EP3477113A1

EP3477113A1 - Scroll compressor

Info

Publication number: EP3477113A1
Application number: EP16907249.3A
Authority: EP
Inventors: Junpei MIZOBATA; Koichi FUKUHARA; Shuhei Koyama
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2016-06-28
Filing date: 2016-06-28
Publication date: 2019-05-01
Also published as: EP3477113A4; JP6641479B2; WO2018003016A1; JPWO2018003016A1; KR20180124130A

Abstract

A scroll compressor includes a through hole penetrating through a base plate portion of a fixed scroll to communicate with a compression chamber, a fixing part provided on a surface of the base plate portion that is opposite to an orbiting scroll to cover the through hole and having an injection port communicating with the through hole, an injection pipe being connected to the injection port, a valve body inserted into the through hole in such a manner that the valve body is configured to reciprocate, and a spring inserted into the through hole and configured to urge the valve body toward the injection port. A flow passage is formed in the valve body or between the valve body and the through hole and is configured to allow refrigerant having flowed into the through hole from the injection port to flow out to the compression chamber. The valve body is configured to close the flow passage between the injection port and the compression chamber when the valve body is urged by the spring to move toward the injection port.

Description

Technical Field

The present invention relates to a scroll compressor configured to compress fluid, and more particularly, to a scroll compressor capable of injecting (charging) fluid to be compressed into a compression chamber.

Background Art

For example, for the purpose of reducing increase in temperature of fluid to be discharged from a compressor, there has been proposed a scroll compressor configured to inject fluid to be compressed into a compression chamber when compression is being performed, that is, before the compression chamber communicates with a discharge port. In such a scroll compressor, in the middle of an injection flow passage configured to allow fluid to be injected to pass through the injection flow passage, there is provided a check valve configured to prevent a reverse flow of the fluid from the compression chamber. Consequently, in the related-art scroll compressor having such configuration, when the scroll compressor is operated under a state in which the fluid is not injected into the compression chamber, the injection flow passage from the compression chamber to the check valve causes dead volume. That is, during the compression of fluid, when the compression chamber communicates with such a portion of the injection flow passage having the dead volume, the fluid is expanded again by the dead volume, with the result that performance of the scroll compressor is degraded.
Consequently, there has been proposed a related-art scroll compressor for which reduction in dead volume is attained (for example, see Patent Literature 1). Specifically, in the scroll compressor described in Patent Literature 1, a base plate portion of a fixed scroll has an injection port penetrating from an outer surface into a compression chamber substantially in a wall-thickness direction. Moreover, a block to which an injection pipe is connected is placed in contact with a portion of the outer surface corresponding to the injection port of the base plate portion of the fixed scroll, thereby defining check valve chambers across the block from each other. A valve seat holding a lead valve configured to open and close, from an inner side, an introduction port of the block from the injection pipe is interposed between the base plate portion of the fixed scroll and the block. Moreover, a valve stopper for a lead valve is provided at a portion of the check valve chamber.

Citation List

Patent Literature

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 11-107950

Summary of Invention

Technical Problem

In the scroll compressor described in Patent Literature 1, it is required that the lead valve be capable of opening and closing the introduction port of the block from the injection pipe, and that the valve seat be installed at a position at which the lead valve can be held in contact with the valve stopper to interpose the valve seat between the base plate portion of the fixed scroll and the block. Consequently, the scroll compressor described in Patent Literature 1 has a problem in that assembly is difficult because it is required that the valve seat be installed with use of a positioning jig.
The present invention has been made to solve the problem described above, and has an object to obtain a scroll compressor capable of injecting fluid into a compression chamber, and is capable of reducing dead volume and achieving easy assembly.

Solution to Problem

According to an embodiment of the present invention, there is provided a scroll compressor including a fixed scroll including a first base plate portion and a first spiral blade formed on one surface of the first base plate portion, an orbiting scroll including a second base plate portion and a second spiral blade formed on a surface of the second base plate portion facing the fixed scroll, defining a compression chamber by combination of the first spiral blade and the second spiral blade, and configured to perform an orbiting motion against the fixed scroll, a first through hole penetrating through the first base plate portion to communicate with the compression chamber, a fixing part provided on a surface of the first base plate portion that is opposite to the orbiting scroll to cover the first through hole and having an injection port communicating with the first through hole, an injection pipe being connected to the injection port, a valve body inserted into the first through hole in such a manner that the valve body is configured to reciprocate, and a spring inserted into the first through hole and configured to urge the valve body toward the injection port. A flow passage is formed in the valve body or between the valve body and the first through hole and the flow passage is configured to allow refrigerant having flowed into the first through hole from the injection port to flow out to the compression chamber. The valve body is configured to close the flow passage between the injection port and the compression chamber when the valve body is urged by the spring to move toward the injection port.

Advantageous Effects of Invention

In the scroll compressor according to an embodiment of the present invention, the valve body and the spring act as a check valve configured to prevent a reverse flow of fluid from the compression chamber to the injection port. The valve body and the spring are provided in the first through hole opened in the first base plate portion of the fixed scroll. Consequently, the scroll compressor according to an embodiment of the present invention is capable of reducing dead volume. Moreover, when the scroll compressor according to an embodiment of the present invention is to be assembled, the valve body and the spring can be assembled by only inserting the valve body and the spring into the first through hole. Consequently, the scroll compressor according to an embodiment of the present invention can easily be assembled.

Brief Description of Drawings

Fig. 1 is a schematic vertical sectional view of a scroll compressor according to Embodiment 1 of the present invention.
Figs. 2 are enlarged views for illustrating main parts of the scroll compressor according to Embodiment 1 of the present invention, and are illustrations of a periphery of a through hole for injection opened in a base plate of a fixed scroll.
Figs. 3 are plan views for illustrating examples of a valve body of the scroll compressor according to Embodiment 1 of the present invention.
Figs. 4 are perspective views for illustrating a valve body and a spring of a scroll compressor according to Embodiment 2 of the present invention and a case configured to accommodate the valve body and the spring.
Figs. 5 are enlarged views for illustrating main parts of the scroll compressor according to Embodiment 2 of the present invention, and are illustrations of a periphery of a through hole for injection opened in a base plate of a fixed scroll.

Description of Embodiments

Embodiment

1

Fig. 1 is a schematic vertical sectional view of a scroll compressor according to Embodiment 1 of the present invention.
In Fig. 1, a flow of refrigerant in a normal compression step is indicated by solid-line thick arrows, and a flow of refrigerant under injection control is indicated by broken-line thick arrows. Moreover, in Fig. 1 and subsequent drawings, for easy recognition of leader lines, hatching on cross sections of some parts is omitted.
The scroll compressor 1 is a fluid machine configured to compress and discharge fluid (for example, refrigerant). The scroll compressor 1 is one of components of a refrigeration cycle apparatus to be used for various industrial machines such as a refrigerator, a freezer, an automatic vending machine, a refrigeration apparatus, and a water heater. In Embodiment 1, as an example of the scroll compressor 1, illustration is given of a scroll compressor of a vertical installation type in which a main shaft 2 is provided along a vertical direction. In the following drawings including Fig. 1, for example, dimensional relationships and shapes of the components are different from those of actual components in some cases.
As illustrated in Fig. 1, the scroll compressor 1 includes a compression mechanism part 3 and a drive mechanism part 4 configured to drive the compression mechanism part 3. The compression mechanism part 3 and the drive mechanism part 4 are accommodated in a shell 5 that is a pressure container (hermetic container). A bottom portion of the shell 5 serves as an oil reservoir configured to store refrigerating machine oil. A suction pipe 6 and a discharge pipe 7 are connected to the shell 5. The suction pipe 6 is configured to allow refrigerant to be sucked into the shell 5. The discharge pipe 7 is configured to allow the compressed refrigerant to be discharged to an outside of the shell 5.
When the compression mechanism part 3 is driven by the drive mechanism part 4, the compression mechanism part 3 performs a function of compressing refrigerant gas sucked through the suction pipe 6 in a compression chamber 8, and discharging the compressed refrigerant gas to a discharge space 10 inside the shell 5 through a discharge port 9. The discharge space 10 is provided in an upper space inside the scroll compressor 1, and is a high-pressure space. The refrigerant gas having been discharged to the discharge space 10 is discharged to the outside of the scroll compressor 1 after passing through the discharge pipe 7 from the discharge space 10.
The compression mechanism part 3 includes a fixed scroll 20 and an orbiting scroll 26. The fixed scroll 20 is fixed to a frame 11 mounted to the shell 5. The orbiting scroll 26 is configured to orbit (that is, perform a revolving motion) against the fixed scroll 20. The fixed scroll 20 includes a base plate portion 21 and a spiral blade 22. The spiral blade 22 is a projection that is formed on one surface (lower surface in Fig. 1) of the base plate portion 21 and has an involute curve shape. The orbiting scroll 26 includes a base plate portion 27 and a spiral blade 28. The spiral blade 28 is a projection that is formed on one surface (upper surface in Fig. 1) of the base plate portion 27 and has an involute curve shape. The fixed scroll 20 and the orbiting scroll 26 are combined so that the spiral blades 22 and 28 are held in mesh with each other. With this configuration, between the spiral blade 22 and the spiral blade 28, there is defined the compression chamber 8 relatively changed in volume to compress the refrigerant.
The base plate portion 21 corresponds to a first base plate portion of the present invention. The spiral blade 22 corresponds to a first spiral blade of the present invention. The base plate portion 27 corresponds to a second base plate portion of the present invention. Moreover, the spiral blade 28 corresponds to a second spiral blade of the present invention.
In a center portion of the base plate portion 21 of the fixed scroll 20, there is formed the discharge port 9 configured to allow the high-pressure refrigerant gas having been compressed in the compression chamber 8 to be discharged. Moreover, in the base plate portion 21, there is opened a through hole 12 configured to allow the refrigerant to be injected into the compression chamber. The through hole 12 penetrates through the base plate portion 21 at a position of communicating with the compression chamber 8 at a time before the compression chamber 8 communicates with the discharge port 9. To allow opening and closing of an injection port 130 described later, a valve body 23 having a block shape and a spring 24 configured to urge the valve body 23 toward the injection port 130 are inserted into the through hole 12. The valve body 23 and the spring 24 act as a check valve configured to allow a flow of refrigerant flowing from the injection port 130 into the compression chamber 8 through the through hole 12 and to regulate a flow in the reverse direction. Details of the through hole 12, the valve body 23, and the spring 24 are described later with reference to Figs. 2 and Figs. 3.
The through hole 12 corresponds to a first through hole of the present invention.
A portion of the compression chamber 8 is defined between an inward surface of the spiral blade 22 of the fixed scroll 20 and an outward surface of the spiral blade 28 of the orbiting scroll 26, and another portion of the compression chamber 8 is defined between an outward surface of the spiral blade 22 of the fixed scroll 20 and an inward surface of the spiral blade 28 of the orbiting scroll 26. Thus, the scroll compressor 1 according to Embodiment 1 has two through holes 12 in the base plate portion 21 of the fixed scroll 20.
Moreover, a chamber 13 is fixed to a surface (upper surface in Fig. 1) of the base plate portion 21 of the fixed scroll 20 that is opposite to the surface having the spiral blade 22 formed on the surface by, for example, a bolt to cover the through holes 12. The chamber 13 has the injection port 130 communicating with the through holes 12. The injection port 130 includes an inflow port 131 and outflow ports 132. An injection pipe 14 is connected to the inflow port 131. One of the outflow ports 132 allows a corresponding one of the inflow ports 131 and a corresponding one of the through holes 12 of the base plate portion 21 of the fixed scroll 20 to communicate with each other. In Embodiment 1, the injection port 130 includes two outflow ports 132 each provided to a corresponding one of two through holes 12. Consequently, the two outflow ports 132 communicate with the inflow port 131 through a connection hole 133. In Embodiment 1, the injection pipe 14 is connected to the injection port 130 with use of a joint 14a. However, the injection pipe 14 may be directly connected to the injection port 130.
The chamber 13 corresponds to a fixing part of the present invention.
The other end of the injection pipe 14 is connected to, for example, a liquid receiver provided to the refrigerant cycle. Liquid refrigerant in the liquid receiver is injected (charged) into the compression chamber 8 through the injection pipe 14, the injection port 130 of the chamber 13, and the through holes 12 of the fixed scroll 20. Whether or not to allow the refrigerant to flow through the injection pipe 14 is switched by, for example, an electromagnetic valve. The amount of refrigerant flowing through the injection pipe 14 may be adjusted with use of a capillary tube to thereby adjust the injection amount of the refrigerant to the compression chamber 8.
Moreover, in the chamber 13, a discharge port 134 penetrating through the chamber 13 is formed at a position facing the discharge port 9 of the base plate portion 21 of the fixed scroll 20. Further, a lead valve 15 configured to close the discharge port 134 and a lead valve pressing part 16 configured to regulate a maximum opening degree of the lead valve 15 are mounted to the chamber 13. That is, the refrigerant gas having been compressed in the compression chamber 8 passes through the discharge port 9 of the fixed scroll 20 and the discharge port 134 of the chamber 13, and pushes up the lead valve 15 to be discharged to the discharge space 10. The chamber 13 may be manufactured by separately preparing a fixing part having the discharge port 134 and a fixing part having the injection port 130 described above.
In a center portion of a surface (lower surface in Fig. 1) of the base plate portion 27 of the orbiting scroll 26 that is opposite to the surface having the spiral blade 28 formed on the surface, there is formed a boss portion 29 having a hollow cylindrical shape. An eccentric shaft portion 2a provided at one end of the main shaft 2 described later is inserted into the boss portion 29 in such a manner that the eccentric shaft portion 2a is surrounded by an inner periphery of the boss portion 29 and the eccentric shaft portion 2a is configured to rotate and slide in the boss portion 29.
An Oldham's joint 17 is provided between the orbiting scroll 26 and the frame 11. The Oldham's joint 17 includes a ring portion, a pair of Oldham's keys formed on an upper surface of the ring portion, and a pair of Oldham's keys formed on a lower surface of the ring portion. The Oldham's keys formed on the upper surface are inserted into key grooves formed in the orbiting scroll 26, and are each configured to slide in one direction. The Oldham's keys formed on the lower surface are inserted into key grooves formed in the frame 11, and are each configured to slide in a direction crossing the one direction. With this configuration, the orbiting scroll 26 performs a revolving motion (orbiting motion) without rotating on its own axis.
The drive mechanism part 4 has a function of driving the orbiting scroll 26 to compress the refrigerant gas by the compression mechanism part 3. That is, when the drive mechanism part 4 drives the orbiting scroll 26 through intermediation of the main shaft 2, the refrigerant gas is compressed by the compression mechanism part 3. The drive mechanism part 4 includes a stator 18 and a rotor 19. The stator 18 is fixed to an inner periphery of the shell 5. The rotor 19 is placed in such a manner that the rotor 19 is surrounded by an inner periphery of the stator 18. The main shaft 2 is fixed to the rotor 19, for example, by press-fitting. That is, when the stator 18 is energized, the rotor 19 rotates integrally with the main shaft 2.
The eccentric shaft portion 2a is formed at one end of the main shaft 2. The eccentric shaft portion 2a is inserted into the boss portion 29 of the orbiting scroll 26 in such a manner that the eccentric shaft portion 2a is configured to rotate and slide in the boss portion 29. Moreover, in the main shaft 2, there is formed an oil-feeding flow passage serving as a flow passage for feeding refrigerating machine oil stored in the oil reservoir to the compression mechanism part 3 and the bearings.
Figs. 2 are enlarged views for illustrating main parts of the scroll compressor according to Embodiment 1 of the present invention, and are illustrations of a periphery of a through hole for injection opened in the base plate of the fixed scroll. Moreover, Figs. 3 are plan views for illustrating examples of the valve body of the scroll compressor according to Embodiment 1 of the present invention.
Figs. 2 are schematic vertical sectional views for illustrating a periphery of the through hole 12 opened in the base plate portion 21 of the fixed scroll 20. Moreover, Fig. 2(A) is an illustration of a state in which the valve body 23 has moved away from the injection port 130 (lower position in Figs. 2) in such a manner that the injection port 130 and the compression chamber 8 communicate with each other. Fig. 2(B) is an illustration of a state in which the valve body 23 has moved toward the injection port 130 (upper position in Figs. 2) in such a manner that the flow passage between the injection port 130 and the compression chamber 8 is closed.
As illustrated in Figs. 2, the through hole 12 of the base plate portion 21 of the fixed scroll 20 includes, for example, a large-diameter portion 12a and a small-diameter portion 12b. The large-diameter portion 12a is a hole opened in a position close to the injection port 130. That is, the large-diameter portion 12a is a hole communicating with the injection port 130. The small-diameter portion 12b is a hole having an inner diameter smaller than that of the large-diameter portion 12a, and is a through hole allowing the large-diameter portion 12a and the compression chamber 8 to communicate with each other.
The valve body 23 has an outer peripheral shape that is substantially the same as an inner peripheral shape of the large-diameter portion 12a, and is inserted into the large-diameter portion 12a. The outer periphery of the valve body 23 is formed to be slightly smaller than the inner periphery of the large-diameter portion 12a in such a manner that the valve body 23 is configured to move upward and downward inside the large-diameter portion 12a. That is, the valve body 23 is configured to reciprocate in a direction of approaching the injection port 130 and in a direction of moving away from the injection port 130.
Moreover, the valve body 23 has a flow passage 23a configured to allow the refrigerant having flowed into the through hole 12 from the injection port 130 to flow out to the compression chamber 8. For example, the flow passage 23a is, as illustrated in Fig. 3(A), at least one groove 23b formed in a surface of the valve body 23 facing the large-diameter portion 12a. Moreover, for example, the flow passage 23a is, as illustrated in Fig. 3(B), at least one cutout 23c formed in the surface of the valve body 23 facing the large-diameter portion 12a. Moreover, for example, the flow passage 23a is, as illustrated in Fig. 3(C), at least one through hole 23d penetrating through the valve body 23 in the reciprocating direction of the valve body 23. Moreover, for example, in a case in which a flow passage is not formed between the valve body 23 and the small-diameter portion 12b when the valve body 23 is lowered, the flow passage 23a may be formed also in the lower surface of the valve body 23 (surface that is away from the injection port 130). It is not always required that the flow passage 23a be formed in the valve body 23. For example, a groove may be formed in an inner peripheral wall of the large-diameter portion 12a to serve as the flow passage 23a. That is, it is only required that the flow passage 23a be formed between the valve body 23 and the through hole 12.
The through hole 23d corresponds to a second through hole of the present invention.
As described above, in addition to the valve body 23, the spring 24 is also inserted into the through hole 12 opened in the base plate portion 21 of the fixed scroll 20. The spring 24 is, for example, a compression spring formed by winding a wire into a coil shape, and is provided between the valve body 23 and the small-diameter portion 12b. That is, the spring 24 has one end placed in contact with a bottom portion of the large-diameter portion 12a, and is configured to urge the valve body 23 toward the injection port 130 with the other end. The spring 24 is not limited to the above-mentioned shape. For example, the spring 24 may be a plate spring. Moreover, as long as the spring 24 can be fixed, the shape of the through hole 12 is also not limited to the shape described above.
Next, description is made of an operation of the scroll compressor 1 having the configuration described above.
When refrigerant is to be injected into the compression chamber 8, the refrigerant flows into the injection port 130 from the injection pipe 14. Consequently, a pressure of the refrigerant supplied to the injection port 130 acts on the surface of the valve body 23 that is close to the injection port 130, that is, the upper surface of the valve body 23. Meanwhile, the pressure of refrigerant in the compression chamber 8 at the position of communicating with the through hole 12 and the urging force of the spring 24 act on the surface of the valve body 23 that is away from the injection port 130, that is, the lower surface of the valve body 23. Consequently, as illustrated in Fig. 2(A), the valve body 23 moves downward to a position at which the pressure of the refrigerant supplied to the injection port 130 is balanced with the pressure of the refrigerant in the compression chamber 8 and the urging force of the spring 24. With this operation, the refrigerant having been supplied to the injection port 130 flows into the large-diameter portion 12a of the through hole 12, passes through the flow passage 23a and the small-diameter portion 12b, and is injected into the compression chamber 8.
Meanwhile, when the injection of the refrigerant into the compression chamber 8 is to be stopped, the supply of refrigerant to the injection pipe 14 is stopped. With this operation, the pressure of the refrigerant acting on the surface of the valve body 23 that is close to the injection port 130, that is, the upper surface of the valve body 23 is reduced. Consequently, as illustrated in Fig. 2(B), the valve body 23 moves toward the injection port 130, that is, upward to be brought into contact with the chamber 13, thereby closing the outflow port 132 of the injection port 130. That is, the valve body 23 closes the flow passage between the injection port 130 and the compression chamber 8. With this operation, the flow passage between the injection port 130 and the compression chamber 8 is closed without causing the reverse flow of the refrigerant in the compression chamber 8 to the injection port 130.
Even when the supply of the refrigerant to the injection pipe 14 is stopped, the pressure of the refrigerant in the injection pipe 14 and the injection port 130 is not immediately reduced. Consequently, when the spring 24 is not provided, a long period of time is required until the pressure of the refrigerant in the injection pipe 14 and the injection port 130 becomes lower than the pressure of the refrigerant in the compression chamber 8 at the position of communicating with the through hole 12 and then the valve body 23 moves toward the injection port 130. Further, during this period, the refrigerant in the compression chamber 8 reversely flows to the injection port 130, with the result that the performance of the scroll compressor 1 is degraded. However, in Embodiment 1, the spring 24 configured to urge the valve body 23 toward the injection port 130 is provided. Thus, when the supply of the refrigerant to the injection pipe 14 is stopped, the injection port 130 can be immediately closed by the valve body 23, thereby degradation in performance of the scroll compressor 1 can be prevented.
As described above, in the scroll compressor 1 according to Embodiment 1, the valve body 23 and the spring 24 act as the check valve configured to prevent the reverse flow of the refrigerant from the compression chamber 8 to the injection port 130. The valve body 23 and the spring 24 are provided in the through hole 12 opened in the base plate portion 21 of the fixed scroll 20. Consequently, in the scroll compressor 1 according to Embodiment 1, when the injection of the refrigerant into the compression chamber 8 is stopped, the reverse flow of the refrigerant in the compression chamber 8 to the injection port 130 can be prevented, thereby dead volume can be reduced. Consequently, the scroll compressor 1 according to Embodiment 1 is capable of preventing degradation in performance. Moreover, when the scroll compressor 1 according to Embodiment 1 is to be assembled, it is only required that the valve body 23 and the spring 24 be inserted into the through hole 12. Consequently, the scroll compressor 1 according to Embodiment 1 can easily be assembled.
Moreover, in the scroll compressor 1 according to Embodiment 1, the check valve structure is made of the valve body 23, which is configured to reciprocate in the through hole 12. Consequently, the thickness of the valve body 23 in the reciprocation direction can be increased. In recent years, high-pressure refrigerant such as carbon dioxide refrigerant having a pressure higher than that of refrigerant used in the related art is sometimes used for a refrigeration cycle apparatus to which the scroll compressor is mounted. When the lead valve as in Patent Literature 1 is employed as a check valve configured to prevent the reverse flow in the injection flow passage, the lead valve has a structure of opening and closing the flow passage by elastic deformation itself, and, because of its structure, the thickness of the lead valve cannot be increased. Consequently, when the high-pressure refrigerant such as carbon dioxide refrigerant is used for the scroll compressor employing the lead valve as the check valve, there is a fear in that the lead valve is broken. However, as described above, the valve body 23 in Embodiment 1 can be increased in thickness of the valve body 23. Consequently, through setting of the thickness of the valve body 23 to such a thickness as to prevent breakage even when a high pressure of the high-pressure refrigerant such as the carbon dioxide refrigerant is applied to the valve body 23, reliability of the scroll compressor 1 can be improved.

Embodiment 2

In Embodiment 1, the valve body 23 and the spring 24 are directly inserted into the through hole 12 opened in the base plate portion 21 of the fixed scroll 20. When the valve body 23 and the spring 24 are accommodated in a case, and the case is inserted into the through hole 12 as described below, the scroll compressor 1 can be assembled more easily. In Embodiment 2, features that are not particularly described are the same as those of Embodiment 1, and the same functions or configurations are described with use of the same reference signs.
Figs. 4 are perspective views for illustrating a valve body and a spring of a scroll compressor according to Embodiment 2 of the present invention and a case configured to accommodate the valve body and the spring. Moreover, Figs. 5 are enlarged views for illustrating main parts of the scroll compressor according to Embodiment 2 of the present invention, and are illustrations of a periphery of a through hole for injection opened in the base plate of the fixed scroll.
Fig. 4(A) is an illustration of a disassembled state of a case 25. Fig. 4(B) is an illustration of an assembled state of the case 25. Moreover, Fig. 5(A) is an illustration of a state in which the valve body 23 has moved away from the injection port 130 (lower position in Figs. 5) in such a manner that the injection port 130 and the compression chamber 8 communicate with each other. Fig. 5(B) is an illustration of a state in which the valve body 23 has moved toward the injection port 130 (upper position in Figs. 5) in such a manner that the flow passage between the injection port 130 and the compression chamber 8 is closed.
The case 25 in Embodiment 2 is inserted into the through hole 12 opened in the base plate portion 21 of the fixed scroll 20 as illustrated in Figs. 5. As illustrated in Figs. 4, this case 25 is made of a combination of a case component 25a and a case component 25b. The case component 25a includes an end plate 251 and a plurality of side wall parts 252. The end plate 251 has a through hole 253. As illustrated in Figs. 5, when the case 25 is inserted into the through hole 12 opened in the base plate portion 21 of the fixed scroll 20, the end plate 251 is brought into contact with the chamber 13. At this time, the through hole 253 of the end plate 251 and the injection port 130 of the chamber 13 communicate with each other. That is, as indicated by the arrows in Fig. 4(B), the through hole 253 of the end plate 251 serves as a flow passage configured to allow the refrigerant to flow into the case 25 from the injection port 130. Moreover, one ends (upper ends in Figs. 5) of the plurality of side wall parts 252 are connected to an outer peripheral portion of the end plate 251.
The case component 25b includes an end plate 254 and a plurality of side wall parts 255. As illustrated in Figs. 5, when the case 25 is inserted into the through hole 12 opened in the base plate portion 21 of the fixed scroll 20, the end plate 254 is placed further away from the chamber 13 than is the end plate 251 of the case component 25a. The plurality of side wall parts 255 are connected to an outer peripheral portion of the end plate 254. At this time, the end plate 254 is connected to the side wall parts 255 at a position higher than one ends (lower ends in Figs. 5) of the side wall parts 255. That is, as illustrated in Figs. 5, when the case 25 is inserted into the through hole 12 opened in the base plate portion 21 of the fixed scroll 20, the one ends (lower ends in Figs. 5) of the side wall parts 255 are brought in contact with the bottom portion of the large-diameter portion 12a. At this time, a space is defined between the end plate 254 and the bottom portion of the large-diameter portion 12a. That is, as indicated by the arrows in Fig. 4(B), this space serves as a flow passage configured to allow the refrigerant having flowed into the case 25 from the injection port 130 to flow out to the small-diameter portion 12b.
The case 25 is assembled by interposing the side wall parts 255 of the case component 25b to the side wall parts 252 of the case component 25a. That is, the side wall of the case 25 is made of the side wall parts 252 and the side wall parts 255. At this time, a space is opened between the side wall parts 255. As indicated by the arrows in Fig. 4(B), this space serves as a flow passage configured to allow the refrigerant having flowed into the case 25 from the injection port 130 to flow out to a space below the end plate 254.
The valve body 23 and the spring 24 are accommodated in the case 25 having the configuration described above. The valve body 23 is configured to reciprocate in the case 25 in a direction of approaching the injection port 130 and in a direction of moving away from the injection port 130. The valve body 23 moves in the direction of approaching the injection port 130 and comes into contact with the end plate 251 of the case 25, thereby closing the through hole 253. The spring 24 is accommodated in the case 25 in such a manner that the spring 24 has one end placed in contact with the end plate 254 and urges the valve body 23 toward the injection port 130 with the other end.
In the case 25 having such configuration, under the state in which the case 25 is inserted into the through hole 12 opened in the base plate portion 21 of the fixed scroll 20 as illustrated in Figs. 5, when the valve body 23 moves in the direction of moving away from the injection port 130, the flow passage indicated by the arrows in Fig. 4(B) is formed. That is, there is formed a flow passage in which the refrigerant having flowed into the case 25 from the through hole 253 of the end plate 251 communicating with the injection port 130 flows out to the space below the end plate 254 through between the side wall parts 255 and flows into the small-diameter portion 12b. This flow passage serves as a flow passage formed between the valve body 23 and the through hole 12. As long as the flow passage allowing the injection port 130 and the compression chamber 8 to communicate with each other can be formed, the configuration and the shape of the case 25 are not limited to the configuration and the shape described above.
Next, description is made of an operation of the scroll compressor 1 having the configuration described above.
When refrigerant is to be injected into the compression chamber 8, the refrigerant flows into the injection port 130 from the injection pipe 14. Consequently, a pressure of the refrigerant supplied to the injection port 130 acts on the surface of the valve body 23 that is close to the injection port 130, that is, the upper surface of the valve body 23. Meanwhile, the pressure of refrigerant in the compression chamber 8 at the position of communicating with the through hole 12 and the urging force of the spring 24 act on the surface of the valve body 23 that is away from the injection port 130, that is, the lower surface of the valve body 23. Consequently, as illustrated in Fig. 5(A), the valve body 23 moves downward to a position at which the pressure of the refrigerant supplied to the injection port 130 is balanced with the pressure of the refrigerant in the compression chamber 8 and the urging force of the spring 24. With this operation, the refrigerant having been supplied to the injection port 130 flows into the case 25 from the through hole 253 of the end plate 251, flows out to the space below the end plate 254 through between the side wall parts 255, and is injected into the compression chamber 8 through the small-diameter portion 12b.
Meanwhile, when the injection of the refrigerant into the compression chamber 8 is to be stopped, the supply of the refrigerant to the injection pipe 14 is stopped. With this operation, the pressure of the refrigerant acting on the surface of the valve body 23 that is close to the injection port 130, that is, the upper surface of the valve body 23 is reduced. Consequently, as illustrated in Fig. 5(B), the valve body 23 moves toward the injection port 130, that is, upward, and is brought into contact with the end plate 251 of the case 25 to close the through hole 253. With this operation, the outflow port 132 of the injection port 130 communicating with the through hole 253 is also closed. That is, the valve body 23 closes the flow passage between the injection port 130 and the compression chamber 8. Consequently, a reverse flow of the refrigerant in the compression chamber 8 to the injection port 130 is prevented, and the flow passage between the injection port 130 and the compression chamber 8 is closed.
Similarly to Embodiment 1, also in the scroll compressor 1 according to Embodiment 2, when the injection of the refrigerant into the compression chamber 8 is stopped, the reverse flow of the refrigerant in the compression chamber 8 to the injection port 130 can be prevented, thereby dead volume can be reduced. Consequently, also in the scroll compressor 1 according to Embodiment 2, similarly to Embodiment 1, degradation of the performance can be prevented.
Further, in the scroll compressor 1 according to Embodiment 2, when the case 25 is assembled in advance under the state in which the valve body 23 and the spring 24 are accommodated in the case 25, the valve body 23 and the spring 24 can be assembled by only inserting the case 25 into the through hole 12 opened in the base plate portion 21 of the fixed scroll 20. Consequently, the scroll compressor 1 according to Embodiment 2 can be assembled more easily than in the case of Embodiment 1.
The configurations of the scroll compressor 1 described in Embodiment 1 and Embodiment 2 are merely examples. The present invention can be implemented even when the configuration of the scroll compressor 1 is suitably changed within the range in which the above-mentioned functions are achieved. Moreover, through inverse arrangement of the valve body 23 and the spring 24 described above, usage other than the check valve for injection can be achieved. For example, with the configuration in which the valve body 23 and the spring 24 are arranged inversely and in which the injection pipe is not provided, when the refrigerant is excessively compressed in the compression chamber 8, the refrigerant can be released from the compression chamber 8 to the discharge space 10. Further, the object to be compressed by the scroll compressor according to the present invention is not limited to the refrigerant. Even when the scroll compressor according to the present invention is used for compression of other gas such as air or nitrogen gas, the above-mentioned effects can be attained.

Reference Signs List

1 scroll compressor 2 main shaft 2a eccentric shaft portion 3 compression mechanism part 4 drive mechanism part 5 shell 6 suction pipe 7 discharge pipe 8 compression chamber 9 discharge port 10 discharge space 11 frame 12 through hole 12a large-diameter portion 12b small-diameter portion 13 chamber 14 injection pipe 14a joint 15 lead valve 16 lead valve pressing part 17 Oldham's joint18 stator 19 rotor 20 fixed scroll 21 base plate portion 22 spiral blade 23 valve body 23a flow passage 23b groove 23c cutout 23d through hole 24 spring 25 case 25a case component 25b case component 26 orbiting scroll 27 base plate portion 28 spiral blade 29 boss portion 130 injection port 131 inflow port 132 outflow port 133 connection hole 134 discharge port 251 end plate 252 side wall part 253 through hole254 end plate 255 side wall part

Claims

A scroll compressor, comprising:
a fixed scroll including a first base plate portion and a first spiral blade formed on one surface of the first base plate portion;

an orbiting scroll including a second base plate portion and a second spiral blade formed on a surface of the second base plate portion facing the fixed scroll, defining a compression chamber by combination of the first spiral blade and the second spiral blade, and configured to perform an orbiting motion against the fixed scroll;

a first through hole penetrating through the first base plate portion to communicate with the compression chamber;

a fixing part provided on a surface of the first base plate portion that is opposite to the orbiting scroll to cover the first through hole and having an injection port communicating with the first through hole, an injection pipe being connected to the injection port;

a valve body inserted into the first through hole in such a manner that the valve body is configured to reciprocate; and

a spring inserted into the first through hole and configured to urge the valve body toward the injection port,

a flow passage being formed in the valve body or between the valve body and the first through hole and being configured to allow refrigerant having flowed into the first through hole from the injection port to flow out to the compression chamber,

the valve body being configured to close the flow passage between the injection port and the compression chamber when the valve body is urged by the spring to move toward the injection port.
The scroll compressor of claim 1, wherein at least one groove is formed in a surface of the valve body facing the first through hole, the at least one groove serving as a flow passage configured to allow the refrigerant having flowed into the first through hole from the injection port to flow out to the compression chamber.
The scroll compressor of claim 1, wherein at least one cutout is formed in a surface of the valve body facing the first through hole, the at least one cutout serving as a flow passage configured to allow the refrigerant having flowed into the first through hole from the injection port to flow out to the compression chamber.
The scroll compressor of claim 1, wherein at least one second through hole is formed in the valve body, the at least one second through hole serving as a flow passage configured to allow the refrigerant having flowed into the first through hole from the injection port to flow out to the compression chamber.
The scroll compressor of any one of claims 1 to 4, wherein the valve body is so thick as to prevent breakage when a pressure of carbon dioxide refrigerant is applied to the valve body.
The scroll compressor of any one of claims 1 to 5, further comprising a case configured to accommodate the valve body and the spring,
wherein the case is inserted into the first through hole.