GB2538005A

GB2538005A - Scroll compressor and refrigeration cycle device using same

Info

Publication number: GB2538005A
Application number: GB1608791.8A
Authority: GB
Inventors: Kanzaki Junya; Nagata Atsushi; Koyama Shuhei
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2014-02-20
Filing date: 2014-02-20
Publication date: 2016-11-02
Anticipated expiration: 2034-02-20
Also published as: WO2015125253A1; JP6218919B2; JPWO2015125253A1; GB201608791D0; GB2538005B

Abstract

The stationary scroll of a scroll compressor has: injection ports extending from the upper part of the stationary scroll to the compression chamber of the scroll compressor; and an injection piping unit provided on the injection ports in the upper part of the stationary scroll and supplying operating fluid to the injection ports. The injection piping unit has: main piping through which operating fluid supplied from the outside to the injection ports flows; lines of branch piping, each having one end connected to the main piping and the other end connected to one of the injection ports; and a joint member to which an end of the main piping and an end of each of the lines of branch piping are fitted and joined.

Description

DESCRIPTION Title of Invention SCROLL COMPRESSOR AND REFRIGERATION CYCLE APPARATUS USING THE SAME

Technical Field

[0001] The present invention relates to a scroll compressor that compresses refrigerant or other mediums circulating in a refrigeration cycle and a refrigeration cycle apparatus using the same.

Background Art

[0002] A scroll compressor known in the art has been proposed that cools the compressor by injecting liquid refrigerant in a liquid receiver constituting a refrigerant circuit into a middle pressure portion during a compression process and evaporating the refrigerant (for example, refer to Patent Literature 1), for example. The scroll compressor according to Patent Literature 1 is provided with two injection ports on an upper surface of a fixed scroll, and an injection pipe is each connected to each of the two injection ports. The injection pipe is constituted of a T-shaped pipe and refrigerant having flowed in the injection pipe separates into two to flow into each of the injection ports.

Citation List Patent Literature [0003] Patent Literature 1: Japanese Unexamined Patent Application Publication No. 11-159479

Summary of Invention

Technical Problem [0004] The injection pipe described in Patent Literature 1 has a structure in which a hole is made on a side wall of the pipe, for example, by burring processing or other methods, and then another pipe is inserted into the hole to be fixed by brazing. Here, in a case where high-pressure liquid refrigerant passes through the injection pipe, such a case where high-pressure refrigerant such as a mixed refrigerant including a CO2 refrigerant, an R32 refrigerant or other refrigerants are used, the wall thicknesses of copper pipes need to be increased in terms of pressure resistance.

However, a thick wall of the injection pipe makes the burring processing or other methods difficult. The insertion depth (fitting length) for brazing, thus, reduces and cracks may be caused at the joint portion due to an excessive stress.

[0005] The present invention has been made to solve the above described problems and an object of the present invention is to provide a scroll compressor that can reliably prevent cracks or other damage on the injection pipe from occurring even when high-pressure refrigerant is used and a refrigeration cycle apparatus using the same.

Solution to Problem [0006] The scroll compressor according to the present invention includes an orbiting scroll having a spiral body and performing an orbiting movement by motor drive, a fixed scroll having a spiral body fitted into the spiral body of the orbiting scroll and cooperating with the orbiting scroll to define a compression chamber for compressing working gas, the fixed scroll having a plurality of injection ports penetrating from an upper part of the fixed scroll to the compression chamber, and an injection pipe unit disposed on the plurality of injection ports on the upper part of the fixed scroll for supplying working fluid to the plurality of injection ports. The injection pipe unit includes a main pipe allowing the working fluid supplied from outside to the plurality of injection ports to flow therein, a plurality of branch pipes formed so that one end of each of the plurality of branch pipes communicates with the main pipe and an other end of each of the plurality of branch pipes is connected to a corresponding one of the plurality of injection ports, and a joint member inserted by and jointing one end of the main pipe and the one end of each of the plurality of branch pipes.

Advantageous Effects of Invention [0007] In the scroll compressor according to the present invention, the main pipe and the plurality of branch pipes are inserted in and joint the joint member, thus the insertion depth (fitting length) of the main pipe and the plurality of branch pipes at the time of joint can be secured even when the thicknesses of the main pipe and the branch pipes are increased, and thus, a crack occurrence on the joint portion due to an excessive stress can be prevented even when a high-pressure working fluid passes through the injection pipe.

Brief Description of Drawings

[0008] [Fig. 1] Fig. 1 is a cross-sectional view of a scroll compressor according to Embodiment 1 of the present invention.

[Fig. 2] Fig. 2 is a perspective view illustrating an example of a fixed scroll in the scroll compressor in Fig. 1.

[Fig. 3] Fig. 3 is a cross-sectional view illustrating an example of a fixed scroll in the scroll compressor in Fig. 1.

[Fig. 4] Fig. 4 is a perspective view illustrating an example of an injection pipe mounted on the fixed scroll in Fig. 2.

[Fig. 5] Fig. 5 is a cross-sectional view illustrating a cross section of a joint member on the injection pipe in Fig. 4.

[Fig. 6] Fig. 6 is a perspective view illustrating an injection pipe unit in the scroll compressor according to Embodiment 2 of the present invention.

[Fig. 7] Fig. 7 is a refrigerant circuit diagram illustrating an embodiment of an air-conditioning apparatus using a scroll compressor according to the present invention.

Description of Embodiments

[0009] Embodiment 1 Embodiments of a scroll compressor according to the present invention will be described hereinafter with reference to the drawings. Fig. 1 is a cross-sectional view of a scroll compressor 1 according to Embodiment 1 of the present invention, Fig. 2 is a perspective view illustrating an example of a fixed scroll in the scroll compressor in Fig. 1, and Fig. 3 is a cross-sectional view illustrating an example of a fixed scroll in the scroll compressor in Fig. 1, and the scroll compressor 1 will be described with reference to Figs. 1 to 3. The scroll compressor 1 in Figs. 1 to 3, which compresses working fluid such as gas refrigerant in a scroll-shaped compression chamber 10A and discharges the fluid, includes a shell 2, a main shaft 3, a motor 4, and a fluid compression unit 10.

[0010] The shell (well-closed container) 2 is formed cylindrically to have well-closed space and has pressure resistance. A suction pipe 2A for sucking working gas into the shell 2 is connected to a side of the shell 2, and a discharge pipe 2B for discharging compressed working gas from the shell 2 is connected on an upper surface. Frames 2D and 2E are fixed on a top side and a bottom side of the shell 2 respectively and an oil sump 2C for storing a lubricant is formed at the bottom of the shell 2.

[0011] The main shaft 3 is supported rotatably on the frames 2D and 2E with bearings or other devices in the shell 2. An eccentric shaft portion is eccentrically attached to the main shaft 3 at an upper end of the main shaft 3, and an orbiting scroll 11 is provided to be capable of an orbital movement on the eccentric shaft portion.

Further, an oil pump (not illustrated) is disposed at the lower end of the main shaft 3 and supplies oil stored at the bottom of the shell 2 through a passage provided inside the main shaft 3 from the upper portion of the eccentric shaft portion to an orbiting bearing 11A.

[0012] The motor 4, which drives the main shaft 3 to rotate, has a rotor 4A and a stator 43. The stator 43 is fixed to the shell 2 and the rotor 4A is fixed to the main shaft 3. When power is supplied from an inverter circuit or other devices, the main shaft 3 and the rotor 4A rotate with respect to the stator 4B.

[0013] The fluid compression unit 10, which compresses working fluid such as gas refrigerant sucked in from the suction pipe 2A, has the orbiting scroll 11 and a fixed scroll 12. A spiral body is formed on each of an upper surface of the orbiting scroll 11 and a lower surface of the fixed scroll 12, and the spiral bodies of the orbiting scroll 11 and the fixed scroll 12 are positioned to face each other. A compression chamber 10A is formed between the spiral bodies of the fixed scroll 12 and the orbiting scroll 11.

[0014] The orbiting scroll 11 is supported by the frame 2D provided inside the shell 2 to perform an orbital movement and the orbiting bearing 11A is disposed on a lower surface of the orbiting scroll 11. Further, an oldham ring (not illustrated) supported on the frame 2D to allow its own orbiting movement is provided between the frame 2D and the orbiting scroll 11 to give an orbiting movement to the orbiting scroll 11 while preventing rotation of the orbiting scroll 11.

[0015] The fixed scroll 12 is disposed on a top of the orbiting scroll 11 and fixed on the frame 2D. A discharge port 12A for discharging working fluid is formed at a center of the fixed scroll 12 and a reed valve 13 for preventing the reverse flow of the compressed working gas is disposed on the discharge port 12A. The range of movement of the reed valve 13 is restricted by a valve guard 14, and the reed valve 13 and the valve guard 14 are fixed on an upper surface of the fixed scroll 12 with a valve bolt 15. The spiral bodies of the orbiting scroll 11 and the fixed scroll 12 are engaged with each other, and thus a plurality of compression chambers 10A whose volumes are varied relatively are formed.

[0016] Further, a valve cover 20 is mounted on a top of the fixed scroll 12 with screws 23. An insertion hole 21 is formed for the insertion of the discharge pipe 23 on the valve cover 20, and working fluid discharged from the discharge port 12A is then ejected outside through the discharge pipe 2B inserted in the insertion hole 21. [0017] Next, the operation of the scroll compressor 1 will be described with reference to Fig. 1. When the motor 4 is energized, the main shaft 3 rotates and the orbiting scroll 11 on the end portion of the main shaft 3 performs an orbital movement. Then, along with the revolution of the orbiting scroll 11, the compression chambers 10A move toward a center while reducing their volumes to compress the refrigerant. Then, after the fluid is compressed in the fluid compression unit 10, the fluid sucked into the shell 2 passes through the discharge port 12A of the fixed scroll 12 and is ejected to the outside of the shell 2 from the discharge pipe 2B through the reed valve 13 and the valve cover 20.

[0018] Here, the scroll compressor 1 is configured to be capable of an injection of liquid refrigerant of a higher pressure than the pressure in the compression chambers 10A into the compression chambers 10A to increase the volume of refrigerant in the compression chambers 10A and cool the inside of the compression chambers 10A. Specifically, as shown in Fig. 2, a plurality of injection ports 12B for introducing liquid refrigerant into the compression chambers 10A are arranged on the fixed scroll 12 so that liquid refrigerant flows into a portion of a middle of compression process of the fixed scroll 12 from the injection ports 12B. Fig. 2 illustrates the case of two injection ports 12B provided; however, more than two maybe be provided. Each injection port 12B is constituted of a through hole penetrating from the upper surface of the fixed scroll 12 to a surface forming the spiral body, and an injection pipe unit 30 for supplying working fluid (liquid refrigerant) to the injection ports 12B is disposed on the injection port 12B.

[0019] Fig. 4 is a perspective view illustrating an example of the injection pipe unit 30. The injection pipe unit 30 in Fig. 4 has a main pipe 31, branch pipes 32A and 32B and a joint member 33. The main pipe 31 and the branch pipes 32A and 32B are made of copper pipes, for example, and made of individual pipes. The main pipe 31 allows working fluid supplied from outside to the injection ports 12B to flow therein and its end joints the joint member 33. On the other hand, one end of each of the branch pipes 32A and 32B joints the joint member 33 and pipe covers 34A and 34B are each connected to a corresponding one of the other ends. The pipe covers 34A and 34B are fixed on the injection ports 12B with screws 35 to connect each of the branch pipes 32A and 32B to a corresponding one of the plurality of injection ports 12B. [0020] The joint member 33, which connects the main pipe 31 and the plurality of branch pipes 32A and 323, is made of a high-strength material such as iron. The one end of the main pipe 31 and ends of the plurality of branch pipes 32A and 32B are inserted in and joint the joint member 33. Fig. 5 is a cross-sectional view illustrating a cross section of the joint member in the injection pipe unit 30 in Fig. 4. As shown in Fig. 5, the joint member 33 has a cylindrical shape having openings 33B at both ends, and has a hole on a side wall 33A for mounting the main pipe 31. The branch pipes 32A and 32B are each fitted into and fixed to a corresponding one of the openings 333 of the joint member 33 and the main pipe 31 is fitted into and fixed to a hole 33H on the side wall 33A.

[0021] Here, each of the branch pipes 32A and 32B is formed to have an outer diameter 1, an inner diameter (1)2, and a wall thickness Dl. On the other hand, the joint member 33 is formed to have an outer diameter 4r10 that is larger than the outer diameter 41 of the branch pipes 32A and 323 and has an inner diameter (IQ that is equal to the inner diameter (IQ of the branch pipes 32A and 323. Further, a wall thickness D10 of the joint member 33 is larger than the wall thickness D1 of the branch pipes 32A and 32B. The main pipe 31 and the branch pipes 32A and 32B may have the same outer diameter and inner diameter and also may have different outer diameters or different inner diameters.

[0022] On the opening 33B sides of the joint member 33, formed are insertion portions 33C that have larger inner diameters than the inner diameter 4)2 of the joint member 33 and into which the branch pipes 32A and 32B are to be inserted. Then, a plurality of branch pipes 32A and 32B are inserted into the insertion portions 33C on the openings 33B on both sides of the joint member 33 and jointed by brazing or other methods. In particular, the insertion portions 33C have larger diameters than the inner diameter 4)2 of the joint member by an amount corresponding to the wall thickness Dl. Thus, when the branch pipes 32A and 32B are inserted into the insertion portions 33C, steps are prevented from forming in the joint member 33.

Hence, the flow resistance can be reduced when working fluid flows in the joint member 33.

[0023] On the other hand, the hole 33H is formed on the side wall 33A of the joint member 33 and the main pipe 31 is fitted into the hole 33H to be jointed. The hole 33H on the side wall 33A of the joint member 33 has a fitting portion 33H1 into which the main pipe 31 is inserted and a penetration portion 33H2 formed to have a diameter smaller than the diameter of the fitting portion 33H1. The fitting portion 33H1 has a predetermined insertion depth (fitting length) D2 and has the same diameter as the outer diameter of the main pipe 31. Then, the main pipe 31 is inserted into the fitting portion 33H1 to be jointed by brazing or other methods. The penetration portion 33H2 has the same size as the inner diameter 4)2 of the main pipe 31. Thus, steps are prevented from forming in the joint member 33 and reduce flow resistance when working fluid flows in the joint member 33.

[0024] As described above, the injection pipe unit 30 introducing high-pressure liquid refrigerant is formed into the pipe structure so that the joint member 33 is added to the direct joint portion of the main pipe 31 and the branch pipes 32A and 32B to secure the insertion depth (fitting length), thereby preventing pipe damage caused by an excessive stress from the rise of working pressure. That is, when high-pressure refrigerant such as a mixed refrigerant including a CO2 refrigerant, an R32 refrigerant or other refrigerants are used, the wall thicknesses of the pipes need to be increased. As in the conventional case, when the structure is used in which both ends of a single branch pipe are connected to the injection ports and the main pipe joints a hole made by burring processing or other methods on the side wall of the branch pipe, the difficulty of the burring processing or others results in reduction of the insertion depth (fitting length) at the time of brazing and may cause cracks due to an excessive stress. On the other hand, the injection pipe unit 30 illustrated in Figs. 1 to 5 can reliably prevent pipe damage or other troubles due to an excessive stress from a working pressure rise by adding the joint member 33 to the direct joint portion of the main pipe 31 and the branch pipes 32A and 32B to form a pipe shape securing the insertion depth (fitting length).

[0025] Moreover, employing a high-strength member such as an iron for the joint member 33 reduces the size of the joint member 33 to achieve space saving and enables the injection pipe unit 30 to be mounted on a back of the fixed scroll 12 where the mounting space is small because of the valve cover 20 or other members. [0026] When the joint member 33 has a cylindrical shape having openings 33B formed at both ends and the hole 33H formed on the side wall 33A, the plurality of branch pipes 32A and 32B are inserted in and joint the openings 33B at the both ends of the joint member 33, and the main pipe 31 is inserted in and joints the hole 33H on the side wall 33A of the joint member 33, the joint member 33 reliably secures the insertion depth (fitting length) of the plurality of branch pipes 32A and 32B to surely prevent pipe damage or other troubles. Further, the degree of freedom of shape and diameter of pipes can be increased in the axial direction and the circumferential direction of the joint member 33, and thus the injection pipe unit 30 can be mounted on the back of the fixed scroll 12 where the mounting space is small due to the valve cover 20 or other members.

[0027] Further, when the hole 33H on the side wall 33A of the joint member 33 has the fitting portion 33H1 for the main pipe to be fitted into and the penetration portion 33H2 formed to have a smaller diameter than the diameter of the fitting portion 33H1, the insertion depth (fitting length) of the main pipe 31 is reliably secured to surely prevent pipe damage or other troubles.

[0028] Embodiment 2 Fig. 6 is a perspective view illustrating an injection pipe unit in the scroll compressor according to Embodiment 2 of the present invention, and an injection pipe unit 130 will be described with reference to Fig. 6. As for the injection pipe unit in Fig. 6, parts having the same structure as those of the injection pipe unit 30 in Fig. 4 are denoted by the same reference signs with omission of the description of the parts. The difference of the injection pipe unit 130 in Fig. 6 from the injection pipe unit 30 in Fig. 4 is the structure of a joint member 133.

[0029] The joint member 133 in Fig. 6 has a cylindrical shape with an opening 33B formed on one side and the other side blocked, and a plurality of holes 33H are formed on the side wall 33A. The main pipe 31 is inserted in and joints the opening 33B of the joint member 133, and each of the plurality of branch pipes 32A and 32B is inserted in and joints a corresponding one of the plurality of holes 33H on the joint member 133. The joint structure of the joint member 133 and the main pipe 31 in Fig. 6 is the same as that of the joint member 33 and the branch pipes 32A and 32B in Fig. 5, and the joint structure of the joint member 133 and the branch pipes 32A and 32B in Fig. 6 is the same as that of the joint member 33 and the main pipe 31 in Fig. 5.

[0030] Even in this case, similarly to Embodiment 1, the injection pipe unit 30 for introducing high-pressure liquid refrigerant can prevent pipe damage caused by an excessive stress due to a working pressure rise by adding the joint member 133 to the direct joint portion of the main pipe 31 and the branch pipes 32A and 32B to form a pipe shape securing the insertion depth (fitting length).

[0031] Embodiment 3 Fig. 7 is a refrigerant circuit diagram showing an embodiment of an air-conditioning apparatus using a scroll compressor according to the present invention, and a refrigeration cycle apparatus 200 will be described with reference to Fig. 7. The refrigeration cycle apparatus 200 connects a scroll compressor 1, a condenser 202, a first expansion valve 203 that is a pressure reducing device, and an evaporator 204 by refrigerant pipes. The scroll compressor 1 compresses refrigerant and is provided with the injection ports 12B as shown in Figs. 1 to 6.

[0032] The condenser 202 transfers heat of refrigerant to a heat medium (for example, air or water) by exchange of heat between refrigerant flowing in a main refrigerant circuit and the heat medium. The condenser 202 exchanges heat between air sent from a fan (not illustrated) and the refrigerant, for example. This condenser 202 has, for example, heat transfer pipes to allow refrigerant to pass therein and heat transfer fins (not illustrated) for enlarging the heat transfer area between refrigerant flowing in the heat transfer pipes and air, and exchanges heat between the refrigerant and the air (open air).

[0033] The first expansion valve 203 allows refrigerant flowing through the main refrigerant circuit to expand by reducing its pressure and is preferably configured to be a controllable valve with its opening degree variable, such as an electronic expansion valve. The evaporator 204 allows refrigerant to absorb heat of a heat medium (for example, air or water) by exchange of heat between refrigerant flowing in the main refrigerant circuit and the heat medium. The condenser 202 exchanges heat between air sent from a fan (not illustrated) and refrigerant, for example. This evaporator 204 has, for example, heat transfer pipes to allow refrigerant to pass therein and heat transfer fins (not illustrated) for enlarging the heat transfer area between refrigerant flowing in the heat transfer pipes and air, and exchanges heat between the refrigerant and indoor air, evaporating the refrigerant for gasification. [0034] Further, the refrigeration cycle apparatus 200 has an injection pipe 205 and an inter-refrigerant heat exchanger 206 for injection into the scroll compressor 1. The injection pipe 205 and the inter-refrigerant heat exchanger 206 are connected to a portion between the condenser 202 and the first expansion valve 203. The injection pipe 205 allows refrigerant to flow to be injected into the injection ports 12B (refer to Figs. 1 to 6), from the portion between the condenser 202 and the first expansion valve 203 through the injection pipe unit 30 or 130 of the scroll compressor 1. The inter-refrigerant heat exchanger 206 exchanges heat between refrigerant flowing from the condenser 202 to the first expansion valve 203 and refrigerant flowing in the injection pipe 205. Moreover, the injection pipe 205 is provided with a second expansion valve 207 for reducing the pressure of refrigerant flowing into one side of the inter-refrigerant heat exchanger 206 and also for regulating the flow rate of refrigerant flowing in the injection pipe 205.

[0035] Even in the case of the refrigeration cycle apparatus 200 according to Embodiment 3, similarly to Embodiments 1 and 2, adding the joint member 33 or 133 to the direct joint portion of the injection pipe unit 30 or 130 used for high-pressure refrigerant such as a mixed refrigerant including a CO2 refrigerant, an R32 refrigerant or other refrigerants and forming the pipe shape securing the insertion depth (fitting length) can prevent pipe damage caused by an excessive stress due to a working pressure rise.

[0036] Embodiments of the present invention are not limited to the above described embodiments. For example, Fig. 7 illustrates that the injection pipe 205 is subjected to heat exchange in the inter-refrigerant heat exchanger 206; however, as long as the circuit allows refrigerant to be injected into the injection ports 12B of the scroll compressor 1, the refrigeration cycle is not limited to that in Fig. 7 and various refrigeration cycles known in the art can be used.

Reference Signs List [0037] 1 scroll compressor, 2 shell, 2A suction pipe, 2B discharge pipe, 2C oil sump, 2D, 2E frame, 3 main shaft, 4 motor, 4A rotor, 4B stator, fluid compression unit, 10A compression chamber, 11 orbiting scroll, 11A orbiting bearing, 12 fixed scroll, 12A discharge port, 12B injection port, 13 reed valve, 14 valve guard, 15 valve bolt, 20 valve cover, 21 insertion hole, 23 screw, 30, 130 injection pipe unit, 31 main pipe, 32A, 32B branch pipe, 33, 133 joint member, 33A side wall, 33B opening, 33C insertion portion, 33H hole, 33H1 fitting portion, 33H2 penetration portion, 34A, 34B pipe cover, 35 screw, 200 refrigeration cycle apparatus, 202 condenser, 203 first expansion valve, 204 evaporator, 205 injection pipe, 206 inter-refrigerant heat exchanger, 207 second expansion valve, D1, D10 wall thickness, (1)1, (1)10 outer diameter, 4)2 inner diameter