COOLANT COMPRESSOR

Abstract

The invention relates to a coolant compressor having a compressor housing (6), an electric drive unit comprising a rotor (4) and a stator (3), a crankshaft (1) rotationally fixedly connected to the rotor (4) and having a longitudinal axis (2); and a piston-cylinder unit (5) that can be driven by the crankshaft (1). In order to permit an increased feed rate of lubricant from a lubricant sump, according to the invention, on an end of the crankshaft (1) that is opposite to the piston-cylinder unit (5) there is arranged a sleeve-like lubricant receptacle (8) for the centrifugal delivery of lubricant out of the lubricant sump in the direction of the piston-cylinder unit (5), wherein the sleeve-like lubricant receptacle (8) is fixed to the crankshaft (1) via a fixing section (9), wherein the fixing section (9) of the sleeve-like lubricant receptacle (8) is at least partly arranged between crankshaft (1) and rotor (4) in the radial direction in relation to the longitudinal axis (2) of the crankshaft (1).

Claims

1. A refrigerant compressor comprising a housing; an electric drive unit comprising a rotor and a stator; a crankshaft having a longitudinal axis that is connected rotationally fixedly to the rotor; a piston-cylinder-unit that can be driven by the crankshaft, wherein, at an end of the crankshaft opposite from the piston-cylinder-unit, a sleeve-shaped lubricant receptacle is arranged for centrifugal conveyance of lubricant from a lubricant sump formed in a bottom region of the compressor housing in the direction of the piston-cylinder unit, wherein the sleeve-shaped lubricant receptacle has a fastening portion by which the sleeve-shaped lubricant receptacle is fastened to the crankshaft, wherein at least a section of the fastening portion of the sleeve-shaped lubricant receptacle is arranged, viewed in the radial direction relative to the longitudinal axis of the crankshaft, between the crankshaft and the rotor.

2. The refrigerant compressor according to claim 1, wherein an inner surface of the fastening portion of the sleeve-shaped lubricant receptacle contacts a circumferential surface of the crankshaft and in that an outer surface of the fastening portion of the sleeve-shaped lubricant receptacle contacts an inner surface of the rotor.

3. The refrigerant compressor according to claim 1, wherein the fastening portion of the sleeve-shaped lubricant receptacle is rotationally fixed between the rotor and the crankshaft.

4. The refrigerant compressor according to claim 1, wherein an overlap of the rotor and the fastening portion in the axial direction relative to the longitudinal axis is more than 50% of the axial extent of the fastening portion relative to the longitudinal axis.

5. The refrigerant compressor according to claim 1, wherein the sleeve-shaped lubricant receptacle has a rotationally symmetrical shape relative to the longitudinal axis, the diameter of the fastening portion being greater than or at least equal to the diameter of a receiving portion of the lubricant receptacle.

6. The refrigerant compressor according to claim 5, wherein the fastening portion of the sleeve-shaped lubricant receptacle extends parallel to the longitudinal axis and in that the sleeve-shaped lubricant receptacle comprises a collar portion adjoining the fastening portion and extending radially outward relative to the longitudinal axis.

7. The refrigerant compressor according to claim 1, wherein the fastening portion of the sleeve-shaped lubricant receptacle has at least one slot-like cutback, the rotor comprising at least one ridge corresponding to the cutback.

8. The refrigerant compressor according to claim 1, wherein the electric drive unit is configured as an external-rotor motor and the rotor has at least one carrier element extending outward radially to the longitudinal axis, the carrier element being rotationally fixedly connected to the crankshaft.

9. The refrigerant compressor according to claim 8, wherein the carrier element has a central through-opening for connecting the crankshaft, wherein an outer surface of the fastening portion of the sleeve-shaped lubricant receptacle contacts a wall surface of the through-opening.

10. The refrigerant compressor according to claim 9, wherein the through-opening is formed by a sleeve-like prolongation of the carrier element and in that an annular support element is pressed onto or shrink-fitted onto the sleeve-shaped prolongation.

11. The refrigerant compressor according to claim 1, wherein the electric drive unit is configured as an internal-rotor motor, and the rotor has a central through-opening for connection to the crankshaft, wherein an outer surface of the fastening portion of the sleeve-shaped lubricant receptacle contacts a wall surface of the through-opening.

12. The refrigerant compressor according to claim 1, wherein a lubricant driver is arranged in the interior of the sleeve-shaped lubricant receptacle.

13. The refrigerant compressor according to claim 1, wherein the housing is hermetically sealable.

14. The refrigerant compressor according to claim 1, wherein the lubricant receptacle is rotationally fixedly fastened to the crankshaft.

15. The refrigerant compressor according to claim 1, wherein an overlap of the rotor and the fastening portion in the axial direction relative to the longitudinal axis is between 75% and 100% of the axial extent of the fastening portion relative to the longitudinal axis.

16. The refrigerant compressor according to claim 6, wherein the collar portion of the sleeve-shaped lubricant receptacle bears against the rotor.

17. The refrigerant compressor according to claim 7, wherein the at least one slot-like cutback extends parallel to the longitudinal axis over the entire extent of the fastening portion.

18. The refrigerant compressor according to claim 12, wherein the lubricant driver and the lubricant receptacle are formed integrally.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0024] 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.

[0025] Therein:

[0026] FIG. 1 shows a sectional representation of a first embodiment variant of a refrigerant compressor according to the invention;

[0027] FIG. 2 shows an enlarged detail representation of a bottom region of the refrigerant compressor according to FIG. 1;

[0028] FIG. 3 shows an additional enlarged detail representation according to FIG. 1;

[0029] FIG. 4 shows a sectional representation of a second embodiment variant of a refrigerant compressor according to the invention;

[0030] FIG. 5 shows a sectional representation of a third embodiment variant of a refrigerant compressor according to the invention;

[0031] FIG. 6 shows an enlarged detail representation of the bottom region of the refrigerant compressor according to FIG. 5.

MODES FOR EMBODYING THE INVENTION

[0032] FIGS. 1 to 3 show a first embodiment variant of a refrigerant compressor according to the invention, having a drive unit configured as an external rotor motor, which is arranged in the interior of a compressor housing 6 that can be hermetically encapsulated. The drive unit comprises a stator 3 and a rotor 4. A crankshaft 1 having a longitudinal axis 2 is arranged centrally relative to the stator 3 and the rotor 4, which crankshaft 1 is connected rotationally fixedly, e.g. form-fittingly, friction-fittingly or integrally, to the rotor 4 in order to drive the piston-cylinder-unit 5 of the refrigerant compressor that cyclically compresses a refrigerant. The crankshaft 1 is mounted in a bearing bushing 17 of a carrier housing 18 carrying the piston cylinder unit 5. The stator 3, which is arranged internally in the radial direction relative to the longitudinal axis 2, subsequently referred to as the radial direction, is fastened to the outer side of the bearing bushing 17.

[0033] The crankshaft 1 is part of a crank assembly, which comprises a crank pin 26 offset eccentrically with respect to the longitudinal axis 2 and connected directly to the crankshaft 1. The piston-cylinder-unit 5 comprises a piston 25, which is guided movable linearly in a cylinder housing 24, a connecting rod 23 connecting the crank pin 26 to the piston 25, a cylinder head arrangement 27 comprising valves, and a suction muffler 28 connected to the cylinder head arrangement 27.

[0034] In the present embodiment, the carrier housing 18 and the cylinder housing 24 are integrally formed, more precisely as a cast part. The carrier housing 18 has multiple prolongations, via which the carrier housing 18 is supported on spring elements 29 in the compressor housing 6 that are arranged in a bottom region 7 of the compressor housing 6. In alternative embodiments, carrier housing 18 and cylinder housing 24 can be formed in two parts and connected to one another via connecting means.

[0035] The rotor 4 comprises, as illustrated in FIG. 2, a plurality of permanent magnets 14, which are arranged outside the stator 3 in the radial direction and are connected to one another in the circumferential direction via a shading circuit ring 15. In order to connect the permanent magnets 14 to the crankshaft 1 by means of a force fit or friction fit, the rotor 4 has a carrier element 12 extending radially outward from the crankshaft 1 and reaching underneath the stator 3. The carrier element 12 is formed substantially in a plate shape and has an elevated edge portion curved in the direction of the piston cylinder unit 5, at which edge portion the permanent magnets 14 and the shading circuit ring 15 are mounted. For connection to the crankshaft 1, the carrier element 12 has a centrally arranged through-opening 13 for positioning the rotor 4 coaxially with respect to the longitudinal axis 2. The carrier element 12 in the present embodiments has a sleeve-shaped prolongation 12a with a circular cylindrical clear cross section, which is arranged centrally, and extends onto the side of the carrier element 12 facing away from the piston cylinder unit 5. The through-opening 13 is formed by the prolongation 12a. Carrier element 12 and prolongation 12a in the present example are integrally formed, the prolongation 12a and the edge portion being formed from the carrier element 12 by means of a deep drawing process, for example.

[0036] 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 supply them with lubricant from a lubricant sump formed in the operating state in the bottom region 7 of the compressor housing 6, the crankshaft 1 has, at the end opposite from the piston-cylinder-unit 5, i.e. the lower end, an eccentric bore 19 arranged eccentrically relative to the longitudinal axis 2 in the radial direction and running at an angle relative to the longitudinal axis 2. Lubricant that reaches the eccentric bore 19 is pressed against the wall of the eccentric bore 19 by the centrifugal force during rotation of the crankshaft 1 and is conveyed in the direction of the piston cylinder unit 5 by the elevated pressure. In the present embodiment, the eccentric bore 19 is configured as a blind hole and is connected at the end facing the piston-cylinder-unit 5 by a first radial bore 20 to a helical groove 22 formed on the circumferential surface of the crankshaft 1 in order to convey the lubricant. A second radial bore 21, which is arranged closer to the lower end of the crankshaft 1 as viewed in the direction of the longitudinal axis 2, is used for venting the lubricant system. The conveyance speed is increased by the venting and simultaneously a negatively acting pulsation is prevented.

[0037] In alternative embodiment variants, the eccentric bore 19 can also be arranged running parallel to the longitudinal axis 2 or, instead of the eccentric bore, an axial bore running coaxially relative to the longitudinal axis 2 can be provided.

[0038] In order to bring lubricant out of the lubricant sump into the eccentric bore 19 without the necessity for a free end of the crankshaft 1 to dip into the lubricant sump, a sleeve-shaped lubricant receptacle 8 is provided, which is rotationally fixed to the crankshaft 1 at the end of the crankshaft 1 remote from the piston-cylinder-unit 5, and thus rotates along with the crankshaft 1. Lubricant enters into a receiving portion 10 of the lubricant receptacle 8 via a lubricant entry opening. Because the lubricant receptacle 8 has a rotationally symmetrical shape relative to the longitudinal axis 2 and is arranged coaxially with the longitudinal axis 2, a lubricant parabola or a paraboloid shaped lubricant column is formed in the lubricant receptacle 8 by the rotation of the lubricant receptacle 8, and passes at the lower end of the crankshaft 1 into the eccentric bore 19 and is conveyed on from there in the direction of the first radial bore 20.

[0039] As the distance between the surface level of the lubricant sump and the first radial bore 20, also referred to as the conveyance height, increases, the conveying power of the lubricant-conveying system decreases. It is therefore one aspect of the invention that a fastening portion 9 of the sleeve-shaped lubricant receptacle 8 is arranged between the rotor 4 and the crankshaft 1. Due to the overlapping of fastening portion 9, rotor 4 and crankshaft 1, a particularly space-saving connection of the lubricant receptacle 8 to the crankshaft 1 can be achieved, whereby the conveyance height can be lowered and thus the conveying power, i.e. the lubricant feed rate per minute, can be increased. The increase of the conveying power can be explained by the fact that, due to the lower conveyance height, the wall thickness of the lubricant paraboloid in the region of the second radial bore 20 is greater and thus more lubricant reaches the helical groove 22. Due to the higher conveying power, a sufficient lubrication of the piston-cylinder-unit 5 can be guaranteed even at lower rotational speeds, so that the refrigerant compressor can be operated as energy-optimally as possible.

[0040] The greater the overlap between fastening portion 9, rotor 4 and crankshaft 1, the lower the conveyance height of the lubricant. In addition to this, it is not necessary for the crankshaft 1 to protrude from the rotor 4 in order to receive the fastening portion 9 of the lubricant receptacle 8, because the rotor 4 is fastened to the crankshaft 1 and the lubricant receptacle 8 is fastened by means of the fastening portion 9 in the same region of the crankshaft 1, namely at the lower end thereof. In the present embodiment, an inner surface of the fastening portion 9 contacts an outer circumferential surface of the crankshaft 1 and an outer surface of the fastening portion 9 contacts an inner surface of the rotor 4, more precisely a wall surface of the through-opening 13. As can be easily recognized in the drawing, the fastening portion 9 has a circular cylindrical clear cross section, in which the lower end of the crankshaft 1 is received, while the carrier element 12 of the rotor 4 bears against the outer surface of the fastening portion 9. The rotor 4 is thus fastened to the crankshaft 1 by interposition of the fastening portion 9 of the sleeve-shaped lubricant receptacle 8, at least in certain portions. While through-opening 13, fastening portion 9 and the lower end of crankshaft 1 overlap completely in the present embodiment, other embodiments can also provide a partial overlapping of through-opening 13 and fastening portion 9, e.g. an overlap of 50%, 75%, 80%, 85%, 90% or 95% relative to the axial extent of the fastening portion 9.

[0041] As can be recognized in detail in FIG. 3, a collar portion 11 adjoins the fastening portion 9 on the side of the fastening portion 9 opposite from the receiving portion 10, which collar portion 11 protrudes at an angle from the fastening portion 9 and extends in the radial direction. In the present embodiment, the collar portion 11 protrudes at a right angle from the fastening portion 9 and bears against an upper side of the carrier element 12 facing the piston-cylinder-unit 5. The collar portion 11 can be used as a stop during assembly, for example. At the same time, the axial play of the crankshaft 1 can be adjusted by the attachment of the lubricant receptacle 8 during the assembly of the crankshaft 1, because the contour of the bearing bushing 17 and the collar portion 11 overlap in the direction of the longitudinal axis 2, so that the rotor 4 need not be installed until a subsequent assembly step, without the risk of an axial slippage of the crankshaft 1 in the bearing bushing 17. The inclination of the axis of the eccentric bore 19 by approximately 3 to 7 relative to the longitudinal axis 2, and the arrangement of the first radial bore 20 and the second radial bore 21, wherein the openings of the two radial bores 20, 21 are arranged opposite from one another, can also be clearly recognized in FIG. 3.

[0042] FIG. 4 shows a second embodiment variant of the invention, which differs only slightly from the first embodiment variant, and therefore only the differences will be discussed below. To improve the connection of the carrier element 12 to the crankshaft 1 and increase the surface pressure between carrier element 12 and fastening portion 9, and between fastening portion 9 and crankshaft 1, an annular support element 30 is pressed onto or shrink-fitted onto the prolongation 12a. In other words, the support element 30 contacts an outer circumferential surface of the prolongation 12a and exerts a force directed radially inward in the direction of the longitudinal axis 2 onto the fastening portion 9. This force increases the surface pressure and thus the quality of the force-fitting or friction-fitting connection between the wall surface of the through-opening 13 and the outer surface of the fastening portion 9 and between the inner surface of the fastening portion 9 and the circumferential surface of the crankshaft 1. The support element 30 contacts a lower side of the carrier element 12 and overlaps approximately 80% of the prolongation 12a.

[0043] FIGS. 5 and 6 show a third embodiment of a refrigerant compressor according to the invention, in which the drive unit is configured as an internal-rotor motor. The rotor 4 is thus arranged inside the stator 3 relative to the longitudinal axis 2. A rotor stack, comprising lamina-like rotor sheets for example, is fastened directly to the crankshaft 1. In this case, the rotor 4 or the rotor laminated stack of the rotor 4 has a central through-opening 13, which is used firstly for fastening to the crankshaft 1 and secondly has a cutback for receiving the bearing bushing 17, because the bearing bushing 17 protrudes axially into the rotor 4.

[0044] The structure of the piston-cylinder-unit 5 corresponds substantially to the structure described in FIG. 1. Because the crankshaft 1 has not been cut away, it is easy to recognize the contour of the helical groove 22, which is formed analogously to the that in the previous embodiments.

[0045] In this embodiment variant as well, the conveying power of the lubricant-conveying system can be improved because the fastening portion 9 of the sleeve-shaped lubricant receptacle 8 is arranged between rotor 4 and crankshaft 1. The inner surface of the fastening portion 9 contacts the outer circumferential surface of the lower end of crankshaft 1, while the outer surface of the fastening portion 9 contacts the inner surface of the rotor 4, more precisely a wall surface of the through-opening 13. In the present embodiment, the dimension of the fastening portion 9 in the direction of the longitudinal axis 2 is selected such that the fastening portion 9 crosses through the entire through-opening 13, and the collar portion 11 bears against an upper surface of the rotor 4 that faces the piston-cylinder-unit 5. Thus the lubricant receptacle 8 can be pushed from above into the rotor 4 during assembly, wherein the collar portion 11 serves as a stop. Alternative embodiment variants can provide that the lubricant receptacle 8 does not have a collar portion 11 and is inserted only in certain portions into the through-opening 13.

[0046] Both embodiment variants can provide that the fastening portion 9 has one or more, for example two, three or four, slot-like cutbacks, which correspond to ridges of the rotor, or to ridges formed in the through-opening 13. When the ridges engage with the cutbacks, a direct contact between rotor 4 and crankshaft 1 in these portions is possible, without interposition of the fastening portion 9 of the lubricant receptacle 8. This can improve the rotationally fixed fastening of the rotor 4 to the crankshaft 1. The fastening portion 9 of the lubricant receptacle 8 and the through-opening 13 of the rotor 4 are normally pressed onto or shrink-fitted onto the crankshaft 1.

[0047] In addition, a lubricant driver 16, which supports the formation of the lubricant paraboloid and increases the conveying power of the conveying device, can be arranged in the lubricant receptacle 9 [sic; 8]. Thus a lubricant driver 16 is arranged in the lubricant receptacle 8 in each of the above-described embodiments, and has at least one or more helical surfaces facing outward in the direction of the inner wall of the lubricant receptacle 8 or facing upward in the direction of the eccentric bore 19 of the crankshaft 1 in order to force the lubricant upward in the axial direction. It is also conceivable that one or more surfaces of the lubricant driver 16 are planar in shape.

LIST OF REFERENCE NUMBERS

[0048] 1 Crankshaft

[0049] 2 Longitudinal axis of crankshaft 1

[0050] 3 Stator

[0051] 4 Rotor

[0052] 5 Piston-cylinder-unit

[0053] 6 Compressor housing

[0054] 7 Bottom region of compressor housing 6

[0055] 8 Sleeve-shaped lubricant receptacle

[0056] 9 Fastening portion of lubricant receptacle 8

[0057] 10 Receiving portion of lubricant receptacle 8

[0058] 11 Collar portion

[0059] 12 Carrier element of rotor 4

[0060] 12a Sleeve-shaped prolongation of carrier element 12

[0061] 13 Through-opening

[0062] 14 Permanent magnet

[0063] 15 Shading ring

[0064] 16 Lubricant driver

[0065] 17 Bearing bushing

[0066] 18 Carrier housing

[0067] 19 Eccentric bore

[0068] 20 First radial bore

[0069] 21 Second radial bore

[0070] 22 Helical groove

[0071] 23 Connecting rod

[0072] 24 Cylinder housing

[0073] 25 Piston

[0074] 26 Crank pin

[0075] 27 Cylinder head arrangement

[0076] 28 Suction muffler

[0077] 29 Spring element

[0078] 30 Annular support element