JP7012881B2 - Scroll compressor - Google Patents

Description

The present invention relates to a scroll compressor used for freezing or air conditioning applications.

For use in a wide capacity range, there is a capacity control type scroll compressor having a bypass hole for returning the compressed gas in the compression chamber to the suction side. In this type of scroll compressor, the bypass hole is opened and closed by a bypass valve to switch the operating state between a full load with a discharge rate of 100% and an unload with a reduced discharge rate.

Since the scroll compressor has a fixed built-in volume ratio, so-called overcompression, in which the fluid is compressed too much by the compression mechanism, may occur under operating conditions where the high / low pressure difference is relatively small. For this reason, there is a method of preventing overcompression by providing a relief port that opens in the compression chamber and performing overcompression relief by so-called high-pressure bypass in which the compressed gas in the compression chamber is released from the relief port to the discharge side (for example). See Patent Document 1).

Japanese Unexamined Patent Publication No. 2000-018182

In Patent Document 1, the relief mechanism for performing overcompression relief by high-pressure bypass is a relief port and a relief valve provided on a fixed scroll, and is completed in a closed container. However, the unloading mechanism that unloads by low-pressure bypass needs to be provided with piping through the closed container to connect the piping and the compression mechanism, and also needs to be equipped with valves. Therefore, an increase in cost was unavoidable.

The present invention has been made in view of these points, and an object of the present invention is to obtain a scroll compressor capable of unloading by low pressure bypass from outside the closed container without connecting a pipe to the compression mechanism portion.

The scroll compressor of the present invention has a closed container, a separator that divides the inside of the closed container into a high pressure space and a low pressure space, a fixed scroll and a swinging scroll, and is formed by engaging the fixed scroll and the swinging scroll. A compression mechanism that sucks fluid from the low-pressure space, compresses it, and discharges it to the high-pressure space, and unloads that limit the discharge amount by bypassing the fluid from the compression chamber to the low-pressure space. A back pressure chamber is formed between the separator and the end face on the opposite side of the swinging scroll of the fixed scroll, which is provided with a mechanism and communicates with the compression chamber during compression through the extraction hole formed in the fixed scroll. The separator is formed with an unload hole that forms part of the unload path that connects the back pressure chamber and the low pressure space, and the unload mechanism moves its position within the unload hole. Equipped with a control valve that opens and closes the unload path, the low pressure in the low pressure space acts on one end face of the control valve in the moving direction, and the other end face is guided from inside the closed container and is higher than the low pressure space. When pressure acts and the pressure difference acting on both end faces of the control valve changes according to the operating conditions, the control valve moves to open and close the unload path, and the unload path is the back pressure. A small diameter control valve that communicates a back pressure chamber communication passage with one end opening in the chamber, a low pressure space communication passage with one end opening in the low pressure space, and the other end of the back pressure chamber communication passage and the other end of the low pressure space communication passage. It is composed of an outer peripheral space, and the separator has a low pressure introduction hole that introduces the low pressure of the low pressure space into the space facing one end face of the control valve, and the high pressure of the high pressure space into the space facing the other end face of the control valve. A high-pressure introduction hole to be introduced is formed .

According to the present invention, the unloading that limits the discharge amount by bypassing the fluid from the compression chamber to the low pressure space is completed in the closed container, and the piping from the outside of the closed container to the compression mechanism section. It can be done without connecting.

It is a schematic vertical sectional view of the scroll compressor according to Embodiment 1 of this invention. It is a figure which shows the compression process which accompanies the eccentric turning of the swing scroll of the scroll compressor of FIG. It is sectional drawing of the main part at the time of unloading of the scroll compressor according to Embodiment 1 of this invention. It is an enlarged schematic diagram of the unloading mechanism part at the time of unloading of the scroll compressor according to Embodiment 1 of this invention. FIG. 3 is a schematic cross-sectional view of a main part of the scroll compressor according to the first embodiment of the present invention when it is not unloaded. It is an enlarged schematic diagram of the unloading mechanism part at the time of non-unloading of the scroll compressor according to Embodiment 1 of this invention. FIG. 3 is a schematic vertical sectional view of a scroll compressor according to a second embodiment of the present invention. It is sectional drawing of the main part of the scroll compressor according to Embodiment 2 of this invention. It is an enlarged schematic diagram of the unloading mechanism part at the time of unloading of the scroll compressor according to Embodiment 2 of this invention. It is an enlarged schematic diagram of the unloading mechanism part at the time of non-unloading of the scroll compressor according to Embodiment 2 of this invention. It is a figure which looked at the fixed scroll of FIG. 7 from the spiral side. It is a figure which looked at the fixed scroll of FIG. 7 from the anti-swirl side. FIG. 7 is a view of the swing scroll of FIG. 7 as viewed from the spiral side. FIG. 7 is a view of the swing scroll of FIG. 7 as viewed from the anti-swirl side. It is a plan view which shows the spiral combination state at the time of unloading of the scroll compressor by Embodiment 2 of this invention. It is an enlarged shape view of the unload mechanism part of FIG. It is a shape diagram of the control valve which is an unload mechanism component of FIG. 7. It is a shape diagram of the spring seat which is an unload mechanism component of FIG. 7. It is a shape diagram of the plug which is an unload mechanism component of FIG. 7. It is a plan view which shows the spiral combination state at the time of non-unloading of the scroll compressor according to Embodiment 2 of this invention. It is an enlarged shape view of the unload mechanism part of FIG.

Embodiment 1.
FIG. 1 is a schematic vertical sectional view of a scroll compressor according to the first embodiment of the present invention. In FIG. 1 and each figure described later, those having the same reference numerals are the same or equivalent thereof, which are common to the entire text of the specification. Furthermore, the forms of the components appearing in the entire specification are merely examples and are not limited to these descriptions. In addition, the high and low temperatures and pressures are not fixed in relation to the absolute values, but are relatively fixed in the state and operation of the system, the device, and the like. Further, the schematic diagram does not faithfully present the structure in consideration of the workability and the assembling property of the embodiment, but is a simple one for simply explaining the configuration.

The scroll compressor 1 has a function of sucking a fluid such as a refrigerant, compressing it, and discharging it as a high-pressure state. Inside the closed container 21 constituting the outer shell, a compression mechanism portion 10, a motor 18, and others Stores the components of. The compression mechanism portion 10 and the motor 18 are connected by a shaft 15. As shown in FIG. 1, in the closed container 21, the compression mechanism portion 10 is arranged above and the motor 18 is arranged below the compression mechanism portion 10. The lower part of the closed container 21 is an oil reservoir, and the lubricating oil 22 is stored.

A frame 14 and a subframe 19 are arranged inside the closed container 21. The frame 14 is arranged above the motor 18 and is located between the motor 18 and the compression mechanism portion 10. The subframe 19 is located below the motor 18. The frame 14 and the subframe 19 are fixed to the closed container 21. A main bearing 14a is provided in the central portion of the frame 14, and an auxiliary bearing 19a is provided in the central portion of the subframe 19. The shaft 15 is rotatably supported by the main bearing 14a and the auxiliary bearing 19a.

A separator 29 that divides the inside of the closed container 21 into a high-pressure space 211 and a low-pressure space 212 is arranged above the compression mechanism portion 10. The upper part of the separator 29 is the high pressure space 211, and the lower part is the low pressure space 212. The separator 29 is fixed to the closed container 21.

A discharge chamber 291a communicating with the first discharge port 111 formed in the fixed scroll 11 is formed between the end surface of the fixed scroll 11 opposite to the swing scroll 12 and the separator 29. At the center of the separator 29, a second discharge port 292 is formed in which the inlet side opens into the discharge chamber 291a, the outlet side opens in the high pressure space 211, and the fluid compressed in the compression chamber 9 is discharged to the high pressure space 211. ing. On the outlet side of the second discharge port 292, there is a discharge valve 25 that opens and closes the second discharge port 292 and a discharge valve stopper 25b that limits the lift amount of the discharge valve 25 in order to prevent backflow of fluid to the discharge chamber 291a. Is provided. When the fluid is compressed to a predetermined pressure in the compression chamber 9, the discharge valve 25 is lifted against the elastic force, and the compressed fluid is discharged from the second discharge port 292 into the high pressure space 211, and the discharge pipe 24 is discharged. It is discharged to the outside of the scroll compressor 1 through.

The separator 29 is further provided with a relief mechanism 220, an unload mechanism 230, and the like, and these configurations will be described in detail again.

The closed container 21 is provided with a suction pipe 23 for sucking the fluid communicating with the low pressure space 212 and a discharge pipe 24 for discharging the fluid communicating with the high pressure space 211.

The compression mechanism unit 10 compresses the fluid sucked from the suction pipe 23 and discharges it into the high-pressure space 211 formed above the closed container 21. The compression mechanism unit 10 includes a fixed scroll 11 and a swing scroll 12, and as shown in FIG. 1, the fixed scroll 11 is arranged on the upper side and the swing scroll 12 is arranged on the lower side. The fixed scroll 11 is composed of a fixed base plate 11a and fixed spiral teeth 11b which are spiral protrusions erected on one surface of the fixed base plate 11a. The swing scroll 12 is composed of a swing base plate 12a and swing spiral teeth 12b which are spiral protrusions erected on one surface of the swing base plate 12a.

The fixed spiral tooth 11b and the swinging spiral tooth 12b are formed, for example, following an involute curve, and the fixed spiral tooth 11b and the swinging spiral tooth 12b are meshed and combined to form the fixed spiral tooth 11b and the swinging spiral tooth 12b. A plurality of compression chambers 9 are formed between the 12b and the 12b.

The fixed scroll 11 and the swing scroll 12 are arranged between the separator 29 and the frame 14. The plane position and posture of the fixed scroll 11 are regulated by a plurality of radial guide members 28 arranged on the outer periphery of the fixed scroll 11. The fixed base plate 11a of the fixed scroll 11 is formed with a pair of air extraction holes 112 having one end opened in the compression chamber 9 and the other end opening in the back pressure chamber 291b described later.

In the swing scroll 12, a cylindrical boss portion 121 is formed at the center of a surface of the swing scroll 12 opposite to the formation surface of the swing spiral tooth 12b. The eccentric portion 15a, which will be described later, is fitted into the boss portion 121 at the upper end of the shaft 15, and the oscillating scroll 12 performs an eccentric turning motion without rotating with respect to the fixed scroll 11.

The motor 18 includes a stator 18a and a rotor 18b fixed to a shaft 15 rotatable on the inner peripheral side of the stator 18a. The stator 18a rotates the rotor 18b by being energized. The outer peripheral surface of the stator 18a is fixedly supported by the closed container 21 by shrink fitting or the like. The rotor 18b rotates when the stator 18a is energized to drive the shaft 15.

The shaft 15 has an eccentric portion 15a formed at the upper end thereof, the eccentric portion 15a is fitted to the boss portion 121 of the swing scroll 12, and the swing scroll 12 makes an eccentric turning motion by the rotation of the shaft 15.

A first balancer 16 is attached to the shaft 15 on the upper side of the motor 18. Further, a second balancer 17 is attached to the lower side of the rotor 18b. The first balancer 16 is attached so that the eccentricity direction is opposite to that of the eccentric portion 15a.

A refueling pump 27 is attached to the lower end of the shaft 15. The lubrication pump 27 supplies the lubricating oil 22 held in the oil reservoir to each sliding portion through the lubrication hole 152 provided inside the shaft 15 according to the rotation of the shaft 15.

In the compression mechanism portion 10, a posture regulating means 13 such as an old dam ring for preventing the rotation motion of the swing scroll 12 during the eccentric turning motion is provided. The posture regulating means 13 is disposed between the frame 14 and the swing scroll 12, and prevents the swing scroll 12 from rotating and enables an eccentric turning motion which is a revolution motion.

In FIG. 1, when the power supply terminal (not shown) provided in the closed container 21 is energized, torque is generated between the stator 18a and the rotor 18b, and the shaft 15 supported by the main bearing 14a and the auxiliary bearing 19a. Rotates. Due to the rotation of the shaft 15, the swing scroll 12 is restricted from rotating by the posture regulating means 13 and makes an eccentric turning motion.

The imbalance caused by the movement of the swing scroll 12 is balanced by the first balancer 16 attached to the shaft 15 and the second balancer 17 attached to the rotor 18b. By the rotation of the shaft 15, the lubricating oil 22 stored in the lower part of the closed container 21 is pumped up by the refueling pump 27 and supplied to each sliding portion from the refueling hole 152 provided in the shaft 15.

The gas sucked into the closed container 21 from the suction pipe 23 is taken into the outermost compression chamber 9 among the plurality of compression chambers 9 due to the eccentric swirling motion of the rocking scroll 12.

The compression chamber 9 that has taken in the gas reduces the volume while moving from the outer peripheral portion toward the center along with the eccentric swirling motion of the swing scroll 12, and compresses the fluid. The compressed fluid is discharged into the high-pressure space 211 by pushing up the discharge valve 25 from the first discharge port 111 provided in the fixed scroll 11 and the second discharge port 292 provided in the separator 29, and is discharged from the discharge pipe 24 to the outside of the closed container 21. Is discharged to.

Hereinafter, the description regarding the operation of the swirl and the position of the bleeding hole 112 is common to the first embodiment and the second embodiment.

FIG. 2 is a diagram showing a compression stroke associated with eccentric turning of the oscillating scroll of the scroll compressor of FIG. In FIG. 2, of the plurality of compression chambers 9, the innermost compression chamber 9 is the innermost chamber 9a, the outermost compression chamber 9 is the outermost chamber 9c, and the compression between the innermost chamber 9a and the outermost chamber 9c. The chamber 9 is called the second chamber 9b in the sense that it is the second compression chamber counted from the inside. FIG. 2 shows an example of a spiral specification of about 2.5 turns.

FIG. 2B shows a state in which the crank angle is the suction completion angle. That is, the suction of the fluid in the outermost compression chamber 9 is completed, and the plurality of compression chambers 9 formed by the fixed spiral teeth 11b and the swinging spiral teeth 12b are, in order from the inside, the innermost chamber 9a and a pair. It shows the place where the second chamber 9b and the pair of outermost chambers 9c are formed. Hereinafter, the suction completion angle refers to the crank angle when the suction of the compression chamber 9 is completed on the winding end side of the spiral tooth.

FIG. 2C shows a state in which the crank angle is the communication angle. In FIG. 2B, the fixed spiral tooth 11b and the swinging spiral tooth 12b are in contact with each other on the winding start side to form a seal forming point 130, so that the innermost chamber 9a and the pair of second chambers 9b are formed. And are formed. On the other hand, in FIG. 2C, immediately before the seal forming point 130 is separated, the second chamber 9b merges with the innermost chamber 9a to become one chamber. Hereinafter, the communication angle refers to the crank angle when the second chamber 9b merges with the innermost chamber 9a to form one chamber.

FIG. 2D shows a state in which the seal forming points 130 are separated from each other and the second chamber 9b is combined with the innermost chamber 9a to form one chamber, and two chambers, the innermost chamber 9a and the outermost chamber 9c. ing.

2 (e) to 2 (f) also show the state of two chambers, the innermost chamber 9a and the outermost chamber 9c.

As described above, the compression chamber 9 has two or three chambers depending on the magnitude of the crank angle with respect to the suction completion angle and the communication angle during one eccentric turning of the swing scroll 12 having a crank angle of 0 to 2π. That is, between the suction completion angle and the communication angle, there are three chambers, the outermost chamber 9c, the second chamber 9b, and the innermost chamber 9a. Between the communication angle and the suction completion angle, there are two chambers, the outermost chamber 9c and the innermost chamber 9a. Then, a new outermost chamber 9c is formed at the suction completion angle, and the outermost chamber 9c up to that point becomes the second chamber 9b, and becomes the outermost chamber 9c, the second chamber 9b, and the innermost chamber 9a. ..

2 (a) to 2 (f), the outermost chamber 9c in which suction is completed in FIG. 2 (b) is eccentric swiveled by the swing scroll 12, and FIGS. 2 (c) and 2 (d). The fluid is compressed by reducing the volume through FIGS. 2 (e), 2 (f), and 2 (a). Then, by reaching FIG. 2B again, the outermost chamber 9c is newly created, so that the outermost chamber 9c so far becomes the second chamber 9b. The second chamber 9b begins to join the innermost chamber 9a at the communication angle of FIG. 2 (c).

The pair of bleeding holes 112 are provided along the inward / outward surfaces of the fixed spiral teeth 11b, respectively, and extend from the winding end 11ba and the winding end 11bb (see FIG. 2B) of the inward / outward surfaces, respectively. It is located about 2.5π inside at the open angle.

Assuming that the crank angle at the time of completion of suction is 0, the outermost chamber 9c whose suction is completed at the crank angle of 0 moves toward the center of the spiral with the eccentric turning motion of the swing scroll 12. When the crank angle is about π / 2, that is, when the seal forming point between the second chamber and the outermost chamber passes through the extraction hole position around 1/4 turn after the suction is completed, the extraction hole 112 opens in the outermost chamber 9c. Begin to. Then, the outermost chamber 9c in which the extraction hole 112 is opened moves in the direction of the center of the spiral while reducing the volume, and at the second suction completion angle in which the swing scroll 12 makes one eccentric swirling motion from the time when the suction is completed. The outer room 9c becomes the second room 9b. Even after the outermost chamber 9c becomes the second chamber 9b in this way, the extraction hole 112 is opened in the second chamber 9b until the extraction hole position of the next second chamber / outermost chamber seal forming point is passed. ing.

In the setting where the passage through the extraction hole position of the seal forming point between the innermost chamber (the second chamber in the case before the communication angle) / the outermost chamber is after the communication angle, the eccentric turning motion of the swing scroll 12 proceeds. After the confluence of the second chamber 9b and the innermost chamber 9a at the communication angle, the extraction hole 112 opens in the innermost chamber 9a. The bleeding hole 112 opens to the second chamber when the seal forming point passes through the bleeding hole position. When the crank angle becomes about π / 4 from the second suction completion angle, the opening of the air extraction hole 112 to the second chamber 9b is completed, and the outermost chamber 9c about 1/4 turn after the second suction completion angle is completed. The air extraction hole 112 begins to open.

Due to the eccentric rotation of the swing scroll 12, when viewed from the air extraction hole 112, the outermost chamber 9c is opened to the approaching outermost chamber 9c, and then the outermost chamber 9c is opened through the second chamber 9b until it becomes the innermost chamber 9a. After that, the operation of starting to open to the next approaching outermost chamber 9c is repeated. The bleeding hole 112 always opens to any of the compression chambers 9, that is, the intermediate pressure compression chamber 37 during one rotation of the eccentric rotation of the swing scroll 12, and supplies the pressure in the compression chamber 9 to the back pressure chamber 291b described later. According to FIG. 2, the extraction hole 112 is closed by the swinging spiral tooth 12b, and strictly speaking, there is a time when the compression chamber 9 is not opened, but the time when the extraction hole 112 is not opened is short, and practically any one of them is substantially always used. It is open to the compression chamber 9.

In the scroll compressor, the built-in volume ratio, that is, (suction completion volume) / (volume of the second chamber when the communication angle is reached) is determined by determining the spiral specification. In the scroll compressor 1, as described above, after the outermost chamber 9c is formed at the suction completion angle, the swing scroll 12 makes one rotation eccentric turning motion to reach the suction completion angle again, so that the outermost chamber 9c is formed. Becomes the second chamber 9b, and the swing scroll 12 further eccentric swivels to reach the communication angle, so that the second chamber 9b joins the innermost chamber 9a. That is, from the formation of the outermost chamber 9c until the outermost chamber 9c merges with the innermost chamber 9a at the communication angle and communicates with the first discharge port 111, the operating conditions of the compression chamber 9 are high. Compression is performed regardless of the low pressure.

The compression ratio or pressure ratio is an index that indicates how much the compression chamber has been compressed from the time when suction is completed, focusing on the increase in pressure as a result of volume reduction. It depends on the amount. It is more rational to define the swirl specification by the built-in volume ratio.

Normally, in a scroll compressor, the built-in volume ratio is a fixed value. Therefore, under operating conditions where the pressure difference between the suction pressure and the discharge pressure is relatively small, for example, overcompression occurs in which the refrigerant is excessively compressed by the compression mechanism unit. That is, as described above, the oscillating scroll makes a one-turn eccentric turning motion from the suction completion angle, and compression is continued in the compression chamber until the communication angle is further reached. Therefore, when compressed to the built-in volume ratio, When the pressure in the compression chamber exceeds the high pressure, a loss due to the pressure increase more than necessary, that is, a so-called overcompression loss occurs.

Reducing the overcompression loss due to having the built-in volume ratio is a problem peculiar to the compression mechanism of the scroll compressor. One of the means is a so-called relief mechanism that discharges from the compression chamber to the high pressure side before reaching the communication angle, that is, performs high pressure bypass. In the first embodiment, the relief port 295 and the relief valve 26, which will be described later, are used as the relief mechanism. Etc. are provided.

The structure that enables unloading by the low pressure bypass of the first embodiment without using a pipe or the like connecting from the outside of the closed container 21 to the compression mechanism portion 10 will be described below.

FIG. 3 is a schematic cross-sectional view of a main part of the scroll compressor according to the first embodiment of the present invention when the scroll compressor is unloaded. FIG. 4 is an enlarged schematic view of the unloading mechanism at the time of unloading the scroll compressor according to the first embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a main part of the scroll compressor according to the first embodiment of the present invention when it is not unloaded. FIG. 6 is an enlarged schematic view of the unloading mechanism of the scroll compressor according to the first embodiment of the present invention when it is not unloaded.

A back pressure chamber 291b is formed between the end surface of the fixed scroll 11 opposite to the swing scroll 12 and the separator 29. The back pressure chamber 291b is composed of an annular recess formed on the surface of the separator 29 on the low pressure space 212 side. An annular sealing member 33 is arranged in the groove of the inner peripheral surface 118 of the back pressure chamber 291b. Further, an annular seal member 34 is arranged in the groove of the outer peripheral surface 119 of the back pressure chamber 291b. As a result, a cylindrical discharge chamber 291a and an annular back pressure chamber 291b are partitioned between the fixed base plate 11a of the fixed scroll 11 and the separator 29.

The discharge chamber 291a communicates with the first discharge port 111, and the high pressure is increased by the fluid discharged from the first discharge port 111. The back pressure chamber 291b communicates with the compression chamber 9 during compression, that is, the intermediate pressure compression chamber 37, via the extraction hole 112 formed in the fixed scroll 11, and becomes an intermediate pressure.

The separator 29 is provided with a relief port 295, a relief valve 26, and a relief valve stopper 26b that limits the lift amount of the relief valve 26 as a relief mechanism 220 for performing overcompression relief. The relief port 295 opens to the back pressure chamber 291b on the inlet side and opens to the high pressure space 211 on the outlet side. The relief valve 26 and the relief valve stopper 26b are provided on the outlet side of the relief port 295.

In a scroll compressor in which the axial position of the fixed scroll is fixed, the tip of the spiral tooth comes into contact with or the base plate of the scroll on the opposite side due to deformation and thermal expansion of the spiral tooth or the base plate during operation. May interfere. In order to avoid this inconvenience, there is a possibility that the tip of the spiral tooth or the base plate of the mating plate will eventually seize. Had to be set. Since the tooth tip clearance set at the time of assembly serves as a fluid leakage path, it has been a factor in reducing the efficiency of the compressor.

On the other hand, the scroll compressor 1 of the first embodiment applies an axial force to the fixed scroll 11 by inducing an intermediate pressure to the back pressure chamber 291b and inducing a discharge pressure to the discharge chamber 291a. The structure is such that it is pressed against the rocking scroll 12 side. Since the so-called axial compliant method is adopted, it is not necessary to set the tooth tip clearance in advance at the time of assembly. As a result, the gap between the tooth tips can be minimized and the leakage loss can be reduced.

The separator 29 further incorporates an unload mechanism 230 that switches between an unload that limits the discharge amount of the scroll compressor 1 by bypassing the fluid from the compression chamber 9 to the low pressure side and a full load with a discharge amount of 100%. ing. Hereinafter, full load may be referred to as non-unload.

The unload mechanism 230 is arranged in an unload hole 296 in which a spool-shaped control valve 31 and an elastic body 32 such as a spring are formed in the separator 29 in the radial direction. A convex portion 29a that prevents the high-pressure introduction hole 294a from being closed by the control valve 31 is formed at the radially inner end of the unload hole 296. The radial outer end of the unload hole 296 is closed with a plug 35c.

The unload mechanism 230 bypasses the fluid in the intermediate pressure compression chamber 37 to the low pressure space 212 via the air extraction hole 112, the back pressure chamber 291b, and the unload path formed in the separator 29. Unload. The unload path includes a back pressure chamber communication passage 293a having one end opened in the back pressure chamber 291b, a low pressure space communication passage 293b having one end opening in the low pressure space 212, and a control valve small diameter portion outer peripheral space 293c in the unload hole 296. It is composed of and.

The control valve 31 is slidably arranged in the unload hole 296, and by sliding in the unload hole 296, the position of the control valve small diameter portion outer peripheral space 293c in the unload hole 296 is moved. That is, the control valve 31 moves to the position where the back pressure chamber communication passage 293a opens with respect to the control valve small diameter portion outer peripheral space 293c (FIG. 4) and the position where the back pressure chamber communication passage 293a closes (FIG. 6) to open and close the unload path. Switch between unload and non-unload.

The separator 29 is formed with a high pressure introduction hole 294a and a low pressure introduction hole 294b that open in the unload hole 296. The high-pressure introduction hole 294a has one end opened in the high-pressure space 211 and the other end opened in the unload hole 296, and the high-pressure fluid of the high-pressure space 211 is introduced into the unload hole 296 at one end surface 31a in the moving direction of the control valve 31. Introduce to the side space. The low pressure introduction hole 294b has one end opened in the unload hole 296 and the other end opened in the low pressure space 212, and the low pressure fluid in the low pressure space 212 is introduced to the other end surface 31b in the moving direction of the control valve 31 in the unload hole 296. It is introduced in the low pressure introduction space 297 on the side.

The elastic body 32 is arranged in the low pressure introduction space 297 on the other end surface 31b side of the control valve 31, and urges the control valve 31 to the high pressure side (right side in FIG. 6). When the operation of the control valve 31 is stopped, the control valve 31 is pressed toward the high pressure side by the urging force of the elastic body 32, and one end surface 31a is in contact with the convex portion 29a. In this state, the control valve 31 opens an unload path including a back pressure chamber communication passage 293a, a control valve small diameter portion outer peripheral space 293c, and a low pressure space communication passage 293b.

When the operating condition of the scroll compressor 1 is that the high / low pressure difference is equal to or less than the set value, the elastic body 32 is more than the differential pressure between the high pressure acting on one end face 31a of the control valve 31 and the low pressure acting on the other end face 31b. The elastic force due to is exceeded. In this case, the control valve 31 is pressed in the direction of the end surface 31a, moves to a position where one end surface 31a of the control valve 31 comes into contact with the convex portion 29a, and stops, as shown in FIGS. The passage 293a and the control valve small diameter portion outer peripheral space 293c communicate with each other. That is, the unload path including the back pressure chamber communication passage 293a, the control valve small diameter portion outer peripheral space 293c, and the low pressure space communication passage 293b is opened. As a result, the fluid in the intermediate pressure compression chamber 37 passes through the extraction hole 112, the back pressure chamber 291b, the back pressure chamber communication passage 293a, the control valve small diameter portion outer peripheral space 293c, and the low pressure space communication passage 293b in this order, and the low pressure space 212. Is discharged to. Therefore, in the intermediate pressure compression chamber 37, the intermediate pressure compression chamber 37 communicates with the extraction hole 112, in other words, until the outer peripheral side seal forming point of the intermediate pressure compression chamber 37 passes through the extraction hole 112. No compression is performed, and capacity control, that is, an unload state is established.

When the operating condition of the scroll compressor 1 exceeds the set value, the difference pressure between the high pressure acting on one end face 31a of the control valve 31 and the low pressure acting on the other end face 31b is the elastic body 32. Exceeds the elastic force of. In this case, as shown in FIGS. 5 and 6, the control valve 31 slides in the direction of the end surface 31b, and the back pressure chamber communication passage 293a is blocked by the control valve 31. As a result, the unload path including the back pressure chamber communication passage 293a, the control valve small diameter portion outer peripheral space 293c, and the low pressure space communication passage 293b is closed, and the unload state is switched to the non-unload state.

In this way, in the unload mechanism 230, the pressure acting on one end surface 31a and the other end surface 31b of the control valve 31 changes according to the operating conditions of the scroll compressor 1, so that the control valve 31 automatically operates. Move and automatically switch between unload and non-unload. The above set value, which is the switching point between unloading and non-unloading, can be adjusted to a desired value by selecting the spring constant of the elastic body 32 in consideration of the pressure acting on both end faces of the control valve 31. Is possible.

Since the unload mechanism 230 guides the high and low pressure acting on both end faces of the control valve 31 from the inside of the closed container 21, the structure is completed inside the closed container 21, and the structure is completed from the outside of the closed container 21 to the compression mechanism portion 10. No piping is required to connect.

Next, the operation of the scroll compressor 1 will be described focusing on the actions of the discharge chamber 291a and the back pressure chamber 291b, and the operations of the relief mechanism 220 and the unload mechanism 230.

During operation, the fixed scroll 11 receives the pressure of the discharge chamber 291a and the back pressure chamber 291b, and the plane position and the posture are regulated by a plurality of radial guide members 28 (see FIG. 2) arranged on the outer periphery of the fixed scroll 11. , It is pressed toward the swing scroll 12 side in the axial direction against the pressure in the compression chamber 9.

During operation under conditions where the difference between high and low pressure is small, as described above, in the unload mechanism 230, the control valve 31 provides an unload path including a back pressure chamber communication passage 293a, a control valve small diameter portion outer peripheral space 293c, and a low pressure space communication passage 293b. Open. As a result, the fluid in the intermediate pressure compression chamber 37 is discharged to the low pressure space 212 through the extraction hole 112, the back pressure chamber 291b, the unload path, and the like, and is in the unload state.

At the time of unloading, the outermost chamber 9c, that is, the intermediate pressure compression chamber 37, performs a compression action that is not always necessary from the suction completion angle to 1/4 rotation. However, since the pressure-increasing range with respect to the volume change immediately after the completion of inhalation is small, the deterioration in performance is limited, and there is no problem in practical use.

During operation under the condition that the high / low pressure difference exceeds the set value, as described above, the control valve 31 in the unload mechanism 230 is composed of the back pressure chamber communication passage 293a, the control valve small diameter portion outer peripheral space 293c, and the low pressure space communication passage 293b. The load path is closed and the non-unload state is set.

Further, when the pressure of the intermediate pressure compression chamber 37 communicating with the back pressure chamber 291b during non-unloading and low compression ratio operation exceeds the discharge pressure, the relief valve 26 is lifted against the elastic force. When the pressure in the second chamber 9b, which is the intermediate pressure compression chamber 37, exceeds the discharge pressure while the swing scroll 12 makes a one-turn eccentric turning motion from the suction completion angle and further reaches the communication angle, the relief valve is used. 26 is lifted against its elastic force. As a result, the fluid in the back pressure chamber 291b is relieved from the relief port 295 into the high pressure space 211, and the overcompression loss is reduced.

In both cases of overcompression relief and unloading described above, the fluid is not discharged directly from the compression chamber 9 into the high pressure space 211 or the low pressure space 212, but is discharged via the back pressure chamber 291b. The back pressure chamber 291b and the flow paths before and after it serve as a buffer. As a result, stable reduction of overcompression loss and capacity control can be realized in which the pressure fluctuation in the compression chamber 9 and the overcompression relief and the pulsation on the unload side do not directly affect each other.

Further, at the time of unloading, the substantially suction completion of the compression chamber 9 in which the extraction hole 112 is open is the timing when the extraction hole 112 is no longer opened. Therefore, the pressure of the boosted portion of the compression chamber 9 at the time of unloading and the plane projected area of the compression chamber 9 which is the pressure receiving area thereof are smaller than those at the time of non-unloading. Therefore, at the time of unloading, the force for pushing up the fixed scroll 11 upward in the axial direction and pulling it away from the swing scroll 12 is less than that at the time of non-unloading. Therefore, it is necessary to reduce the back pressure during unloading as compared with non-unloading so that the axial downward force acting on the fixed scroll 11 does not become excessive as compared with the axial upward force.

However, if the unloading is performed with the intermediate pressure remaining in the back pressure chamber 291b for some reason, the back pressure for pressing the fixed scroll 11 against the swing scroll 12 does not decrease. In this case, the pressing force of the axial compliant, that is, the downward force in the axial direction becomes excessive, and there is a possibility that problems such as an increase in sliding loss and seizure of the tooth tip may occur.

In the first embodiment, since the unloading and the pressure release of the back pressure chamber 291b are performed by the same element called the control valve 31, the unloading does not occur with the intermediate pressure remaining in the back pressure chamber 291b. It is possible to avoid such a problem.

As described above, in the first embodiment, the unloading hole 296 is formed in the separator 29, and the control valve 31 moves in the unloading hole 296 to open and close the unloading path 230. It is equipped with. The low pressure and high pressure acting on both end faces of the control valve 31 to move the position of the control valve 31 are guided from the inside of the closed container 21, and the structure related to unloading is completed in the closed container 21. Therefore, unloading can be performed without connecting the pipe from the outside of the closed container 21 to the compression mechanism portion 10. Therefore, it is not necessary to connect the compression mechanism portion 10 to the pipe outside the closed container 21 or to provide valves in the pipe as in the conventional case, and the cost can be reduced.

Further, in the first embodiment, switching between unloading and non-unloading is automatically switched according to the operating conditions. That is, the transition from non-unload to unload and the return from unload to non-unload are automatically performed. Therefore, it is possible to avoid an increase in cost due to the pipe connection for the switching operation from the outside, and it is not necessary to operate the switching valve or the like. This makes it possible to obtain an efficient scroll compressor 1 with a wide range of capacities.

In the first embodiment, the control valve 31 closes the unload path when the high / low pressure difference exceeds a preset value, and opens the unload path when the high / low pressure difference is equal to or less than the set value. In this way, unloading and non-unloading can be switched according to the difference between high and low pressure.

In the first embodiment, the unload mechanism 230 includes an elastic body 32 that urges the control valve 31 to the high pressure side to position the control valve 31 at a position that opens the unload path. The control valve 31 moves from the position where the unload path is opened to the position where the unload path is closed when the differential pressure corresponding to the high / low pressure difference that changes according to the operating conditions exceeds the urging force of the elastic body 32. As a result, the transition from non-unload to unload and the return from unload to non-unload can be automatically performed.

In the first embodiment, the unload hole 296 is formed in the separator 29. The unload path is composed of a back pressure chamber communication passage 293a having one end opened in the back pressure chamber 291b, a low pressure space communication passage 293b having one end opening in the low pressure space 212, and a control valve small diameter portion outer peripheral space 293c. .. In the separator 29, the low pressure introduction hole 294b for introducing the low pressure of the low pressure space 212 into the space facing one end surface 31b of the control valve 31 and the high pressure of the high pressure space 211 in the space facing the other end surface 31a of the control valve 31. A high-pressure introduction hole 294a for introducing the above is formed. With this structure, high and low pressure can be applied to both end faces of the control valve 31 from inside the closed container 21.

Further, in the first embodiment, the relief port 295 and the unload path are formed in the separator 29, each communicating with the back pressure chamber 291b, and the back pressure chamber 291b passes through the air extraction hole 112 provided in the fixed scroll 11. It communicates with the intermediate pressure compression chamber 37. Due to the configuration in which the extraction hole 112 common to the relief mechanism 220 and the unload mechanism 230 opens in the intermediate pressure compression chamber 37, the extraction hole 112 is the only port that opens in the compression chamber 9 in both overcompression relief and unloading. Is. Therefore, the number of ports opened in the compression chamber 9 can be minimized as compared with the conventional configuration in which independent ports are required for each of the overcompression relief and the unload.

In the first embodiment, the tooth tip clearance can be minimized and the compression efficiency can be improved by pressing the fixed scroll 11 toward the swing scroll 12 side by the pressure of the discharge chamber 291a and the back pressure chamber 291b. .. Further, in addition to reducing the overcompression loss under the low compression ratio condition by the high pressure side relief from the back pressure chamber, it becomes possible to obtain a highly efficient scroll compressor under a wide range of conditions and capacitance range.

In the first embodiment, the back pressure chamber communication passage 293a is closed by the control valve 31 to close the unload path including the back pressure chamber communication passage 293a, the control valve small diameter portion outer peripheral space 293c, and the low pressure space communication passage 293b. However, the unload path may be closed by blocking the low pressure space communication passage 293b.

Embodiment 2.
In the first embodiment, the unload hole 296 is formed in the separator 29, but in the second embodiment, the unload hole 117 is formed in the fixed scroll 11. Hereinafter, the points where the second embodiment is different from the first embodiment will be mainly described.

FIG. 7 is a schematic vertical cross-sectional view of the scroll compressor according to the second embodiment of the present invention. FIG. 8 is a schematic cross-sectional view of a main part of the scroll compressor according to the second embodiment of the present invention. The portion surrounded by the dotted line in FIG. 8 corresponds to the unload mechanism 230. FIG. 9 is an enlarged schematic view of the unloading mechanism at the time of unloading the scroll compressor according to the second embodiment of the present invention. FIG. 10 is an enlarged schematic view of the unloading mechanism of the scroll compressor at the time of non-unloading according to the second embodiment of the present invention. In FIGS. 8 to 10, the arrows shown in the operating pressure introduction side hole 124 and the pressure receiving pocket 115 indicate the direction of the hydraulic pressure.

FIG. 11 is a view of the fixed scroll of FIG. 7 as viewed from the spiral side. FIG. 12 is a view of the fixed scroll of FIG. 7 as viewed from the anti-swirl side. FIG. 13 is a view of the swing scroll of FIG. 7 as viewed from the spiral side. FIG. 14 is a view of the swing scroll of FIG. 7 as viewed from the anti-swirl side.

FIG. 15 is a plan view showing a spiral combination state at the time of unloading of the scroll compressor according to the second embodiment of the present invention. FIG. 16 is an enlarged view of the unloading mechanism of FIG. FIG. 17 is a shape diagram of the control valve of the unload mechanism of FIG. 7. FIG. 18 is a shape view of the spring seat 36 of the unload mechanism of FIG. 7. FIG. 19 is a shape diagram of the plug of the unload mechanism of FIG. 7. FIG. 20 is a plan view showing a spiral combination state when the scroll compressor according to the second embodiment of the present invention is not unloaded. 21 is an enlarged view of the unloading mechanism of FIG. 20.

In the unload mechanism 230 of the second embodiment, the spool-shaped control valve 31, the elastic body 32 such as a spring, and the spring seat 36 are unload holes 117 formed in the fixed base plate 11a of the fixed scroll 11. Is located in. As shown in FIGS. 11 and 12, the unload hole 117 is formed so as to penetrate the fixed base plate 11a from the outer periphery of the fixed base plate 11a of the fixed scroll 11 without passing through the spiral center. As shown in FIG. 16, one end side of the unload hole 117 is closed with a plug 35a, and the other end side is closed with a spring seat 36.

The unload mechanism 230 allows the fluid in the intermediate pressure compression chamber 37 to pass through the bleeding hole 112, the back pressure chamber 291b, and the unload path configured in the unload hole 117 formed in the fixed base plate 11a. Unloading is performed by bypassing to the low pressure space 212. The unload path consists of a back pressure chamber communication passage 113 having one end opened in the back pressure chamber 291b, a low pressure space communication passage 114 having one end opening in the low pressure space 212, and the other end of the back pressure chamber communication passage 113 and a low pressure space connection. It is composed of a control valve small diameter portion outer peripheral space 120 that communicates with the other end of the passage 114. The control valve small diameter portion outer peripheral space 120 is a part of the unload hole 117.

The control valve 31 is slidably arranged in the unload hole 117, and is oriented toward the plug 35a of the unload hole 117 (left side in FIG. 16) by the elastic body 32 arranged between one end surface 31a and the spring seat 36. ) Is pressed. As a result, the control valve 31 is arranged in the unload hole 117 with the other end surface 31b in contact with the tip of the plug 35a. As shown in FIGS. 16 and 19, the tip of the plug 35a is formed to have a smaller diameter than the rear unload hole 117 closing portion, and blocks the operation pressure introduction hole 116 described later formed in the fixed scroll 11. There is no such thing. In FIGS. 7 to 9, the shape of the plug 35a and the like are different from the above description, but FIGS. 7 to 9 are schematic views, and the shape shown in FIG. 19 is only an example of a specific shape.

As shown in FIG. 18, the tip of the spring seat 36 is formed to have a diameter smaller than the diameter of the unload hole 117, and the elastic body 32 is inserted between the outer circumference of the small diameter portion and the inner surface of the unload hole 117. A pressure equalizing pore 36a penetrates the central portion of the spring seat 36.

The fixed base plate 11a and the fixed spiral tooth 11b of the fixed scroll 11 are formed with an operating pressure introduction hole 116 that penetrates the fixed spiral tooth 11b in the vertical direction. One end of the operating pressure introduction hole 116 is opened in the unload hole 117 in the operating pressure introduction space 298 facing the end surface 31b on the plug 35a side of the control valve 31. The other end of the operating pressure introduction hole 116 is opened in a circular and concave pressure receiving pocket 115 formed on the tooth tip surface of the fixed spiral tooth 11b. The diameter of the pressure receiving pocket 115 is set to a diameter that can include the swing locus of the operating pressure introducing vertical hole 125, which will be described later, and the pressure receiving pocket 115 always communicates with the operating pressure introducing vertical hole 125.

As shown in FIGS. 8 and 14, the rocking base plate 12a of the rocking scroll 12 has an operating pressure introduction side hole 124 that guides hydraulic pressure from inside the boss portion 121 of the rocking scroll 12 to the pressure receiving pocket 115 of the fixed scroll 11. And the operating pressure introduction vertical hole 125 is formed. The operating pressure introduction horizontal hole 124 is a horizontal horizontal hole of the rocking base plate 12a, and the operating pressure introduction vertical hole 125 is a vertical hole extending vertically from the operating pressure introduction horizontal hole 124 and opening on the upper surface of the rocking base plate 12a. be.

The lubrication pump 27 is driven by the rotation of the shaft 15, and the lubricating oil 22 rises in the lubrication hole 152 and is supplied to the inside of the upper part of the boss portion 121. The lubricating oil 22 supplied to the boss portion 121 is supplied to the unload hole 117 via the operating pressure introduction horizontal hole 124, the operating pressure introduction vertical hole 125, the pressure receiving pocket 115, and the operating pressure introduction hole 116. As a result, hydraulic pressure corresponding to the resistance from the upper part to the downstream side of the boss portion 121 of the swing scroll 12 and the pump pressure of the refueling pump 27 acts on the end surface 31b on the operating pressure introduction space 298 side of the control valve 31.

A low pressure always acts on the end face 31a on the opposite side of the operating pressure introduction space 298 of the control valve 31. This is because the space facing the end surface 31a of the control valve 31 is equalized with the low pressure space 212 by the pores 36a formed in the spring seat 36.

When the scroll compressor 1 is operated at a relatively low speed, that is, when the rotation speed of the shaft 15 is equal to or less than the set rotation speed, the refueling amount of the refueling pump 27 is small and the refueling oil pressure is low. Therefore, the force derived from the acting pressure on the end face 31a on the opposite side of the operating pressure introduction space 298 and the elastic force of the elastic body 32 rather than the force derived from the acting pressure on the end surface 31b on the operating pressure introduction space 298 side of the control valve 31. The total of is higher. In this case, as shown in FIGS. 15 and 16, the control valve 31 moves toward the plug 35a and comes into contact with the tip of the plug 35a. As a result, as shown in FIG. 9, the back pressure chamber communication passage 113, the control valve small diameter portion outer peripheral space 120, and the low pressure space communication passage 114 communicate with each other, and the unload path is opened.

As a result, the fluid in the intermediate pressure compression chamber 37 passes through the extraction hole 112, the back pressure chamber 291b, the back pressure chamber communication passage 113, the control valve small diameter portion outer peripheral space 120, and the low pressure space communication passage 114 in this order, and the low pressure space 212. Is discharged to. Therefore, in the intermediate pressure compression chamber 37, the intermediate pressure compression chamber 37 communicates with the extraction hole 112, in other words, until the outer peripheral side seal forming point of the intermediate pressure compression chamber 37 passes through the extraction hole 112. No compression is performed, and capacity control, that is, an unload state is established.

When the rotation speed of the shaft 15 exceeds the set rotation speed, the amount of refueling of the refueling pump 27 increases, and the refueling oil pressure rises. As a result, the force derived from the acting pressure on the end face 31b on the operating pressure introduction space 298 side of the control valve 31, the force derived from the acting pressure on the end face 31a on the opposite side of the operating pressure introduction space 298, and the elastic force of the elastic body 32. Exceeds the total of. At this time, as shown in FIGS. 10, 20, and 21, the control valve 31 moves away from the plug 35a in the direction of compressing the elastic body 32, and as shown in FIG. 10, the low-pressure space communication passage 114 is the control valve. It is blocked by 31. As a result, the unload path including the back pressure chamber communication passage 113, the control valve small diameter portion outer peripheral space 120, and the low pressure space communication passage 114 is closed, and the unload state is switched to the non-unload state.

In this way, in the unload mechanism 230, the pressure acting on both end faces of the control valve 31 changes according to the operating rotation speed of the scroll compressor 1, so that the control valve 31 automatically moves, and unloading and non-loading are performed. Automatically switch between unloading. The set rotation speed, which is the switching point between unloading and non-unloading, is adjusted to a desired value by selecting the spring constant of the elastic body 32 in consideration of the pressure acting on both end faces of the control valve 31. It is possible.

The unload mechanism 230 guides low pressure and hydraulic pressure, which are operating pressures, acting on one end surface 31a and the other end surface 31b of the control valve 31 from the inside of the closed container 21. That is, the unload mechanism 230 has a structure completed inside the closed container 21, and does not require a pipe or the like to connect from the outside of the closed container 21 to the compression mechanism portion 10.

As described above, according to the second embodiment, as in the first embodiment, the leakage loss of the tooth tip clearance due to the axial pressing is reduced, and the overcompression loss is reduced under the low compression ratio condition by the high pressure side relief. You can get the effect. Further, according to the second embodiment, as in the first embodiment, the capacity is controlled by the unloading mechanism completed in the closed container, the configuration with the minimum number of ports opened in the compression chamber, and the pressure fluctuation in the compression chamber. Stable operation can be realized because the pulsations on the relief side and the unload side do not affect each other. Further, according to the second embodiment, as in the first embodiment, the unloading and the pressure release of the back pressure chamber are performed by the operation of a single element called the control valve, so that the reliability is high, the wide operating range, and the high. An efficient scroll compressor can be obtained at low cost.

Further, in the second embodiment, by using the hydraulic pressure depending on the rotation speed as the operating pressure of the unload mechanism, the capacity control can be used in a wider range as compared with the first embodiment. Under partial load conditions for air conditioning applications, the lower the load factor, the lower the compression ratio and the lower the differential pressure. If an attempt is made to respond to a decrease in the load factor simply by reducing the operating rotation speed, a relative increase in leakage loss due to low-speed operation will occur. Therefore, the minimum rotation speed should be maintained higher by unloading operation than during non-unloading operation. Is valid.

Since the high and low pressure depends on the temperature difference between the high temperature heat source and the low temperature heat source in the refrigeration cycle, when the small temperature difference and the reduction in the air conditioning load have a correlation as in the above partial load condition, the high and low pressure difference in the first embodiment. It is effective in a mechanism that shifts to unload operation depending on the dependency. On the other hand, for example, in a system composed of one outdoor unit and a large number of indoor units, it may be better to unload regardless of the difference in high and low pressure. When cooling operation of only one indoor unit is performed at high outside temperature, the difference in high and low pressure depending on the temperature difference between indoor and outdoor is large, and the air conditioning load is small compared to the capacity of the outdoor unit due to the decrease in the number of indoor units in operation. Therefore, it is desirable to unload it.

If the outdoor unit capacity control corresponding to the minimum number of indoor units in operation is performed by reducing the operating rotation speed without unloading, the compressor operates at a low speed, which causes performance deterioration due to an increase in leakage loss as described above. In addition, since the differential pressure is caused by the temperature difference, the load derived from the differential pressure acting on each member of the compression mechanism (for example, the bearing load) is not small, so in order to avoid bearing seizure due to low-speed high differential pressure operation. It is not possible to operate at a low speed that exceeds the limit. That is, there are operating conditions in which the unloading mechanism that starts depending on the differential pressure is not effective.

According to the rotation speed-dependent unload operation transition of the second embodiment, the rotation speed is significantly low even when the refrigerating capacity required is small compared to the capacity of the system although the pressure difference is not low. There is an effect that it becomes possible to avoid driving.

The scroll compressor 1 of the second embodiment includes a refueling pump 27 at the lower end of the shaft 15. The lubrication pump 27 supplies the lubricating oil 22 stored in the lower part of the closed container 21 to the compression mechanism portion 10 through the lubrication hole 152 provided through the shaft 15 by the rotation of the shaft 15. The hydraulic pressure of the lubricating oil 22 supplied from the lubrication pump 27 acts on the end surface 31b on the operating pressure introduction space 298 side of the control valve 31. Further, a low pressure in the low pressure space acts on the end surface 31a on the side opposite to the operating pressure introduction space 298 of the control valve 31. With this configuration, the pressure difference acting on both end faces of the control valve 31 changes according to the operating conditions, and the position of the control valve 31 can be moved to open and close the unload path.

In the second embodiment, the control valve 31 closes the unload path when the rotation speed of the shaft 15 exceeds the preset rotation speed, and opens the unload path when the rotation speed is equal to or less than the set rotation speed. do. In this way, unloading and non-unloading can be switched according to the rotation speed of the shaft 15.

In the second embodiment, the unload hole 117 is formed in the fixed scroll 11. The unload path is composed of a back pressure chamber communication passage 113 having one end opened in the back pressure chamber 291b, a low pressure space communication passage 114 having one end opening in the low pressure space 212, and a control valve small diameter portion outer peripheral space 120. .. In the spring seat 36 in the unload hole 117, pores 36a for introducing the low pressure of the low pressure space 212 are formed on the end face 31a side of the control valve 31 on the side of the counter-operated pressure introduction space. Further, the fixed scroll 11 is formed with a pressure receiving pocket 115 and an operating pressure introduction hole 116, which are operating pressure introduction paths for supplying hydraulic pressure from the oil supply pump 27 to the operating pressure introduction space 298 on the end surface 31b side of the control valve 31. ing. With this structure, low pressure and hydraulic pressure, which are operating pressures, can be applied to both end faces of the control valve 31 from inside the closed container 21.

In the second embodiment, the back pressure chamber communication passage 113, the control valve small diameter portion outer peripheral space 120, and the low pressure space communication passage 114 are closed by blocking the low pressure space communication passage 114 with the control valve 31. However, the unloading path may be closed by blocking the back pressure chamber communication passage 113.

1 scroll compressor, 9 compression chamber, 9a innermost chamber, 9b second chamber, 9c outermost chamber, 10 compression mechanism, 11 fixed scroll, 11a fixed base plate, 11b fixed spiral tooth, 11ba winding end, 11bb winding End, 12 swing scroll, 12a swing base plate, 12b swing spiral tooth, 13 posture regulating means, 14 frame, 14a main bearing, 15 axis, 15a eccentric part, 16 1st balancer, 17 2nd balancer, 18 Motor, 18a stator, 18b rotor, 19 subframe, 19a auxiliary bearing, 21 closed container, 22 lubricating oil, 23 suction pipe, 24 discharge pipe, 25 discharge valve, 25b discharge valve stopper, 26 relief valve, 26b relief valve stopper, 27 Refueling pump, 28 radial guide member, 29 separator, 29a convex part, 31 control valve, 31a end face, 31b end face, 32 elastic body, 33 seal member, 34 seal member, 35a plug, 35b plug, 35c plug, 36 spring Seat, 36a pore, 37 intermediate pressure compression chamber, 111 first discharge port, 112 extraction hole, 113 back pressure chamber communication passage, 114 low pressure space communication passage, 115 pressure receiving pocket, 116 operating pressure introduction hole, 117 unload hole, 118 Back pressure chamber peripheral surface, 119 Back pressure chamber outer peripheral surface, 120 Control valve small diameter outer peripheral space, 121 Boss, 124 Operating pressure introduction horizontal hole, 125 Operating pressure introduction vertical hole, 130 Seal formation point, 152 Refueling hole, 211 High pressure space, 212 Low pressure space, 220 relief mechanism, 230 unload mechanism, 291a discharge chamber, 291b back pressure chamber, 292 second discharge port, 293a back pressure chamber communication passage, 293b low pressure space connection passage, 293c Control valve small diameter outer circumference Space, 294a high pressure introduction hole, 294b low pressure introduction hole, 295 relief port, 296 unload hole, 297 low pressure introduction space, 298 operating pressure introduction space.

Claims (8)

With a closed container
A separator that divides the inside of the closed container into a high-pressure space and a low-pressure space,
A compression mechanism unit having a fixed scroll and an oscillating scroll, sucking a fluid from the low pressure space into a compression chamber formed by engaging the fixed scroll and the oscillating scroll, compressing the fluid, and discharging the fluid into the high pressure space. When,
It is provided with an unloading mechanism that limits the discharge amount by bypassing the fluid from the compression chamber to the low pressure space.
A back pressure chamber communicating with the compression chamber during compression is formed between the end surface of the fixed scroll opposite to the swing scroll and the separator through an air extraction hole formed in the fixed scroll. The separator is formed with an unload hole forming a part of an unload path communicating the back pressure chamber and the low pressure space.
The unloading mechanism
A control valve that opens and closes the unload path by moving its position in the unload hole is provided.
During operation, the low pressure in the low pressure space acts on one end face in the moving direction of the control valve, and the pressure higher than that in the low pressure space guided from the inside of the closed container acts on the other end face.
The control valve moves to open and close the unload path by changing the pressure difference acting on both end faces of the control valve according to the operating conditions.
The unload path includes a back pressure chamber communication passage having one end opened in the back pressure chamber, a low pressure space communication passage having one end opening in the low pressure space, and the other end of the back pressure chamber communication passage and the low pressure space connection. It is composed of a control valve small diameter portion outer peripheral space that communicates with the other end of the passage.
The separator has a low pressure introduction hole for introducing a low pressure in the low pressure space into a space facing the one end face of the control valve, and a high pressure in the high pressure space in the space facing the other end face of the control valve. A scroll compressor in which a high-pressure introduction hole to be introduced is formed. With a closed container
A separator that divides the inside of the closed container into a high-pressure space and a low-pressure space,
A compression mechanism unit having a fixed scroll and an oscillating scroll, sucking a fluid from the low pressure space into a compression chamber formed by engaging the fixed scroll and the oscillating scroll, compressing the fluid, and discharging the fluid into the high pressure space. And the shaft that drives the compression mechanism
Lubricating oil attached to the lower end of the shaft and stored in the lower part of the closed container by rotation of the shaft is supplied to the compression mechanism portion through a lubrication hole provided through the shaft. With a pump,
It is provided with an unloading mechanism that limits the discharge amount by bypassing the fluid from the compression chamber to the low pressure space.
A back pressure chamber communicating with the compression chamber during compression is formed between the end surface of the fixed scroll opposite to the swing scroll and the separator through an air extraction hole formed in the fixed scroll. The fixed scroll is formed with an unload hole forming a part of an unload path communicating the back pressure chamber and the low pressure space.
The unloading mechanism
A control valve that opens and closes the unload path by moving its position in the unload hole is provided.
During operation, the low pressure in the low pressure space acts on one end face in the moving direction of the control valve, and the pressure higher than that in the low pressure space guided from the inside of the closed container acts on the other end face.
The control valve moves to open and close the unload path by changing the pressure difference acting on both end faces of the control valve according to the operating conditions.
A scroll compressor on which the hydraulic pressure of the lubricating oil supplied from the lubrication pump acts on the other end surface of the control valve. The scroll compression according to claim 2, wherein when the rotation speed of the shaft exceeds the preset rotation speed, the unload path is closed, and when the rotation speed is equal to or less than the set rotation speed, the unload path is opened. Machine. The unload path includes a back pressure chamber communication passage having one end opened in the back pressure chamber, a low pressure space communication passage having one end opening in the low pressure space, and the other end of the back pressure chamber communication passage and the low pressure space. It is composed of a control valve small diameter portion outer peripheral space that communicates with the other end of the communication passage.
The fixed scroll has a low pressure introduction hole for introducing a low pressure in the low pressure space into a space facing the one end face of the control valve, and a space facing the other end face of the control valve from the refueling pump. The scroll compressor according to claim 2 or 3, wherein the operating pressure introduction hole for supplying the hydraulic pressure is formed. Claims 1 to 4 of the control valve close the unload path when the high / low pressure difference exceeds a preset value, and open the unload path when the pressure difference is equal to or less than the set value. The scroll compressor according to any one of the above. The unload mechanism includes an elastic body that urges the control valve to the high pressure side to position the control valve at a position that opens the unload path.
The invention according to any one of claims 1 to 4, wherein the control valve moves from a position where the unload path is opened to a position where the unload path is closed when the differential pressure corresponding to the pressure difference exceeds the urging force of the elastic body. Scroll compressor. The separator is formed with a port having an inlet side opening to the back pressure chamber and an outlet side opening to the high pressure space, and a relief port for relieving an overcompressed fluid in the compression chamber to the high pressure space. The scroll compressor according to any one of claims 1 to 6, further comprising a relief valve for opening and closing the relief port on the outlet side of the relief port. A discharge chamber in which the first discharge port formed in the fixed scroll opens is formed between the end surface of the fixed scroll opposite to the swing scroll and the separator, and the separator has a discharge chamber. A second discharge port is formed in which the inlet side opens to the discharge chamber and the outlet side opens to the high pressure space, and the fluid compressed in the compression chamber is discharged to the high pressure space. The scroll compressor according to claim 7, further comprising a discharge valve that opens and closes the second discharge port on the outlet side of the above.

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