JP2009270509A - Displacement compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize an oil return means in a displacement compressor. <P>SOLUTION: This displacement compressor includes the oil return means returning oil poured from an oil storage portion 125 storing oil into a compression chamber 100 compressing working fluid, separately from the working fluid after compression to the oil storage portion. The oil return means has an oil return chamber 95 temporarily storing separated oil led from an oil separation means, and a float valve element 70ab composed of a hollow float 70a and a float valve portion 70b respectively floating on accumulated oil in the oil return chamber, accumulated on the bottom of the oil return chamber. The float valve element 70ab opens/closes a float hole 70c connected to an oil return passage 80 allowing the oil return chamber to communicate with the oil storage portion. The hollow float 70a is formed with a float pressure equalizing passage 70a2 allowing a hollow portion to communicate with a working fluid area in the oil return chamber. Thereby, it is possible to eliminate differential pressure between the hollow portion and the working fluid area in the oil return chamber and there is no more requirement to consider pressure-resistant design. Accordingly, a small hollow float can be configured. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a positive displacement compressor, and in particular, oil return means for separating oil injected into a compression chamber for compressing a working fluid from an oil storage section storing oil and returning it to the oil storage section after being separated from the compressed working fluid. The present invention relates to a positive displacement compressor provided.

  Conventionally, in order to improve the sealing performance of the compression chamber and the lubricity between the compression chamber forming elements, the oil stored in the oil storage section is injected into the compression chamber, and the oil is separated from the compressed working fluid and returned to the oil. It is known to return to the oil storage part again by means.

  As a specific configuration of the oil return means, for example, as described in Patent Document 1, a float valve body having a specific gravity smaller than that of oil is floated on the separated oil stored in the oil return chamber, and a float corresponding to the amount of stored oil is obtained. It is known to open and close the communication path between the oil return chamber and the oil storage part by the vertical movement of the valve body.

JP 2006-70871 A

  Patent Document 1 explains that the float valve body is made of a substance having a specific gravity smaller than that of oil. However, the specific gravity is smaller than that of oil and is chemically stable in a high-temperature and high-pressure environment of a compressed working fluid. It is not easy to find a new substance.

  In this regard, as installed in a commercial oil separator (Danphos, OUB1, etc.) used in the refrigerant cycle, it is sealed to return the separated oil separated from the working fluid in the pressurized space to the low pressure space. It is known to use a float having a hollow structure, and it is conceivable to employ a hollow float for the float valve body described in Patent Document 1.

  However, when using a hollow float in a high-pressure region, it is essential to have a pressure-resistant design that prevents the float from collapsing due to the pressure difference between the hollow part and the outside, so the hollow float is formed of a relatively thick metal material. There is a need to. On the other hand, the hollow float needs to secure buoyancy for floating in oil, and in order to ensure the necessary buoyancy using a metal material with a large specific gravity and large self-weight, the size of the hollow float must be increased. I don't get it. As a result of the increase in size of the oil return means having the hollow float in this way, it may be difficult to incorporate the oil return means into the compressor casing. Therefore, downsizing of the oil return means is desired.

  Therefore, an object of the present invention is to reduce the size of oil return means in a positive displacement compressor. Another object is to increase the reliability while reducing the size of the oil return means.

  The positive displacement compressor of the present invention includes a compression chamber constituting portion that constitutes a compression chamber that compresses a working fluid, an oil storage portion that stores oil to be supplied to the compression chamber, and an operation that is compressed and discharged by the compression chamber constituting portion. An oil separation means for separating oil from a fluid, an oil return means for returning the separated oil separated by the oil separation means to an oil storage section, and a compression chamber component, an oil storage section, an oil separation means, and an oil return means. And a return oil chamber in which the oil return means temporarily stores the separated oil introduced from the oil separation means via the oil communication path, and the oil return chamber stored at the bottom of the oil return chamber. A hollow float that floats on stagnant oil, and a valve portion that opens and closes a communicating portion between the oil return chamber and the oil storage portion by the hollow float are configured.

  In order to solve the above problem, the hollow float is characterized in that a float pressure equalizing passage is formed to communicate the hollow portion and the working fluid region of the oil return chamber.

  That is, by forming the float pressure equalization path in the hollow float, the differential pressure between the hollow portion and the working fluid region of the oil return chamber can be ignored, so that it is not necessary to consider pressure resistance design. Therefore, for example, a hollow float can be formed by using a resinous material having a specific gravity close to that of oil as a raw material and reducing the thickness, so that the weight of the hollow float is reduced. As a result, the size of the hollow float can be reduced, and the oil return means can be reduced in size.

  When the float pressure equalizing passage is formed in the hollow float as in the positive displacement compressor of the present invention, there is a risk that oil may enter the hollow portion from the float equalizing passage. If a large amount of oil is stored in the hollow portion, the buoyancy of the float cannot be secured, and the reliability may be impaired.

  Therefore, the present invention suppresses the amount of oil that enters the hollow portion through the float pressure equalizing path, or discharges the oil to the outside even if the oil once enters the hollow portion, and enters the hollow portion. By providing the float intrusion oil suppressing means for suppressing the amount of oil, the oil return means can be reduced in size and reliability can be improved. Specifically, the float infiltration oil suppression means is realized by the following mode.

  For example, the oil separation means swirls the working fluid and separates the oil by centrifugal separation, and the separation in which the working fluid separated from the oil disposed in the central portion of the centrifugal separation chamber flows inside And a working fluid communication path that communicates between the working fluid area of the centrifuge chamber and the working fluid area of the oil return chamber, the working fluid on the centrifuge chamber side of the working fluid communication path. A zone-side opening is formed in the working fluid zone inside the separation ring.

  According to this, since the oil content in the working fluid is lower on the inner side of the separation ring than on the outer side, the oil in the oil return chamber working fluid region that is mainly filled with the working fluid guided through the working fluid communication path. The content rate decreases. As a result, since the amount of oil contained in the working fluid in the oil return chamber working fluid region where the float pressure equalizing passage opens is small, even if the working fluid flows in from the float pressure equalizing passage, the accompanying oil intrusion is extremely small. .

  Although the working fluid region side opening of the working fluid communication path on the centrifuge chamber side is formed in the working fluid region inside the separation ring as an example, in short, the working fluid with a low oil content in the centrifuge chamber is returned. By forming the working fluid communication path so as to flow into the working fluid region of the oil chamber, the oil content in the working fluid region of the oil return chamber is reduced and the amount of oil entering the hollow portion can be suppressed.

  Also, for example, by forming the opening on the working fluid region side of the oil return chamber of the float pressure equalizing passage in a place where oil does not easily enter, such as the top of the hollow float, the amount of oil entering the hollow portion can be suppressed. .

  Further, for example, by forming the opening on the hollow portion side of the float pressure equalizing passage at the bottom of the hollow portion, even if oil enters the hollow portion, it can be discharged to the outside of the hollow float. That is, when the compressor is actually operated, the discharge pressure fluctuates to some extent. Therefore, the working fluid is always float-balanced so that the pressure in the hollow portion and the pressure in the working fluid region in the oil return chamber are uniform. Entering and exiting the pressure path. Therefore, even if the oil enters the hollow part from the float pressure equalization path and accumulates in the bottom part, the working fluid is discharged from the hollow part to the outside of the float by forming the opening on the hollow part side at the bottom part of the hollow part. When doing so, the oil accumulated in the bottom can be discharged simultaneously.

  In addition, for example, a structure that prevents oil from entering the hollow portion, such as a protruding portion that protrudes upward, is formed around the opening on the working fluid region side of the oil return chamber of the float pressure equalizing passage of the hollow float. Can be adopted.

  Also, for example, in order to prevent the oil from entering the hollow portion when the oil level of the oil staying in the oil return chamber rises abnormally for some reason, the oil return chamber of the float pressure equalization channel on the top surface of the oil return chamber The structure which provides the sealing body which has elasticity in the position which opposes the opening by the side of the said working fluid area, and covers a float pressure equalization path at the time of an oil level rise can be employ | adopted suitably.

  According to the present invention, the oil return means in the positive displacement compressor can be reduced in size. Further, it is possible to improve the reliability while reducing the size of the oil return means.

  Hereinafter, an embodiment of a positive displacement compressor to which the present invention is applied will be described. In the following description, the same functional parts are denoted by the same reference numerals, and redundant description is omitted. Further, the present invention is not limited to the following embodiments, and the embodiments can be used in appropriate combinations as needed.

(First embodiment)
A first embodiment in which the present invention is applied to a scroll compressor in which a casing has a suction pressure will be described with reference to FIGS. 1 to 15 and FIG. 21. First, the overall configuration, function, and operation of the scroll compressor according to the present embodiment will be described with reference to FIG. FIG. 1 is a longitudinal sectional view of a scroll compressor according to the first embodiment of the present invention.

  The scroll compressor 1 includes a compression chamber constituent unit 10 that compresses a working fluid, a crankshaft 6 that is a compression chamber driving unit that drives the compression chamber constituent unit 10, and a motor 7 that is a rotational drive source of the crankshaft 6. Also, bearings 23, 24, and 25 that support the crankshaft 6, an internal gear type oil supply pump 30 that supplies oil to the bearings 23, 24, and 25, and a discharge oil separation that separates the discharge oil and returns it to the oil storage chamber. The oil return part 40 and the casing 8 which accommodated the compression chamber structure part 10, the compression chamber drive part, the bearings 23, 24, 25, the oil supply pump 30, and the discharge oil separation oil return part 40 are provided as main components.

  The scroll compressor 1 is a vertical scroll compressor in which a crankshaft 6 is arranged vertically, and a discharge oil separating oil returning unit 40, a compression chamber constituting unit 10, a motor 7, and an oil supply pump 30 are arranged in this order from the top. .

  The casing 8 is provided with an oil storage portion 125 that stores the oil in the internal space while setting the internal space to the suction pressure. The casing 8 includes an upper casing 8b, a cylinder casing 8a, and a bottom casing 8c.

  The compression chamber constituting unit 10 includes a fixed scroll 2 having a fixed end plate 2b and a fixed spiral body 2a standing upright thereto, a revolving scroll 3 having a revolving end plate 3b and a swirling spiral body 3a standing up thereto, and both scrolls 2 3, a compression chamber 100 that compresses the working fluid by reducing the volume, and a back pressure chamber 110 that is provided on the back surface of the orbiting scroll 3 and serves as an intermediate pressure space that is higher than the suction pressure and lower than the discharge pressure. It has.

  The fixed scroll 2 is mainly composed of a fixed spiral body 2a, a fixed end plate 2b, and an attachment portion 2c around which the attachment surface 2c has a surface substantially the same as the tooth tip of the fixed spiral body 2a. The fixed end plate 2b is provided with a bypass valve 22 composed of a compression spring, a valve plate and a spring retainer for avoiding over-compression and liquid compression, and a discharge port 2d near the center.

  A discharge oil separating oil return cylinder 55 is screwed so as to cover the upper part of the cylinder, and a discharge chamber 120 is formed, and a discharge pipe 52 that further protrudes to the upper part of the discharge chamber 120 is mounted. The discharge cover 51 is fixed with screws, and an oil separation chamber 90 and an oil return chamber 95 are formed. Furthermore, a suction port 2e for sucking the working fluid is provided on the side surface of the mounting portion 2c.

  The orbiting scroll 3 includes an orbiting spiral body 3a and an orbiting end plate 3b, and an orbiting bearing 23 is provided at the center of the back surface of the orbiting end plate 3b. A main bearing 24 is provided at the center of the frame 4, and the crankshaft 6 is inserted into the main bearing 24. Then, the eccentric pin portion 6 a at the top of the crankshaft 6 is inserted into the orbiting bearing 23, and the orbiting scroll 3 is attached to the frame 4. Here, the Oldham ring 5 is engaged with the frame 4 in order to prevent the orbiting scroll 3 from rotating.

  Next, the fixed scroll 2 is placed from above the orbiting scroll 3 so that the orbiting spiral body 3 a and the fixed spiral body 2 a are engaged with each other, and the attachment portion 2 c of the fixed scroll 2 is screwed to the frame 4. As a result, a plurality of compression chambers 100, which are generally closed spaces between the spiral bodies 3a, 2a, and a suction chamber 105 communicating with the suction port 2e are formed, and a back pressure chamber 110 is formed on the back of the orbiting scroll 3. Is done. Further, a slewing bearing chamber 115 is formed on the upper surface of the pin portion 6a. The rotor 7a is fixed to the crankshaft 6 that projects downward from the frame 4.

  The subassembly rotor 7a formed as described above is inserted into the stator 7b fixedly arranged on the cylinder casing 8a, and the subassembly frame 4 is fixed to the cylinder casing 8a. Thereby, the motor 7 is formed.

  A sub-bearing support plate 50 is fixed to the lower portion of the cylinder casing 8a, and the lower end portion of the crankshaft 6 projects below the sub-bearing support plate 50 by incorporating the sub-assembly. A sub bearing 25 comprising a ball bush 25a and a ball holder 25b for holding the ball bush 25a is mounted on the protruding lower end of the crankshaft 6, and the ball holder 25b is fixed to the sub bearing support plate 50. An oil supply pump 30 is formed integrally with the sub bearing 25 below the sub bearing 25. Further, the suction pipe 53 is fixed at a position facing the suction port 2e on the side surface of the cylinder casing 8a.

  Next, after connecting the electric wire from the motor 7 to the internal terminal of the hermetic terminal 54 welded to the upper casing 8b, the upper casing 8b is welded to the cylinder casing 8a. Further, the discharge pipe 52 is brazed to the upper casing 8b. A bottom casing 8c is welded to the bottom of the cylinder casing 8a and the casing 8 is formed by the upper casing 8b, the cylinder casing 8a, and the bottom casing 8c. Thereby, the lower part of casing 8 serves as oil storage part 125 which accumulates oil.

  Next, the detailed configuration and operation of the scroll compressor 1 will be described with reference to FIGS. 1 to 4, 12 to 15, and 21 mainly from the viewpoint of the flow of working fluid and the flow of oil. . 2A is a detailed enlarged view of a portion M in FIG. 1, FIG. 2B is an enlarged view of a main portion of FIG. 2A, FIG. 3 is a detailed enlarged view of a portion N of FIG. . 12 is a detailed enlarged view of a portion P in FIG. 1, FIG. 13 is a sectional view taken along line FF in FIG. 12, FIG. 14 is a detailed enlarged view of a portion Q in FIG. FIG. FIG. 21 is an enlarged longitudinal sectional view of the float valve body.

  First, the flow of the working fluid will be mainly described. The working fluid that enters the casing 8 from the suction pipe 53 and uses the suction pressure in the casing 8 enters the suction chamber 105 through the suction port 2e. Accordingly, the rotation of the crankshaft 6 using the motor 7 as a drive source causes the orbiting scroll 3 to orbit and form a compression chamber 100 between the spiral bodies 2a and 3a. As a result, the working fluid in the suction chamber 105 is confined in the compression chamber 100 and then transferred to the center side while the volume is reduced. Thus, the working fluid whose pressure has been increased to the discharge pressure is discharged from the discharge port 2d or the bypass valve 22 to the discharge chamber 120.

  Next, as shown in FIGS. 12 and 13, the working fluid flows from the discharge expansion chamber 90 a to the upper portion of the internal space of the discharge oil separation oil return cylinder 55 through the discharge communication hole 90 b, and the oil is discharged by the nozzle-like blowing path 90 c. The oil is discharged into the oil separation chamber 90 in a direction along the inner wall surface of the separation chamber 90. Then, the working fluid flows downward while swirling in the oil separation chamber 90 and is discharged out of the compressor from a discharge pipe provided inside a separation ring 90 d disposed in the center of the oil separation chamber 90. The oil separation chamber 90 adheres oil (described later) mixed in the working fluid mainly in a mist state to the inner wall surface of the oil separation chamber 90 by a centrifugal separation action, thereby reducing the oil content of the working fluid.

  Here, if the blowing path 90c has the same width, the processing becomes easy and the manufacturing cost is reduced. Further, the blowing path 90c may be inclined slightly downward rather than horizontally. Accordingly, in order to prevent the working fluid that has made a round along the inner wall surface of the oil separation chamber 90 from joining with the flow of the working fluid that newly flows into the oil separation chamber 90 from the blowing channel 90c, the flow generated by the merge is generated. This has the effect of reducing the disturbance of the oil and improving the oil separation efficiency.

  The blowing path 90c may be slightly inclined downward, and an inclined protrusion may be provided in a portion that covers the upper surface of the blowing path 90c with the discharge cover 51 so that the vertical width of the blowing path 90c is the same. . Thereby, since the flow of the working fluid does not expand in the vertical direction, there is an effect that the disturbance of the working fluid flow is reduced and the oil separation efficiency is further improved.

  Next, the oil flow will be mainly described. The oil accumulated in the oil storage part 125 is pumped from the lower part to the upper part by the oil supply pump 30 driven by the rotation of the crankshaft 6 through the oil supply vertical hole 6b which is an oil supply hole penetrating the crankshaft 6 in the axial direction. The The description around the oil pump will be described later. First, the path of the oil pumped by the oil pump will be described.

  First, the first oil supply passage is a sub-bearing oil supply passage that supplies oil to the sub-bearing 25 through the auxiliary bearing oil supply lateral hole 6g. The second oil supply passage is a main bearing oil supply passage having an extremely low flow resistance, which flows from the main bearing oil supply lateral hole 6c through the main bearing groove 6d to the main bearing 24 and then flows into the back pressure chamber 110 ( (See FIG. 3). The third oil supply passage is a swing bearing oil supply passage having an extremely small flow resistance, which flows from the swing bearing chamber 115 through the swing bearing groove 6e to the swing bearing 23 and then flows into the back pressure chamber 110. These second and third oil supply passages can be regarded as back pressure chamber inflow passages that flow into the back pressure chamber 110.

  The oil that has flowed into the back pressure chamber 110 from the back pressure chamber inflow path is agitated by the Oldham ring 5 that moves in the back pressure chamber 110 and the protrusions of the orbiting scroll 3, and promotes the gasification of the working fluid dissolved therein. The pressure rises rapidly. As a result, in the back pressure control valve 26, the back pressure, which is the pressure in the back pressure chamber 110, becomes higher than the suction pressure, so that the pulling scroll 3 is pulled away from the fixed scroll 2 by the compressed fluid in the compression chamber 100. An attractive force against the separating force can be quickly applied to the orbiting scroll 3. As a result, the orbiting scroll 3 is reliably pressed against the fixed scroll 2 not only during normal operation but also immediately after startup, and the compression operation is reliably and stably maintained.

  However, if the back pressure is too high, the urging force acting between the scrolls 2 and 3 increases, causing a reduction in compression performance due to sliding loss. For this reason, a back pressure chamber outflow passage 135 is provided to connect the back pressure chamber 110 and the casing internal space connected to the oil storage portion 125 for extracting oil and working fluid from the back pressure chamber 110 when the back pressure rises excessively. It has been. In the middle of the outflow path 135, there is provided a back pressure control valve 26 that is controlled to open when the difference between the back pressure and the suction pressure (pressure in the casing internal space) exceeds a predetermined value.

  The back pressure control valve 26 includes a compressed valve spring 26b, a valve plate 26c, and a valve cap 26d, and the predetermined value corresponds to the amount of compression of the valve spring 26b and is a substantially constant value. When this back pressure control is used as a compressor in an air-conditioning cycle, it can be used together with the above-described bypass valve 22 to achieve an optimal back pressure setting under a very wide range of operating conditions and to improve the compression performance. Play.

  The final fourth oil supply passage is a suction chamber oil supply passage having a throttling function that flows from the swivel bearing chamber 115 through the end plate horizontal hole 3c in the swivel end plate 3b into the suction chamber 105 through the suction chamber pore 3d with the restriction. 130 (see FIGS. 3 and 4). Here, in order to perform the hole processing from the side surface of the swivel end plate 3b, the side plate opening is sealed with a stopper plug. The oil that has flowed into the suction chamber 105 through the suction chamber oil supply passage 130 enters the compression chamber 100 together with the working fluid, improves the sealing performance of the compression chamber 100, realizes leakage suppression, and improves the compression performance. For this reason, the suction chamber oil supply passage 130 is a compression chamber oil supply means.

  Further, since this oil does not pass through the bearing, it is at a low temperature, does not heat the fluid in the suction chamber 105, avoids a decrease in volumetric efficiency, and has an effect of improving the compression performance. As will be described later, since the pressure is reduced in the suction chamber pores 3d, the oil flows into the suction chamber 105 in the form of a mist due to the vaporization of the working fluid in the oil. Therefore, this oil is easy to ride on the leakage flow in the compression chamber 100, and the sealing performance is further improved. Furthermore, since the heat of vaporization is taken away from the oil by the vaporization of the working fluid, the temperature of the oil decreases. For this reason, since the fluid in the suction chamber 105 can be cooled, the compression performance can be improved, and the specific volume of the working fluid can be reduced, so that the volume efficiency is improved.

  As described above, the oil that has flowed into the suction chamber 105 is discharged into the discharge chamber 120 together with the working fluid from the discharge port 2d and the bypass valve 22 after achieving the effect of improving the sealing performance of the compression chamber 100. As described in the explanation of the flow of the working fluid (see FIGS. 12 and 13), the oil after this goes to the oil separation chamber 90 through the discharge expansion chamber 90a, the discharge communication hole 90b, and the blowout passage 90c together with the working fluid. Further, the oil is discharged from the working fluid in the oil separation chamber 90 and adhered to the circumferential inner wall of the oil separation chamber 90.

  The attached oil moves downward along the wall surface due to the viscous force and gravity received from the working fluid, and reaches the conical bottom surface 90e which is the bottom surface of the oil separation chamber 90. Since this bottom surface has a conical shape, the oil collects at the center of the bottom surface, is guided to the oil communication passage 75 by the inclined bottom groove 90f, and has an oil return chamber 95 having a bottom surface at a position lower than the oil separation chamber 90. Flows into the lower part.

  In addition, a working fluid communication passage 85 is provided that connects the upper part of the oil separation chamber 90 and the upper part of the oil return chamber 95 (oil return chamber working fluid area 95a), which is surely a working fluid area (see FIG. 15). Since this working fluid communication passage 85 causes a pressure equalizing action to make the working fluid pressures in the oil separation chamber 90 and the oil return chamber 95 the same, the oil surface heights in the oil separation chamber 90 and the oil return chamber 95 are the same. It becomes.

  Here, in the oil return chamber 95, a float valve body 70ab (which will be described in detail later with reference to FIG. 21) in which a float 70a floating in oil and a float valve portion 70b provided therebelow are integrated, and a float valve portion 70b. Is provided with a float valve 70 configured to adjust the opening degree (see FIG. 12).

The float hole 70c is connected to an oil return path 80 formed by connecting a fixed oil return path 80a provided in the fixed scroll 2 and a frame oil return groove 80b provided in the frame 4 (see FIG. 14). Since the outlet of the oil return passage 80 is an internal space of the casing 8 that is the suction pressure, the float valve 70 is a valve that partitions the discharge pressure and the suction pressure, which are the pressure of the oil return chamber 95. As a result, the float downward force applied to the float 70a is the sum of the force accompanying the differential pressure between the suction pressure and the discharge pressure (referred to as differential pressure) and the gravity applied to the float valve body 70ab. (However, the differential pressure may be almost negligible depending on the valve configuration.)
The oil that has flowed into the oil return chamber 95 provided with the float valve 70 temporarily accumulates in the oil return chamber 95 (the oil accumulated in the oil return chamber is hereinafter referred to as oil return chamber accumulated oil 95b). As the volume in which the float valve body 70ab is immersed in the return chamber retaining oil 95b increases, the buoyancy that is the upward force of the float increases. Therefore, when the oil return chamber retention oil 95b reaches a certain oil level, the upward force of the float is increased. Exceeds the float downward force, and the float valve body 70ab starts to float. As a result, a gap is created between the float valve portion 70b and the float hole 70c, and the float valve 70 is opened.

  Due to the opening of the float valve 70, the oil return chamber staying oil 95b flows out to the oil return passage 80, passes through holes and gaps provided at various locations on the stator 7b of the motor 7 between the oil ring 56 and the inner wall of the casing, Finally, it returns to the oil storage part 125 at the lower part of the casing. After the float valve opens, when the staying oil level decreases and the buoyancy applied to the float 70a decreases, the float valve 70 closes again and the return oil staying oil 95b starts to accumulate again.

  By repeating the mechanism as described above, the oil return chamber staying oil 95b in the oil return chamber 95 maintains a substantially constant oil level in the oil return chamber. In this way, since the return oil staying oil 95b always maintains a constant oil level, the working fluid at the discharge pressure is prevented from blowing through the working fluid communication passage 85 and the oil return passage 80 into the low pressure side casing internal space. it can. As a result, there is also an effect of avoiding a significant decrease in the compressor performance due to the short circuit in the compressor of the flow of the working fluid. By the way, the oil level in the oil separation chamber 90 becomes the same as the oil level in the oil return chamber 95 by the pressure equalizing action of the working fluid communication passage 85 as described above (see FIG. 15).

  Next, the oil supply pump will be described. As described above, the oil supply pump 30 boosts the oil in the oil storage portion 125 as the suction pressure and the working fluid dissolved therein to the back pressure higher than the suction pressure, and then the auxiliary bearing 25, the main bearing 24, It plays a role of supplying the slewing bearing 23, the suction chamber 105, and the back pressure chamber 110.

  As described above, the oil pump 30 also plays a role of boosting pressure along with the transfer of oil. Therefore, the pump work is increased, and the improvement of the performance of the oil pump 30 is particularly important for improving the compression performance of the scroll compressor 1. In this embodiment, a measure is adopted in which the pump elements are pressed against each other to reduce the seal gap, and leakage is suppressed to improve performance. Thereby, in this embodiment, the performance improvement of the oil supply pump 30 is implement | achieved, suppressing the increase in the processing cost accompanying the improvement of the shape and dimensional accuracy of a pump component.

  The oil supply pump 30 that realizes the above operation will be specifically described with reference to FIGS. 2A, 2 </ b> B, and FIGS. 5 to 11. 5 is a cross-sectional view taken along line LL in FIG. 2A, FIG. 6 is a plan view of a base plate 30d of the oil pump 30 in FIG. 2A, FIG. 7 is a perspective view of the inner rotor 30a of the oil pump 30 in FIG. 9 is a perspective view of the outer rotor 30b of the oil pump 30 of FIG. 2, FIG. 9 is an explanatory diagram of the pressure area of the bottom surfaces of the rotors 30a and 30b in FIG. 2A, and FIG. FIGS. 11A and 11B are explanatory diagrams of the discharge pressure region of the oil pump 30 in FIG. 2A.

  First, the configuration of the oil supply pump 30 will be described. The oil supply pump 30 is an internal gear pump having an inner rotor 30a that is an external gear and an outer rotor 30b that is an internal gear that has one more tooth than the external gear as meshing elements.

  Unlike a normal inner rotor, the inner rotor 30a is integrally formed on the upper side surface of the inner rotor tooth profile portion 30a1 forming an external gear and the inner rotor tooth profile portion 30a1, and the upper side of the outer rotor 30b. It is an inner rotor with an end plate composed of an end plate portion 30a2 protruding to the surface side (see FIG. 7). The end plate portion 30a2 constitutes a cover that covers the upper side surface of the inner rotor tooth profile 30a1 (the boundary surface between the inner rotor tooth profile 30a1 and the end plate portion 30a2) and the upper side surface of the outer rotor 30b.

  The inner rotor 30a is attached to the oil supply pump shaft portion 6f protruding from the lower end of the crankshaft 6. Here, a D-shaped mounting hole 30j is provided in the inner rotor 30a so that the inner rotor 30a rotates integrally with the crankshaft 6, and a cut surface is provided in the oil pump shaft portion 6f (see FIGS. 5 and 7). ). The oil pump shaft portion 6f is formed to be thinner than the main shaft portion of the crankshaft 6 with a stepped portion. The upper surface of the inner rotor 30a comes into contact with this stepped portion.

  The other outer rotor 30b is mounted in the pump cylinder 30c integrated with the ball holder 25b so as to mesh with the inner rotor 30a, and is eccentric with respect to the center of the inner rotor 30a (center of the crankshaft 6). It is rotatably arranged at the position. The ball holder 25b and the pump cylinder 30c constitute a housing 28. And base plate 30d is arrange | positioned so that the lower side surface of both rotor 30a, 30b may be covered.

  The base plate 30d is disposed in close contact with the lower surface of the pump cylinder 30c and is fixed by bolts. The base plate 30d is formed with a pump suction groove 30e and a pump discharge groove 30f on a surface facing both the rotors 30a and 30b (see FIG. 6). A pump suction hole 30g which is a through hole is opened in the pump suction groove 30e.

  Since the pump suction groove 30e and the pump discharge groove 30f do not use the compression action due to the volume reduction of the pump chamber 140, the pump suction groove 30e and the pump discharge groove 30f have a shape having an elongated groove portion over the entire side of the expansion side and the reduction side of the pump chamber 140. To do. Therefore, it is necessary to align the pump chamber 140 with the pump suction groove 30e and the pump discharge groove 30f, and positioning holes 30h and 30i are provided in the base plate 30d and the pump cylinder 30c (ball holder 25b), respectively (FIGS. 6 and 6). 5), and the alignment reference for assembly. Here, each of the two positioning holes 30h and 30i is configured not to face each other by 180 degrees and to avoid an assembly error that reverses the suction side and the discharge side.

  Next, the operation of the oil supply pump 30 will be described. The rotation of the crankshaft 6 accompanying the operation of the scroll compressor 1 (the direction of the arrow in FIG. 5) rotates the inner rotor 30a, and the outer rotor 30b rotates accordingly. Accordingly, the plurality of pump chambers 140 shown in FIG. 5 separated by the engagement of the rotors 30a and 30b expands the volume on the pump suction groove 30e side, so that the oil in the oil storage section 125 is removed from the pump suction hole 30g. Inhale.

  The pump chamber 140 transfers oil to the oil supply vertical hole 6b in order to reduce the volume on the pump discharge groove 30f side. However, since the oil sent to the oil supply vertical hole 6b enters the back pressure chamber 110 through the main bearing 24 and the slewing bearing 23 and does not involve the restriction, the oil supply pump 30 uses the suction pressure oil as the back pressure. Responsible for boosting pressure. That is, the oil supply pump 30 does not simply transfer the oil to the oil supply vertical hole 6b, but performs pressure-feeding with pressure increase.

  For this reason, if there is a gap between the side surfaces of both the rotors 30a and 30b, leakage due to a pressure difference occurs from the discharge side serving as the back pressure to the suction side of the suction pressure, and the capability of the oil supply pump 30 is reduced. As a conventional general countermeasure against this, either install a large-capacity oil pump with large energy consumption, or install a high-performance oil pump that suppresses leakage with a high-precision pump element that increases processing costs. Was considered.

  In the present embodiment, the former greatly reduces the energy efficiency of the scroll compressor. Therefore, in the present embodiment, the latter measure is further improved to suppress leakage and improve the performance of the oil pump. It was realized.

  A means for improving the oil pump performance while suppressing the processing cost increase will be described below. The basic guideline for the leakage suppression measure is to reduce the cross-sectional area of the leak channel, that is, to reduce the clearance of the elements constituting the leak channel. However, if the clearance is reduced too much, local interference between pump components may occur, leading to an increase in sliding loss, which may reduce the performance of the oil pump. For this reason, it is necessary to reduce the clearance without causing local interference between the pump components.

  In this embodiment, the end plate 30a2 is attached to the side surface of the inner rotor, which is a component of the oil pump 30, and the end plate is energized by the thrust force of the crankshaft 6 by biasing the inner rotor 30a. The part 30a2 is operated while being urged toward the outer rotor 30b. Here, as shown in FIG. 5, the outer edge of the end plate portion 30a2 is provided so as to cover the entire pump chamber 140 formed between the two rotors.

  Further, the thickness of the tooth profile of the outer rotor 30b (see FIG. 8) is made slightly thicker (see FIG. 2B) than the thickness of the tooth profile of the inner rotor 30a (see FIG. 7). In FIG. 2B, the clearance is illustrated with an emphasis for explanation, and the actual clearance level on the inner rotor side is about 10 to 100 μm. As a result, the upper rotor side surface of the outer rotor slides in close contact with the end plate portion 30a2, and the lower side surface of the outer rotor slides in close contact with the base plate 30d, so that the side clearance of the outer rotor 30b can be substantially zero. It becomes.

  As a result, it is possible to greatly suppress leakage in the side clearance of the outer rotor 30b. Therefore, since the performance of the oil supply pump 30 is greatly improved without increasing the tooth profile accuracy of both the rotors 30a and 30b, the processing cost can be reduced and the energy efficiency of the scroll compressor 1 can be improved at the same time.

  Since the inner rotor 30a is sandwiched between the crankshaft 6 and the outer rotor 30b, and the outer rotor 30b is sandwiched between the end plate portion 30a2 of the inner rotor 30a and the base plate 30d, the axial positions of the rotors 30a and 30b are determined. . For this reason, it is possible to stabilize the performance of the oil supply pump and improve the oil supply reliability even under operating conditions in which the pressure fluctuations around the rotors 30a and 30b are large.

  Next, the biasing force of the inner rotor 30a to the outer rotor 30b will be described. Generally speaking, this urging force is obtained by dividing the surface of the crankshaft 6 and the rotor portions provided at the lower end thereof into one piece, and dividing the surface thereof into surface elements, and obtaining the normal vector (of the small surface element). The value obtained by multiplying the inner product of the upward unit vector in the direction of the crankshaft axis by the pressure of the portion is integrated over the entire surface.

As is clear from FIGS. 1 and 2, in the present embodiment, back pressure is applied to all the upper parts of the crankshaft 6 with the main bearing 24 as a boundary, and the suction pressure is applied to the lower parts except for the bottom surfaces of both rotors. It depends. If the pressure reference is the suction pressure, in order for the inner rotor 30a to urge toward the outer rotor 30b side, the upper part from the suction pressure is defined as the following (Expression 1): is required.
ΔP (p) ≡p- (suction pressure) ………………………… (Formula 1)
ΔP (back pressure) × (Crankshaft main shaft cross-sectional area)>
(Force due to pressure higher than the suction pressure on the bottom of both rotors engaged) (Equation 2)
In this case, the urging force is expressed by the following (Equation 3).
Energizing force = ΔP (back pressure) x (Crankshaft main shaft cross-sectional area)-
(Force due to the pressure higher than the suction pressure of the meshing rotor bottoms) (Equation 3)
Here, the force due to the pressure equal to or higher than the suction pressure at the bottom surfaces of the meshing rotors is expressed by the following (formula 4).
Force due to the pressure higher than the suction pressure on the bottom of both meshing rotors =
ΣΔP (p) × (pressure p region area) (Formula 4)
In order to obtain the urging force, as described above, the calculation of (Equation 4) is required. To calculate this precisely, an estimate of the pressure distribution on the bottom surfaces of both rotors and an integral calculation using the estimated value are required. It is necessary and extremely troublesome.

  Therefore, a simple calculation method of (Equation 4) described above is proposed below. First, a region where pressure is determined at the bottom surfaces of both meshing rotors is obtained. The case of this embodiment is shown in FIG. FIG. 9 is a view of the bottom surfaces of both rotors as viewed from below. The region where the oil discharged from the oil pump 30 is present (cross hatched portion) is the back pressure region, and the suction oil of the oil pump 30 is present.

  The region (one-way hatched portion) is determined as the suction pressure region. Here, although not explicitly shown in FIG. 9, the outer peripheral portion of the outer rotor 30 b has a suction pressure. This is because the oil pump back space 145 has a gap between the ball bush 25a and the ball holder 25b (see FIG. 2A). The oil pump back space 145 is a space located on the upper side surface side of the oil pump 30 and is a space facing the end plate portion 30a2 in the present embodiment.

  Next, the pressure in the region where the pressure is not fixed (the region without hatching in FIG. 9) is estimated as follows. Considering a half line drawn from the center of the oil supply vertical hole 6b, which is the oil outlet from the oil supply pump 30, the intersection with the above-described pressure determination region is examined. Then, the midpoint of the line segment that crosses the pressure indeterminable region and becomes the pressure deterministic region at which both ends are different (R11 in the case of the half straight line R1, R22 in the case of the half straight line R2) is obtained, and the suction pressure is obtained. And the back pressure boundary. On the other hand, a line segment that crosses the pressure undetermined region and whose both ends are the same pressure determined region (R12 in the case of the half line R1, R21 in the case of the half line R2) is the same pressure region as the pressure at both ends. It is considered. By the procedure as described above, the pressure undetermined region is divided into a back pressure region and a suction pressure region.

  FIG. 10 shows the division situation in the present embodiment. The rough hatched portion in FIG. 10 is a region obtained by dividing the pressure undetermined region by the above-described procedure, and the cross hatched portion is the back pressure region and the one-way hatched portion is the suction pressure region. As described above, as a result of being divided into the back pressure region and the suction region, (Equation 4) is simplified as follows and can be easily calculated.

Force due to the pressure higher than the suction pressure of the meshing rotor bottoms = ΣΔP (p) × (pressure p area area)
= ΔP (back pressure) x (back pressure area) + ΔP (suction pressure) x (suction pressure area)
= ΔP (back pressure) x (back pressure area)
(∵ΔP (suction pressure) = 0) (Formula 4 ')
By substituting (Equation 4 ′) into (Equation 2) and (Equation 3), a target energization determination formula and an energizing force calculation formula are derived.
(Crankshaft main shaft cross-sectional area)>
(Back pressure area of the bottom of both rotors) (Formula 2 ')
Energizing force = ΔP (back pressure) x {(Crankshaft main shaft cross-sectional area)-
(Back pressure area at the bottom of both rotors)} (Formula 3 ′)
The energization determination of this embodiment is performed by (Equation 2 ′). The back pressure regions on the bottom surfaces of both rotors are the regions shown in FIG. 11 (this is a region where the fine cross-hatched portion and the rough cross-hatched portion in FIG. 8 are combined). It can be seen from the calculation that the area of this region is smaller than the cross-sectional area of the crankshaft main shaft. Therefore, the inner rotor 30a biases the outer rotor 30b and reduces the side clearance between the rotors 30a and 30b.

  Further, the urging force can be obtained from (Equation 3 ′), but since the back pressure control valve 26 is used in this embodiment, ΔP (back pressure) in this equation is the value of the back pressure control valve 26. The predetermined value itself corresponds to the compression amount of the valve spring 26b. Therefore, by combining with the back pressure control method using the back pressure control valve 26, the urging force can always be secured at a constant value under any operating condition. For this reason, the inner rotor 30a can be stably urged to the outer rotor 30b under any operating condition, and the high performance of the oil pump 30 can be realized stably, so that the oil pump 30 is mounted. In addition to the high performance of the scroll compressor 1, high oil supply reliability can be realized.

  Next, the float valve body 70ab in the oil return chamber 95 which is a characteristic part of the positive displacement compressor of the present embodiment will be described with reference to FIG. The float valve body 70ab adopts a hollow float structure having a float hollow portion 70a1 as the float 70a. However, the float hollow portion 70a1 and the oil return chamber working fluid region of the oil return chamber 95 which is an outer region thereof are provided. A float pressure equalizing passage 70a2 that communicates is provided. The float valve portion 70b includes a resin valve core 70b2 integrated with the resin float 70a and a metal needle cone 70b1 fixed to the surface thereof.

  As a result of the provision of the float pressure equalizing path 70a2, there is no pressure difference between the inside and outside of the float, and the withstand voltage design becomes unnecessary. Therefore, it is not necessary to require material strength for the float material, and it is made of a resin material typified by PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), or PTFE (polytetrafluoroethylene) other than metal materials. Can do.

  As a result, since the specific gravity is a material close to oil and pressure resistance is not required, a small float can be realized with a thin hollow body structure, and the float 70a can be made extremely compact. Moreover, since PBT and PPS have thermoplasticity, they can be molded and have the effect of reducing manufacturing costs. Furthermore, in the case of PBT, glass fiber reinforcement can be performed. Therefore, when glass fiber reinforcement is performed, it becomes possible to produce a float having a very thin thickness. As a result, a float with a lighter weight can be realized, and the float can be further miniaturized.

  As a result, the oil return means having the float valve as a constituent element can be reduced in size and incorporated in the positive displacement compressor, so that the compressor-related elements can be integrated and an easy-to-use positive displacement compressor can be realized. Further, even when the oil return means is provided as an auxiliary device outside the positive displacement compressor, the auxiliary device is compact, and there is an effect that the degree of freedom of the layout of the entire apparatus is increased. Of course, the weight can be reduced.

  Here, the float outer side opening (the opening on the working fluid region side of the oil return chamber 95) of the float pressure equalizing passage 70a2 is provided on the upper surface (top) of the float 70a. This is because, as shown in FIG. 21, a float outer opening is provided at a position farthest from the oil surface of the normal oil return chamber staying oil 95b.

  Therefore, even if the oil level rises for some reason, there is a low possibility that oil will enter the float hollow portion 70a1 from the float pressure equalizing path 70a2, and there is an effect that the float operation can be reliably realized over a long period of time. As described above, providing the float pressure equalizing path 70a2 on the float upper surface can reduce the oil that enters the float hollow portion 70a1 through the float pressure equalizing path 70a2, and thus serves as a basic float infiltration oil suppressing means.

  Further, as described above, since the working fluid communication passage 85 is provided (see FIG. 15), the pressure in the oil return chamber 95 and the oil separation chamber 90 is always equal, and the oil in the oil return chamber in the oil return chamber 95 is constant. There is no difference between the oil level of 95b and the oil separation chamber 90. Therefore, as shown in FIG. 21, the oil return chamber staying oil 95b is stably held at a substantially constant height, and therefore, there is a risk that the oil enters from the float pressure equalizing passage 70a2 that opens to the working fluid region of the oil return chamber. The nature becomes low. Therefore, there is an effect that the float operation can be surely realized over a long period of time.

  As described above, the provision of the working fluid communication passage 85 can reduce the oil that enters the float hollow portion 70a1 through the float pressure equalizing passage 70a2, and thus serves as a float infiltration oil suppression means. In the present embodiment, the communication path between the oil separation chamber 90 and the return oil chamber 95 is divided into two, the oil communication path 75 and the working fluid communication path 85, but the oil level height of the return oil chamber staying oil 95b. It is good also as one communicating path installed in.

  The needle cone 70b1 is made of stainless steel, but can be replaced with a material having the same degree of hardness. The needle cone 70b1 is outsert-molded into the valve core 70b2. However, the present invention is not limited to this, and both may be bonded.

(Second Embodiment)
Next, the scroll compressor of 2nd Embodiment of this invention is demonstrated using FIG. FIG. 16 is an enlarged cross-sectional view of main parts of the oil separation chamber 90 and the oil return chamber 95 in the scroll compressor according to the second embodiment of the present invention (an enlarged view of the S portion in FIG. 12 which is an enlarged view of the P portion in FIG. 1). . The second embodiment is different from the first embodiment in the following points, and the other points are the same as those in the first embodiment.

  In the second embodiment, an opening on the oil separation chamber side of the working fluid communication passage 85 that connects the upper portion of the oil separation chamber 90 serving as a working fluid region and the oil return chamber working fluid region 95a is provided inside the separation ring 90d. Is. The working fluid communication path 85 is realized by temporarily connecting the separation ring side communication path 85a and the oil return chamber side communication path 85b to a recess provided on the upper surface of the discharge cover 51 and covering the recess with a communication path cap 85c. .

  Since the oil content in the working fluid is lower inside the separation ring 90d than in the outside, the oil content in the return oil chamber working fluid region 95a that is mainly filled with the working fluid from the working fluid communication passage 85 is lowered. As a result, since the amount of oil contained in the working fluid in the oil return chamber working fluid region 95a where the float pressure equalizing passage 70a2 opens is small, even if the working fluid flows in from the float equalizing passage 70a2, the intrusion of the oil does not occur. Very little. As a result, since the oil that enters the float hollow portion 70a1 can be reduced, the float operation can be sustained over a long period of time. That is, it is understood that this is one of the float infiltration oil suppression means.

(Third embodiment)
Next, the scroll compressor of 3rd Embodiment of this invention is demonstrated using FIG.17 and FIG.18. FIG. 17 is an enlarged cross-sectional view of the main parts of the oil separation chamber 90 and the oil return chamber 95 in the scroll compressor according to the third embodiment of the present invention (S portion enlarged view of FIG. 12 which is a P portion enlarged view of FIG. 1), 18 is an enlarged view of the vicinity of the oil return chamber on the upper surface of the discharge oil separation oil return cylinder 55. The third embodiment is different from the first embodiment in the points described below, and the other points are the same as those in the first embodiment, and thus redundant description is omitted.

  In this third embodiment, a working fluid communication path is formed in which a working fluid communication passage 85 that connects the upper part of the oil separation chamber 90 serving as a working fluid region and the oil return chamber working fluid region 95a is formed on the upper surface of the discharge oil separation oil return cylinder 55. It is formed by the groove 85d.

  This eliminates the need for oblique hole machining and reduces the machining cost. In addition, since extremely shallow groove processing is possible, the working fluid communication path 85 having a large flow path resistance can be realized.

  Accordingly, since the flow rate of the working fluid is extremely large, the fluctuation in the pressure of the oil separation chamber 90 that fluctuates irregularly is not transmitted to the oil return chamber 95, so that the oil in the oil return chamber accumulated oil 95 b in the oil return chamber 95 is obtained. The surface is stabilized. Therefore, generation | occurrence | production of the oil mist accompanying the wave of the return oil chamber retention oil 95b is suppressed, and the raise of the oil content rate of the return oil chamber working fluid area 95a can be suppressed.

  As a result, the amount of oil contained in the working fluid in the oil return chamber working fluid region 95a where the float pressure equalizing passage 70a2 opens remains small, and even if the working fluid flows in from the float equalizing passage 70a2, the oil intrusion accompanying it Is extremely small. As a result, since the oil that enters the float hollow portion 70a1 can be reduced, the float operation can be sustained over a long period of time. That is, it is understood that this is one of the float infiltration oil suppression means.

(Fourth embodiment)
Next, the scroll compressor of 4th Embodiment of this invention is demonstrated using FIG. FIG. 19 is an enlarged view of the vicinity of the oil return chamber on the upper surface of the discharge oil separation oil return cylinder 55 in the scroll compressor according to the fourth embodiment of the present invention. The fourth embodiment is different from the third embodiment in the points described below, and the other points are the same as those in the third embodiment, and therefore, redundant description is omitted.

  In the fourth embodiment, the working fluid communication passage 85 that connects the upper portion of the oil separation chamber 90 serving as a working fluid region and the oil return chamber working fluid region 95a is a communication groove that is processed on the upper surface of the discharge oil separation oil return cylinder 55. The opening on the oil separation chamber side is a blower outlet vicinity working fluid communication passage 85e provided in the vicinity of the rear of the blowing passage 90c. In other words, the opening on the working fluid region side of the oil separation chamber is formed at the end portion in the swirling direction starting from the discharge port on which the working fluid on the side wall surface of the oil separation chamber is swirled and discharged.

  In the vicinity of the oil separation chamber side opening of the working fluid communication passage 85e in the vicinity of the air outlet, there is only the working fluid that has substantially made a round along the inner wall of the oil separation chamber 90, so that the oil separation is completed to some extent and the oil content is low This is where the working fluid is located. Therefore, the oil content rate of the oil return chamber working fluid region 95a which is mainly filled with the working fluid from the working fluid communication passage 85e near the outlet is lowered.

  As a result, since the amount of oil contained in the working fluid in the oil return chamber working fluid region 95a where the float pressure equalizing passage 70a2 opens is small, even if the working fluid flows in from the float equalizing passage 70a2, the intrusion of the oil does not occur. Slightly. As a result, since the oil that enters the float hollow portion 70a1 can be reduced, the float operation can be sustained over a long period of time. That is, it is understood that this is one of the float infiltration oil suppression means.

(Fifth embodiment)
Next, the scroll compressor of 5th Embodiment of this invention is demonstrated using FIG. FIG. 20 is an enlarged view of the vicinity of the oil return chamber on the upper surface of the discharge oil separation oil return cylinder 55 in the scroll compressor according to the fifth embodiment of the present invention. The fifth embodiment is different from the fourth embodiment in the points described below, and the other points are the same as those in the fourth embodiment, and therefore, redundant description is omitted.

  In the fifth embodiment, the working fluid communication passage 85 that connects the upper portion of the oil separation chamber 90 serving as the working fluid region and the oil return chamber working fluid region 95a is formed as a communication groove that is processed on the upper surface of the discharge oil separation oil return cylinder 55. The oil return chamber tangential direction working fluid communication passage 85f has a connecting direction with the oil return chamber as a direction along the cylindrical oil return chamber wall. In other words, the opening on the working fluid region side of the oil return chamber of the working fluid communication passage 85 is formed so that the working fluid flowing in from the oil separation chamber flows along the side wall surface of the oil return chamber.

  When the working fluid flows into the oil return chamber 95, the flow becomes a flow along the inner wall of the oil return chamber 95. Therefore, the oil in the working fluid is centrifuged and adheres to the oil return chamber wall. As a result, the oil content of the oil return chamber working fluid region 95a where the float pressure equalizing passage 70a2 opens is further reduced, so even if the working fluid flows in from the float pressure equalizing passage 70a2, the accompanying oil intrusion is extremely small. Slightly. As a result, since the oil that enters the float hollow portion 70a1 can be reduced, the float operation can be sustained over a long period of time. That is, it is understood that this is one of the float infiltration oil suppression means.

(Sixth embodiment)
Next, the scroll compressor of 6th Embodiment of this invention is demonstrated using FIG. FIG. 22 is an enlarged vertical sectional view of a float valve body in the scroll compressor according to the sixth embodiment of the present invention. The sixth embodiment is different from the first to fifth embodiments in the following points, and the other points are the same as those in the first to fifth embodiments. .

  In the sixth embodiment, the float pressure equalizing passage 70a2 provided in the float valve body 70ab in the oil return chamber 95 is extended by the float pressure equalizing pipe 70a9 to the float hollow portion 70a1 which is the float inner space. The lower end of the pressure pipe 70a9 is set near the bottom of the float hollow portion 70a1.

  That is, the float pressure equalizing pipe 70a9 provides the float inner opening (opening on the hollow portion side of the float pressure equalizing path) of the float pressure equalizing path 70a2 at the bottom of the float hollow part 70a1. In other words, the float pressure equalizing passage 70a2 is formed to extend from the opening on the working fluid region side of the oil return chamber formed at the top of the hollow float to the opening on the hollow portion side formed at the bottom of the hollow portion. It consists of a float pressure equalizing pipe 70a9.

  When the compressor is actually operated, it is difficult to suppress the fluctuation (swing) of about 0.001 MPa even for a short time of about 1 minute even if the normal level control is applied so that the discharge pressure is constant. is there. When the operating state including the start and stop changes, a pressure fluctuation of several MPa easily occurs. That is, assuming that the specific gravity of the oil is 1, the discharge pressure fluctuation of 10 cm to several thousand cm is always generated in the oil head.

  As a result, the pressure of the float hollow portion 70a1 that is the internal space of the float valve body 70ab is always equalized with the pressure of the oil return chamber working fluid region 95a that is the external space of the float valve body 70ab that is linked to the discharge pressure. The working fluid enters and exits the float pressure equalizing path 70a2. That is, the float valve body 70ab performs a breathing operation in the float pressure equalizing path 70a2.

  In the present embodiment, suppose that oil enters the float hollow portion 70a1 from the float pressure equalizing passage 70a2 and accumulates beyond the lower end of the float pressure equalizing pipe 70a9. As described above, since the float valve body 70ab performs a breathing operation, when discharging the working fluid, an operation of simultaneously discharging the oil accumulated at the bottom of the float hollow portion 70a1 occurs. The pressure difference required for this discharge operation is the oil head of the length of the float pressure equalizing pipe 70a9, but considering the size of the compressor, it is about several centimeters to 10 centimeters, and the above pressure fluctuation value is sufficient. I understand.

  As a result, even if the oil enters the float hollow portion 70a1 from the float pressure equalizing path 70a2, the oil can be discharged to the lower end of the float pressure equalizing pipe 70a9 as shown in FIG. There is an effect that it can be realized.

  From the above, the fact that the float inner opening of the float pressure equalizing passage 70a2 is provided near the bottom of the float hollow portion 70a1, which is the float inner space, makes use of the breathing motion in the float pressure equalizing passage 70a2 due to fluctuations in the discharge pressure. Since the infiltrated oil into the hollow portion 70a1 can be discharged, no new power is required, and the float infiltrated oil suppressing means is effective at low cost.

  Furthermore, as a specific configuration for providing the float inner opening of the float pressure equalizing passage 70a2 near the bottom of the float hollow portion 70a1, the float pressure equalizing pipe extends to the float hollow portion 70a1 and extends to the vicinity of the bottom of the float hollow portion 70a1. Since it can be realized by providing only 70a9, the configuration is extremely simple, and it becomes an effective float intrusion oil suppressing means at a lower cost. In addition, when the bottom surface of the float hollow portion 70a1 is a mortar-shaped bottom surface 70a10 having a conical concave shape, the amount of oil that can be discharged increases, and the amount of oil remaining becomes very small. As a result, since the weight of the float 70a after oil discharge can be reduced, there is an effect that the float valve can be further miniaturized.

(Seventh embodiment)
Next, the scroll compressor of 7th Embodiment of this invention is demonstrated using FIG. FIG. 23 is an enlarged longitudinal sectional view of a float valve body in a scroll compressor according to a seventh embodiment of the present invention. The seventh embodiment is different from the sixth embodiment in the following points, and the other points are the same as those in the sixth embodiment, and thus redundant description is omitted.

  In the seventh embodiment, the float pressure equalizing passage 70a2 provided in the float valve body 70ab in the oil return chamber 95 is extended to below the float hollow portion 70a1 that is the float inner space by the float pressure equalizing pipe 70a9. The float pressure equalizing tube 70a14 that bends freely is connected to the lower end thereof, and the lower end of the float pressure equalizing tube 70a14 is set near the bottom of the float hollow portion 70a1.

  That is, the float pressure equalizing pipe 70a9 and the float pressure equalizing tube 70a14 provide the float inner opening of the float pressure equalizing path 70a2 at the bottom of the float hollow part 70a1. In other words, the float pressure equalizing passage 70a2 extends from the opening on the working fluid region side of the oil return chamber formed at the top of the hollow float to the opening on the hollow portion side formed at the bottom of the hollow portion, and at least The opening on the hollow portion side is formed of a deformable tube.

  In consideration of workability, the float pressure equalizing pipe 70a9 is integrated with the float upper body 70a12 and the float lower body 70a13 (including the float valve 70b), and both are bonded or crimped together. Thus, the float valve body 70ab is manufactured.

  By adopting the float pressure equalizing tube 70a14, the float inner opening of the float pressure equalizing path 70a2 can be easily brought closest to the bottom of the float hollow part 70a1 without improving the dimensional accuracy of the parts. Become. As a result, the amount of remaining oil becomes smaller, and the weight of the float 70a after the oil is discharged can be reduced, so that the float valve can be further reduced in size. Further, since the float valve body 70ab is divided into two parts, it is easy to manufacture a mold, and there is an effect that the processing cost can be reduced.

(Eighth embodiment)
Next, the scroll compressor of 8th Embodiment of this invention is demonstrated using FIG. FIG. 24 is an enlarged vertical sectional view of a float valve body in the scroll compressor according to the eighth embodiment of the present invention. The eighth embodiment is different from the seventh embodiment in the points described below, and the other points are the same as those in the seventh embodiment, and therefore, redundant description is omitted.

  In the eighth embodiment, the float pressure equalizing pipe is separated from the float upper body 70a12 and integrated with the float valve part 70b separated from the float lower body 70a13, and a bottom hole is formed on the side surface near the mortar-shaped bottom surface of the float pressure equalizing path 70a2. A float central axis 70a15 provided with 70a16 is employed. The float center shaft 70a15 is made of a metal such as stainless steel, and the float valve portion 70b is made of only stainless steel.

  In other words, the float pressure equalizing passage 70a2 is formed to extend from the float valve portion 70b to the opening on the working fluid region side of the oil return chamber formed at the top of the hollow float, and at the bottom of the hollow portion, the hollow portion A side opening is formed.

  Since the mandrel passes through the float valve body 70ab, it is easy to increase the overall rigidity. Therefore, the thickness of the float upper body 70a12 and the float lower body 70a13 can be further reduced, the weight of the float 70a can be further reduced, and the float valve can be further reduced in size.

(Ninth embodiment)
Next, the scroll compressor of 9th Embodiment of this invention is demonstrated using FIG. FIG. 25 is an enlarged cross-sectional view of the float pressure equalizing path outside opening in the scroll compressor according to the first to eighth embodiments of the present invention (enlarged view of the U portion in FIGS. 21 to 24). The ninth embodiment is different from the first to eighth embodiments in the following points, and the other points are the same as those in the first to eighth embodiments. .

  In the ninth embodiment, the vicinity of the outer opening of the float pressure equalizing path 70a2 is projected from the upper surface of the float 70a. Since the oil adhering to the float surface can be prevented from reaching the outer opening of the float pressure equalizing passage 70a2 due to the flow of the working fluid in the oil return chamber 95, the oil entering the float hollow portion 70a1 can be reduced, and the float There is an effect that the operation can be continued for a long time. That is, it becomes one of the float infiltration oil suppression means.

(10th Embodiment)
Next, a scroll compressor according to a tenth embodiment of the present invention will be described with reference to FIG. FIG. 26 is an enlarged cross-sectional view of the float pressure equalizing path outside opening in the scroll compressor according to the first to ninth embodiments of the present invention (an enlarged view of the U portion in FIGS. 21 to 24). The tenth embodiment is different from the first to ninth embodiments in the following points, and the other points are the same as those in the first to ninth embodiments. .

  In the tenth embodiment, an oil-repellent film 70a5 is provided around the outer opening of the float pressure equalizing path 70a2. According to this, when the oil adhering to the float surface approaches the outside opening of the float pressure equalizing passage 70a2 due to the flow of the working fluid in the oil return chamber 95, it becomes spherical oil by the oil-repellent film, and the contact angle is large. Therefore, it becomes easy to separate from the float surface.

  For this reason, since it can suppress the oil which reaches the outer side opening part of the float pressure equalizing path 70a2 along the float surface, the oil which permeates into the float hollow part 70a1 can be reduced, and the effect that the float operation can be continued for a long period of time. There is. That is, it becomes one of the float infiltration oil suppression means. An example of such a film having oleaginous properties is a silicone (silica ketone) film.

(Eleventh embodiment)
Next, a scroll compressor according to an eleventh embodiment of the present invention will be described with reference to FIG. FIG. 27 is an enlarged cross-sectional view of the float pressure equalizing path outside opening in the scroll compressor according to the first to tenth embodiments of the present invention (an enlarged view of the U portion in FIGS. 21 to 24). The eleventh embodiment is different from the first to tenth embodiments in the following points, and the other points are the same as those in the first to tenth embodiments. .

  In the eleventh embodiment, a porous membrane 70a6 having a large number of holes smaller than the oil mist in the oil return chamber working fluid region 95a and larger than the molecules of the working fluid around the outer opening of the float pressure equalizing passage 70a2. It is something that stretches.

  Thereby, since pressure equalization is achieved through the working fluid and oil is not passed, oil that enters the float hollow portion 70a1 can be eliminated, and the float operation can be maintained almost permanently. That is, it becomes one of the float infiltration oil suppression means. An example of a film having such characteristics is silicone (silica ketone) rubber. This porous film 70a6 adheres to the float surface so as to cover the outer opening of the float pressure equalizing path 70a2. However, when it cannot adhere, you may fix with the fixing body 70a7 using the screw 70a8.

(Twelfth embodiment)
Next, the scroll compressor of 12th Embodiment of this invention is demonstrated using FIG. FIG. 28 is an enlarged cross-sectional view (floor V enlarged view of FIG. 12) of the periphery of the float pressure equalizing passage outside opening of the oil return chamber in the scroll compressor of the twelfth embodiment of the present invention. The twelfth embodiment is different from the first to eleventh embodiments in the following points, and the other points are the same as those in the first to eleventh embodiments. .

  In the twelfth embodiment, a sealing body 60 made of a rubber-like elastic body is provided at a location facing the outer opening of the float pressure equalizing passage 70a2 of the discharge cover 51 that constitutes the upper surface of the oil return chamber 95. is there.

  As a result, when the oil level of the oil return chamber staying oil 95b rises abnormally for some reason, the outer opening of the float pressure equalizing passage 70a2 is sealed as described above when the float 70a rises until it contacts the discharge cover 51. It is occluded by the body 60. That is, the float pressure equalizing passage closing means is configured.

  At the stage where the outer opening of the float pressure equalizing passage 70a2 is closed by the sealing body 60, the float valve body 70ab floats on the return oil chamber staying oil 95b. The pressure does not rise to the height of the outer opening of the pressure equalizing passage 70a2, and the oil does not enter the float hollow portion 70a1. That is, when the abnormal oil level rise begins to occur, the float pressure equalizing passage 70a2 is prophylactically closed, so that the float valve body 70ab is buried in oil and the float hollow portion 70a1 is filled with oil. The worst case can be avoided.

  From the above, there is an effect that the oil that enters the float hollow portion 70a1 can be reduced and the float operation can be continued for a long period of time. That is, it becomes one of the float infiltration oil suppression means. In this embodiment, since the float pressure equalizing path 70a2 is protruded, there is an effect that the pressure equalizing path is reliably closed.

(13th Embodiment)
Next, the scroll compressor of 13th Embodiment of this invention is demonstrated using FIG. FIG. 29 is an enlarged cross-sectional view (floor V enlarged view of FIG. 12) of the float pressure equalizing passage outer side opening portion of the oil return chamber in the scroll compressor according to the thirteenth embodiment of the present invention. The thirteenth embodiment is different from the twelfth embodiment in the points described below, and the other points are the same as those in the twelfth embodiment, and therefore redundant description is omitted.

  In the thirteenth embodiment, a sealing body 61 with a plug made of metal or plastic is provided at a location facing the float pressure equalizing passage 70a2 of the discharge cover 51 that constitutes the upper surface of the oil return chamber 95, and the plug portion 61a is provided. It is inserted into the float pressure equalizing path 70a2. The plug portion 61a is tapered. In other words, a downwardly convex plug portion that is inserted into the float pressure equalizing path is formed in the sealing body.

  As a result, when the oil level of the oil return chamber staying oil 95b rises abnormally for some reason, the outer opening of the float pressure equalizing passage 70a2 is sealed as described above when the float 70a rises until it contacts the discharge cover 51. While being blocked by the body 60, the plug portion 61a having a large diameter is inserted into the float pressure equalizing passage 70a2 to narrow the diameter gap.

  That is, since the radial gap of the float pressure equalizing path 70a2 is tangled, a more reliable float pressure equalizing path closing means can be realized. From the above, there is an effect that the oil entering the float hollow portion 70a1 can be further reduced and the float operation can be continued for a longer period of time. That is, it becomes one of the float infiltration oil suppression means. Further, since the plug portion 61a also serves as a guide for the vertical movement of the float valve body 70ab, there is an effect that a smooth opening / closing operation of the float valve is realized.

(14th Embodiment)
Next, a scroll compressor according to a fourteenth embodiment of the present invention is described with reference to FIG. FIG. 30 is an enlarged cross-sectional view of the periphery of the float pressure equalizing passage outside opening of the oil return chamber in the scroll compressor according to the fourteenth embodiment of the present invention (enlarged view of V portion in FIG. 12). The fourteenth embodiment is different from the thirteenth embodiment in the following points, and the other points are the same as those in the thirteenth embodiment.

  In the fourteenth embodiment, a compression helical spring 64 is provided between the plug-sealed sealing body 61 and the float 70a. As a result, when the oil level of the oil return chamber staying oil 95b rises abnormally for some reason, the sealing body 60 at the outer opening of the float pressure equalizing passage 70a2 when the float 70a rises until it contacts the discharge cover 51. Floating pressure equalization is further ensured by the blockage due to pressure, the narrowing of the diameter gap due to insertion of the large diameter plug portion 61a into the float pressure equalizing passage 70a2, and the narrowing of the flow path due to compression of the compression spring spring 64. Road block means can be realized.

  From the above, there is an effect that the oil entering the float hollow portion 70a1 can be further reduced and the float operation can be continued for a longer period of time. That is, it becomes one of the float infiltration oil suppression means. In addition, when the return oil staying oil 95b disappears for some reason, the posture of the float valve body 70ab can be prevented from becoming unstable, and the float valve 70 can be prevented from being closed.

(Fifteenth embodiment)
Next, the scroll compressor of 15th Embodiment of this invention is demonstrated using FIG. FIG. 31 is an enlarged cross-sectional view (floor V enlarged view of FIG. 12) around the float pressure equalizing passage outer side opening of the oil return chamber in the scroll compressor of the fifteenth embodiment of the present invention. The fifteenth embodiment is different from the fourteenth embodiment in the following points, and the other points are the same as those in the fourteenth embodiment, so redundant description is omitted.

  In the fifteenth embodiment, the sealing body with a stopper is a sealing body 62 with a movable stopper that is not fixed to the discharge cover 51 and a stopper 62a. Thereby, positioning of the discharge cover 51 becomes unnecessary, and there is an effect of improving the assembling property.

(Sixteenth embodiment)
Next, the scroll compressor of 16th Embodiment of this invention is demonstrated using FIG. FIG. 32 is a side view of the float valve body of the oil return chamber in the scroll compressor according to the sixteenth embodiment of the present invention. The sixteenth embodiment is different from the first to fifteenth embodiments in the following points, and the other points are the same as those in the first to fifteenth embodiments. .

  In the sixteenth embodiment, a plurality of shallow vertical grooves 70a17 extending to at least the oil level height of the normal oil return chamber staying oil 95b are provided on the side surface of the float valve body 70ab. The vertical groove 70a17 does not extend to the upper surface of the float 70a. Thereby, since the danger that the side surface of the float 70a will contact | adhere to the inner wall of the oil return chamber 95 which opposes by the condensation force of oil can be reduced, there exists an effect which can ensure a float operation | movement.

  In the present embodiment, the scroll compressor has been described as an example of the positive displacement compressor. However, the present invention is not limited to this, and the present invention is also applicable to, for example, a reciprocating type, a rotary type, and a screw type compressor. Can do. In the present embodiment, the oil storage unit is installed in a pressure region lower than the discharge pressure of the working fluid. However, the present invention is not limited thereto, and the oil storage unit includes oil return means for returning the separated oil to the oil storage unit by a hollow float. Can be applied to any compressor.

It is a longitudinal cross-sectional view of the scroll compressor which concerns on 1st-16th embodiment of this invention. It is a detailed enlarged view of the M section in FIG. It is a principal part enlarged view of FIG. 2A. FIG. 2 is a detailed enlarged view of a portion N in FIG. 1. It is a top view of the turning scroll of FIG. It is LL sectional drawing of FIG. 2A. It is a top view of the base plate of the oil pump of FIG. 2A. It is a perspective view of the inner rotor of the oil supply pump of FIG. 2A. It is a perspective view of the outer rotor of the oil pump of FIG. 2A. It is explanatory drawing of the pressure range of the bottom face of both the rotors of FIG. 2A. It is explanatory drawing of the raising force concerning both rotors of FIG. 2A. It is explanatory drawing of the discharge pressure area | region of the oil supply pump 30 of FIG. 2A. It is a detailed enlarged view of the P section of FIG. It is FF sectional drawing of FIG. FIG. 2 is a detailed enlarged view of a Q part in FIG. 1. It is an enlarged view of the S section in FIG. It is an enlarged view of FIG. 12S part of the scroll compressor which concerns on 2nd Embodiment of this invention. It is an enlarged view of FIG. 12S part of the scroll compressor which concerns on 3rd Embodiment of this invention. It is an oil supply chamber vicinity enlarged view of the upper surface of the discharge oil separation oil return cylinder of the scroll compressor which concerns on 3rd Embodiment of this invention. It is an oil return chamber vicinity enlarged view of the discharge oil separation oil return cylinder upper surface of the scroll compressor which concerns on 4th Embodiment of this invention. It is an oil return chamber vicinity enlarged view of the discharge oil separation oil return cylinder upper surface of the scroll compressor which concerns on 5th Embodiment of this invention. It is an expansion longitudinal cross-sectional view of the float valve body of the scroll compressor which concerns on 1st Embodiment of this invention. It is an expanded longitudinal cross-sectional view of the float valve body of the scroll compressor which concerns on 6th Embodiment of this invention. It is an expanded longitudinal cross-sectional view of the float valve body of the scroll compressor which concerns on 7th Embodiment of this invention. It is an expansion longitudinal cross-sectional view of the float valve body of the scroll compressor which concerns on 8th Embodiment of this invention. It is the float pressure equalization path outer side opening expanded sectional view of the float of the scroll compressor concerning a 9th embodiment of the present invention (U section enlarged view of Drawings 21-24). It is the float pressure equalization path outer side opening expanded sectional view of the float of the scroll compressor which concerns on 10th Embodiment of this invention (U part enlarged view of FIGS. 21-24). It is a float pressure equalizing path outer side opening enlarged sectional view (U section enlarged view of Drawing 21-Drawing 24) of the float of the scroll compressor concerning an 11th embodiment of the present invention. It is the float pressure equalization path outer side opening periphery expanded sectional view (V part enlarged view of FIG. 12) of the oil return chamber of the scroll compressor which concerns on 12th Embodiment of this invention. It is the float pressure equalization path outer side opening periphery expanded sectional view (V section enlarged view of FIG. 12) of the oil return chamber of the scroll compressor which concerns on 13th Embodiment of this invention. It is the float pressure equalization path outer side opening periphery expanded sectional view (V section enlarged view of FIG. 12) of the oil return chamber of the scroll compressor which concerns on 14th Embodiment of this invention. It is the float pressure equalization path outer side opening part expansion sectional view (V section enlarged view of FIG. 12) of the oil return chamber of the scroll compressor which concerns on 15th Embodiment of this invention. It is a float valve body side view of the oil return chamber of the scroll compressor which concerns on 16th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Scroll compressor 2d Discharge port 2e Suction port 6 Crankshaft 7 Motor 8 Casing 10 Compression chamber structure part 30 Oil supply pump 40 Discharge oil separation oil return part 52 Discharge pipe 53 Suction pipe 60 Sealing body 61a Plug part 70a Float 70b Float valve Portion 70ab Float valve element 70c Float hole 70 Float valve 70a1 Float hollow portion 70a2 Float pressure equalizing path 70a5 Oil-repellent film 70a6 Porous film 70a9 Float pressure equalizing pipe 70a14 Float pressure equalizing tube 70a16 Bottom hole 75 Oil communication path 80 Oil return path 85 Working fluid communication path 90 Oil separation chamber 95 Oil return chamber 100 Compression chamber 105 Suction chamber 110 Back pressure chamber 120 Discharge chamber 125 Oil storage section

Claims (17)

A compression chamber constituting portion that constitutes a compression chamber that compresses the working fluid, an oil storage portion that stores oil to be supplied to the compression chamber, and an oil that separates the oil from the working fluid compressed and discharged by the compression chamber constituting portion Separation means, oil return means for returning the separated oil separated by the oil separation means to the oil storage section, the compression chamber constituting section, the oil storage section, the oil separation means, and a casing containing the oil return means With
The oil return means includes a return oil chamber for temporarily storing the separated oil guided from the oil separation means through an oil communication path, and a hollow float for floating in the return oil chamber accumulated oil stored at the bottom of the oil return chamber. And a positive displacement compressor having a valve portion that opens and closes a communication portion between the oil return chamber and the oil storage portion by the hollow float,
The displacement type compressor is characterized in that the hollow float is formed with a float pressure equalizing passage communicating the hollow portion and the working fluid region of the oil return chamber. The positive displacement compressor according to claim 1, wherein
The oil separation means includes a centrifugal separation chamber that rotates the working fluid and separates the oil by centrifugal separation, and a separation that is disposed in a central portion of the centrifugal separation chamber and from which the working fluid separated from the oil flows inside. And a working fluid communication path that communicates the working fluid area of the centrifugal separation chamber and the working fluid area of the oil return chamber,
The working fluid communication path is a positive displacement compressor in which an opening on the working fluid region side on the centrifugal separation chamber side is formed in a working fluid region on the inner side of the separation ring. The positive displacement compressor according to claim 1, wherein
The oil separation means is configured to have a centrifugal separation chamber that circulates the working fluid and separates the oil by centrifugation, and includes a working fluid region in the centrifugal separation chamber and a working fluid region in the oil return chamber. A working fluid communication path is provided,
In the working fluid communication path, the opening on the working fluid region side of the centrifuge chamber is formed at the end portion in the swirling direction starting from the discharge port on the side wall surface of the centrifuge chamber from which the working fluid is swirled and discharged. Positive displacement compressor. The positive displacement compressor according to claim 1, wherein
The oil separation means is configured to have a centrifugal separation chamber that circulates the working fluid and separates the oil by centrifugation, and includes a working fluid region in the centrifugal separation chamber and a working fluid region in the oil return chamber. A working fluid communication path is provided,
The working fluid communication path is a positive displacement compression in which the opening on the working fluid region side of the oil return chamber is formed so that the working fluid flowing in from the centrifugal separation chamber flows along the side wall surface of the oil return chamber. Machine. The positive displacement compressor according to claim 1, wherein
The float pressure equalizing path is a positive displacement compressor in which an opening on the working fluid region side of the oil return chamber is formed at the top of the hollow float. The positive displacement compressor according to claim 1, wherein
The float pressure equalizing path is a positive displacement compressor in which an opening on the hollow portion side is formed at a bottom portion of the hollow portion. The positive displacement compressor according to claim 1, wherein
The bottom part of the hollow part is formed in a conical concave shape, and the float pressure equalization path is a positive displacement compressor in which an opening on the hollow part side is formed in a conical top part of the conical concave bottom surface. The positive displacement compressor according to claim 1, wherein
The float pressure equalizing passage is formed to extend from an opening on the working fluid region side of the oil return chamber formed at the top of the hollow float to an opening on the hollow portion side formed at the bottom of the hollow portion. This is a positive displacement compressor made up of pressure equalizing pipes. The positive displacement compressor according to claim 1, wherein
The float pressure equalizing path extends from an opening on the working fluid region side of the oil return chamber formed at the top of the hollow float to an opening on the hollow portion side formed at the bottom of the hollow portion, and at least A positive displacement compressor in which the opening on the hollow portion side is formed of a deformable tube. The positive displacement compressor according to claim 1, wherein
The float pressure equalizing path is formed to extend from the valve portion to an opening on the working fluid region side of the oil return chamber formed at the top of the hollow float, and at the bottom of the hollow portion the hollow portion A positive displacement compressor composed of a pressure equalizing pipe with an opening on the side. The positive displacement compressor according to claim 1, wherein
A positive displacement compressor in which a projecting portion projecting upward is formed around an opening on the working fluid region side of the oil return chamber of the float pressure equalizing path of the hollow float. The positive displacement compressor according to claim 1, wherein
A positive displacement compressor in which a soot treatment section is formed on the peripheral surface of the opening on the working fluid region side of the oil return chamber of the float pressure equalizing path of the hollow float. The positive displacement compressor according to claim 1, wherein
A porous member in which a large number of holes smaller than the oil mist in the working fluid region of the oil return chamber and larger than the molecules of the working fluid are formed in an opening on the working fluid region side of the oil return chamber of the float pressure equalizing path Is a positive displacement compressor. The positive displacement compressor according to claim 1, wherein
A positive displacement compressor provided with a float pressure equalizing passage closing means for closing the float pressure equalizing passage when the oil level of the oil in the return oil chamber rises above a set value. The positive displacement compressor according to claim 14, wherein
The float pressure equalizing passage closing means is constituted by an elastic sealing body provided at a position facing the opening on the working fluid region side of the oil returning chamber of the float pressure equalizing passage on the top surface of the oil returning chamber. A positive displacement compressor. The positive displacement compressor according to claim 15, wherein
The said sealing body is a positive displacement compressor formed by having a downward convex-shaped plug part inserted in the said float equalization path. A compression chamber constituting portion that constitutes a compression chamber that compresses the working fluid by reducing the volume, a compression chamber driving portion that drives the compression chamber constituting portion to perform a reduction operation of the compression chamber, and compression in the compression chamber A casing in which the discharged working fluid is guided, the compression chamber constituting portion, the compression chamber driving portion, and the discharge chamber, and the internal space is held at a pressure lower than the discharge pressure of the discharge chamber And
The internal space of the casing is provided with an oil storage part for storing oil, and a compression chamber oil supply means for guiding the oil in the oil storage part to the compression chamber,
The discharge chamber is separated by oil separation means for separating the oil supplied to the compression chamber by the compression chamber oil supply means and guided to the discharge chamber together with the working fluid from the working fluid. An oil return means for returning the separated oil to the oil storage part is provided,
The oil return means includes an oil return chamber for temporarily storing the separated oil guided from the oil separation means through an oil communication path, an oil return passage communicating the oil return chamber and the oil storage section, A positive displacement compressor comprising a hollow float that floats in oil that has accumulated in the oil return chamber accumulated at the bottom of the oil return chamber, and a valve portion that opens and closes the oil return path in conjunction with the vertical movement of the hollow float. There,
The displacement type compressor is characterized in that the hollow float is formed with a float pressure equalizing passage that communicates a hollow portion with an oil return chamber working fluid region that is a working fluid region of the oil return chamber.

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