EP4621241A1

EP4621241A1 - Compressor

Info

Publication number: EP4621241A1
Application number: EP23894354.2A
Authority: EP
Inventors: Masakazu ISHITOBI; Yoshiaki Miyamoto; Takashi Watanabe; Syusaku Goto
Original assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Current assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Priority date: 2022-11-25
Filing date: 2023-10-26
Publication date: 2025-09-24
Also published as: WO2024111342A1; EP4621241A4; JP2024076709A

Abstract

Provided is a compressor with which costs required for manufacturing and assembling a rotary compression mechanism can be reduced. The compressor comprises a rotating shaft (15) which extends in a direction of an axis (X) and which includes an eccentric shaft portion (41) that is eccentric with respect to the axis (X), a rotor (42) provided on the eccentric shaft portion (41), and a cylinder (44) inside which a compression chamber (C1) accommodating the rotor (42) is formed, wherein: a suction space (44a) to which a refrigerant is guided from the outside and a communication hole (44b) through which the compression chamber (C1) communicates with the suction space (44a) are formed in the cylinder (44); and the communication hole (44b) extends in a second direction (D2) that is inclined with respect to a first direction (D1) orthogonal to the direction of the axis (X), and does not penetrate through an outer circumferential surface of the cylinder (44).

Description

Technical Field

The present disclosure relates to a compressor including a rotary compression mechanism.

Background Art

A refrigerant flow passage for guiding a refrigerant from an outside to a compression chamber is formed in a cylinder of a rotary compression mechanism (rotary compressor).
As disclosed in, for example, PTL 1, a part of the refrigerant flow passage is formed by inserting a tool such as a drill from an outer peripheral surface of the cylinder in a radial direction to machine a lateral hole and then sealing an opening with a sealing plug after the lateral hole is machined.

Citation List

Patent Literature

[PTL 1] International Publication No. WO2020/217385

Summary of Invention

Technical Problem

However, in the method of forming a refrigerant flow passage by machining a lateral hole, as in PTL 1, a sealing plug (plug) is required, so that costs for manufacturing the sealing plug and costs for assembling the sealing plug to the cylinder are incurred. That is, costs required for manufacturing and assembling a rotary compression mechanism are incurred.
The present disclosure has been made in view of such circumstances, and an object of the present disclosure is to provide a compressor capable of reducing costs required for manufacturing and assembling a rotary compression mechanism.

Solution to Problem

In order to solve the above problem, a compressor of the present disclosure adopts the following measures.
A compressor according to an aspect of the present disclosure includes a rotary shaft that extends in a direction of an axis and has an eccentric shaft portion that is eccentric with respect to the axis, a rotor that is provided on the eccentric shaft portion, and a cylinder in which a compression chamber that accommodates the rotor is formed, in which a suction space to which a refrigerant is guided from an outside and a communication hole through which the compression chamber and the suction space communicate with each other are formed in the cylinder, and the communication hole extends along a second direction inclined with respect to a first direction orthogonal to the direction of the axis and does not penetrate an outer peripheral surface of the cylinder. Advantageous Effects of Invention
According to the present disclosure, it is possible to reduce the costs required for manufacturing and assembling the rotary compression mechanism.

Brief Description of Drawings

Fig. 1 is a cross-sectional view of a compressor according to an embodiment of the present disclosure.
Fig. 2 is a cross-sectional view of a rotary compression mechanism.
Fig. 3 is a cross-sectional view of a cylinder.

Description of Embodiments

Hereinafter, a compressor according to an embodiment of the present disclosure will be described with reference to the drawings.

[Overview of Compressor]

As shown in Fig. 1, a compressor 1 is used for an air conditioner and compresses a refrigerant Rf, which is a gas such as carbon dioxide, in two stages. The compressor 1 is fixed to an installation surface FL via a leg portion 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 rotary shaft 15.
The housing 11 includes a main body portion 21 having a cylindrical shape, an upper cover portion 22 that closes an opening in an upper portion of the main body portion 21, and a lower cover portion 23 that closes an opening in a lower portion of the main body portion 21.
Then, a sealed space is formed inside the housing 11 defined by the main body portion 21, the upper cover portion 22, and the lower cover portion 23.
The rotary shaft 15 is provided to extend vertically along an axis X inside the housing 11. The rotary shaft 15 is a member for transmitting a driving force from the electric motor 14 to the rotary compression mechanism 12 and the scroll compression mechanism 13.
A portion of the rotary shaft 15 on an upper end (one end) side is rotatably supported by a scroll-side bearing 31. In addition, a portion of the rotary shaft 15 on a lower end (the other end) side is rotatably supported by two bearings, that is, an upper bearing 32A (rotary-side upper bearing) and a lower bearing 32B (rotary-side lower bearing).
The electric motor 14 is disposed at the center of the rotary shaft 15 in a longitudinal direction and on an outer peripheral side of the rotary shaft 15, and rotates the rotary shaft 15 around the axis X.
The electric motor 14 has a rotor 38 fixed to an outer peripheral surface of the rotary shaft 15, and a stator 39 that faces the rotor 38 in a radial direction with a gap from an outer peripheral surface of the rotor 38 and that is fixed to an inner wall of the main body portion 21 of the housing 11 by shrink fitting or the like.
The rotor 38 is provided with rotor passages 38a provided at predetermined intervals in a circumferential direction with respect to the axis X. Each rotor passage 38a penetrates the rotor 38 in an up-down direction (axis X direction). The refrigerant Rf discharged from the rotary compression mechanism 12 flows upward through the rotor passages 38a.
Rotor weights 37 (balance weights) are provided on an upper surface and a lower surface of the rotor 38. Each rotor weight 37 is fixed by a pin 38c that penetrates laminated steel plates of the rotor 38 in the axis X direction (co-tightening). Details of the shape of the rotor weight 37 will be described below.
An oil separation plate 38b is fixed to an upper surface of the rotor weight 37 installed on an upper portion of the rotor 38. The oil separation plate 38b has a disk shape and is disposed to extend in a horizontal direction. The oil separation plate 38b rotates around the axis X together with the rotor 38.
The electric motor 14 is connected to a power source via an inverter (not shown) and rotates the rotary shaft 15 at a variable frequency.
The rotary compression mechanism 12 is provided on the lower end side of the rotary shaft 15 inside the housing 11.
The rotary compression mechanism 12 has a compression chamber C1 for compressing the refrigerant Rf. The refrigerant Rf compressed in the compression chamber C1 is discharged from a rotary discharge pipe 43 to a region below the electric motor 14 within the housing 11 via the upper bearing 32A.
Details of the rotary compression mechanism 12 will be described below.
The scroll compression mechanism 13 is provided on the upper end side of the rotary shaft 15 inside the housing 11.
The scroll compression mechanism 13 includes a fixed scroll 51 fixed to the scroll-side bearing 31, and an orbiting scroll 57 disposed below the fixed scroll 51 to face the fixed scroll 51.
The fixed scroll 51 has an end plate 52 fixed to an upper surface of the scroll-side bearing 31 and a fixed wrap 53 protruding downward from the end plate 52.
A discharge hole 52a is formed in a central portion (in the vicinity of the axis X) of the end plate 52 to penetrate along the axis X direction.
The orbiting scroll 57 is disposed to be interposed between the scroll-side bearing 31 and the fixed scroll 51 in the axis X direction.
The orbiting scroll 57 has an end plate 58 connected to an eccentric shaft portion 56 of the rotary shaft 15 and an orbiting wrap 59 protruding upward from the end plate 58.
The end plate 58 is slidably connected to the eccentric shaft portion 56 provided at an upper end of the rotary shaft 15 via a drive bush 55, and performs an orbiting motion eccentrically with respect to the axis X as the rotary shaft 15 rotates.
The orbiting wrap 59 meshes with the fixed wrap 53 to form a compression chamber C2 for compressing the refrigerant Rf between the orbiting wrap 59 and the fixed wrap 53.
A balance weight chamber 63 is formed between a recess formed at the center of the scroll-side bearing 31 and a lower portion of the orbiting scroll 57. Oil is accumulated in the balance weight chamber 63.
In the balance weight chamber 63, a rotary shaft weight 54 (balance weight) rotates together with the rotary shaft 15.
The rotary shaft weight 54 is shrink-fitted to the drive bush 55 and is inserted into the eccentric shaft portion 56.
The rotary shaft weight 54 performs an orbiting motion eccentrically with respect to the axis X as the rotary shaft 15 rotates, thereby balancing with the orbiting scroll 57, which rotates eccentrically with respect to the axis X, relative to the rotary shaft 15.
The refrigerant Rf compressed by the rotary compression mechanism 12 and discharged into the housing 11 is sucked into the compression chamber C2 from an outer peripheral side of the scroll compression mechanism 13 and is compressed toward a central side.
The compressed refrigerant Rf is discharged to the outside of the housing 11 through the discharge pipe 34 or the like, via the discharge hole 52a formed in the fixed scroll 51.
A cover 48 is provided below the scroll-side bearing 31 to cover the scroll-side bearing 31.
The cover 48 is formed by sheet metal processing, and has a cylindrical shape whose diameter is gradually increased from below to above.
A suction opening 48a is formed at a lower end of the cover 48. That is, the suction opening 48a is an annular region that is open downward and that is formed between the cover 48 and the rotary shaft 15 in the circumferential direction with respect to the axis X.
The cover 48 partitions a space on the electric motor 14 side of the housing 11 and a space on the scroll-side bearing 31 side, and only the refrigerant Rf sucked in through the suction opening 48a 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 provided in a lower portion and a pressure equalization pipe 62 provided in an upper portion.
The socket 65 is provided at the upper portion of the oil level tank 60, and a level gauge (not shown) is installed in the socket 65.
Oil is guided from the oil reservoir inside the housing 11 via the lower pipe 61 into the oil level tank 60, and an oil level in the oil reservoir can be measured by the level gauge installed in the socket 65.
An oil return pipe 67, which extends in the up-down direction while coming into contact with an inner wall of the housing 11, is provided inside the housing 11. The oil return pipe 67 is provided such that an upper end (one end) is fixed to the scroll-side bearing 31 and a lower end (the other end) is positioned in the oil reservoir in the lower portion of the housing 11.

[Details of Rotary Compression Mechanism]

As shown in Fig. 2, the rotary compression mechanism 12 is, for example, a two-cylinder mechanism, and includes two eccentric shaft portions 41 provided on the rotary shaft 15, a rotor 42 fixed to each eccentric shaft portion 41, two cylinders 44 in which the compression chamber C1 is formed, and one separate plate 45 that separates the upper cylinder 44 and the lower cylinder 44.
Each eccentric shaft portion 41 is a shaft portion that is eccentric with respect to the axis X, which is a rotational axis of the rotary shaft 15.
One eccentric shaft portion 41 and the other eccentric shaft portion 41 are provided to be separated from each other in the axis X direction.
Each rotor 42 is a cylindrical member, and is inserted into and fixed to each eccentric shaft portion 41.
Each rotor 42 is accommodated in a space formed inside each cylinder 44, and forms the compression chamber C1 together with each cylinder 44.
In the rotary compression mechanism 12 of the present embodiment that is a two-cylinder mechanism, two cylinders 44 are provided, and one cylinder 44 and the other cylinder 44 are provided to be separated from each other in the axis X direction so as to correspond to the positions of the eccentric shaft portions 41.
In addition, the separate plate 45 is provided between the upper cylinder 44 and the lower cylinder 44 so as to be in close contact with each cylinder 44, and partitions the upper compression chamber C1 and the lower compression chamber C1.
The refrigerant Rf is supplied to each compression chamber C1 from outside the cylinder 44.
Specifically, in the case of the compression chamber C1 formed in the upper cylinder 44, the refrigerant Rf is supplied to a suction space 44a formed in the upper cylinder 44 via a suction pipe 33, a suction boss 35 (boss part), and a refrigerant flow passage 36 formed in the upper bearing 32A, and then is supplied to the compression chamber C1 via a communication hole 44b through which the suction space 44a and the compression chamber C1 communicate with each other.
In addition, in the case of the compression chamber C1 formed in the lower cylinder 44, the refrigerant Rf is supplied to a suction space 44a formed in the lower cylinder 44 via the suction space 44a formed in the upper cylinder 44 and a communication space 45a formed in the separate plate 45, and then is supplied to the compression chamber C1 via a communication hole 44b through which the suction space 44a and the compression chamber C1 communicate with each other.
The suction space 44a formed in the upper cylinder 44 penetrates the cylinder 44 in the axis X direction, but the suction space 44a formed in the lower cylinder 44 does not penetrate the cylinder 44 in the axis X direction and has a bottom.
In addition, the suction spaces 44a need only be continuously formed to communicate with each other along the axis X direction, and the specific shape thereof is not limited.
As shown in Figs. 2 and 3, the communication hole 44b is a through-hole through which the compression chamber C1 and the suction space 44a, which are separated by a member or a material forming the cylinder 44, communicate with each other.
The communication hole 44b extends along a second direction D2. In other words, the communication hole 44b has an axis along the second direction D2.
The communication hole 44b does not reach an outer peripheral surface of the cylinder 44.
The second direction D2 is inclined with respect to a first direction D1 orthogonal to the axis X direction.
For example, in a case where the axis X extends in a vertical direction, the first direction D1 extends in the horizontal direction, and the second direction D2 is inclined with respect to the horizontal direction.
Note that the second direction D2 does not coincide with the axis X direction.
It is preferable that the size, position, and angle (that is, the angle in the second direction D2) of the communication hole 44b are set as follows.
That is, as shown in Fig. 3, when the communication hole 44b is virtually extended along the second direction D2, it is preferable that the extension line (drawn by a dashed double-dotted line in Fig. 3) is set not to interfere with the cylinder 44 (a member forming the cylinder 44 in which the communication hole 44b is provided).
In this manner, for example, by inserting a cutting tool such as a drill from the inside of the compression chamber C1 (an inner peripheral surface of the cylinder 44) toward the suction space 44a along the second direction D2, the communication hole 44b can be formed without the drill interfering with the cylinder 44 and without forming another hole in the outer peripheral surface of the cylinder 44.
As shown in Fig. 3, the communication hole 44b (the second direction D2) may be inclined downward from the suction space 44a toward the compression chamber C1, or may be inclined upward from the suction space 44a toward the compression chamber C1.
Note that, from the viewpoint of smooth flow of the refrigerant Rf, it is preferable that the communication hole 44b is inclined downward from the suction space 44a toward the compression chamber C1.
As shown Fig. 2, each cylinder 44 and the separate plate 45 are fixed (fastened) to the upper bearing 32A and the lower bearing 32B from below by bolts (not shown) in a form of being interposed between the upper bearing 32A and the lower bearing 32B.
As shown in Fig. 1, an oil pump 49 fixed by a bolt is provided below the cylinder 44.
The oil pump 49 sucks in oil from an oil reservoir in the lower portion of the housing 11 and guides the oil to the scroll-side bearing 31 side via an oil supply hole 15a that penetrates along the axis X of the rotary shaft 15.
The rotary compression mechanism 12 may be a single cylinder or may be three or more cylinders. In this case, it goes without saying that the number of the eccentric shaft portions 41, the number of the rotors 42, the number of the cylinders 44, and the number of the separate plates 45 can be appropriately changed according to the number of the cylinders.
In addition, the suction spaces 44a formed in the respective cylinders 44 need only be continuously formed along the axis X direction via the communication space 45a of the separate plate 45, and the shapes thereof are not particularly limited.
According to the present embodiment, the following effects are achieved.
The communication hole 44b formed in the cylinder 44 extends along the second direction D2 inclined with respect to the first direction D1 orthogonal to the direction of the axis X and does not penetrate the outer peripheral surface of the cylinder 44. Therefore, in forming the communication hole 44b, the tool need only be inserted from the compression chamber C1 (the inner peripheral surface of the cylinder 44) toward the suction space 44a along the second direction D2, and it is not necessary to insert the tool from the outer peripheral surface of the cylinder 44 toward the compression chamber C1.
Therefore, a lateral hole through which the outer peripheral surface and the inner peripheral surface of the cylinder 44 communicate with each other, that is, a lateral hole through which the outside of the cylinder 44 and the compression chamber C1 communicate with each other is not formed, so that it is not necessary to manufacture or assemble a plug for closing the lateral hole. In this manner, it is possible to reduce the costs required for manufacturing and assembling the rotary compression mechanism 12.
In addition, the extension line of the communication hole 44b along the second direction D2 does not interfere with the cylinder 44 in which the communication hole 44b is formed, so that it becomes easier to insert the tool from the compression chamber C1 toward the suction space 44a along the second direction D2.
A plurality of pairs of the eccentric shaft portion 41 and the cylinder 44 are provided, the cylinders 44 are disposed side by side in the axis X direction, and the suction spaces 44a formed in the respective cylinders 44, which are continuously formed over the plurality of cylinders 44 along the axis X direction, communicate with each other along the axis X direction. Therefore, even in the multi-cylinder rotary compression mechanism 12, it is possible to reduce the costs required for manufacturing and assembly.
The structure of the rotary compression mechanism 12 including the cylinder 44 in which the communication hole 44b is formed can be applied not only to the compressor 1 including the rotary compression mechanism 12 and the scroll compression mechanism 13 as in the present embodiment but also to a compressor including only the rotary compression mechanism 12, for example.
The compressor according to the embodiment of the present disclosure described above is understood as follows, for example.
That is, a compressor (1) according to a first aspect of the present disclosure includes a rotary shaft (15) that extends in a direction of an axis (X) and has an eccentric shaft portion (41) that is eccentric with respect to the axis, a rotor (42) that is provided on the eccentric shaft portion, and a cylinder (44) in which a compression chamber (C1) that accommodates the rotor is formed, in which a suction space (44a) to which a refrigerant (Rf) is guided from an outside and a communication hole (44b) through which the compression chamber and the suction space communicate with each other are formed in the cylinder, and the communication hole extends along a second direction (D2) inclined with respect to a first direction (D1) orthogonal to the direction of the axis and does not penetrate an outer peripheral surface of the cylinder.
With the compressor according to this aspect, the cylinder is formed with the suction space to which the refrigerant is guided from the outside and the communication hole through which the compression chamber and the suction space communicate with each other, and the communication hole extends along the second direction inclined with respect to the first direction orthogonal to the direction of the axis and does not penetrate the outer peripheral surface of the cylinder. Therefore, in forming the communication hole, the tool need only be inserted from the compression chamber (the inner peripheral surface of the cylinder) toward the suction space along the second direction, and it is not necessary to insert the tool from the outer peripheral surface of the cylinder toward the compression chamber. Therefore, a lateral hole through which the outer peripheral surface and the inner peripheral surface of the cylinder communicate with each other, that is, a lateral hole through which the outside of the cylinder and the compression chamber communicate with each other is not formed, so that it is not necessary to manufacture or assemble a plug for closing the lateral hole. In this manner, it is possible to reduce the costs required for manufacturing and assembling the rotary compression mechanism.
In addition, in the compressor according to a second aspect of the present disclosure, in the first aspect, an extension line of the communication hole along the second direction does not interfere with the cylinder in which the communication hole is formed.
With the compressor according to this aspect, the extension line of the communication hole along the second direction does not interfere with the cylinder in which the communication hole is formed, so that it becomes easier to insert the tool from the compression chamber toward the suction space along the second direction.
In addition, in the compressor according to a third aspect of the present disclosure, in the first aspect or the second aspect, a plurality of pairs of the eccentric shaft portion and the cylinder are provided, the cylinders are disposed side by side in the direction of the axis, and the suction spaces formed in the respective cylinders communicate with each other along the direction of the axis.
With the compressor according to this aspect, a plurality of pairs of the eccentric shaft portion and the cylinder are provided, the cylinders are disposed side by side in the axis direction, and the suction spaces formed in the respective cylinders communicate with each other along the axis direction. Therefore, even in the multi-cylinder rotary compression mechanism, it is possible to reduce the costs required for manufacturing and assembly.

Reference Signs List

1: compressor
3: leg portion
11: housing
12: rotary compression mechanism (low-stage compression mechanism)
13: scroll compression mechanism (high-stage compression mechanism)
14: electric motor
15: rotary shaft
15a: oil supply hole
21: main body portion
22: upper cover portion
23: lower cover portion
31: scroll-side bearing
32A: upper bearing (rotary-side upper bearing)
32B: lower bearing (rotary-side lower bearing)
33: suction pipe
34: discharge pipe
35: suction boss (boss part)
36: refrigerant flow passage
37: rotor weight (balance weight)
38: rotor
38a: rotor passage
38b: oil separation plate
38c: pin
39: stator
41: eccentric shaft portion
42: rotor
43: rotary discharge pipe
44: cylinder
44a: suction space
44b: communication hole
45: separate plate
45a: communication space
48: cover
48a: suction opening
49: oil pump
51: fixed scroll
52: end plate
52a: discharge hole
53: fixed wrap
54: rotary shaft weight (balance weight)
55: drive bush
56: eccentric shaft portion
57: orbiting scroll
58: end plate
59: orbiting wrap
60: oil level tank
61: lower pipe
62: pressure equalization pipe
63: balance weight chamber
65: socket
C1: compression chamber
C2: compression chamber
D1: first direction
D2: second direction
FL: installation surface
X: axis

Claims

A compressor comprising:
a rotary shaft that extends in a direction of an axis and has an eccentric shaft portion that is eccentric with respect to the axis;

a rotor that is provided on the eccentric shaft portion; and

a cylinder in which a compression chamber that accommodates the rotor is formed,

wherein a suction space to which a refrigerant is guided from an outside and a communication hole through which the compression chamber and the suction space communicate with each other are formed in the cylinder, and

the communication hole extends along a second direction inclined with respect to a first direction orthogonal to the direction of the axis and does not penetrate an outer peripheral surface of the cylinder.
The compressor according to Claim 1,
wherein an extension line of the communication hole along the second direction does not interfere with the cylinder in which the communication hole is formed.
The compressor according to Claim 1 or 2,
wherein a plurality of pairs of the eccentric shaft portion and the cylinder are provided,

the cylinders are disposed side by side in the direction of the axis, and

the suction spaces formed in the respective cylinders communicate with each other along the direction of the axis.