45a) for sucking the refrigerant discharged from the side compression mechanism from around the rotating shaft portion is provided at the lower end, and the space in the housing is formed so as to guide the refrigerant to the suction side of the high stage side compression mechanism. and a partitioning cover (45), wherein the intake opening of the cover is provided inside the coil end (39b) of the electric motor and below the upper end of the coil end.

Refrigerant discharged from the low-stage compression mechanism is discharged into the housing, and this discharged refrigerant is led to the high-stage compression mechanism through the intake opening of the cover. Since the cover partitions the inside of the housing, only the refrigerant that has passed through the suction opening of the cover is led to the high-stage compression mechanism.
The intake opening of the cover is provided inside the coil end of the electric motor and below the upper end of the coil end. As a result, the refrigerant guided from the outer circumference to the inner circumference of the coil end flows downward, turns around, is reversed, and then flows into the suction opening at the lower end of the cover. Since the refrigerant is guided into the cover after the direction of the flow of the refrigerant is repeatedly deflected in this way, the oil entrained in the refrigerant can be separated as much as possible.
A scroll compression mechanism, for example, is used as the high-stage compression mechanism, and a rotary compression mechanism, for example, is used as the low-stage compressor.

In the compressor according to one aspect of the present disclosure, a baffle plate (38b) is provided below the suction opening to block the flow of refrigerant toward the suction opening.

A baffle plate was installed below the intake opening to block the flow of refrigerant toward the intake opening. As a result, it is possible to suppress the oil guided from the oil reservoir below the housing from being led to the suction opening together with the refrigerant.

In the compressor according to one aspect of the present disclosure, the cover has a substantially conical shape with a diameter expanding upward from the suction opening.

Since the cover has a substantially conical shape whose diameter expands upward from the suction opening, the refrigerant sucked from the suction opening can be smoothly guided to the suction portion located on the outer peripheral side of the high-pressure side compression mechanism.

In the compressor according to one aspect of the present disclosure, the cover has a stepped portion whose diameter changes stepwise.

The cover has a stepped portion whose diameter changes stepwise. Thereby, the direction of the refrigerant flowing along the cover can be changed, and the oil accompanying the refrigerant can be separated. The number of stepped portions may be one or plural.

1 compressor 3 leg 11 housing 12 rotary compression mechanism (low-stage side compression mechanism)
13 scroll compression mechanism (high stage side compression mechanism)
14 electric motor 15 rotating shaft (rotating shaft portion)
15a Oil supply hole 21 Body portion 22 Upper lid portion 23 Lower lid portion 31 Upper bearing (bearing portion)
31a Oil return hole 31b Vertical hole 32 Lower bearing 33 Suction pipe 34 Discharge pipe 38 Rotor 38a Rotor passage 38b Oil separation plate (baffle plate)
39 Stator 39a Stator passage 39b Upper coil end 39c Lower coil end 41 Eccentric shaft 42 Rotor 43 Rotary discharge pipe 44 Cylinder 45, 45' Cover 45a Suction opening 48 Bolt 49 Oil pump 51 Fixed scroll 52 End plate 52a Discharge hole 53 Fixed Wrap 54 Balance weight 55 Bush 56 Eccentric shaft portion 57 Orbiting scroll 58 End plate 59 Orbiting wrap 60 Oil level tank 61 Lower pipe 62 Pressure equalizing pipe 63 Balance weight chamber 65 Oil separator oil return pipe 67 Oil return pipe 68 Boss 70 Rod member 75 Stabilizing Plate C1 Compression chamber C2 Compression chamber FL Installation surface O1 Oil reservoir X Axis

Claims

a housing having an oil reservoir below;
a rotating shaft part housed in the housing and rotating about a longitudinal axis;
an electric motor provided at the center of the rotating shaft in the direction of the longitudinal axis to rotationally drive the rotating shaft;
a low-stage compression mechanism connected to the lower end of the rotating shaft portion for compressing and discharging refrigerant into the housing;
a high-stage compression mechanism that is connected to the upper end of the rotary shaft and sucks and compresses refrigerant discharged from the low-stage compression mechanism into the housing;
A suction opening for sucking the refrigerant discharged from the low-stage compression mechanism from around the rotating shaft is provided at the lower end, and the space in the housing is formed so as to guide the refrigerant to the suction side of the high-stage compression mechanism. a partitioning cover,
with
The compressor, wherein the suction opening of the cover is provided inside the coil end of the electric motor and below the upper end of the coil end.
The compressor according to claim 1, wherein a baffle plate is provided below the suction opening to block the flow of refrigerant toward the suction opening.
The compressor according to claim 1 or 2, wherein the cover has a substantially conical shape with a diameter expanding upward from the suction opening.
The compressor according to claim 3, wherein the cover has a stepped portion whose diameter changes stepwise.