JP2007247562A - Refrigerant compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reliable and low cost refrigerant compressor capable of eliminating a lubricating pump and lubricating lubricated part such as a bearing with an extremely simple structure. <P>SOLUTION: This refrigerant compressor 10 is provided with a refrigerant suction hole 2a provided on a main housing 2 and leading refrigerant flowing into a motor chamber 7 to a scroll suction chamber 4a of compression mechanism parts 3, 4, a pressure difference generating means 2a, 21 generating pressure difference between the motor chamber 7 and the scroll suction chamber 4a, and a lubricating passage 9a leading lubricating oil in an oil reservoir part to lubricated parts 5, 6, 15, 3, 4 by pressure difference generated by the pressure difference generating means 2a, 21. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a refrigerant compressor used, for example, in a refrigeration apparatus, and is particularly suitable as a compressor for CO ₂ .

  As a conventional technique, as in Patent Document 1, a structure in which stored lubricating oil is pumped and supplied to a portion to be lubricated by a known positive displacement oil pump is common.

Japanese Patent No. 3274900

  However, the positive displacement oil pump has the following problems. That is, while this type of oil pump can reliably deliver oil, its configuration requires precise parts, which increases the cost of the compressor. Moreover, it cannot be said that the reliability is sufficient due to problems such as a failure of the oil supply pump and wear.

  With reference to FIG. 10, the configuration and operation of the prior art (Patent Document 1) will be briefly described. In the sealed case 91, a compression mechanism portion 84 is accommodated in the upper portion, and a motor 87 and the like are accommodated in the central portion. Reference numeral 47 denotes an oil reservoir provided at the lower part of the case, and an oil supply pump P provided at the lower end of the rotating shaft 93 is installed in an immersed state. In the prior art, the motor, the oil reservoir, and the like constitute a so-called low-pressure dome type in which the peripheral pressure is substantially the suction pressure (gas pressure sucked by the compression mechanism portion 84).

  In the compressor, as is well known, it is necessary to supply lubricating oil to the rotary shaft bearing portion, the compression mechanism portion 84, and the like. In the prior art, the oil reservoir 47 is located in the lower part and the part requiring oil supply is located in the upper part. Therefore, the lubricating oil must be fed upward by some means. In the prior art, means is used that pressurizes the lubricating oil in the oil reservoir 47 by the positive displacement oil pump P and feeds it to the upper lubricated part through an oil supply hole provided in the rotary shaft 94.

  The details of the oil pump P are shown in FIG. The oil pump P is composed of parts such as a pump cylinder 56 having a cylinder chamber 60 that is eccentric with respect to the center of the rotation shaft, a roller pin 54, a thrust plate 57, and a seal plate 55. All of these parts require high-precision machining, which increases costs. Furthermore, the oil supply pump P has a possibility of causing problems such as wear and seizure of the pump sliding portion.

  The present invention has been made in view of the above problems, and an object of the present invention is to eliminate an oil pump that is composed of a large number of parts processed with high accuracy and has the possibility of wear, seizure, etc. in the sliding part. Another object of the present invention is to provide a highly reliable and low-cost refrigerant compressor that makes it possible to supply oil to a lubricated part such as a bearing with an extremely simple structure.

  This invention provides the refrigerant compressor as described in each claim of a claim as a means for solving the said subject.

  According to the first aspect of the present invention, the compression mechanism portion sucks in the refrigerant through the refrigerant suction hole and sends out the compressed oil, and at the same time, the lubricating oil is supplied from the oil reservoir portion of the sealed case through the oil supply hole penetrating the rotating shaft. Has the role of inhaling. The suction of the required amount of lubricating oil is defined by the differential pressure forming means disposed in the refrigerant suction hole. The role of the conventional oil pump is replaced by the compression mechanism and the differential pressure forming means. For this reason, the conventional oil supply pump comprised from many components which require a highly accurate process becomes unnecessary.

According to the second aspect of the present invention, the oil supply passage is an oil supply hole penetrating the rotation shaft in the axial direction, one end of the oil supply hole is disposed in the oil reservoir, and another end of the oil supply hole is the scroll suction chamber. It is arranged in the vicinity. A specific configuration of the oil supply passage is shown.
According to the third aspect of the present invention, the rotating shaft is supported by the main bearing and the sub bearing arranged in the main housing. The rotating shaft is stably supported by two bearings.
According to the invention described in claim 4, the oil supply hole includes a bearing oil supply hole for supplying lubricating oil to at least one of the main bearing and the auxiliary bearing.
According to the fifth aspect of the present invention, the oil groove is formed on the outer peripheral side of the rotating shaft journal of the bearing oil supply hole.

  According to the invention described in claim 6, the differential pressure forming means is either an orifice, a reed valve or a disc valve. Thus, a specific means for realizing the differential pressure forming means, which is a feature of the present invention, is provided.

According to the invention described in claim 7, the refrigerant is CO ₂ . The present invention uses the pressure loss of the refrigerant suction hole as a means for forming the differential pressure. Generating a pressure loss at the refrigerant suction hole reduces the pressure of the refrigerant flowing into the compression chamber, thereby reducing the efficiency of the compressor. However, the degree of efficiency reduction is significantly less for CO ₂ refrigerants than for conventional refrigerants such as R134a. Refrigerant pressure at the same temperature conditions are high much CO ₂ refrigerant than conventional refrigerant, the pressure difference between the discharge pressure and the suction pressure also CO ₂ refrigerant is because a high pressure much more than the conventional refrigerant.

A first embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 shows a scroll compressor used in a refrigeration apparatus, for example. The compressor 10 has a configuration in which the compression mechanism units 3 and 4 are installed in the upper portion and the motor 8 is installed in the middle portion, and a so-called low-pressure dome type in which the peripheral pressure of the motor chamber 7 is almost the suction pressure of the compression mechanism portions 3 and 4. It has become. Furthermore, an oil reservoir 14 for storing lubricating oil is provided below the motor chamber 7. The rotary shaft 9 has an oil supply hole 9a penetrating both ends thereof. One end thereof is immersed in the lubricating oil in the oil reservoir 14. The rotating shaft 9 is supported by the main bearing 5 and the auxiliary bearing 31.

  Reference numeral 1 denotes an airtight case. A main housing 2 is provided in the airtight case 1 and rotatably supports the rotary shaft 9. Compression mechanisms 3 and 4 (described later) are provided at the upper part of the rotating shaft 9, and a motor 8 including a stator 8a and a rotor 8b is provided at the lower part. That is, the rotation shaft 9 connects the motor 8 and the compression mechanism units 3 and 4, and the motor 8 rotationally drives the compression mechanism units 3 and 4 via the rotation shaft 9.

  The compression mechanism sections 3 and 4 are composed of a fixed scroll blade 4 attached and fixed to the main housing 2 and an orbiting scroll blade 3 attached to an eccentric portion 9 h at the upper end of the rotary shaft 9.

  Both the fixed scroll blade 4 and the orbiting scroll blade 3 are constituted by end plate portions 4c and 3c and spiral wing portions provided integrally with the end plate portions 4c and 3c. These wing parts are engaged with each other, and a compression chamber S is formed as a spiral space part surrounded by the end plate parts 4c and 3c.

  A concave portion is provided at the center of the upper surface of the fixed scroll blade end plate portion 4c, and a discharge port 4b communicating with the spiral center of the compression chamber S is provided through the end plate portion 4c.

  Further, on the upper surface side of the fixed scroll blade end plate portion 4c, a discharge chamber 4d is provided around the discharge port 4b, and a check valve 16 is provided at the center to communicate with the discharge port 4b.

  A discharge pipe 12 is disposed on the upper side of the hermetic case 1 and communicates with a condenser (not shown) of the refrigeration apparatus. A suction pipe 11 is disposed on the lower side surface of the sealed case 1 and communicates with an evaporator (not shown) of the refrigeration apparatus. An oil reservoir 14 for collecting lubricating oil is formed at the inner bottom of the sealed case 1, and an oil supply pipe (not shown) connected to the lower end of the rotating shaft 9 or the rotating shaft 9 is connected to the oil reservoir 14. Immerse the lower end of the. The lower end portion of the rotating shaft 9 is supported by the auxiliary bearing 31 and has an auxiliary bearing oil supply hole 9i. A large number of small holes 32 a are arranged in the auxiliary bearing support plate 32.

Next, the operation of the compressor according to the present invention will be described.
The refrigerant gas that circulates through the refrigeration system and the lubricating oil that merges with the refrigerant gas and circulates through the system flows into the compressor 10 through the suction pipe 11 due to the suction action of the compression mechanisms 3 and 4. The former refrigerant gas that has flowed in passes through the air gaps of the motor 8 including the rotor 8b and the stator 8a, and flows into the motor chamber 7 while cooling the motor 8. Further, the refrigerant gas passes through the refrigerant suction hole 2a provided in the main housing 2, and reaches the scroll suction chamber 4a. The refrigerant gas is compressed and pressurized in the compression chamber S of the compression mechanism unit composed of the fixed scroll 4 and the orbiting scroll 3, and then sent out from the discharge pipe 12 through the discharge chamber 13.

  On the other hand, the latter lubricating oil that flows together with the refrigerant gas flows into the motor chamber 7 where the flow velocity of the refrigerant gas is significantly lower than that in the suction pipe 11, so that it separates from the refrigerant gas and settles downward due to the gravity of the lubricating oil itself. The oil is stored in the oil sump portion 14.

Next, the lubrication mechanism of the compressor 10 according to the present invention will be described.
The present invention is characterized in that the lubricating oil stored in the lower part of the compressor is fed to the lubricated parts 5, 6, 15, 3, 4 without using an oil pump. It is the pressure difference (differential pressure) of the refrigerant gas formed between the upper end and the lower end of the oil supply hole 9a that causes the lubricating oil to flow to the lubricated part. That is, a pressure difference is formed such that the upper end side of the oil supply hole is lower than the lower end of the oil supply hole 9a. By forming this moderate pressure difference between both ends, the lubricating oil is circulated from the oil reservoir portion 14 toward the upper lubricated portions 5, 6, 15, 3, 4 and supplied to the lubricated portion. This is the gist of the present invention.

Next, a configuration for forming a pressure difference between the upper and lower ends of the oil supply hole 9a will be described.
As shown in FIG. 1, the refrigerant gas flowing in from the suction pipe 11 passes through a gap between the rotor and the stator of the motor 8 and flows into the orbiting scroll chamber 3 a through the refrigerant suction hole 2 a provided in the main housing 2. To do. After that, it enters the scroll suction chamber 4a, flows into the compression chamber S formed by the fixed and orbiting scroll, and is compressed and discharged. In the figure, the refrigerant pressure at each location is indicated by P1, P2, and P3. Since the refrigerant gas passage of the motor 8 usually has a large flow passage cross-sectional area, there is substantially no pressure drop of the refrigerant gas in this portion. Accordingly, the pressure in the motor chamber 7 side space below the main housing 2 is the same everywhere, and this is indicated by P1.

  As shown in FIG. 2, the refrigerant gas passes through the refrigerant suction hole 2 a provided in the main housing 2 and sucks and flows into the orbiting scroll chamber 3 a. Here, by appropriately setting the diameter of the refrigerant suction hole 2a, that is, the flow path cross-sectional area, an appropriate pressure drop is formed at this point. That is, when the refrigerant pressure in the orbiting scroll chamber 3a is P2, P2 <P1, and the pressure is negative with respect to the motor chamber pressure P1.

  The crank chamber 3b communicates with the orbiting scroll chamber 3a through a lubricating oil passage 3d provided on the back of the orbiting scroll end plate 3c and oil grooves 15a, b, c, and d provided in the thrust bearing 15. For this reason, the crank chamber 3 b has a negative pressure close to the orbiting scroll chamber pressure as compared with the motor chamber 7. When this pressure is P3, the relationship between the pressures is P1> P3≈P2.

  The upper end of the rotary shaft is located in the orbiting scroll boss 3e, and the upper end of the oil supply hole 9a is opened in the boss 3e. Since the boss base has a boss communication hole 3f, the pressure inside the boss is It becomes substantially equal to P3. As a result, the pressure at the lower end opening of the oil supply hole 9a provided in the rotating shaft 9 is P1, the upper end opening pressure is P3, the lower end is high, and the upper end is low. When this pressure difference is ΔP, ΔP≈P1−P2, and when ΔP exceeds a predetermined value, the lubricating oil in the oil reservoir 14 is sucked up through the opening of the oil supply hole 9a provided in the rotating shaft 9. Then, it reaches the open end and flows out from here to the crank chamber 3b.

Next, the flow of the lubricating oil and the method for supplying it to the lubricated part will be described.
Lubricating oil is sent to the outer periphery of the rotating shaft by the centrifugal force caused by the rotation of the rotating shaft 9 in the bearing oil supply holes 9b, 9c provided in the respective journal portions 9f, 9g of the rotating shaft 9, and the inner surfaces of the bearing metals 5, 6 An oil film is formed between the journal portions 9f and 9g.

  On the other hand, the lubricating oil flowing out from the upper end of the through oil supply hole 9a of the rotating shaft 9 flows out into the crank chamber 3b through the orbiting scroll boss portion communication hole 3f. Part of the lubricating oil that has entered the crank chamber 3b passes through the oil groove of the thrust bearing 15 and flows out into the orbiting scroll chamber while lubricating the thrust sliding surface. Others flow out to the orbiting scroll chamber 3a through an oil passage provided on the back of the orbiting scroll end plate.

  The lubricating oil flowing into the orbiting scroll chamber 3a merges with the refrigerant gas flowing in from the refrigerant suction hole 2a provided in the main housing 2, and flows into the compression chamber S through the scroll suction chamber 4a. The lubricating oil lubricates the side surfaces and tooth tips of the scroll teeth that are in sliding motion, and then flows out from the discharge pipe 12 together with the discharge gas to the system side. Into the oil reservoir 14 and stored in the oil reservoir 14.

  Thereafter, this cycle is repeated.

  The surroundings of the orbiting scroll will be described in detail with reference to FIGS. As shown in FIG. 2, the thrust bearing plate 15 is a member made of two substantially disk-shaped wear-resistant materials. One is mounted on the main housing and the other is mounted on the orbiting scroll. The thrust bearing plate 15 is fixed in its relative position by fitting a detent pin 2b installed in each of the main housing 2 and the orbiting scroll 3 into a detent pin hole 15e provided in the plate.

  On one side of the thrust bearing plate 15, oil grooves 15a to 15d are provided as shown in FIG. Various shapes of the oil groove are possible, but in this embodiment, a circular groove 15b is provided at the center of the ring, and a shape in which radial grooves are provided on the inner peripheral side 15a and the outer peripheral side 15c from the groove is shown as an example. . The lubricating oil flowing in from the inner peripheral side 15a flows out to the outer peripheral side through 15b and 15c, and also flows into the flat portion 15f from the oil groove to lubricate the thrust sliding surface 15f.

  In FIG. 2, the end plate oil passage groove 3d is provided on the rear surface of the orbiting scroll end plate 3c so as to straddle the thrust bearing plate 15 on the orbiting scroll side. The crank chamber 3b and the orbiting scroll chamber 3a communicate with each other through this groove. By this communication, the pressure in the crank chamber 3b can be set to a low pressure close to the pressure in the orbiting scroll chamber 3a. Furthermore, a boss portion communication hole 3f is provided at the base of the orbiting scroll boss portion 3e, whereby the inside of the boss portion can be similarly reduced in pressure.

  Based on the above principle, the lubricating oil in the oil reservoir 14 is sucked into the oil supply hole 9 a provided in the rotating shaft 9. The sucked lubricating oil flows into the crank chamber 3b through the boss communication hole 3f, and then a part passes through the oil groove of the thrust bearing plate 15 and the other flows out through the end plate oil passage groove 3d to the orbiting scroll chamber 3a. To do.

  Next, the oil grooves 9d and 9e provided on the rotating shaft 9 will be described. FIG. 4 shows oil grooves 9d and 9c for sufficiently flowing lubricating oil between the shaft journal portions 9f and 9g and the bearing metals 5 and 6 in the main bearing portion 5 and the eccentric crank portion 9h. The oil grooves 9d and 9c are provided as long grooves in the axial direction at positions where the main bearing oil supply hole 9b and the orbiting scroll bearing oil supply hole 9c are opened. As is well known, the positions of the bearing oil supply holes 9b and 9c and the oil grooves 9d and 9c on the shaft outer periphery are provided at positions where no load is applied, so that the formation of the oil film responsible for the load is not hindered.

  The above is the same as a general oil groove, but this embodiment has the following features. That is, the length of the oil grooves 9d, 9c is made smaller than the width of the bearing metals 5, 6. The reason is as follows. When the pressure in the outer space 7 of the rotating shaft 9 is compared with the pressure in the rotating shaft through oil supply hole 9a, the pressure in the rotating shaft through oil supply hole 9a is lower than the pressure in the outer space 7 as described above. On the other hand, the lubricating oil flows out through the bearing oil supply holes 9b and 9c from the inner side to the outer side due to the centrifugal force generated by the rotation of the shaft. If the oil grooves 9d and 9c communicate with the outer space 7, the pressure in the oil grooves 9d and 9c becomes higher than the pressure in the oil supply holes 9b and 9c, and the oil supply holes 9b and 9c are directed outward. There is a possibility that the flow of the lubricating oil will be hindered. In view of this, the present invention has a structure in which the oil groove does not communicate with the outer space.

Next, the necessary differential pressure will be described.
In the present invention, lubricating oil is circulated from a low position to a high position by a pressure difference (differential pressure). The pressure difference required for this depends on the distance between the low and high positions. This is equal to the length of the rotating shaft 9. Depending on the capacity of the compressor 10, the length of the CO ₂ compressor having a stroke volume of 4.5 cm ³ is approximately 20 cm as an example. When the density of the lubricating oil is 900 kg / m ³ and the pressure difference required to suck up the lubricating oil to a height of 20 cm is ΔP, ΔP is about 1800 Pa. This is a pressure that only sucks up, and a further pressure difference is required to circulate. It has been experimentally found that the pressure difference for distribution is 2000 Pa. When the pressure difference for distribution is set to 2000 Pa, the total pressure difference ΔP is about 3800 Pa. This is the differential pressure required between the pressures P1 and P2 in FIG.

Next, the dimension of the refrigerant suction hole will be described.
The differential pressure is formed by the pressure loss of the refrigerant suction hole provided in the main housing. Assuming a stroke volume of 4.5 cm ³ , a compressor rotational speed of 1000 rpm, a temperature of 10 ° C., and a refrigerant of CO ₂ , the diameter of the refrigerant suction hole 2a suitable for forming a differential pressure of 3800 Pa is approximately φ4 for one hole. 0.2 mm and the cross-sectional area of the channel is 13.9 mm ² .

  This trial calculation is for the case where the number of the refrigerant suction holes 2a is one, but when a plurality of the refrigerant suction holes 2a are provided, the diameter is naturally smaller. For example, if there are two refrigerant suction holes 2a, the appropriate hole diameter is 3.0 mm.

Next, the operation and effect of the present invention will be described.
The present invention relates to a structure that enables oil supply to lubricated parts 3, 4, 5, 6 with an extremely simple configuration in a hermetic compressor 10 having an oil reservoir 14 at the lower part of a hermetic case 1. .

  In the conventional general structure shown in FIG. 10, a positive displacement oil pump P is installed at the lower end of the rotating shaft, and lubricating oil is pumped by the pump P through an oil passage 51 provided in the rotating shaft 94. It adopts a configuration to do.

  Needless to say, the oil supply is surely made, but on the other hand, the oil pump requires a lot of parts that require precise processing, resulting in an increase in cost. Furthermore, the oil pump itself, which inevitably has a large number of sliding portions, has the possibility of occurrence of sliding portion wear, seizure, and the like, leading to a decrease in the reliability of the compressor itself.

  On the other hand, in the present invention, by forming a pressure difference between both ends of the rotating shaft, the lubricating oil in the lower oil reservoir is sucked and fed to the crank chamber side by the oil supply holes penetrating the both ends, and is supplied to the lubricated portion. It is characterized by refueling.

  Setting the crank chamber side to a lower pressure than the end immersed in oil is achieved by forming a pressure loss in the refrigerant suction hole by appropriately setting the diameter of the refrigerant suction hole provided in the main housing. Is done.

  According to the present invention, it is possible to configure a lubrication mechanism without using an oil supply pump that increases costs and reduces reliability.

The present invention is particularly suitable for a system and a compressor using CO ₂ (carbon dioxide) as compared with the conventional refrigerant R134a and the like. The reason is described below.

The present invention uses the principle of pressure loss of the refrigerant suction hole 2a provided in the main housing 2 as means for forming the differential pressure. As is well known, forming a pressure loss in the refrigerant suction hole 2a lowers the refrigerant pressure flowing into the compression chamber S, thereby reducing the efficiency of the compressor. Specifically, the compression work increases. However, the degree of work increase is significantly less for CO ₂ refrigerant than for conventional refrigerant.

  Table 1 shows the same boundary conditions, that is, the respective refrigerant pressures when the suction refrigerant gas temperature and the discharge refrigerant gas temperature are the same, and the rate of increase in compression work when the aforementioned 3800 Pa is given as the pressure loss of the refrigerant suction hole ( %).

Table 1 is an example of a typical operating conditions, while the increase in compression work when the refrigerant R134a is 1.2 percent, in the case of CO ₂ refrigerant is only slightly 0.2%. This is qualitatively due to the following reasons.

As is clear from Table 1, the refrigerant pressure under the same temperature condition is much higher in CO ₂ than in R 134a, and the pressure difference between the discharge pressure and the suction pressure is much larger in CO ₂ . Of course, this is due to the difference in refrigerant characteristics.

On the other hand, the differential pressure required to suck the lubricating oil, that is, the pressure loss generated in the refrigerant suction hole 2a provided in the main housing 2 is the same 3800 Pa regardless of the type of refrigerant. Therefore, the influence of the pressure conditions concerning compression, CO ₂ towards the refrigerant is much less impact on the compression work also increased CO ₂ it is considerably smaller in the refrigerant. This is the reason why the present invention is particularly suitable for a CO ₂ refrigerant compressor.

  Furthermore, a preferable differential pressure characteristic for the compressor according to the present invention will be described, and a structure for realizing this will be shown as a second embodiment and a third embodiment.

Preferred differential pressure characteristics are as follows.
(1) A differential pressure required at the time of low rotation of the compressor is formed.
The compressor is generally driven by an inverter motor, and is steadily operated at a predetermined rotation speed, for example, 2500 rpm by gradually increasing the rotation speed from, for example, 200 rpm. Accordingly, it is preferable that a necessary differential pressure, for example, 3800 Pa is formed even in a low rotation region during steady rotation.

(2) No excessive differential pressure is formed when the compressor rotates at a high speed.
In the differential pressure forming structure (simple suction hole) shown in the first embodiment, the refrigerant gas flow rate increases and the differential pressure increases as the compressor speed increases. Of course, the efficiency of the compressor is reduced. Therefore, a preferable differential pressure characteristic is that a predetermined differential pressure is formed at a low rotation (for example, 200 rpm) and there is no extreme increase in the differential pressure even at a high rotation (for example, 5000 rpm).

A second embodiment for realizing this will be described with reference to FIGS.
A feature of the second embodiment is that a differential pressure valve 21 is provided on the refrigerant gas outlet side of the refrigerant suction hole 2a, that is, on the orbiting scroll chamber 3a side. An example of the structure of the differential pressure valve 21 is shown in FIG. The differential pressure valve 21 is a so-called reed valve, and includes a thin plate-like valve plate 21a made of a spring steel material and a stopper 21b that restricts the lift of the valve plate 21a. FIG. 7 shows the arrangement of the differential pressure valve 21 on the main housing 2 when the main housing 2 is viewed from the orbiting scroll side 3.

  The valve plate 21a is curved so as to be in close contact with the valve seat surface 2s with an appropriate force in the mounted state. For this reason, even when the refrigerant is at a very low flow rate, a differential pressure sufficient to open the valve is formed. If this differential pressure is set to 3800 Pa, for example, it becomes possible to suck the lubricating oil at any low speed.

  On the other hand, as the intake gas flow rate increases as the compressor rotational speed increases, the valve opening amount, so-called lift amount, gradually increases. Therefore, the differential pressure formation by simply adjusting the hole diameter of the refrigerant suction hole shown in the first embodiment is performed. The increase in differential pressure is less than that of the method. That is, it is possible to suppress a reduction in the efficiency of the compressor even at a high speed. Needless to say, in the second embodiment, the flow passage area of the refrigerant suction hole 2a is set sufficiently large so that the differential pressure is not formed in the refrigerant suction hole 2a.

  FIG. 8 shows a third embodiment of the differential pressure valve. FIG. 8 (a) is a cross-sectional view of the differential pressure valve, and shows a structure in which a disc-like disc valve 22 is pressed against the valve seat 2t by a spiral valve spring 22c. FIG. 8 (b) is a plan view of the disc valve when FIG. 8 (a) is viewed from the X side. An arc-shaped notch 22 a is provided on the outer periphery of the disk 22. By opening the valve, the refrigerant gas flows into the orbiting scroll chamber 3a through the notch 22a. Similar to the second embodiment, the present embodiment also forms a differential pressure sufficient to open the valve even when the flow rate is extremely low, and allows the lubricating oil to be sucked.

  Furthermore, the third embodiment can freely select the spring characteristics of the valve spring as compared with the second embodiment. Therefore, by selecting a spring having a small spring constant, that is, a spring having a small load change with respect to the displacement, there is an advantage that the change in the differential pressure with respect to the gas flow rate can be made extremely small.

  FIG. 9 shows the differential pressure characteristics of each embodiment according to the present invention. In the first embodiment, a differential pressure is formed by setting the refrigerant suction hole 2a provided in the main housing 2 to an appropriate small diameter. As the compressor speed increases, the differential pressure increases in a form close to a square curve. In a compressor having a wide operating speed range, there may be a case where the compression loss in the compression mechanisms 3 and 4 cannot be ignored.

  In the second embodiment, a differential pressure is formed by the reed valve 21. Appropriate differential pressure is generated from low rotation (low flow rate), and there is little increase in differential pressure at high rotation. In the third embodiment, the differential pressure is formed by the disk valve 22, and the differential pressure is substantially constant regardless of the rotational speed, and is most excellent in terms of compression loss. Which differential pressure forming means is to be used is selected from the range of rotation speed of the compressor, the tolerance of compression loss, and the like.

In the refrigerant compressors according to the first and second embodiments, the rotation shaft is arranged in the vertical direction, and the motor chamber is arranged below the compression mechanism unit. However, the present invention is not limited to this, and the rotation shaft is arranged. May be arranged in the horizontal direction so that the compression mechanism and the motor chamber are arranged in the horizontal direction in the sealed case.
In the refrigerant compressors in the first and second embodiments, a scroll-type compression mechanism is taken as an example of the compression mechanism, but the present invention is not limited to this, and a swash plate type is used. In addition, various types of compression mechanisms such as a rolling piston type may be used instead of the scroll type compression mechanism.
In the refrigerant compressor in the above embodiment, the rotation shaft is supported by the main bearing provided in the main housing and the sub-bearing arranged in the motor chamber. However, the present invention is not limited to this. Alternatively, a bearing support member separate from the main housing may be provided, or the rotating shaft may be supported only by the main bearing.

It is a refrigerant compressor of a 1st embodiment concerning the present invention. It is an expanded sectional view of FIG. It is a top view of the thrust bearing plate of FIG. It is an oil groove of the rotating shaft which concerns on this invention. It is a refrigerant compressor of a 2nd embodiment concerning the present invention. It is an enlarged view of the differential pressure valve of FIG. It is a top view of the differential pressure valve of FIG. It is a refrigerant compressor of a 3rd embodiment concerning the present invention. It is a differential pressure characteristic figure of each embodiment concerning the present invention. It is an oil supply apparatus of the refrigerant compressor of a prior art. It is an enlarged view of the oil supply apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing case 2 Main housing 2a Refrigerant suction hole 3 Orbiting scroll 4 Fixed scroll 5 Main bearing 6 Orbiting scroll bearing 7 Motor chamber 8 Motor 9 Rotating shaft 10 Refrigerant compressor

Claims (7)

A motor (8),
Compression mechanism (3, 4);
A rotating shaft (9) connecting the motor (8) and the compression mechanism (3, 4);
A sealed case (1) for housing the motor (8), the compression mechanism (3, 4) and the rotating shaft (9);
A main housing (2) that shields the compression mechanism (3, 4) from the motor chamber (7);
In the refrigerant compressor (10) comprising an oil reservoir (14) provided at the lower part of the motor chamber (7),
A refrigerant suction hole (2a) provided in the main housing (2) for guiding the refrigerant flowing into the motor chamber (7) to the scroll suction chamber (4a) of the compression mechanism (3, 4);
Differential pressure forming means (2a, 21) for forming a differential pressure between the motor chamber (7) and the scroll suction chamber (4a);
An oil supply passage (9a) for guiding the lubricating oil in the oil reservoir to the lubricated parts (5, 6, 15, 3, 4) by the differential pressure formed by the differential pressure forming means (2a, 21). A refrigerant compressor (10) characterized in that: The oil supply passage (9a) is an oil supply hole (9a) penetrating the rotating shaft (9) in the axial direction,
One end of the oil supply hole is disposed in the oil reservoir,
The refrigerant compressor (10) according to claim 1, wherein another end of the oil supply hole is disposed in the vicinity of the scroll suction chamber (4a).   The refrigerant compressor according to claim 2, wherein the rotating shaft (9) is supported by a main bearing (5) disposed in the main housing (2) and a sub bearing (31). (10).   The refrigerant compressor according to claim 3, wherein the oil supply hole (9a) includes bearing oil supply holes (9b, 9c, 9i) for supplying lubricating oil to at least one of the main bearing and the auxiliary bearing. (10).   The refrigerant compressor (10) according to claim 4, wherein oil grooves (9d, 9e) are formed on the outer peripheral side of the rotary shaft journal of the bearing oil supply holes (9b, 9c).   The differential pressure forming means (2a, 21) is any one of an orifice (2a), a reed valve (21), and a disk valve (22). The refrigerant compressor (10) described in 1. The refrigerant compressor (10) according to any one of claims 1 to 6, wherein the refrigerant is CO ₂ .

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