Refrigerant Compressor Unit

Abstract

In order to improve a refrigerant compressor of the type mentioned in the introduction such that it is ensured that, even in the event of a tilt along a longitudinal direction of the refrigerant compressor unit relative to a horizontal course of the longitudinal direction, lubricant can reliably be drawn off by suction out of the lubricant sump, in order to prevent excessive accumulation of lubricant in the lubricant sump, it is proposed that there should be provided on the bottom side of the motor compartment a receiving point that takes a form such that the receiving point supplies lubricant from the lubricant sump to the suction-removal unit.

Claims

1. A refrigerant compressor unit, comprising a piston compressor, which is driven by a drive motor, and an overall housing having a housing body that forms a drive housing portion with a drive compartment for the piston compressor and forms a motor housing portion with a motor compartment for receiving the drive motor, wherein refrigerant that is supplied to the piston compressor flows through the motor compartment such that there is formed in the motor compartment, on the bottom side, a lubricant sump out of which lubricant is drawn off by suction by a suction-removal unit and is transferred to a lubricant bath in the motor compartment, wherein there is provided on the bottom side of the motor compartment a receiving point that takes a form such that, in particular in the event of tilting within a tilting tolerance range by the refrigerant compressor unit relative to a starting position, the receiving point receives lubricant from the lubricant sump and supplies it to the suction-removal unit.

2. The refrigerant compressor unit as claimed in claim 1, wherein the receiving point forms a well in relation to the area surrounding it on the bottom side.

3. The refrigerant compressor unit as claimed in claim 1, wherein the receiving point is arranged in the motor compartment such that, in the event of tilting of the refrigerant compressor unit such that an axis of rotation of a compressor shaft is within a tilting tolerance range of ±15° relative to a horizontal orientation in the starting position, the lubricant sump extends as far as the receiving point and lubricant from the lubricant sump enters the receiving point.

4. The refrigerant compressor unit as claimed in claim 1, wherein the receiving point is arranged in a bottom region of the motor compartment that runs from an intermediate wall, which separates the motor compartment from the drive compartment, to below a region of the stator facing the intermediate wall, and in particular runs for at most half of the extent of the stator in the longitudinal direction.

5. The refrigerant compressor unit as claimed in claim 1, wherein the receiving point lies between the intermediate wall and a stator lamination body that comprises pole shoes of the stator.

6. The refrigerant compressor unit as claimed in claim 1, wherein the receiving point is arranged on the bottom side of the motor compartment, as seen in the direction of gravity below winding heads of the stator that face the intermediate wall.

7. The refrigerant compressor unit as claimed in claim 1, wherein the receiving point is formed in a recess relative to a bottom face of the motor compartment.

8. The refrigerant compressor unit as claimed in claim 7, wherein the receiving point is formed on a bottom body of the motor housing portion.

9. The refrigerant compressor unit as claimed in claim 8, wherein the receiving point is shaped into the bottom body.

10. The refrigerant compressor unit as claimed in claim 1, wherein, for the purpose of forming the receiving point, the bottom body is provided with a shape that runs in the direction of a support surface of the housing body.

11. The refrigerant compressor unit as claimed in claim 1, wherein the receiving point lies in a central region of the motor compartment on the bottom side, as seen in a direction transverse to the longitudinal direction of the overall housing.

12. The refrigerant compressor unit as claimed in claim 1, wherein, in the direction of a housing cover that closes off the motor compartment, the lubricant sump is delimited by a closing-off wall arranged between the stator and the housing cover.

13. The refrigerant compressor unit as claimed in claim 1, wherein an extent of the lubricant sump in the direction of a housing cover that closes off the motor compartment is delimited by a lubricant displacement body arranged between the stator and the housing cover.

14. The refrigerant compressor unit as claimed in claim 13, wherein the lubricant displacement body is held against the housing cover.

15. The refrigerant compressor unit as claimed in claim 14, wherein the lubricant displacement body is integrally formed on the housing cover.

16. The refrigerant compressor unit as claimed in claim 12, wherein the lubricant displacement body forms the closing-off wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG. 1 shows a side view of a refrigerant compressor unit according to the invention;

[0046] FIG. 2 shows a section along the line 2-2 in FIG. 1;

[0047] FIG. 3 shows a section along the line 3-3 in FIG. 2;

[0048] FIG. 4 shows a section similar to FIG. 3, with the axis of rotation of the compressor shaft tilted by +15° relative to the horizontal, and

[0049] FIG. 5 shows a section similar to FIG. 3, with the compressor shaft tilted by −15° relative to the horizontal.

DETAILED DESCRIPTION OF THE INVENTION

[0050] An exemplary embodiment of a refrigerant compressor unit 10 illustrated in FIGS. 1 and 2 comprises an overall housing that is designated 12 as a whole and extends in a longitudinal direction 14.

[0051] In this arrangement, the overall housing 12 comprises a housing body 16, which likewise extends in the longitudinal direction 14 and which carries on a first end face a first end-face cover 22 and on a second end face a second end-face cover 24 that is also provided, for example on its side remote from the housing body 16, with a flange face 26 for the purpose of mounting a frequency converter 28.

[0052] As illustrated in FIGS. 2 and 3, the housing body 16 comprises a drive housing portion 32 of a piston compressor that is designated 40 as a whole, wherein the drive housing portion 32 surrounds a drive compartment 34 that extends between the first end-face cover 22 and an intermediate wall 36 of the housing body 16 lying between the drive housing portion 32 and a motor housing portion 42 of the central housing body 16.

[0053] The motor housing portion 42, for the purpose of receiving an electric motor comprises a motor compartment 44, which for its part itself lies between the intermediate wall 36 and the second end-face cover 24, wherein the motor compartment 44 also extends from the motor housing portion 42 into the second end-face cover 24.

[0054] Seated in the motor compartment 44 is the electric motor, which is designated as a whole and comprises a stator 52, arranged in the motor compartment 44, and a rotor 54, surrounded by the stator 52, wherein the rotor 54 is rotatable about an axis of rotation 56.

[0055] For this purpose, the rotor 54 is seated on a compressor shaft of the piston compressor 40, which is designated 60 as a whole and carries the rotor 54 by a rotor carrier portion 62 extending within the motor compartment 44, and on which the rotor 54 is mounted such that it is rotatable about the axis of rotation 56. However, the compressor shaft 60 also extends into the drive compartment 34 and has a drive portion 64 that passes through the drive compartment 34 and carries a plurality of eccentrics 66.

[0056] The compressor shaft 60, for its part, is mounted rotatably within the overall housing 12, in a bearing receptacle 72 provided on the intermediate wall 36 and a bearing receptacle 74 provided on the first end-face cover 22, such that the drive portion 64 with the eccentrics 66 lies between the bearing receptacles 72 and 74, while the rotor carrier portion 62 extends from the bearing receptacle 72, with a free end within the motor compartment 44.

[0057] As illustrated in FIGS. 2 and 3, the drive portion 64 of the compressor shaft 60, with its eccentrics 66, serves to drive a plurality of cylinders 82 of the piston compressor 40, and these are arranged in the drive housing portion 32, for example in the form of two cylinder banks 84 and 86, wherein each of the cylinders 82 has a cylinder chamber 92 in which a piston 94 is movable in a stroke direction 96, and wherein for example each cylinder chamber 92 is surrounded by a cylinder bushing 98 seated in the drive housing portion 32.

[0058] Each of the pistons 94 is, for its part, driven by a piston rod 102, which on one side is mounted in articulated manner on the piston 94 and on the other surrounds one of the eccentrics 66.

[0059] The cylinder chambers 92 of each of the cylinder banks 84 and 86 are closed off by a valve plate 104 and 106 respectively, wherein the respective valve plate 104 or 106 carries a cylinder head 112 or 114 respectively on its side remote from the respective cylinder chamber 92.

[0060] The cylinder head 112 is associated with the first cylinder bank 84, and the cylinder head 114 is associated with the second cylinder bank 86.

[0061] For example, each of the valve plates 104, 106 and each of the cylinder heads 112 and 114 engage over all the cylinder chambers 92 of the cylinders 82 of the respective cylinder bank 84 or 86.

[0062] For example, the refrigerant compressor unit 10 having the two cylinder banks 84 and 86 operates as a two-stage compressor, that is to say that refrigerant that is drawn in by suction at suction pressure PS by way of a suction connector 122 is first compressed to an intermediate pressure PZ by the cylinders 82 of the first cylinder bank 84, which form a low-pressure stage, and then either flows through a duct in the housing body 16 or via an external conduit 124 into the motor compartment 44, flows through the motor compartment 44 and from there enters an intermediate-pressure duct 126 of the drive housing portion 32, with the result that the refrigerant at intermediate pressure PZ can enter the suction chamber of the cylinder head 114 of the cylinder bank 86 and is ultimately compressed to high pressure PH by the cylinders 82 of the second cylinder bank 86, which form a high-pressure stage, wherein the refrigerant under high pressure PH can then exit from a high-pressure connector 128.

[0063] Further, in the exemplary embodiment there is provided in the first end-face cover 22 a lubricant supply unit 130 (FIG. 3) that, by means of a pumping unit 138 arranged for example on the first bearing cover 22 and associated in particular with the bearing receptacle 74, moves lubricant out of a lubricant bath 132 that is arranged in the drive compartment 34, via a filter 134 arranged therein and a receiving duct 136 running in the first cover 22, and into a compressor shaft duct 142 that runs within the compressor shaft 60, preferably coaxially with the axis of rotation 56, wherein the compressor shaft duct 142 runs from the bearing receptacle 74 as far as the bearing receptacle 72, and a transverse duct 144 leads from the compressor shaft duct 142 in the region of the bearing receptacle 72, in the region of the intermediate wall 36, to a receptacle 146 which is provided in the bearing receptacle 72 and which runs around the compressor shaft 60 and from which in turn a conveying duct 148 of a suction-removal unit 150 runs through the intermediate wall 36, which moreover has a supply conduit 152 that adjoins the conveying duct 148 and runs as far as an ejector 154.

[0064] Further, and where necessary, the suction-removal unit 150 comprises a nonreturn valve 156 that is connected on the suction side of the ejector 154 and arranged in the intermediate wall 36, and a suction duct 158 that is guided from the nonreturn valve 156 into the motor compartment 44, such that the suction-removal unit 150 is able to draw off lubricant by suction from the motor compartment 44, during which this lubricant flows through the nonreturn valve 156 and is supplied from the ejector 154 to the lubricant bath 132 in the drive compartment 34, as described for example in DE 2 250 947.

[0065] In this arrangement, the suction duct 158 may be formed by a pipe piece or—as illustrated—by a bore in the bottom side.

[0066] Instead of the nonreturn valve 156, however, it is also possible to provide only a connector element which is arranged in the intermediate wall 36.

[0067] As mentioned above, refrigerant flows through the motor compartment 44 and—because the refrigerant carries lubricant with it, in particular when it comes from the low-pressure stage—as the lubricant flows through the motor compartment 44, it settles therein on the bottom side of the motor compartment 44 in the form of a lubricant sump 162, and with the aid of the suction-removal unit 150 is transferred to the lubricant bath 132 of the drive compartment 34.

[0068] For the purpose of receiving the lubricant from the lubricant sump 162, there is provided on the bottom side of the motor compartment 44 a receiving point 164 which takes a form such that it feeds lubricant out of the lubricant sump 162 and into the suction-removal unit 150, in particular the suction duct 158 thereof.

[0069] In the illustrated exemplary embodiment, the position of the receiving point 164 is selected such that the refrigerant compressor unit 10 can be operated even in a condition in which the axis of rotation 56 does not run horizontally but may run at a tilt of ±15° in relation to the horizontal orientation, as illustrated in FIG. 4 and FIG. 5.

[0070] The result of this is that the receiving point 164 is formed in a recess 184 relative to a bottom face 166 of the motor compartment 44, and moreover that the receiving point 164 is positioned in a bottom region 168, which is adjacent to the intermediate wall 36 and extends from the intermediate wall 36 to below a longitudinal partial region 172 of the stator 52 that is arranged facing the intermediate wall 36, wherein the longitudinal partial region 172 comprises at most half of the extent of the stator 52 in the longitudinal direction 14.

[0071] Preferably, the receiving point 164 lies between the intermediate wall 36 and a stator lamination body 174 of the stator 52 that comprises pole shoes of the stator 52, in particular in a region of the motor compartment 44 in which there lie winding heads 176 of the stator 52, and hence below these winding heads 176.

[0072] In the illustrated exemplary embodiment, the bottom face 166 is formed by a bottom body 182 of the motor housing portion 42 and, for the purpose of forming the receiving point 164, the recess 184 is shaped into the bottom body 182.

[0073] Preferably, for the purpose of forming the recess 184, the bottom body 182 is provided with a shape 186 that runs in the direction of a support surface 188 of the housing body 16.

[0074] However, it is also conceivable for the bottom face 166 to be formed with the receiving point 164 in a bottom tray, which is inserted into the motor housing portion 42, of the motor compartment 44.

[0075] Moreover, an improvement in the tolerance to tilting is achieved by limiting the quantity of lubricant in the lubricant sump 162, and for this purpose there is provided, preferably between the stator 52 and the second bearing cover 24, a closing-off wall 192 that is elevated above the bottom face 166 and extends, transversely to the longitudinal direction 14, over a width of the motor compartment 44 and in particular up to a height above the bottom face 166 that corresponds at least to a height of a surface 194 of the lubricant sump 162 when the refrigerant compressor unit is tilted such that the second bearing cover 24 is lower down than the first bearing cover 22 (FIG. 4).

[0076] Preferably, the closing-off wall 192 lies close to the winding heads 196 of the stator 52 that face the second bearing cover 24.

[0077] In the simplest case, the closing-off wall 192 is held against the second bearing cover 24, in particular being integrally formed in one piece therewith.

[0078] In particular, the closing-off wall 192 is part of a lubricant displacement body 198 that projects into the motor compartment 44 between the stator 52 and the second bearing cover 24 and is preferably arranged on the second bearing cover 24, for reducing the volume of lubricant in the motor compartment 44.

[0079] Further, for the purpose of guiding away condensate, the lubricant displacement body 198 is provided on the bottom side with a drainage duct 202, through which condensate that accumulates in the interior of the lubricant displacement body 198 can flow away.

[0080] The second bearing cover 26 is preferably also provided with cooling fins 204, which project into the motor compartment 44 and extend from a bearing cover wall 206 adjoining the frequency converter 28 in the direction of the electric motor 50, in order also to cool the frequency converter 28 by way of the refrigerant flowing through the motor compartment 44.

[0081] Preferably, from the bearing cover rear wall 206, the cooling fins 204 extend far enough in the direction of the electric motor 50 for their ends 208 to run at approximately the same spacing from the bearing cover rear wall 206 as the closing-off wall 192.