JP2012515873A - Compressors, especially radial piston compressors that use carbon dioxide as refrigerant - Google Patents

Abstract

The present invention relates to a compressor, in particular a radial piston compressor, and more particularly to a compressor (10) using CO ₂ as a refrigerant, a compressor unit (12) for compressing the refrigerant, and a drive shaft for driving the compressor unit (12). (22) and a motor chamber (18) substantially delimited by a motor housing (16), wherein the motor chamber (18) is at least partially formed in the drive shaft (22). The connecting passage (45) is fluidly connected to the gas suction side of the compressor (10), particularly to the suction gas chamber (26), and a device (60) for storing at least one oil in the fluid connecting passage (45). 62, 64) are installed.
[Selection] Figure 1

Description

The present invention relates to a compressor, in particular a radial piston compressor, and relates to a compressor using CO ₂ as a refrigerant according to the introduction of claim 1.

Compressors, in particular, compressors using, for example, R134a, R404A, R507, R407C, R22, or R744 (CO ₂ ) are indispensable today. It is especially used in the field of air conditioning and cooling during transport, and also in the cold storage and static refrigeration of food in the medical field. This type of compressor is also essential today in the field of building air conditioning.

Examples of compressors used in some of the above-mentioned fields are known from the applicant's catalog of hermetic compressors. In particular, 2-cylinder, 4-cylinder, 6-cylinder, and 8-cylinder reciprocating compressors are known from this catalog, and their stroke capacity is approximately 62 to 3,215 cm ³ .

  Furthermore, DE 10356373 A1 discloses a radial piston type compressor, which comprises a compressor unit for compressing refrigerant and a drive shaft for driving the compressor unit. In the compressor disclosed in DE 10356373 A1, the central points of the pistons are arranged on a common surface, and the drive shaft passes through this surface perpendicularly, or the central axis extending in the longitudinal direction of the drive shaft is It is orthogonal to this plane.

  Further, in the prior art, the compressor, in particular, the drive shaft of the compressor is operably connected to an electric motor, and the motor is substantially separated by a motor housing that defines the motor chamber. A radial piston compressor is known that is fluidly connected to a suction gas chamber through which compressed refrigerant is sucked through a hole provided in a drive shaft. In order to cool the motor, a part of the mass flow rate of the suction gas is sent from the suction gas chamber to the motor chamber through the duct, and is returned to the suction gas through the hole provided in the drive shaft described above. Because of such flow conditions, the partial mass flow rate returning to the intake gas contains oil. This oil is used to lubricate bearings and the like. However, depending on the operating state of the compressor (for example, when the rotational speed is low), the optimum lubricating action may not be exhibited.

  In view of the above-described prior art, the problem to be solved by the present invention is to provide a compressor having excellent lubricating performance in a wide operating range.

  This object is achieved by a compressor comprising the features of claim 1, further features and advantages of the invention are set forth in the following description of the drawings and in the dependent claims.

In the following, the invention will be described in an exemplary manner on the basis of the accompanying drawings and possible embodiments.
FIG. 1 is a partial cross-sectional view illustrating a first embodiment of a compressor according to the present invention. FIG. 2 is a diagram illustrating the embodiment of FIG. 1 vertically. FIG. 3 is a diagram showing the details of FIGS. 1 and 2. FIG. 4 is a view showing a second embodiment of the compressor according to the present invention in the same manner as FIG. FIG. 5 is a view showing a third embodiment of the compressor according to the present invention in the same manner as FIG.

  For example, as shown in FIGS. 1 and 2, the first embodiment of the compressor 10 according to the present invention includes a compressor unit 12 and a motor unit 14. The motor unit 14 includes a motor housing 16, and in the first embodiment, this housing partially divides not only the motor chamber 18 but also the compressor unit 12. In addition to the motor 20, a drive shaft 22 is disposed in the motor chamber 18, and the motor 20 is operably connected to the compressor unit 12 via the drive shaft. In the first embodiment described here, the compressor unit 12 comprises six pistons 24 arranged in the radial direction. The piston 24 is arranged on a common surface extending by a long piston axis extending in the longitudinal direction of the piston, and this surface is orthogonal to the drive shaft 22. It should be noted that clearly different numbers of pistons 24 can be arranged at this joint, the number of which depends on the technical requirements of the user of the compressor 10 (capacity and desired compression capacity). Should.

The compressor unit 12 is provided for refrigerant compression. For example, a refrigerant such as R134a, R404A, R507, R407C, R22, or preferably R744 (CO ₂ ) is conceivable. On the suction side, this refrigerant enters a cylinder bore 28 (formed in the radial direction) of the compressor 10 via a suction gas chamber 26 arranged on the suction side, and a piston 24 reciprocates in the cylinder bore. Arranged to exercise. The refrigerant is compressed by the movement of the piston 24 in the radial direction. When the piston 24 reaches the upper position of the cylinder lumen 28, that is, when the piston 24 reaches a radially outward position directed outward, the compressed refrigerant is compressed gas chamber disposed on the high pressure side. 30, from which compressed refrigerant is provided to the cooling circuit of the compressor 10.

  In addition to the compressor unit 12 and the motor unit 14, the compressor 10 is provided with an electronic terminal box 32, which is fixed to the motor housing 16 of the compressor 10 using a fixing member such as a screw. The stator of the motor 20 is installed in the motor housing 16 and can be fixed to the motor 20 using screws, for example.

  In the terminal box 32, an electronic terminal of the compressor 10, particularly a terminal for supplying current or voltage to the motor 20 is arranged. Further, the terminal box 32 accommodates an electronic component for motor protection, and a component such as a thermostat 38 for thermal protection can be connected to the terminal box 32. The terminal box 32 includes a plurality of cable inlets 36 for supplying power, and can be closed using, for example, a closing member when not in use, as shown in FIG. The cable inlet 36 shown in the drawing is preferably punched in advance and initially closed, and is preferably pushed out and opened during use. Therefore, there is no need for a separate part, and there is a pre-punched area on the outline of the terminal box 32, which can be easily opened.

Since the pressure of the refrigerant (for example, CO ₂ ) is high, the thermal protection thermostat 38 is preferably arranged in the motor housing 16 separately from the refrigerant instead of directly contacting the refrigerant. Thus, the thermal protection thermostat 38 is only indirectly thermally connected to the refrigerant. The thermal protection thermostat 38 may be connected to a component in the terminal box 32 by a cable 39, for example, via one of the cable inlets 36.

  In order to lubricate the compressor 10, a lubricant is disposed in the compressor 10 in the form of oil 41. Although the oil 41 is stored in the motor chamber 18, the oil 41 not only lubricates the components of the compressor 10 disposed in the motor chamber 18, but the configuration of the compressor 10 disposed outside the motor chamber 18. Lubricate parts. This region of the motor chamber 18 is necessary to lubricate the bearings 40, 42, 44 (the front bearing bush 42, the rear bearing bush 44, and the bearing 40 that supports the drive shaft 22 with the motor housing 16). . Outside the motor chamber 18, it is necessary to properly lubricate the moving parts of the compression unit 12, in particular the piston 24.

  The compressor 10 is provided with a fluid connection path 45 between the motor chamber 18 and the suction side (suction gas chamber 26). This connection is used for returning the partial mass flow for cooling the motor to the bearings 40, 42. , 44 also serves to lubricate. Most of the fluid connection path 45 is formed in the drive shaft 22 and, in particular, is constituted by an in-axis notch in the form of a bore 46 extending in the axial direction in the drive shaft 22. In addition, the fluid connection path 45 includes four notches radially disposed in the drive shaft 22, which notches fluidly connect to the bore 46, a first radial bore 48, a second notch. It takes the form of a radial bore 50, a third radial bore 52 and a fourth radial bore 54. A first radial bore 48 that extends through the entire drive shaft 22 extends to have two openings to the motor chamber 18 and receives a partial mass flow rate that also contains oil or oil mist. . Second, third and fourth radial bores 50, 52, 54 are provided for lubricating the bearings 40, 42, 44. The oil 41 spreads radially through these bores to each part of the bearing to be lubricated. The outflow of the oil 41 in the radial direction is supported by the rotational movement of the drive shaft 22 and the centrifugal force generated thereby.

  In order to cool the motor, the suction gas chamber 26 is connected to the motor chamber 18 by the fluid connection path 45 as described above. The fluid connection path 45 comprises a first radial bore 48 which acts in particular as a partial mass flow inlet and a bore 46 fluidly connected to the first radial bore. To lubricate the bearing 44 (second bearing bush), the fluid connection path includes a radial bore 54 fluidly connected to the bore 46. The radial bore 54 is fluidly coupled to a second in-shaft notch in the form of a second bore 56 extending axially into the drive shaft 22, which is in cross section from the bore 46. The end opposite to the motor chamber 18 is fluidly connected to the suction gas chamber 26. The gas suction side end of the bore 56 is provided with a reduced cross section in the form of a nozzle 58, which delimits the inflow of oil into the intake gas chamber 26. The nozzle 58 is selected from off-the-shelf products as required, and the corresponding cross-section and flow rate are adapted according to the design needs.

  Also, according to alternative embodiments of the present invention, in addition to or instead of the nozzle 58, the inflow of oil may be caused by a bore cross section of the radial bore 54 or the axial bore 56, such as the bore cross section itself, or , By a constriction located in the bore 54 or 56, or by an opening or flap. The openings or flaps can be designed to be non-adjustable or adjustable, so that the oil flow or lubricant through the intake gas chamber 26 can be external parameters and, if appropriate, parameters of the compressor itself. Can be controlled or adjusted accordingly. Furthermore, the nozzle 58 is of variable cross-section and / or a nozzle with an upstream valve that opens and closes with a predetermined or variable clock cycle, whereby the oil supplied to the intake gas chamber 26. The amount may be adjusted or controlled.

  The two on-axis notches 46, 56 are preferably formed in the drive shaft 22 in the radial direction and spaced from each other in the drive shaft 22 and are preferably bores parallel to the axial direction.

  In particular, in order to ensure oil supply to the bearings 42, 44, a device for storing oil in the form of a cylindrical member or tube 60 is provided in the fluid connection path 45, and this device is connected to the nozzle 58. Enough oil 41 is reliably supplied to the radial bores 52, 54. In addition to the oil storage function, the tube 60 is fluidly connected to the suction gas on the side opposite to the motor chamber, so that the partial mass flow rate reliably returns from the motor to the suction gas chamber. The oil overflow device, which is pushed into the drive shaft 22 and takes the form of a tube 61 extending into the shaft bore 46, serves to discharge the excessively stored oil 41. However, it should be noted that the tube 60 is not for lubricating the compressor unit 12, but rather is provided only for the overflow function when a large amount of oil is stored. The device for storing oil in the form of a tube 60 is designed to store oil 41 while maintaining an uninterrupted fluid connection. The tube 60 has a smaller outer diameter than the diameter of the axial bore 46, and the tube 60 is concentric with the axial bore 46 and protrudes into the axial bore. Alternatively, it is conceivable that they are not concentric but are arranged parallel to the bore 46.

  FIG. 2 shows the compressor 10 shown in FIG. 1 installed in the vertical direction, in which the lubricant in the form of oil 41 covers the radial notch (radial bore 48). ing. Even if the radial notch is covered with oil, the compressor can still be operated, in which case the radial bore 48 is also placed above the oil level and sucks oil mist instead of oil 41. It is possible to do.

  In addition to or as an alternative to the tube 60 as an oil reservoir, a fluid connection 45 between the motor chamber 18 and the gas suction side or the suction gas chamber 26, for example an opening 62 in the drive shaft 22 (see FIG. 4) Or a reservoir-like or bucket-like notch 64 (see FIG. 5) extending radially. As shown in FIG. 5, a reservoir-like notch 64 is formed in the area of the radial bores 52, 54. It is naturally conceivable to provide such a reservoir-like notch also in the area of further notches / bore radially arranged on the drive shaft. The centrifugal force generated when the drive shaft 22 rotates ensures the oil supply to the notch 64.

Although the invention has been described on the basis of embodiments of specific feature point combinations, the invention extends to further combinations that are specified but not fully described by the dependent claims.

Claims (15)

Compressor (10), in particular radial piston compressor, and further compressor (10) using CO ₂ as a refrigerant, compressor unit (12) for compressing refrigerant, and drive shaft for driving compressor unit (12) (22) and a motor chamber (18) substantially partitioned by a motor housing (16), the motor chamber (18) being on the gas suction side of the compressor (10), in particular the suction gas chamber (26). In a compressor fluidly coupled via at least one fluid connection (45) formed at least partially in the drive shaft (22),
A compressor (60, 62, 64) for storing at least one oil is installed in the fluid connection path (45). Compressor (10) according to claim 1,
A compressor characterized in that the at least one oil storage device (60, 62, 64) is configured to maintain an uninterrupted fluid connection. Compressor (10) according to claim 1 or 2,
Compressor characterized in that the fluid connection channel (45) comprises a first on-axis notch (46) formed in the axial direction in the drive shaft (22), in particular cylindrical. The compressor (10) according to any one of claims 1 to 3,
The fluid connection channel (45) is at least one particularly cylindrical radial notch (48, 50, 52, 54), the notch being fluidly connected to the drive shaft. compressor. Compressor (10) according to claim 3 or 4,
The fluid connection path (45) includes a tubular member (60) having an outer diameter smaller than the diameter of the on-axis notch (46), and the tubular member (60) is formed on the on-axis notch ( 46) a compressor arranged parallel to or concentric with 46) and protruding at least partially into said axial notch. Compressor (10) according to claim 5,
Compressor characterized in that the tubular member (60) is fluidly connected to the gas suction side, in particular to the suction gas chamber (26). A compressor (10) according to any one of claims 3 to 6,
The fluid connection path (45) comprises a second axial notch (56), in particular a cylindrical shape, formed axially in the drive shaft, whose cross section, in particular the diameter, is the first. Smaller than the on-axis notch (46),
The second axial notch (56) is fluidly connected to the first axial notch (46) at one end, and the other end opens to the gas suction side. Compressor characterized by that. Compressor (10) according to claim 7,
The second on-axis notch (56) is at one end by at least one radial notch (54), preferably on the first on-axis notch (46), preferably the first on-axis notch (46). A compressor fluidly connected to a radial bore extending radially relative to an on-axis notch. Compressor (10) according to any one of claims 1 to 8,
Compressor characterized in that the fluid connection path (45) has a reduced cross-section. Compressor (10) according to claim 9,
The compressor is characterized in that the portion where the cross-section is reduced includes a nozzle (58), an opening (62), or a portion or flap in which the material of the notch is reduced. Compressor (10) according to claim 9 or 10,
The compressor is characterized in that the portion where the cross-section is reduced is provided in the second axial notch (56) and / or the radial notch (54). Compressor (10) according to any one of claims 9 to 11,
Compressor characterized in that the point of reduced cross section is adjustable, in particular comprising a controllable or adjustable cross section. The compressor (10) according to any one of claims 1 to 12,
The fluid connection path (45) further comprises at least one, in particular, a reservoir-like or bucket-like notch (64), the notch being provided in the drive shaft (22), The compressor characterized by storing (41). The compressor (10) according to any one of claims 1 to 13,
A compressor characterized in that an oil overflow device for determining the amount of oil (41) to be stored or stored is provided. Compressor (10) according to claim 14,
The oil overflow device is disposed in a radial cutout in the drive shaft (22) and protrudes into a fluid connection path (45) between the motor chamber (18) and the gas suction side. A compressor comprising a member (61).

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