JP4107492B2 - Scroll compressor for helium and scroll compressor for helium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionHelium scroll compressor andThe present invention relates to a helium scroll compressor, and in particular, helium gas is used as a working gas for cryopump equipment in the ultra-high vacuum field.Helium scroll compressor andIt is suitable for a scroll compressor for helium.
[0002]
[Prior art]
As a scroll compressor for helium related to conventional inverter control, for example, there is one described in Patent Document 1 (Prior Art 1). The scroll compressor includes a compressor unit that compresses helium gas as a working gas, an electric motor unit that drives the compressor unit, a sealed container that houses the compressor unit and the motor unit, and an oil injection that penetrates the sealed container. And an oil injection mechanism for injecting the lubricating oil into the compressor section by a differential pressure through the pipe. The compressor section described above forms a compression chamber by meshing a fixed scroll that erects a spiral wrap on the end plate and a revolving scroll that erects the spiral wrap on the end plate with the wraps inside each other. The volume is reduced by moving around the compression chamber, and the helium gas is compressed and discharged into the sealed container. The oil injection mechanism described above is formed so that the lubricating oil stored at the bottom of the hermetic container is guided to the outside, cooled, and supplied. Further, the above-described electric motor unit is configured by an AC-specific motor unit, and the above-described control device is configured by an AC-specific inverter control device capable of controlling the rotation speed of the scroll compressor.
[0003]
On the other hand, as an air-conditioning scroll compressor related to inverter control, for example, there is one described in Patent Document 2 (Prior Art 2). The scroll compressor includes a compressor unit that compresses R22 refrigerant as a working refrigerant, an electric motor unit that drives the compressor unit, and a sealed container that houses the compressor unit and the electric motor unit. The compressor section described above forms a compression chamber by meshing a fixed scroll that erects a spiral wrap on the end plate and a revolving scroll that erects the spiral wrap on the end plate with the wraps inside each other. The volume is reduced by moving around the compression chamber, and the refrigerant gas is compressed and discharged into the sealed container. Further, the above-described motor unit is configured by a DC-specific motor unit, and the above-described control device is configured by an AC-specific inverter control device capable of controlling the rotation speed of the scroll compressor.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 3-271583
[Patent Document 2]
Japanese Patent Laid-Open No. 5-172065
[0005]
[Problems to be solved by the invention]
In the prior art 1, in the case of a comparatively small helium-use scroll compressor having a compressor rated output of 2.2 kW to 4.4 kW class, the motor unit is configured by an AC motor unit and the control device is Since it is composed of an inverter controller with an AC specification that can control the rotation speed of the scroll compressor, the efficiency of the inverter controller and the efficiency of the motor section are generally low, and there is a problem with the energy saving performance of the scroll compressor as a whole. It was.
[0006]
That is, when the efficiency of the electric motor unit is low, the amount of heat generated by the electric motor unit increases, so it is necessary to cool the entire scroll compressor by performing a large amount of oil injection into the oil injection mechanism unit. When the oil injection amount increases, the oil agitation loss of the compressor portion increases, and as a result, the input to the motor portion increases, and also from this point, the heat generation amount of the motor portion increases. .
[0007]
In addition, there is a problem in that the motor input and the inverter input are increased and the performance is further deteriorated in the maximum rotation speed range where the variable speed is possible. Due to this increase in input during high-speed rotation, there is a problem in that the bearing load increases, thereby reducing the bearing life. In particular, when a cylindrical roller bearing portion is used as a main bearing, a decrease in the bearing life has been a problem.
[0008]
Further, in the compressor unit that houses the scroll compressor of the prior art 1 described above, it is necessary to increase the capacity of the oil cooler incorporated in the unit by increasing the oil injection amount. There was a problem peculiar to the compressor unit that the external dimensions of the compressor became large, and as a result, the overall size of the compressor unit became too large.
[0009]
On the other hand, since the scroll compressor of the prior art 2 does not include an oil injection mechanism, the sealing effect of the compressor and the function of improving the volume efficiency cannot be obtained sufficiently in the low speed range, and the coefficient of performance decreases in the low speed range. There was a problem that.
[0010]
  The object of the present invention is to achieve high performance, small size and light weight, and is inexpensive and highly reliable.Helium scroll compressor andIt is to obtain a scroll compressor for helium.
[0011]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention provides:Lubricating through a compressor section that compresses helium gas as working gas, an electric motor section that drives the compressor section, a sealed container that houses the compressor section and the motor section, and an oil injection pipe that penetrates the sealed container An oil injecting mechanism for injecting oil into the compressor section by differential pressure, wherein the compressor section includes a fixed scroll that erects a spiral wrap on the end plate and a spiral shape on the end plate. A compression chamber is formed by meshing the orbiting scroll that stands upright with the wraps facing each other, and the volume is reduced by moving the compression chamber around the compression chamber, and the helium gas is compressed and discharged into the sealed container. The oil injection mechanism is formed such that the lubricating oil stored in the bottom of the hermetic container is led to the outside and cooled and supplied, and the electric motor part is It is composed of a four-phase DC motor section and controlled by a DC inverter control device capable of controlling the rotational speed. The compressor section has a volume ratio Vr of the scroll wrap section shown in the following formula (1) of around 2.1. The fixed scroll and the orbiting scroll meshed with each other having a scroll tooth profile of the following formula (2), the injection oil parameter Uo shown in the following formula (2) is configured to be in the range of 0.125 to 0.135. This is a helium scroll compressor.
  Vr = (2λ1−4π + α) / (2λs + 2π + α) (1)
Here, λ1: end angle of wrap winding, λS: start angle of wrap winding, π: circumference ratio, α: ratio of turning radius εth and basic circle radius a of the scroll wrap.
Uo = (Vr × Qoil) / Vth (2)
  Where Vth: stroke volume of the compressor (cm ³ / Rev), Vr: set volume ratio, Qoil: injection oil amount (liter / minute).
  The present invention also provides:A scroll compressor having a compressor section that compresses helium gas as a working gas, and an electric motor section that drives the compressor section; an oil separator that separates lubricating oil in the helium gas discharged from the scroll compressor; A gas cooler that cools the helium gas flowing from the oil separator, an oil cooler that cools the lubricating oil, and a control device that drives and controls the scroll compressor are housed in the unit.Scroll compressor for heliumThe scroll compressor includes an oil injection mechanism that injects the lubricating oil cooled by the oil cooler into the compressor portion by a differential pressure, and the oil injection mechanism is configured to receive the lubricating oil stored at the bottom of the hermetic container. Formed to be guided to the outside and cooled,The compressor unit forms a compression chamber by meshing a fixed scroll that erects a spiral wrap on the end plate and a revolving scroll that erects the spiral lap on the end plate with the wraps inside each other. Move the chamber around the center to reduce the volume and compress the helium gas to discharge into the sealed container,The motor section is composed of a three-phase, four-pole direct current specification motor section, and the control device is composed of a direct current specification inverter control device capable of controlling the rotation speed of the scroll compressor.The compressor unit includes the fixed scroll and the orbiting scroll, which are meshed with each other and have a scroll tooth profile with a volume ratio Vr of the scroll wrap unit shown in the above equation (1) of about 2.1. A helium scroll compressor characterized in that the injection oil parameter Uo shown in (2) is in the range of 0.125 to 0.135.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
A helium scroll compressor according to an embodiment of the present invention will be described below with reference to FIGS.
[0017]
First, the overall configuration of the helium scroll compressor 910 according to this embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a configuration diagram of a helium refrigeration apparatus including an oil-filled helium scroll compressor according to an embodiment of the present invention, and FIG. 2 is a perspective view of the helium scroll compressor. In FIG. 1, the scroll compressor 100 is simply shown on the side, but actually, the scroll compressor 100 is used as a vertical type as shown in FIG.
[0018]
The helium refrigeration apparatus includes a helium scroll compressor 910 and a refrigerator 800. The scroll compressor 910 for helium and the refrigerator 800 are connected via pipes 720 and 730.
[0019]
The helium scroll compressor 910 includes components of the refrigeration cycle 911 excluding the refrigerator 800, an injection circuit 913 that cools the lubricating oil in the scroll compressor 100 and injects it into the compression chamber of the scroll compressor 100, and scroll compression. A DC inverter control device 400 that controls the rotational speed of the machine 100 and a cooling fan 440 that ventilates and cools the DC inverter control device 400 are configured.
[0020]
The refrigeration cycle 911 includes an oil-filled hermetic scroll compressor 100 with a built-in direct current motor, an oil separator 700, a gas cooler 710, and a refrigerator 800. These devices are connected in series via pipes 550, 702, 720, 730, and 752, and are configured to be a closed loop that circulates the working refrigerant. In addition, a pipe 740 that bypasses the gas cooler 710 and the refrigerator 800 from the oil separator 700 and returns the oil to the scroll compressor 100 is provided. Helium gas is used as a working refrigerant for this refrigeration cycle. The scroll compressor 100 is of the 2-5 horsepower class and the stroke volume of 30-80 cc class.
[0021]
In such a refrigeration cycle, the high-temperature and high-pressure helium gas discharged from the scroll compressor 100 is separated by the oil separator 700 and then cooled by the gas cooler 710. Next, the helium gas is adiabatically expanded in the helium refrigerator 800 and then returned to the scroll compressor 100 again as suction gas through the pipes 730 and 752. In this way, a function as a refrigeration apparatus is obtained.
[0022]
The oil injection circuit 913 includes an oil strainer 38, an oil cooler 33,CatA throttling means 271 composed of a piary tube, an oil amount adjusting valve, and the like is provided, and these are connected in series via pipes 36, 36a, 36b. The oil injection circuit 913 is connected between an oil take-out pipe 30 communicating with the lubricating oil stored in the scroll compressor 100 and an oil injection pipe 31 communicating with the compression chamber of the scroll compressor 100. Yes.
[0023]
The lubricating oil stored in the scroll compressor 100 flows into the oil take-out pipe 30 due to a differential pressure between the discharge pressure applied to the lubricating oil and the intermediate pressure in the compression chamber. The inflowing lubricating oil removes dust and the like by the oil strainer 38, and then is appropriately cooled by the oil cooler 33. The oil injection amount is adjusted by the throttle means 271, and the compression chamber of the scroll compressor 100 is discharged from the oil injection pipe 31. Injected into.
[0024]
The DC inverter control device 400 is disposed outside the scroll compressor 100 and is electrically connected to the scroll compressor 100. Then, power supplied from the commercial power source 500 is converted into power by the DC inverter control device 400 and supplied to the scroll compressor 100. Specifically, the rotational speed of the scroll compressor 100 is changed by controlling the DC voltage applied to the motor unit 3 by the DC inverter 400 and the DC voltage commutation action (polar conversion action unique to the brushless motor). .
[0025]
The above-described devices constituting the helium scroll compressor 910 are accommodated in a unit 912 indicated by a one-dot chain line in FIG. Further, these devices are arranged in the unit 912 as shown by the broken lines in FIG. 2 and connected by piping, wiring, or the like. The arrangement of these devices is designed so that the entire arrangement space is compact and the piping and wiring are shortened. In this case, downsizing of the scroll compressor 100, the oil cooler 33, and the gas cooler 710 is important. In this embodiment, the scroll compressor 100, the oil cooler 33, and the gas cooler 710 are greatly reduced as described later. The external dimensions of the unit 912 can be greatly reduced. The unit 912 is formed of a substantially rectangular box having outer dimensions of a width dimension L1, a depth dimension L2, and a height dimension L3. In order to ventilate the cooling fan 440, a vent hole 912a is provided on the front surface or side surface. The unit external dimensions (L1, L2, L3 dimensions) are reduced by about a dozen percent as the scroll compressor 100, the gas cooler 710, and the oil cooler 33 can be miniaturized by a dramatic improvement in the coefficient of performance described later. As a result, the weight of the unit can be reduced.
[0026]
Next, details of the main part of the helium scroll compressor 910 will be described with reference to FIGS. 3 is a block diagram of the main part of the scroll compressor for helium in FIG. 1, FIG. 4 is a cross-sectional view taken along line AA in FIG. 3, FIG. 5 is a plan view of the fixed scroll in FIG. 7 is a plan view of the orbiting scroll of FIG. 3, and FIG. 8 is a longitudinal sectional view of the orbiting scroll of FIG.
[0027]
In FIG. 3, the scroll compressor part 2 is accommodated in the upper part of the sealed container 1, and the electric motor part 3 is accommodated in the lower part. The sealed container 1 is partitioned into an upper chamber 1a and an electric motor chamber 1b. The scroll compressor unit 2 forms a compression chamber (sealed space) 8 by meshing the fixed scroll 5 and the orbiting scroll 6 with each other.
[0028]
The fixed scroll 5 is composed of a disc-shaped end plate 5a and a wrap 5b that stands upright and has an involute curve or a curve approximate thereto, and has a discharge port 10 at the center and suction ports 15a, 15a, 15b. The orbiting scroll 6 is composed of a disc-shaped end plate 6a, a wrap 6b that is upright and formed in the same shape as the wrap of the fixed scroll, and a boss portion 6c that is formed on the anti-wrap surface of the end plate 6a. .
[0029]
The frame 11 has bearings 26 and 27 at the center. The rotating shaft 15 is supported on these bearing portions 26 and 27. An eccentric shaft portion 15 a is provided on one side of the rotation shaft 15. The eccentric shaft portion 15a is inserted into the boss portion 6c so as to be capable of turning.
[0030]
The fixed scroll 5 is fixed to the frame 11 with a plurality of bolts 11e. The orbiting scroll 6 is supported on the frame 11 by an Oldham mechanism 12 comprising an Oldham ring and Oldham key. As a result, the orbiting scroll 6 is formed so as to orbit with respect to the fixed scroll 5 without rotating. The compression chamber 8 is moved in the central direction by the orbiting motion of the orbiting scroll 6, and accordingly, the volume of the compression chamber 8 is reduced and the helium gas is compressed and discharged from the discharge chamber 10 into the sealed container 1. Accordingly, in the present embodiment, the inside of the sealed container 1 becomes the discharge pressure.
[0031]
An electric motor shaft portion 16 b is formed on the other side (lower portion) of the rotating shaft 16. The motor shaft portion 16a is directly connected to the DC motor portion 3a. This motor unit 3 is a three-phase four-pole motor specification, three-phase permanent magnet synchronous motor without a commutator, and is a DC brushless motor. Since the electric motor unit 3 forms a magnetic pole by using the rotor 3b as a permanent magnet and does not require an exciting current in the AC electric motor, the electric motor efficiency is remarkably improved. As a result, the motor input / current can be greatly reduced.
[0032]
In the DC motor unit 3 of the DC specification, the motor torque can be increased by setting the length S1 of the stator 3a to be longer than the length S2 of the rotor 3b. For example, by setting the length S1 of the stator 3a to 70 mm with respect to the length S2 of the rotor 3b = 65 mm, the maximum torque of the motor unit 3 can be increased by about 10 to 15%.
[0033]
A DC-type inverter control device 400 arranged externally is electrically connected to the power supply terminal portion 340 electrically connected to the winding of the stator 3a of the DC motor portion 3. The DC inverter control device 400 is connected to a commercial power source 500. The output frequency of the DC inverter control device 400 is, for example, 50 Hz to 200 Hz. In this case, since the motor unit 3 has the three-phase four-pole DC specification stator 3a, the rotational speed of the rotary shaft 16 of the compressor is a synchronous speed of 25 Hz to 100 Hz.
[0034]
A suction pipe 17 is connected to the suction port 15 of the fixed scroll 5. The suction pipe 17 passes through the sealed container 1 and is connected to the suction port 15 in the vertical direction. The upper chamber 1a in which the discharge port 10 is open communicates with the electric motor chamber 1b through passages 18a and 18b. The electric motor chamber 1 b communicates with a discharge pipe 20 that penetrates the sealed container 1. The upper and lower portions of the motor chamber 1b are communicated with each other via gaps 25a and 25b between the DC-specific motor stator 3a and the side wall of the sealed container 1, and a gap 25c between the motor stator 3a and the motor rotor 3b. ing.
[0035]
A balance weight 9a and a sub balance weight 9b are provided on the rotating shaft 16 and the rotor 3b in order to cancel the centrifugal force generated by the turning motion of the turning scroll 6. An O-ring 21 is provided between the suction pipe 17 and the fixed scroll 5 to seal the high pressure part and the low pressure part.
[0036]
A space 23 (hereinafter referred to as a back pressure chamber) surrounded by the scroll compressor unit 2 and the frame 11 is formed on the back surface of the end plate 6 a of the orbiting scroll 6. A helium gas having an intermediate pressure between suction pressure and discharge pressure is introduced into the back pressure chamber 23 through a pore 6 e formed in the end plate 6 a of the orbiting scroll 6, and the axial direction in which the orbiting scroll 6 is pressed against the fixed scroll 5. Is given.
[0037]
The lubricating oil 24 stored in the bottom of the sealed container 1 is sucked up into the oil suction pipe 16d by the differential pressure between the high pressure in the sealed container 1 and the intermediate pressure in the back pressure chamber 23, and then in the rotary shaft 16 The central hole 50 is raised and supplied to the slewing bearing 32 and from the auxiliary bearing 26 to the main bearing 27 (cylindrical roller bearing portion) through the lateral hole 51.
[0038]
The lubricating oil 24 supplied to the bearings 32, 26, 27 is injected into the compression chamber 8 through the back pressure chamber 23, mixed with the compressed gas, and discharged to the upper chamber 1a together with the discharge gas. The forming prevention oil plate 28 is disposed on the surface of the lubricating oil 24 stored at the bottom of the hermetic container 1 so as to prevent the forming phenomenon of the lubricating oil 24 that occurs when the scroll compressor 100 is started. It has become.
[0039]
As the scroll wraps 5b and 6b of the fixed scroll 5 and the orbiting scroll 6, those having a scroll tooth profile shape in which the set volume ratio Vr of the scroll wrap portion shown in the following equation (1) is around 2.1 are used.
[0040]
Vr = (2λ1−4π + α) / (2λs + 2π + α) (1)
Here, λ1: wrap winding end angle (involute extension angle), λS: wrap winding start angle (involute extension angle), π: circumference ratio, α: turning radius εth and ratio of the basic circle radius a of the scroll wrap (= Εth / a).
[0041]
The reason why the set volume ratio Vr of the scroll wrap portion is set to around 2.1 is that the discharge pressure Pd / suction pressure Ps = 1.7 to 5.0 is advantageous in terms of efficiency as the operating pressure ratio range. This is because, in particular, when the rotational speed of the scroll compressor 100 is controlled, the operation frequency in a low operation pressure ratio region (for example, discharge pressure Pd / suction pressure Ps = 1.7 to 3.5) increases.
[0042]
At the bottom of the hermetic container 1, lubricating oil is stored, and an oil take-out pipe 30 for taking out the lubricating oil 24 to the outside is provided. An inflow portion 30 a of the oil take-out pipe 30 is opened into the lubricating oil 24 at the bottom of the sealed container 1, and the oil take-out pipe 30 is communicated with the inside of the lubricating oil 24.
[0043]
In addition, a single oil injection pipe 31 for injecting the lubricating oil 24 into the compression chamber 8 in the middle of the compression of the scroll compressor unit 2 is provided at the upper part of the sealed container 1.
[0044]
The oil take-out pipe 30 and the oil injection pipe 31 are connected via an oil strainer 38, an oil cooler 33, and a throttle means 271. The oil take-out pipe 30, the oil strainer 38, the oil cooler 33, the throttle means 271 and the oil injection pipe 31 are connected by an oil pipe 36, thereby forming an oil injection circuit 913.
[0045]
The oil injection pipe 31 is connected to an oil injection port 22 provided in the end plate part 5 a of the fixed scroll 5 through the sealed container 1 in order to cool the working helium gas of the scroll compressor part 2. As shown in FIGS. 5 and 6, the opening of the oil injection port 22 is located between the wraps 5 b of the fixed scroll 5 (the wrap tooth groove portion) and faces the tooth tip surface of the wrap 6 b of the orbiting scroll 6. Is provided. With such a configuration, the lubricating oil 24 supplied to the oil injection pipe 31 from the bottom of the sealed container 1 is injected into the lap tooth groove portion of the fixed scroll 5 through the port 22.
[0046]
Here, in order to enhance the cooling effect of the helium gas in the compression process of the scroll compressor 100, it is configured to be cooled from the helium gas suction process. That is, the oil injection port 22 is connected to the compression chamber 8 and is provided at a position intermittently communicating with the suction chamber 5f on the outer peripheral portion of the scroll wrap by the orbiting motion of the orbiting scroll 6. In other words, the oil injection mechanism communicates with the compression chamber 8 and also intermittently communicates with the suction chamber 5f.
[0047]
The hole diameter do of the oil injection port 22 is set larger than the wrap thickness t and smaller than the groove width dimension Dt. Thereby, even when the amount of oil injection due to the differential pressure is large, helium gas easily escapes from the oil injection port 22 into the oil injection pipe 31 during the compression process, and pressure pulsation in the oil injection pipe 31 is reduced. Can be made.
[0048]
With the above configuration, when DC power is supplied from the commercial power source 500 to the DC motor unit 3 through the DC inverter controller 400, the motor shaft 16b directly connected to the DC motor rotor 3b rotates and the eccentric shaft 16a is eccentric. When rotating, the orbiting scroll 6 performs an orbiting motion via the orbiting bearing 32.
[0049]
By this turning motion, the compression chamber 8 gradually moves to the center and the volume is reduced. Accordingly, helium gas enters the suction chamber 5f from the suction pipe 17 through the suction ports 15a and 15b as working gas, and the lubricating oil 24 that lubricates the bearings 32, 26, and 27 is the outer periphery of the orbiting scroll end plate of the orbiting scroll 6. The lubricating oil 24 flows into the suction chamber 5f from a minute gap or the like of the portion and enters the working gas, and the lubricating oil 24 supplied to the oil injection pipe 31 is injected into the compression chamber 8 through the port 22. The working gas containing the lubricating oil 24 that has passed through the bearings 32, 26, and 27 and the lubricating oil 24 injected from the port 22 is compressed in the compression chamber 8 and discharged from the discharge port 10 to the upper chamber 1a, and the passage 18a. , 18b and flows into the motor room 1b. In FIG. 3, the solid line arrows indicate the flow of the lubricating oil 24, and the thick double line arrows indicate the flow of the helium gas.
[0050]
The working gas and the lubricating oil 24 that have flowed into the motor chamber 1b in a wide space from the narrow passages 18a and 18b have a rapid decrease in the flow velocity and the flow direction is changed, so that the amount of the lubricating oil 24 contained in the working gas is large. The part is separated, and part of the working gas passes through the passage 25a and the space 1c below the electric motor, rises again through the passage 25b, and flows out into the discharge pipe 20. The lubricating oil 24 flows down through the gaps 25 a and 25 b on the outer periphery of the motor rotor and is retained at the bottom of the sealed container 1.
[0051]
The lubricating oil 24 stored at the bottom of the sealed container 1 is applied with the discharge pressure in the sealed container 1 and is sucked into the oil suction pipe 16d by the differential pressure between the high pressure discharge pressure and the intermediate pressure in the back pressure chamber 23. After being raised, the central hole 50 in the rotary shaft 16 is raised and supplied to the slewing bearing 32, and also supplied from the auxiliary bearing 26 to the main bearing 27 (cylindrical roller bearing portion) through the lateral hole 51.
[0052]
In addition, the lubricating oil 24 stored at the bottom of the hermetic container 1 has an inflow portion 30a of the oil take-out pipe 30 due to the differential pressure between the discharge pressure applied to the lubricating oil and the intermediate pressure in the compression chamber 8 in which the port 22 is open. Then, the oil flows into the oil take-out pipe 30. The lubricating oil 24 that has flowed into the oil take-out pipe 30 passes through the oil pipe 36 and reaches the oil strainer 38, where dust and the like are removed, and then passes through the oil pipe 36 and reaches the oil cooler 33. To cool appropriately. The cooled lubricating oil 24 is adjusted to an appropriate oil injection amount by the throttle means 271, supplied to the oil injection pipe 31, and injected into the compression chamber 8 through the port 22. The oil injected into the compression chamber 8 in this manner serves to cool the working gas in the compression chamber 8 and lubricate sliding portions such as the scroll wrap tip.
[0053]
The lubricating oil 24 injected into the compression chamber 8 serves to cool the working gas in the compression chamber 8 and lubricate sliding portions such as the scroll wrap tip. Then, as described above, the lubricating oil 24 is compressed together with the working gas, and is then discharged from the discharge port 10 into the upper chamber 1a, and is separated from the working gas in the motor chamber 1b in the same manner as described above. Accumulated at the bottom.
[0054]
In this embodiment, the high-pressure chamber system in which the inside of the sealed container 1 is at the discharge pressure is used. However, in the present invention, scroll compression for helium in the low-pressure chamber system in which the inside of the sealed container 1 is at a pressure lower than the discharge pressure (for example, suction pressure) It is also targeted for the machine. In that case, the lubricating oil 24 separated from the oil separator 700 installed outside the compressor is cooled by an external oil cooler (not shown), and the cooled lubricating oil is supplied to the oil injection pipe. It is sufficient to connect from 31 to the oil injection mechanism part of the scroll compressor part and to the bearing oil supply mechanism.
[0055]
  The fact that the coefficient of performance of the scroll compressor 910 for helium of this embodiment is excellent will be described with reference to FIGS. 9 and 10. FIG. 9 shows results of changes in the compressor rotational speed between the scroll compressor for helium equipped with the DC inverter and the DC motor section of this embodiment and the scroll compressor for helium equipped with the AC inverter and AC motor section of Prior Art 1. FIG. 10 shows a comparison of the change in the coefficient K. FIG. 10 includes the DC inverter and the DC motor part of the prior art 2.air conditioningIt is a figure which shows the change of the coefficient of performance K with respect to the change of the compressor rotation speed in the scroll compressor for a vehicle. The coefficient of performance K in FIG. 9 is the amount of helium gas discharged gas (Nm³/ H) divided by inverter input (kW) (Nm³The coefficient of performance K in FIG. 10 is a value (kcal / h · W) obtained by dividing the refrigeration capacity (kcal) by the inverter input (W).
[0056]
According to the present embodiment, as is clear from FIG. 9, the coefficient of performance Kh can be improved by several tens of% with respect to the coefficient of performance K1 of the prior art 1, especially several tens of% at a low speed range (for example, 1400 to 1600 rpm). There is a remarkable improvement effect. Such an improvement effect in the low speed region is because, in the case of helium applications, the cooling effect on the whole compressor by the lubricating oil 24 of the oil injection mechanism for cooling the working gas functions more significantly as the speed decreases. is there. That is, since the lubricating oil 24 is supplied to the compression chamber 8 with a differential pressure, the oil injection amount becomes a substantially constant amount regardless of the compressor rotational speed. The amount of cooling required to cool the heat generated by the scroll compressor 100 (such as the heat generated by the electric motor and the heat generated by the sliding portion) decreases as the speed decreases, so the cooling effect by the lubricating oil 24 increases as the speed decreases. There is an effect peculiar to the scroll compressor for helium which is further increased.
[0057]
The above-mentioned improvement in the coefficient of performance Kn greatly improves the motor efficiency by the application of the DC inverter control device 400 and the DC motor unit 3, and accordingly, the heat generation amount of the motor is greatly suppressed, and the entire compressor is cooled. This is because the amount of oil injection to be performed can be set much smaller than that of the prior art 1. The improvement effect of the coefficient of performance in the high speed range includes the improvement effect due to the reduction of the oil stirring loss power due to the decrease in the oil injection amount in addition to the improvement effect of the motor efficiency. Further, the effect of improving the coefficient of performance in the low speed region further includes the improvement effect of the volume efficiency accompanying the sealing effect in the compression chamber 8 by the lubricating oil 24 and the improvement effect by reducing the internal compression power.
[0058]
On the other hand, in the scroll compressor provided with the DC inverter control device and the DC motor unit for air conditioning in which CFC 22 or the like is used as the refrigerant, the coefficient of performance changes as shown in FIG. That is, in the air conditioning application, the coefficient of performance decreases in the low speed range even if the DC inverter is used. This is because the oil injection mechanism is not provided, and therefore the sealing effect in the compression chamber 8 and the function of improving the volume efficiency are not sufficient in the low speed region.
[0059]
As described above, the scroll compressor for helium according to the present embodiment including the DC inverter device 400 and the DC motor unit 3 has a unique effect that is not found in air conditioning applications.
[0060]
The helium scroll compressor 910 of the present embodiment will be described with reference to FIG. 11 with a high helium gas capacity Qg and a small oil rise amount Xo. FIG. 11 shows changes in the He gas capacity (the same value as the helium gas discharge gas amount (Nm3 / h)) Qg and the oil rising amount Xo flowing out of the compressor with respect to the change in the discharge gas temperature Td.
[0061]
In the prior art 1, since the motor efficiency is low, the amount of heat generated by the motor becomes large, and the discharge gas temperature Td has to be increased, and becomes 70 ° C. or higher. However, in this embodiment, the motor efficiency is increased. As a result, the amount of heat generated by the electric motor is reduced, and the discharge gas temperature Td can be lowered to, for example, Td = 50 to 65 ° C. Therefore, as is apparent from FIG. 11, according to this embodiment, it is possible to operate in a state where the helium gas capacity Qg is high and the oil rising amount Xo is low. As a result, the lubricating oil 24 can be reliably held in the sealed container 1, and the oil shortage phenomenon at the bearings 26, 27, and 32 can be avoided.
[0062]
In particular, in this embodiment, there is provided a throttle means 271 that adjusts the amount of cooling injection oil that flows into the oil injection mechanism so that the discharge gas temperature Td, which is the surface temperature of the discharge pipe 20, is about 65 ° C. or less. . That is, an oil amount adjusting valve 271 is provided in the oil pipe 36 that guides the lubricating oil 24 from the lower part of the sealed container 1 to the oil injection pipe 31. Thus, in this embodiment, the helium gas capability Qg is high and the operation can be performed with the oil rising amount Xo being low.
[0063]
The scroll compressor for helium according to the present embodiment is characterized in that the injection oil parameter Uo shown in the following equation (2) is set to be 0.125 to 0.135.
[0064]
Uo = (Vr × Qoil) / Vth (2)
Where Vth: stroke volume of the compressor (cm^Three/ lev), Vr: set volume ratio, Qoil: injection oil amount (liter / minute).
[0065]
Practically, the value of the injection oil parameter Uo is suitably in the range of 0.125 to 0.135. This point will be described with reference to FIGS. FIG. 12 is a diagram showing a change in the oil injection amount with respect to the compressor rotational speed of the helium scroll compressor in the helium scroll compressor of the present embodiment and the prior art 1, and FIG. It is a figure which shows the change of the coefficient of performance with respect to the oil injection parameter of the scroll compressor for helium in a scroll compressor.
[0066]
As is apparent from FIG. 12, according to the present embodiment, it is possible to reduce the oil injection amount of the prior art 1 over the entire range from the low speed range to the high speed range of the compressor.
[0067]
Further, according to the present embodiment, since the oil injection parameter Uo can be set to a low range, specifically, Uo can be set to a range of 0.125 to 0.135, as is apparent from FIG. It is possible to operate in a good state of Kh ′.
[0068]
With reference to FIG. 14, it will be described that the discharge gas temperature Td of the scroll compressor 910 for helium of this embodiment is low and the inverter input Win is small. FIG. 14 shows changes in the discharge gas temperature Td and the inverter input Win with respect to changes in the oil injection amount Qoil.
[0069]
As shown in FIG. 14, the discharge gas temperature Td and the inverter input Win decrease with a decrease in the oil injection amount. In the prior art 1, since the motor efficiency is low, the motor heat generation amount is large and the oil injection amount is inevitably increased. However, in this embodiment, the motor efficiency is improved by about 10% to several percent. Therefore, the heat generation amount of the electric motor is reduced, and the oil injection amount can be greatly reduced.
[0070]
This is the reason why the coefficient of performance of the present embodiment is drastically improved over the prior art 1. That is, by the scroll compressor for helium of this embodiment provided with a DC inverter control device and a DC motor unit, (1) improvement of the efficiency of the motor unit, (2) optimization of the oil injection amount Qoil, that is, the discharge gas temperature Td (3) Reduction of compression power, thereby reducing inverter input, (4) Reduction of stirring loss power by reducing oil injection amount, and inverter input thereby Can be reduced. These overall effects lead to an improvement in the coefficient of performance of more than a dozen percent, and an effect specific to helium applications can be realized.
[0071]
As described above, in this embodiment, the DC inverter control device and the scroll compressor for exclusive use of helium, which has a DC specification motor unit employing a permanent magnet and has an oil injection mechanism in the scroll compressor unit for cooling. By combining the above, it is possible to realize a high-performance helium scroll compression device of several tens of percent or more compared to the prior art 1, and further, a helium compression unit device can achieve a weight reduction and downsizing of 10% or more. It is obtained.
[0072]
The effects of the present embodiment are summarized as follows.
(1) In a wide operating frequency range, it is possible to provide a helium compressor having high energy saving performance by using a scroll compressor for helium. Compared to conventional devices, it is possible to achieve high performance that is several tens of percent particularly in a low operating frequency range.
(2) Since the amount of injection oil can be reduced by about 20%, the overall dimensions of the helium compressor unit can be reduced due to a reduction in the capacity of the oil cooler.
(3) Due to the difference in the discharge gas temperature, the amount of oil rising is reduced, oil retention at the bottom of the compressor is ensured, and the oil shortage phenomenon at the bearing portion can be avoided. For this reason, the reliability of a compressor can be improved. Due to the synergistic effect with the above item (2), the weight can be further reduced and the product cost can be kept low.
(4) Higher performance reduces the compressor load, extends the bearing life of the main bearing part, allows the discharge gas temperature to be set to 65 ° C or lower, reduces the coil temperature, and increases the motor protection function. The effect of improving the reliability of the machine is also derived. That is, the motor burnout can be prevented and a highly reliable helium compressor can be provided.
[0073]
【The invention's effect】
  As is clear from the above description, according to the present invention, high performance, miniaturization, and weight reduction can be achieved, and inexpensive and highly reliable.Helium scroll compressor andA scroll compressor for helium can be obtained.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a helium refrigeration apparatus including an oil-filled helium scroll compressor according to an embodiment of the present invention.
FIG. 2 is a perspective view of the helium scroll compressor.
FIG. 3 is a configuration diagram of a main part of the scroll compressor for helium in FIG. 1;
4 is a cross-sectional view taken along the line AA in FIG. 3;
FIG. 5 is a plan view of the fixed scroll of FIG. 3;
6 is a longitudinal sectional view of the fixed scroll of FIG.
7 is a plan view of the orbiting scroll of FIG. 3. FIG.
8 is a longitudinal sectional view of the orbiting scroll of FIG.
FIG. 9 is a diagram showing a coefficient of performance with respect to the number of rotations of the compressor in the helium scroll compressor of FIG. 1 and the helium scroll compressor of prior art 1;
10 is a diagram of prior art 2. FIG.air conditioningIt is a figure which shows the coefficient of performance with respect to the rotation speed of the compressor of the scroll compressor for a vehicle.
11 is a graph showing changes in helium gas capacity and oil rising amount with respect to changes in discharge gas temperature Td in the scroll compressor for helium in FIG. 1 and the scroll compressor for helium in Prior Art 1. FIG.
12 is a diagram showing a change in the amount of oil injection with respect to the rotational speed of the helium scroll compressor in the helium scroll compressor of FIG. 1 and the helium scroll compressor of prior art 1. FIG.
13 is a graph showing a change in coefficient of performance with respect to an oil injection parameter of the scroll compressor for helium in the scroll compressor for helium in FIG. 1 and the scroll compressor for helium in Prior Art 1. FIG.
14 is a graph showing changes in discharge gas temperature and inverter input with respect to the oil injection amount of the helium scroll compressor in the helium scroll compressor of FIG. 1 and the helium scroll compressor of Prior Art 1. FIG.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 1 ... Airtight container, 1a ... Discharge chamber, 1b ... Electric motor room, 3 ... DC motor part, 3a ... Electric motor stator, 3b ... Electric motor rotor, 5 ... Fixed scroll, 5a ... Fixed scroll end plate, 5b ... Wrap, 5f ... Inhalation Chamber, 6 ... orbiting scroll, 6a ... orbiting scroll end plate, 6b ... wrap, 6c ... boss, 8 ... compression chamber, 9a, 9b ... balance weight, 10 ... discharge port, 11 ... frame, 12 ... Oldham mechanism, 15, DESCRIPTION OF SYMBOLS ... Suction port, 16 ... Rotating shaft, 16a ... Eccentric shaft part, 16b ... Electric motor shaft part, 16d ... Oil suction pipe, 17 ... Suction pipe, 18a, 18b ... Passage, 20 ... Discharge pipe, 21 ... O-ring, 22 ... Port, 24 ... Lubricating oil, 25a, 25b, 25c ... Gap, 26 ... Auxiliary bearing, 27 ... Main bearing, 30 ... Oil take-out pipe, 30a ... Inflow part, 31 ... Oil injection pipe, 32 ... Swivel bearing, DESCRIPTION OF SYMBOLS 3 ... Oil cooler, 36 ... Oil piping, 38 ... Oil strainer, 100 ... Scroll compressor, 271 ... Throttling means, 390 ... Power supply line, 400 ... DC inverter control apparatus, 440 ... Cooling fan, 500 ... Commercial power supply 550 ... piping, 700 ... oil separator, 710 ... gas cooler, 720 ... piping, 730 ... suction piping, 740 ... oil return pipe, 752 ... suction piping, 800 ... refrigerator, 910 ... scroll compressor for helium, 912 ... Unit.

Claims (2)

Lubricating through a compressor section that compresses helium gas as working gas, an electric motor section that drives the compressor section, a sealed container that houses the compressor section and the motor section, and an oil injection pipe that penetrates the sealed container In a helium scroll compressor comprising an oil injection mechanism for injecting oil into the compressor section by differential pressure,
The compressor unit forms a compression chamber by meshing a fixed scroll that erects a spiral wrap on the end plate and a revolving scroll that erects the spiral lap on the end plate with the wraps inside each other. Move the chamber around the center to reduce the volume and compress the helium gas to discharge into the sealed container,
The oil injection mechanism is formed such that the lubricating oil stored at the bottom of the sealed container is led to the outside and cooled and supplied.
The motor unit is constituted by a DC motor of three-phase four-pole, is controlled by the rotational speed controllable DC inverter control device,
The compressor section is
The fixed scroll and the orbiting scroll, which are meshed with each other, have a scroll tooth profile in which the volume ratio Vr of the scroll wrap portion shown in the following formula (1) is around 2.1,
A scroll compressor for helium, characterized in that the injection oil parameter Uo shown in the following formula (2) is in the range of 0.125 to 0.135 .
Vr = (2λ1−4π + α) / (2λs + 2π + α) (1)
Here, λ1: end angle of wrap winding, λS: start angle of wrap winding, π: circumference ratio, α: ratio of turning radius εth and basic circle radius a of the scroll wrap.
Uo = (Vr × Qoil) / Vth (2)
Here, Vth: stroke volume of the compressor (cm ³ / rev), Vr: set volume ratio, Qoil: injection oil amount (liter / min). A scroll compressor having a compressor section that compresses helium gas as a working gas, and an electric motor section that drives the compressor section; an oil separator that separates lubricating oil in the helium gas discharged from the scroll compressor; A helium scroll in which a gas cooler that cools helium gas flowing from the oil separator, an oil cooler that cools lubricating oil, and a control device that drives and controls the scroll compressor are housed in the unit. In the compression device ,
The scroll compressor includes an oil injection mechanism that injects the lubricating oil cooled by the oil cooler into the compressor unit by a differential pressure,
The oil injection mechanism is formed such that the lubricating oil stored at the bottom of the sealed container is led to the outside and cooled and supplied.
The compressor unit forms a compression chamber by meshing a fixed scroll that erects a spiral wrap on the end plate and a revolving scroll that erects the spiral lap on the end plate with the wraps inside each other. Move the chamber around the center to reduce the volume and compress the helium gas to discharge into the sealed container,
The motor part is composed of a three-phase four-pole DC specification motor part,
The control device comprises a DC specification inverter control device capable of controlling the rotation speed of the scroll compressor ,
The compressor section is
The fixed scroll and the orbiting scroll, which are meshed with each other, have a scroll tooth profile in which the volume ratio Vr of the scroll wrap portion shown in the following formula (1) is around 2.1,
Parameter injection oil shown in the following equation (2) - helium scroll compressor in which data Uo is characterized by being configured to be in the range of from 0.125 to 0.135.
Vr = (2λ1−4π + α) / (2λs + 2π + α) (1)
Here, λ1: end angle of wrap winding, λS: start angle of wrap winding, π: circumference ratio, α: ratio of turning radius εth and basic circle radius a of the scroll wrap.
Uo = (Vr × Qoil) / Vth (2)
Here, Vth: stroke volume of the compressor (cm ³ / rev), Vr: set volume ratio, Qoil: injection oil amount (liter / min).

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