REFRIGERANT COMPRESSOR

Abstract

The invention relates to a refrigerant compressor, comprising: a preferably hermetically sealable compressor housing; an electric drive unit, comprising a rotor (4) and a stator (3); a crankshaft (1), which is connected to the rotor (4) for conjoint rotation and which has a longitudinal axis (2); a piston-cylinder unit, which can be driven by the crankshaft (1); wherein the electric drive unit is designed as an external rotor motor and the rotor (4) has a carrier element (12) extending outward radially with respect to the longitudinal axis (2) at least in some sections and the carrier element (12) is connected to the crankshaft (1) for conjoint rotation. According to the invention, in order to enable an increased delivery rate of lubricant from a lubricant sump together with preferably low or reduced height of the compressor, a sleeve-shaped lubricant receiver (8) for centrifugally conveying lubricant from a lubricant sump formed in a bottom region of the compressor housing toward the piston-cylinder unit is provided on a side of the carrier element (12) facing away from the piston-cylinder unit (5), the sleeve-shaped lubricant receiver (8) being joined to the carrier element (12) for conjoint rotation.

Claims

1. A refrigerant compressor with a, compressor housing; an electric drive unit comprising a rotor and a stator; a crankshaft having a longitudinal axis that is nonrotatably connected to the rotor; a piston-cylinder-unit that can be driven by the crankshaft; where the electric drive unit is made as an external rotor motor and the rotor has a carrier element that extends at least partially radially outward with respect to the longitudinal axis, and the carrier element is connected nonrotatably to the crankshaft, wherein a sleeve-shaped lubricant receptacle for centrifugal transport of lubricant from a lubricant sump formed in a bottom region of the compressor housing in the direction of the piston-cylinder-unit is provided on a side of the carrier element facing away from the piston-cylinder-unit, where the sleeve-shaped lubricant receptacle is nonrotatably connected to the carrier element.

2. The refrigerant compressor as in claim 1, wherein the carrier element has a central through-opening running coaxially with respect to the longitudinal axis, where the sleeve-shaped lubricant receptacle is a separate component, and a fastening portion of the sleeve-shaped lubricant receptacle is attached to the carrier element in the region of the through-opening.

3. The refrigerant compressor as in claim 2, wherein the through-opening is formed for the connection of the crankshaft by a sleeve-shaped prolongation of the carrier element.

4. The refrigerant compressor as in claim 3, wherein the sleeve-shaped prolongation extends to the side of the carrier element facing away from the piston-cylinder-unit, a section of the crankshaft is nonrotatably connected to the through-opening, and the fastening portion of the sleeve-shaped lubricant receptacle is attached to an outer, with respect to the longitudinal axis, surface of the sleeve-shaped prolongation.

5. The refrigerant compressor as in claim 4, wherein a ring-shaped supporting element that extends radially outward with respect to the longitudinal axis surrounds at least a section of the fastening portion of the sleeve-shaped lubricant receptacle.

6. The refrigerant compressor as in claim 5, wherein the fastening portion of the sleeve-shaped lubricant receptacle is formed at least in part by the ring-shaped supporting element.

7. The refrigerant compressor as in claim 5, wherein the ring-shaped supporting element is pressed or shrink-fit onto the fastening portion of the sleeve-shaped lubricant receptacle.

8. The refrigerant compressor as in claim 1, wherein a fastening portion of the sleeve-shaped lubricant receptacle extends parallel to the longitudinal axis and that the sleeve-shaped lubricant receptacle has a collar section extending radially outward with respect to the longitudinal axis and connecting to the fastening portion.

9. The refrigerant compressor as in claim 3, wherein the sleeve-shaped prolongation extends to the side of the carrier element that faces the piston-cylinder-unit, where the sleeve-shaped prolongation is connected nonrotatably to the crankshaft, and the fastening portion of the sleeve-shaped lubricant receptacle is held nonrotatably in the through-opening formed by the sleeve-shaped prolongation.

10. The refrigerant compressor as in claim 1, wherein the sleeve-shaped lubricant receptacle and the carrier element are made in one piece, where the lubricant receptacle is formed from the carrier element by a forming operation, and the end of the crankshaft facing away from the piston-cylinder-unit is held nonrotatably in the sleeve-shaped lubricant receptacle.

11. The refrigerant compressor according to claim 1, wherein the housing is hermetically scalable.

12. The refrigerant compressor as in claim 3, wherein the sleeve-shaped prolongation is formed from the carrier element by means of a forming operation.

13. The refrigerant compressor as in claim 8, wherein the collar section of the sleeve-shaped lubricant receptacle bears against the carrier element.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0025] The invention will now be explained in more detail by means of embodiment examples. The drawings are examples and are intended to present the ideas of the invention, but not to limit it in any way or even to render it conclusively.

[0026] Here:

[0027] FIG. 1 shows a sectional view of a first embodiment of a refrigerant compressor according to the invention;

[0028] FIG. 2 shows an enlarged detail of a bottom region of the refrigerant compressor in FIG. 1;

[0029] FIG. 3 shows a sectional view of a bottom region of a second embodiment of the refrigerant compressor according to the invention.

WAYS OF IMPLEMENTING THE INVENTION

[0030] FIGS. 1 and 2 show a first embodiment of a refrigerant compressor according to the invention with a drive unit made as an external rotor motor, which is disposed in a hermetically sealable compressor housing 6. The drive unit comprises a stator 3 and a rotor 4. A crankshaft 1 having a longitudinal axis 2 is disposed centrally relative to the stator 3 and rotor 4, which crankshaft 1 is connected nonrotatably to a carrier element 12 of the rotor 4, for example in a form fit, friction fit, or positive lock fit, so as to drive a piston-cylinder-unit 5 of the refrigerant compressor, which cyclically compresses a refrigerant. The crankshaft 1 is mounted in a bearing bushing 17 of a carrier housing 18 that carries the piston-cylinder-unit 5. The stator 3, which is inwardly disposed in the radial direction with respect to the longitudinal axis 2, is mounted on the outer side of the bearing bushing 17.

[0031] The crankshaft 1 is part of a crank drive, which crank drive has a crankpin 26 eccentrically offset with respect to the longitudinal axis 2 and connected directly to the crankshaft 1. The piston-cylinder-unit 5 comprises a piston 25, which can be moved linearly back and forth in a cylinder housing 24, a connecting rod 23 connecting the crankpin 26 to the piston 25, a cylinder head system 27 comprising valves, and a suction muffler 28 connected to the cylinder head system 27.

[0032] In this embodiment example, the carrier housing 18 and the cylinder housing 24 are made in one piece, more precisely as a cast part. The carrier housing 18 has a plurality of continuations, via which the carrier housing 18 is mounted in the compressor housing 6 on spring elements 21, which are disposed in a bottom region 7 of the compressor housing 6. In alternative embodiments, the carrier housing 18 and cylinder housing 24 can be made in two pieces and connected to each other by connecting means.

[0033] The rotor 4 comprises, as shown in FIG. 2, a plurality of permanent magnets 14, which are disposed outside of the stator 3 in the radial direction and are connected to each other in the circumferential direction by a shading ring 15. In order to connect the permanent magnets 14 nonrotatably to the crankshaft 1 by force fit or friction fit, the rotor 4 comprises the carrier element 12, which extends radially outward from the crankshaft 1 and grips the stator 3 from below. The carrier element 12 is essentially made in the shape of a plate and has a raised edge section that is curved in the direction of the piston-cylinder-unit 5, on which the permanent magnets 14 and the shading ring 15 are attached. For connection to the crankshaft 1, the carrier element 12 has a centrally disposed through-opening 13, so as to position the rotor 4 coaxially with respect to the longitudinal axis 2. In these embodiment examples, the carrier element 12 has a sleeve-shaped prolongation 19 with a circular cylindrical clear cross section, which is disposed centrally and to which the side of the carrier element 12 facing away from the piston-cylinder-unit 5 extends. The through-opening 13 in this case is formed by the prolongation 19. Carrier element 12 and prolongation 19 in this embodiment example are made in one piece, where the prolongation 19 and the edge section are formed from the carrier element 12 by a forming process, for example a deep drawing process. The lower end of the crankshaft 1 is in this embodiment example pressed into the through-opening 13, so as to make the nonrotatable connection of carrier element 12 and crankshaft 1.

[0034] In order to lubricate the bearing points of the crankshaft 1 in the bearing bushing 17 and the piston-cylinder-unit 5 in an operating state of the refrigerant compressor and to provide lubricant from a lubricant sump formed in the bottom region 7 of the compressor housing 6 in the operating state, the crankshaft 1 has, at the end opposite the piston-cylinder-unit 5, in other words at the lower end, an eccentric drilling running at an angle to the longitudinal axis 2, in other words running essentially axially, which is eccentrically disposed with respect to the longitudinal axis 2 in the radial direction. Lubricant that gets into the eccentric drilling is forced to the wall of the eccentric drilling because of the centrifugal force in the rotation of the crankshaft 1 and, because of the increased pressure, is transported in the direction of the piston-cylinder-unit 5. For example, the eccentric drilling can be made as a blind hole connected to the end facing the piston-cylinder-unit 5 via a radial drilling 20 with a helical groove 22 formed on the outer surface of the crankshaft 1 for transport of the lubricant.

[0035] In alternative embodiments, the eccentric drilling can also be disposed running parallel to the longitudinal axis 2 or instead of the eccentric drilling an axial drilling running coaxially with respect to the longitudinal axis 2 can be provided.

[0036] In order to bring lubricant from the lubricant sump into the eccentric drilling of the crankshaft 1 without needing a free end of the crankshaft 1 to dip into the lubricant sump, a sleeve-shaped lubricant receptacle 8, which is attached to the carrier element 12 and thus is nonrotatably connected to the crankshaft 1, is provided. The lower end of the crankshaft 1 here is pressed into the through-opening 13 of the prolongation 19 of the carrier element 12. In this embodiment example, the sleeve-shaped lubricant receptacle 8 and the carrier element 12 are made in two parts, where a fastening portion 9 of the lubricant receptacle 8 contacts the prolongation 19 of the carrier element 12.

[0037] As can easily be seen in FIG. 2, the fastening portion 9 has a circular cylindrical clear cross section, where an inner surface of the fastening portion 9 bears against an outer surface of the sleeve-shaped prolongation 19 of the carrier element 12. In other words, the fastening portion 9 of the sleeve-shaped lubricant receptacle 8 is pushed onto the prolongation 19. In order to make a nonrotatable connection between the lubricant receptacle 8 and carrier element 12, the fastening portion 9 is as a rule pressed or shrink-fit onto the v 19 of the carrier element 12 so that a force fit or friction fit connection is made.

[0038] In order to improve, on the one hand, the connection of the carrier element 12 to the crankshaft 1 and, on the other hand, the connection of the fastening, portion 9 to the prolongation 19 and to increase the surface pressure between the carrier element 12 and the fastening portion 9 or between the fastening portion 9 and the crankshaft 1, a section of the fastening portion 9 is made as a ring-shaped supporting element 11. In this case, it is the end of the fastening portion facing the carrier element 12, where the ring-shaped supporting element 11 extends over about 80% of the fastening portion 9 looking in the axial direction. The ring-shaped supporting element 11 has a very large wall thickness by comparison with the rest of the lubricant receptacle 8, so that the fastening portion 9 has high stiffness in the region of the supporting element 11. A more reliable support of the fastening portion 9 on the prolongation 19 is ensured through this.

[0039] In alternative embodiments, the ring-shaped supporting element 11 can also be a part that is pressed or shrink-fit onto the fastening portion 9 and is a separate part from the lubricant receptacle 8. In other words, the supporting element 11 contacts an outer circumferential surface of the fastening portion 9 and exerts a force on the fastening portion 9 directed inwardly in the direction of the longitudinal axis 2. The surface pressure and the quality of the force fit or friction fit connection between the inner surface of the through-opening 13 and the crankshaft or between the inner surface of the fastening portion 9 and the outer surface of the prolongation 19 is increased. The supporting element 11 contacts a lower side of the carrier element 12 and overlaps about 80% of the prolongation 19.

[0040] It goes without saying that the ring-shaped supporting element 11 is indeed advantageous for the attachment of the lubricant receptacle 8 on the prolongation 19 but is not absolutely necessary. Alternatively, or in addition to the supporting element 11, the uppermost section of the lubricant receptacle 8 can also have a collar section, which extends outward in the radial direction at least in part.

[0041] Lubricant enters a receiving portion 10 of the lubricant receptacle 8 via a lubricant inlet hole. Since the lubricant receptacle 8 has a rotationally symmetric form with respect to the longitudinal axis 2 and is disposed coaxially with respect to the longitudinal axis 2, a lubricant parabola or a parabola-shaped column of lubricant is formed in the lubricant receptacle 8 by its rotation, passes into the eccentric drilling at the lower end of the crankshaft 1, and is transported farther there in the direction of the first radial drilling 20.

[0042] With increasing distance between the level of liquid in the lubricant sump and the radial drilling 20, which is also called the transport height, the transport power of the lubricant-conveying system decreases. An especially space-saving connection of the lubricant receptacle 8 to the crankshaft 1 is achieved by the attachment of the lubricant receptacle 8 to the sleeve-shaped prolongation 19 of the carrier element, so that the transport height can be reduced, and with this the transport power, thus the lubricant throughput per minute, can be increased. The increase of the transport power can be explained in that, because of the lower transport height, the wall thickness of the lubricant parabola in the region of the radial drilling 20 is greater and thus more lubricant reaches the helical groove 22.

[0043] It is provided in an alternative embodiment variation of the invention, which is not shown, that the lubricant receptacle 8 and carrier element 12 are made in one piece and the lubricant receptacle 8 is connected to the carrier element 12 or to the crankshaft 1 nonrotatably through this. The one-piece embodiment can be achieved, for example, by making the carrier element 12 together with the lubricant receptacle 8 from a plate-shaped blank in a deep drawing process. In this embodiment, the lower end of the crankshaft 1 is pressed into an upper section of the lubricant receptacle 8, or the lubricant receptacle 8 is shrink-fit onto the lower end of the crankshaft 1.

[0044] FIG. 3 shows a second embodiment variation of the invention, which differs from the first embodiment in individual aspects, due to which only the differences will be discussed below.

[0045] While the sleeve-shaped prolongation 19 of the carrier element 12 extends to the side facing away from the piston-cylinder-unit 5 in the first embodiment, in this embodiment example, the prolongation 19 extends in the direction of the piston-cylinder-unit 5 (compare with FIG. 1). In other words, the prolongation 19 in this embodiment example is curved upward. The prolongation 19 is again made in one piece with the carrier element 12 and can be made by a bending or deep drawing process. In the first embodiment example, the lower end of the crankshaft 1 is disposed in the through-opening 13 made by the sleeve-shaped prolongation 19 of the carrier element 12. In the second embodiment example, the face side of the lower end of the crankshaft 1 has a central recess 29, in which recess 29 the sleeve-shaped prolongation 19 is held nonrotatably. For example, the prolongation 19 can be pressed into the recess 29. The lubricant receptacle 8 in this case is held nonrotatably in the through-opening 13. This can also be produced, for example, by pressing the lubricant recess 8 into the through-opening 13.

[0046] In addition, a lubricant driver 16, which supports the formation of the lubricant parabola and increases the transport power of the oil transport device, can be disposed in the lubricant receptacle 8. Thus; a lubricant driver 16, which has at least one or more helical surfaces, which push the lubricant outward in the direction of the inner wall of the lubricant receptacle 8 or are Made for pushing the lubricant in the axial direction upward in the direction of the eccentric drilling of the crankshaft 1, is disposed in the lubricant receptacle 8 in each of the embodiment examples described previously. It is also conceivable for the one or more surfaces of the lubricant driver 16 to be made flat.

REFERENCE NUMBER LIST

[0047] 1 Crankshaft [0048] 2 Longitudinal axis of crankshaft 1 [0049] 3 Stator [0050] 4 Rotor [0051] 5 Piston-cylinder-unit [0052] 6 Compressor housing [0053] 7 Bottom region of compressor housing 6 [0054] 8 Sleeve-shaped lubricant receptacle [0055] 9 Fastening portion of lubricant receptacle 8 [0056] 10 Receiving portion of lubricant receptacle 8 [0057] 11 Ring-shaped supporting element [0058] 12 Carrier element of rotor 4 [0059] 13 Through-opening [0060] 14 Permanent magnet [0061] 15 Shading ring [0062] 16 Lubricant driver [0063] 17 Bearing bushing [0064] 18 Carrier housing [0065] 19 Sleeve-shaped prolongation of carrier element 12 [0066] 20 Radial drilling [0067] 21 Spring element [0068] 22 Helical groove [0069] 23 Connecting rod [0070] 24 Cylinder housing [0071] 25 Piston [0072] 26 Crankpin [0073] 27 Cylinder head arrangement [0074] 28 Suction muffler [0075] 29 Recess of crankshaft 1