LUBRICANT RECEPTACLE FOR A COOLANT COMPRESSOR AND COOLANT COMPRESSOR

Abstract

The invention relates to a lubricant receptacle (1) for vertically conveying lubricant by means of a crankshaft (2) of a coolant compressor (3), said lubricant receptacle (1) comprising at least one rotationally symmetrical, sleeve-type receiving section (4) for receiving lubricant, wherein the longitudinal axis (8) of the receiving section (4) can be arranged coaxially with a longitudinal axis of the crankshaft (2) of the coolant compressor (3), and comprising a securing section (16) connected to the receiving section (4) in order to secure the lubricant receptacle (1) on the crankshaft (2), as well as comprising at least one end region (5) connected to the receiving section (4) which closes the the receiving section (4) apart from an inlet opening (6), wherein the inlet opening (6) permits the entry of lubricant from a lubricant sump (7) of the coolant compressor (3) into the receiving section (4) of the lubricant receptacle (1) protruding at least partially into the lubricant sump (7), wherein the inlet opening (6) is arranged in the end region (5) around the longitudinal axis (8), wherein, when viewed in the direction of the longitudinal axis, the inlet opening (6) either has a circular peripheral shape and a mid-point of the inlet opening is offset in relation to the longitudinal axis (8), or the inlet opening (6) has a non-circular peripheral shape when viewed in the direction of the longitudinal axis.

Claims

1. A lubricant receptacle for vertical conveyance of lubricant by means of a crankshaft of a refrigerant compressor, the lubricant receptacle comprising at least one rotationally symmetrical sleeve-shaped receiving portion for receiving lubricant, wherein the longitudinal axis of the receiving portion can be arranged coaxially with a longitudinal axis of the crankshaft of the refrigerant compressor (3), a fastening portion adjoining the receiving portion in order to fasten the lubricant receptacle to the crankshaft, and at least one end region adjoining the receiving portion and closing off the receiving portion apart from an inlet opening, wherein the inlet opening enables the entry of lubricant from a lubricant sump of the refrigerant compressor into the receiving portion of the lubricant receptacle, said lubricant receptacle protruding at least in portions into the lubricant sump, wherein the inlet opening is arranged in the end region surrounding the longitudinal axis, wherein the inlet opening, as viewed in the direction of the longitudinal axis, has either a circular peripheral shape and a center of the inlet opening is offset from the longitudinal axis, or the inlet opening has a non-circular peripheral shape as viewed in the direction of the longitudinal axis.

2. The lubricant receptacle according to claim 1, wherein the inlet opening, viewed in the direction of the longitudinal axis, has the shape of an ellipse.

3. The lubricant receptacle according to claim 1, wherein the inlet opening has the shape of an elongated hole.

4. The lubricant receptacle according to claim 3, wherein the elongated hole is delimited in a semicircular shape at both ends and the long side of the elongated hole is longer than the radius of the semicircular delimitations.

5. The lubricant receptacle according to claim 4, wherein the length of the long side of the elongated hole is between the value of the radius of the semicircular delimitations and twice the value thereof.

6. The lubricant receptacle according to claim 1, wherein the size of the inlet opening is between 5 and 30 percent of the clear cross-sectional area of the receiving portion.

7. A system comprising a crankshaft of a refrigerant compressor and a lubricant receptacle according to claim 1, wherein the lubricant receptacle is arranged coaxially with the crankshaft and is rotationally fixedly connected to the crankshaft.

8. A refrigerant compressor having a hermetically sealable compressor housing, an electrical drive unit arranged in a housing interior of the compressor housing and comprising a rotor and a stator, a crankshaft rotationally fixedly connected to the rotor, and a piston-cylinder unit which is arranged in the housing interior and comprises a piston movably mounted in a cylinder of the piston-cylinder unit, which piston can be driven by the crankshaft to compress refrigerant, wherein the refrigerant compressor has a lubricant receptacle according to claim 1 in order to convey lubricant from a lubricant sump formed in a bottom region of the compression housing via the crankshaft to the piston-cylinder unit, wherein the lubricant receptacle is rotationally fixedly connected to the crankshaft.

9. The refrigerant compressor according to claim 8, wherein the end region of the lubricant receptacle protrudes at least in portions into the lubricant sump such that the inlet opening is arranged within the lubricant sump in order to enable entry of lubricant from the lubricant sump into the receiving portion of the lubricant receptacle.

10. The refrigerant compressor according to claim 8, wherein the lubricant receptacle is fastened by means of the fastening portion to an end portion of the crankshaft remote from the piston-cylinder unit and/or to the rotor.

11. The lubricant receptacle according to claim 6, wherein the between 5 and 30 percent of the clear cross-sectional area is between 10 and 25 percent.

12. The lubricant receptacle according to claim 11, wherein the between 10 and 25 percent is between 15 and 20 percent.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0038] The invention will now be explained in detail with reference to embodiments. The drawings are for the sake of example and are intended to present the inventive concept, but not to restrict it, much less reproduce it exhaustively

[0039] Therein:

[0040] FIG. 1 shows a lubricant receptacle according to the invention,

[0041] FIG. 2 shows the lubricant receptacle from FIG. 1 viewed along the longitudinal axis thereof,

[0042] FIG. 3 shows a refrigerant compressor according to the invention having a lubricant receptacle according to the invention, and

[0043] FIG. 4 shows the lubricant receptacle according to the invention with a lubricant paraboloid forming in the lubricant receptacle in an operating state of the refrigerant compressor.

MODES FOR EMBODYING THE INVENTION

[0044] FIG. 1 shows an embodiment variant of a lubricant receptacle 1 according to the invention. The lubricant receptacle 1 is constructed from a plurality of sleeve-like portions, each having constant diameter, wherein the transitions between these portions of constant diameter are continuous in the embodiment variant shown, but can also be discrete, i.e. step-shaped for example, without loss of generality.

[0045] The lubricant receptacle 1 comprises a fastening portion 16 for fastening the lubricant receptacle 1 to a crankshaft 2 or a rotor 11 of a lubricant compressor 3 (see FIG. 3), and a receiving portion 4, used for receiving lubricant, adjoining the fastening portion 16 and having a diameter that is reduced in comparison to the fastening portion 16.

[0046] This receiving portion 4 itself has a cylindrical lateral surface and is closed off by an end region 5 of the lubricant receptacle 1 at the lower side, i.e. at a side remote from the fastening portion 16.

[0047] The above yields a sleeve-like structure of the lubricant receptacle 1, which is open toward the top and closed off by the end region 5 toward the bottom, apart from an inlet opening 6 for lubricant. Both the fastening portion 16 and the receiving portion 4 are rotationally symmetrical relative to rotation about a longitudinal axis 8 of the receiving portion 4.

[0048] In the operating state of the lubricant receptacle 1, in which the lubricant receptacle 1 is arranged coaxially with crankshaft 2 and rotationally fixedly connected to the crankshaft 2, the inlet opening 6 establishes a fluidic connection between a housing interior of the refrigerant compressor 3 and the receiving portion 4.

[0049] FIG. 2 shows the lubricant receptacle 1 from FIG. 1 as a two-dimensional projection along the longitudinal axis 8 of receiving portion 4. In particular, the arrangement and shape of the inlet opening 6 arranged in the end region 5 is clearly visible in FIG. 2.

[0050] The shape of the inlet opening 6, which is formed as an elongated hole in this specific embodiment, has the effect that a projection 18 of the end region 5 along the longitudinal axis 8 is no longer symmetrical under rotation about an intersection point 19 of the longitudinal axis 8 with the end region 5. Only the rotation of the projection 18 about the intersection point 19 by an angle of 360? images the projection 18 of the end region 5 back on itself, and therefore the condition for rotational symmetry, according to which two-dimensional objects are rotationally symmetrical if a rotation about a point by every arbitrary angle images the object onto itself, is specifically not fulfilled.

[0051] Precisely this asymmetry of the end region 5 of the lubricant receptacle 1 caused by the inlet opening 6 has the effect that, in the operating state of the lubricant receptacle 1in which operating state the lubricant receptacle 1 is rotationally fixedly connected to the crankshaft 2 of the refrigerant compressor 3 and arranged coaxially with the crankshaft 2 such that at least the end region 5 protrudes in portions into a lubricant sump 7 of the refrigerant compressor 3 (see FIG. 3)no gas bubbles interrupting the lubricant flow are formed in the region of the lubricant receptacle 1, more particularly in the region of the inlet opening 6, and a continuous lubricant supply for all components intended to be lubricated in the refrigerant compressor 3 can be ensured.

[0052] FIG. 3 shows an embodiment variant of the refrigerant compressor 3 according to the invention comprising, in a compressor housing 9, a drive unit 10, a piston-cylinder unit 13 and a crankshaft 2 connecting the drive unit 10 to the piston cylinder unit 13, wherein the lubricant receptacle 1 according to the invention is connected coaxially and rotationally fixedly to the crankshaft 2 in such a manner that the lubricant receptacle 1 protrudes at least in portions into the lubricant sump 7 formed in a bottom region 17 of the compressor housing 9.

[0053] In the illustrated embodiment variant, the crankshaft 2 is rotationally fixedly connected to the rotor 11 surrounding a stator 12 of the drive unit 10 for the refrigerant compressor 3 according to the invention, and is set into rotation by the drive unit 10. This rotational movement of the crankshaft 2 firstly causes a piston 14 of the piston cylinder unit 13 to be moved periodically back and forth between two dead center points of a cylinder 15 in order to draw in refrigerant from the housing interior, compress it and then discharge it; secondly, the rotating crankshaft 2 also sets the lubricant receptacle 1 into a rotational motion which has the effect that the lubricant having reached the receiving portion 4 through the inlet opening 6 assumes the shape of a paraboloid 20.

[0054] With an appropriate selection of the production parameters for the lubricant receptacle 1 (in particular the internal diameter of the receiving portion 4) and of the process parameters for the operating state of the refrigerant compressor 3 according to the invention (in particular the rotational speed of the crankshaft 2), the lubricant in the receiving portion 4 reaches a level due to the shape of the paraboloid 20 that enables a passage of lubricant from the lubricant receptacle 1 into the crankshaft 2.

[0055] For further conveyance of the lubricant, the crankshaft 2 can be produced at least in portions as a hollow cylinder, in which case lubricant can escape from the crankshaft 2 via openings in the lateral surface of the hollow cylinder and reach the components of the refrigerant compressor 3 provided for lubrication; in such a case, the maximum level must reach at least up to a first opening in the lateral surface. The crankshaft 2 can also be implemented as a solid cylinder, however, and be furnished with an eccentric bore 21, generally running upward at an incline, by means of which bore 21 the further conveyance of the lubricant is achieved. In the case of an inclined bore 21, a lower maximum level of the lubricant may sometimes be sufficient, because it need merely enable a passage of lubricant into the bore 21 and not cover the entire distance up to the first opening. Within the inclined bore 21 of the crankshaft 2, the lubricant is pressed against a wall of the bore 21 and thereby conveyed up to the first opening in the lateral surface of the crankshaft 2.

[0056] FIG. 4 shows a lubricant receptacle 1 connected to a crankshaft 2 in the refrigerant compressor 3 at different points in time t, t+1, t+2 and t+3 of an operating state of the refrigerant compressor 3. In time step t, the paraboloid 20 can be seen without gas bubbles. As soon as the outgassing effect begins within the lubricant receptacle 1, the shape of the paraboloid changes. An apex 22 of the paraboloid 20 drops farther and farther in the direction of the end region 5 of the lubricant receptacle 1, as the development of the paraboloid 20 from time t via time t+1 up to time t+2 shows. Finally a part of the paraboloidnamely the part containing the gas bubblecan escape the lubricant receptacle 2 via the inlet opening 6 as soon as the apex 22 of the paraboloid 20 reaches the end region 5. This is ensured in that the inlet opening 6 is arranged surrounding the longitudinal axis 8 in the end region 5. While the gas bubble is leaving the lubricant receptacle 1 through the inlet opening 6, it closes the latter off and thereby prevents lubricant from reaching the lubricant receptacle 1 from the lubricant sump 7. The fact that the inlet opening 6 either has a circular peripheral shape and a center of the outlet opening is offset from the longitudinal axis 8, or that the inlet opening 6 has a non-circular peripheral shape viewed in the direction of the longitudinal axis, ensures however that the gas bubble becomes unstable and tears away from the lubricant receptacle 1 or from the inlet opening 6 and again releases it.

LIST OF REFERENCE NUMBERS

[0057] 1 Lubricant receptacle [0058] 2 Crankshaft [0059] 3 Refrigerant compressor [0060] 4 Receiving portion [0061] 5 End region [0062] 6 inlet opening [0063] 7 Lubricant sump [0064] 8 Longitudinal axis [0065] 9 Compressor housing [0066] 10 Drive unit [0067] 11 Rotor [0068] 12 Stator [0069] 13 Piston-cylinder unit [0070] 14 Piston [0071] 15 Cylinder [0072] 16 Fastening portion [0073] 17 Bottom region [0074] 18 Projection of the end region [0075] 19 intersection of longitudinal axis and end region [0076] 20 Paraboloid [0077] 21 Bore of the crankshaft [0078] 22 Apex of the paraboloid