EP3628866B1 - Lubricant holder for a refrigerant compressor - Google Patents

Description

• das Innenelement mit seiner Mantelfläche zumindest abschnittsweise innerhalb des lichten Querschnitts des Hülsenelements angeordnet ist,
• in Richtung vom unteren Ende zum oberen Ende des Hülsenelements gesehen das untere Ende der Mantelfläche vor dessen oberen Ende angeordnet ist und
• das Innenelement und das Hülsenelement relativ zueinander um die Längsachse des Hülsenelements und/oder die Längsachse des Innenelements verdrehbar sind, wobei sich der lichte Querschnitt vom unteren Ende zum oberen Ende des Hülsenelements hin zumindest in einem zur Aufnahme des Innenelements vorgesehenen Aufnahmesegment verjüngt und wobei sich das Innenelement im Bereich der Mantelfläche vom unteren Ende zum oberen Ende der Mantelfläche hin verjüngt und wobei die Innenwand und/oder die Mantelfläche mindestens eine spiralförmig verlaufende Rille aufweist.

The present invention relates to a lubricant receptacle for the vertical conveyance of lubricant by means of a crankshaft of a refrigerant compressor according to claim 1, comprising a sleeve element with a clear cross section delimited by an inner wall, which extends along a longitudinal axis of the sleeve element from an upper end to a lower end of the sleeve element extends, the lubricant receptacle further comprising an inner element having an outer surface that extends along a longitudinal axis of the inner element from a lower end to an upper end, wherein in an operating state of the lubricant receptacle

• the inner element is arranged with its lateral surface at least in sections within the clear cross section of the sleeve element,
• viewed in the direction from the lower end to the upper end of the sleeve element, the lower end of the lateral surface is arranged in front of the upper end thereof and
• the inner element and the sleeve element can be rotated relative to one another about the longitudinal axis of the sleeve element and/or the longitudinal axis of the inner element, with the clear cross-section tapering from the lower end to the upper end of the sleeve element at least in a receiving segment provided for receiving the inner element and with the Inner element in the area of the lateral surface tapers from the lower end to the upper end of the lateral surface and wherein the inner wall and/or the lateral surface has at least one spirally running groove.

STATE OF THE ART

In refrigerant compressors with a hermetically encapsulated compressor housing, an electric drive unit arranged in the interior of the compressor housing, comprising a rotor and a stator, a crankshaft non-rotatably connected to the rotor, and with a piston-cylinder unit arranged in the interior of the housing, which has a movable in a Cylinder of the piston-cylinder unit comprises pistons mounted, which can be driven by the crankshaft for compressing refrigerant, ensuring adequate lubrication of all moving components is of particular importance. For this purpose it can be provided that lubricant which collects in a lubricant sump covering a bottom area of the compressor housing is conveyed via the crankshaft in the direction of the cylinder.

For this purpose, a sleeve-shaped lubricant receptacle is often provided, which is connected to the crankshaft in a rotationally fixed manner and is arranged coaxially with it and protrudes with an end section into the lubricant sump. Lubricant that has penetrated through an inlet opening from the lubricant sump into a cylindrical receiving section of the lubricant receiver is forced into a paraboloid shape due to the rotation of the lubricant receiver - which is caused by rotation of the crankshaft - with the paraboloid moving along the inner wall of the lubricant receiver and along the Forms the inner wall of the crankshaft—hollow or provided with a bore. Such a lubricant recording is for example from the AT 15828 U1 famous.

A maximum rise to which the lubricant located in the receiving section of the lubricant receptacle can be raised in this way is in the range of the clear inner diameter of the crankshaft or the bore and depends on the square of the rotational speed of the lubricant holder and the square of the clear inner radius of the crankshaft or the lubricant holder. The lubricant can then escape from the crankshaft to points to be lubricated via at least one outlet bore.

With an appropriate selection of the production parameters (e.g. inside radius of the crankshaft, height of the outlet bores) and process parameters (e.g. rotational speed of the crankshaft, viscosity of the lubricant), it is thus possible to transport the lubricant from the bottom of the compressor housing via the compressor crankshaft to the bearing points by means of the lubricant intake of the main bearing of the crankshaft, the crank pin and the connecting rod of the refrigerant compressor.

In practice, compressors with variable speeds are increasingly being used - in contrast to conventional compressors with a fixed speed, which only have two states, namely zero speed and a working speed of typically 3000 ^rpm . In the case of compressors with variable speeds, depending on the required cooling capacity, very low speeds are regularly achieved in ^practice - typically a minimum of 800 rpm. Since, as explained above, the height of rise depends squarely on the rotational speed or the speed, low speeds pose a major problem for reliable lubrication.

Attempts to improve pumping performance by means of an inner element have so far proved unsatisfactory. In this case, the cylindrical receiving section is open at the bottom and the likewise cylindrical inner element is arranged in the receiving section, so that a Gap between a lateral surface of the inner element and the inner wall of the receiving portion results. The inner element is essentially fixed in position, typically by being connected to the stator. The inner element typically has a spiral-shaped groove running from bottom to top on its outer surface, which promotes the delivery of the lubricant. The inner element must have a sufficiently large radius so that the rotational speed or tangential speed and thus the achievable centrifugal force acting on the lubricant in the area of the outer surface is large enough to achieve good pumping capacity even at low speeds. On the other hand, such large radii result in an abrupt structural transition and hence a high abrupt pressure drop between the inner member and the bore in the crankshaft, which disadvantageously reduces lubricant flow. Although smaller diameters of the inner element reduce the pressure drop, they do not generate sufficiently large centrifugal forces at low speeds.

Another disadvantage of known inner member approaches is that the width of the gap between the inner member and the inner wall of the female portion is critical. In principle, a smaller gap would tend to result in better conveying capacity. Due to the viscosity of the lubricant, however, the gap cannot be made too small, otherwise friction losses would reduce efficiency. This means that the selection of the gap width must be made from these points of view as the best possible compromise. In practice, however, it has been found that depending on the exact operating parameters of the refrigerant compressor and the thermal expansion of the lubricant on the one hand and the lubricant holder including the inner element on the other hand, the gap width (like the viscosity of the lubricant) is not stable but changes. It comes in sequence too undesired strong fluctuations in the flow rate, which, especially at low speeds, carries the risk of too low a flow rate and the associated consequential damage.

From the U.S. 2010/074771 A1 discloses an oil pump for a refrigeration compressor, comprising a sleeve having an inner surface, an upper portion fixed to a crankshaft and a rotor, whereby the sleeve is rotationally driven, and a lower portion, the lower end of which is immersed in lubricating oil. The oil pump further includes an elongate pump body disposed within the inner surface of the sleeve, the sleeve and pump body each having a conical profile and tapering from bottom to top. The inner surface of the sleeve has a helical groove. The relative movement between the sleeve and the pump body causes oil to flow upwards.

OBJECT OF THE INVENTION

It is therefore the object of the present invention to provide a lubricant receptacle which avoids the disadvantages described above and ensures reliable lubrication even at low speeds, as is regularly the case in practice, particularly in compressors with variable speeds.

PRESENTATION OF THE INVENTION

• das Innenelement mit seiner Mantelfläche zumindest abschnittsweise innerhalb des lichten Querschnitts des Hülsenelements angeordnet ist,
• in Richtung vom unteren Ende zum oberen Ende des Hülsenelements gesehen das untere Ende der Mantelfläche vor dessen oberen Ende angeordnet ist und
• das Innenelement und das Hülsenelement relativ zueinander um die Längsachse des Hülsenelements und/oder die Längsachse des Innenelements verdrehbar sind, vorgesehen, dass sich der lichte Querschnitt vom unteren Ende zum oberen Ende des Hülsenelements hin zumindest in einem zur Aufnahme des Innenelements vorgesehenen Aufnahmesegment verjüngt und dass sich das Innenelement im Bereich der Mantelfläche vom unteren Ende zum oberen Ende der Mantelfläche hin verjüngt.

In order to achieve the above object, a lubricant receptacle for the vertical conveyance of lubricant by means of a crankshaft of a refrigerant compressor comprises a sleeve element with a clear cross section delimited by an inner wall, which extends along a longitudinal axis of the sleeve element from an upper end to a lower end of the sleeve member, the lubricant receptacle further comprising an inner member having an outer surface extending along a longitudinal axis of the inner member from a lower end to an upper end, wherein in an operative state of the lubricant receptacle

• the inner element is arranged with its lateral surface at least in sections within the clear cross section of the sleeve element,
• viewed in the direction from the lower end to the upper end of the sleeve element, the lower end of the lateral surface is arranged in front of the upper end thereof and
• the inner element and the sleeve element can be rotated relative to one another about the longitudinal axis of the sleeve element and/or the longitudinal axis of the inner element, provided that the clear cross section tapers from the lower end to the upper end of the sleeve element at least in a receiving segment provided for receiving the inner element and that the inner element in the region of the lateral surface tapers from the lower end to the upper end of the lateral surface.

Since only the relative rotation of the sleeve element and the inner element to one another is important, the inner element can, for example, be connected to the crankshaft in a rotationally fixed manner and the sleeve element can be rotationally fixed—apart from a negligible, minor angle of rotation. During operation of the compressor, the crankshaft rotates and, accordingly, the inner element rotates, whereas the sleeve element does not rotate.

Or the sleeve element can be connected to the crankshaft in a rotationally fixed manner and the inner element can be rotationally fixed except for a negligible, minor angle of rotation.

A non-rotatable connection between the inner element or sleeve element and the crankshaft can in principle be direct or indirect, ie with the interposition of at least one other element such as a seal, a fastener, etc., take place.

The sleeve element can be connected to the crankshaft, in particular in the region of its upper end. It would be conceivable, for example, for the sleeve element to be slid onto the crankshaft with its clear cross-section in the region of the upper end and to be held thereon, for example by means of a press fit. For this purpose, it can be provided that the clear cross section in the region of the upper end compared to the im Recording segment existing taper extended again to accommodate the crankshaft.

For the sake of good order, it is noted that it is not excluded that the sleeve element is itself a part or section of a larger element. In any case, the clear section extends over this part or section, i.e. over the sleeve element.

According to what was said above, the sleeve element and the inner element are designed in such a way that in the operating state the inner element is arranged with its lateral surface at least in sections within the clear cross section of the sleeve element. I.e. the inner element is at least partially accommodated in the receiving segment.

According to what has been said above, the sleeve element and the inner element are designed in such a way that in the operating state viewed in the direction from the lower end to the upper end of the sleeve element, the lower end of the lateral surface is arranged in front of the upper end thereof. This means that the receiving segment of the clear cross section and the inner element, in particular its lateral surface, are oriented at least approximately the same. In practice, when used in an operating refrigerant compressor, the result is that the lower ends of the sleeve element and the shell surface are arranged in the vertical direction below the upper ends of the sleeve element and the shell surface.

The cross section of the inner element or the geometry of the inner element with its outer surface is preferably adapted to the clear cross section or at least to the receiving segment. For example, it would be conceivable for the clear cross section or the receiving segment to have a certain sequence of, preferably fine, steps for the purpose of narrowing, and for the lateral surface to have a corresponding sequence of steps.

According to the above, the sleeve element and the inner element are designed such that in the operating state the inner element and the sleeve element can be rotated relative to one another about the longitudinal axis of the sleeve element and/or the longitudinal axis of the inner element. This means that the at least partial arrangement of the inner element in the receiving segment is such that a gap with a certain gap width is created between the lateral surface and the inner wall, which delimits the clear cross section and thus in particular the receiving segment. Accordingly, lubricant from a lubricant sump of the refrigerant compressor can enter this gap if the inner element and the sleeve element protrude at least in sections into the lubricant sump. The sleeve element projects into the lubricant sump, in particular in the area of its lower end, and the inner element in particular in the area of the lower end of its lateral surface.

The lubricant can in particular be an oil that is customary when used in refrigerant compressors.

The rotation of the crankshaft causes the sleeve element and the inner element to rotate relative to one another, in particular when the sleeve element is connected in a rotationally fixed manner to the crankshaft. In this case, the inner element preferably does not rotate relative to the stator, or only rotates through a limited angular range, whereas the sleeve element rotates completely. As already stated above, however, a reverse design is also possible, in which the inner element rotates completely and the sleeve element does not rotate relative to the stator, or only rotates through a limited angular range.

Due to the viscosity of the lubricant or the friction between the lubricant and the sleeve element or the inner element, a corresponding centrifugal force. This pushes the lubricant in the gap in the direction from the lower end to the upper end of the lateral surface and thus in the direction of the crankshaft. Due to the narrowing of the inner element or the receiving segment, it can have a large diameter in the area of the lower end of the outer surface, whereby sufficiently high tangential speeds or centrifugal forces can be realized even at low speeds to ensure reliable lubricant delivery. On the other hand, the tapering of the inner element or the receiving segment can ensure that in the region of the upper end of the lateral surface there is a substantially continuous transition, ie a transition without an abrupt drop in pressure, for the lubricant from the gap into a bore of the crankshaft. Accordingly, an adverse reduction in the flow of the lubricant can be avoided.

In order to further improve the delivery of the lubricant, it is provided that the inner wall and/or the lateral surface has at least one groove running in a spiral shape. I.e. the inner wall and/or the lateral surface can also have several grooves.

In addition to the gap, the at least one groove provides an additional delivery volume for the lubricant that is independent of the gap width. Due to the centrifugal forces acting on the lubricant, the lubricant is forced into and through the at least one groove.

The lateral surface preferably has the at least one spiral-shaped groove which runs in the direction from the lower end to the upper end of the lateral surface. The at least one groove can extend from the lower end to the upper end of the lateral surface. You can theoretically, for example, start only in the area of the lower end and/or stop in the area of the upper end, so that a certain overhang of the lateral surface over the groove in the area of the lower and/or upper end is given. Seen in the direction of the longitudinal axis of the inner element, the at least one groove runs spirally around this longitudinal axis, it being possible for the groove to theoretically also end on the longitudinal axis. For the sake of good order, it is noted that the course of the groove is of course also given in the opposite direction, ie from the upper end to the lower end of the lateral surface.

In order to optimize the flow of lubricant, in particular with regard to its stability or continuity, the invention provides that the at least one groove has a varying pitch angle, which preferably increases from the lower end to the upper end of the lateral surface.

In a preferred embodiment of the lubricant receptacle according to the invention, it is provided that the clear cross section of the sleeve element is designed in the shape of a truncated cone, at least in its receptacle segment. On the one hand, this proves to be favorable in terms of production technology. On the other hand, this also has a favorable effect on the flow behavior of the lubricant or oil, since there is a correspondingly smooth inner wall at least in the receiving segment.

If the inner wall has the at least one groove, what is said above naturally means that the clear cross-section of the sleeve element is designed in the shape of a truncated cone, at least in its receiving segment, apart from the at least one groove.

In a preferred embodiment of the lubricant receptacle according to the invention, it is provided that the lateral surface of the inner element is designed as the lateral surface of a truncated cone. On the one hand, this again proves to be favorable in terms of manufacturing technology. On the other hand, this also has a favorable effect on the flow behavior of the lubricant or oil, since there is a smooth lateral surface.

If the lateral surface has the at least one groove, what is said above naturally means that the lateral surface, apart from the at least one groove, is designed as the lateral surface of a truncated cone.

Particularly favorable flow conditions are present when at least the receiving segment is designed in the shape of a truncated cone, in particular when a design corresponding to the lateral surface is carried out. Accordingly, in a particularly preferred embodiment of the lubricant receptacle according to the invention, it is provided that the truncated cone shape of the receptacle segment of the clear cross section is based on a cone with a first opening angle, that the truncated cone shape according to which the lateral surface is formed is based on a cone with a second opening angle and that the absolute difference between the first opening angle and the second opening angle is less than or equal to 10°, preferably less than or equal to 5°, particularly preferably equal to 0°. The absolute difference is to be understood as the absolute value of the difference between the two opening angles.

In a preferred embodiment of the lubricant receptacle according to the invention, it is provided that the inner element has at least one protruding wing and/or a fastening element, preferably an eyelet, for a fixing means in the region of the lower end of the lateral surface. This configuration serves to ensure that the inner element does not rotate or only rotates by a certain angular amount when the crankshaft rotates, whereas the sleeve element rotates with the crankshaft. For this purpose, the wing, which dips into the lubricant sump, is sufficient due to the viscosity of the lubricant, ie the lubricant causes a sufficiently large resistance to rotation of the inner element. To increase this resistance, the area of the wing can be made correspondingly larger. Typically, the at least one wing does not protrude from the lateral surface, but from a kind of base surface of the Inner member that is substantially normal to the longitudinal axis of the inner member. In particular, the at least one wing extends at least in sections parallel—and normal—to the longitudinal axis and points away from the upper end of the lateral surface.

Alternatively or additionally, a fixing means, for example in the form of a bracket or a bracket, can be provided, which is fastened to the fastening element on the one hand and is supported on an essentially immovable element, e.g. on the stator, on the other hand or is rigidly connected to it.

The fixing means can also serve to mount the inner element in a fixed or movable manner in relation to the longitudinal axis, ie with a directional component parallel to the longitudinal axis, of the sleeve element. Alternatively or additionally, the buoyancy experienced by the inner element when immersed in the lubricant sump can be used for the purpose of such a bearing. In particular, the inner element can be designed in such a way that it floats on the lubricant (ie does not sink completely), which represents a particularly cost-effective mounting of the inner element. Accordingly, in a preferred embodiment of the lubricant holder according to the invention, it is provided that the inner element is made of a material, preferably a plastic, whose density is lower than the density of the lubricant. It would also be conceivable to manufacture the inner element from a light metal or a light metal alloy, in particular an aluminum alloy, to achieve the desired density.

It is analogous to the above in a refrigerant compressor with a hermetically encapsulated compressor housing, an electric drive unit arranged in the interior of the compressor housing, comprising a rotor and a stator, a crankshaft non-rotatably connected to the rotor, and a piston-cylinder arranged in the interior of the housing -Unit, which comprises a piston which is movably mounted in a cylinder of the piston-cylinder unit and which can be driven by the crankshaft to compress refrigerant, according to the invention that the refrigerant compressor has a lubricant receptacle according to the invention which is in the operating state, in order to collect lubricant from one in one To promote bottom area of the compressor housing trained lubricant sump over the crankshaft.

As also explained above, the inner member or the sleeve member can be non-rotatably connected to the crankshaft. Accordingly, in a preferred embodiment of the refrigerant compressor according to the invention, it is provided that the sleeve element of the lubricant receptacle is connected to the crankshaft in a rotationally fixed manner.

In a preferred embodiment of the refrigerant compressor according to the invention, it is provided that the crankshaft has a bore, preferably at least partially oblique to an axis of rotation of the crankshaft, which is in fluid communication with the clear cross section of the sleeve element, with the inner element protruding into the bore. This arrangement is possible due to the narrowing of the inner element and ensures a particularly good transition for the lubricant from the gap into the bore of the crankshaft. The lubricant can then escape from the crankshaft—more precisely, from the bore of the crankshaft—to points to be lubricated via at least one outlet bore. Preferably there are several exit bores provided, which are arranged one behind the other seen along the axis of rotation of the crankshaft.

According to what has already been said above, it is provided in a preferred embodiment of the refrigerant compressor according to the invention that the inner element is movable in relation to the longitudinal axis of the sleeve element. The gap width is changed by a corresponding movement of the inner element parallel to the longitudinal axis of the sleeve element. Accordingly, the gap width can be adjusted to operating parameters such as the temperature and/or the viscosity of the lubricant and/or the speed in order to enable an optimal flow of the lubricant. For example, with a lubricant that is becoming thinner, the gap width can be reduced in order to bring about increased delivery.

In particular, such an adjustment or regulation of the gap width can take place automatically or by itself in a simple manner. For this purpose, a preferred embodiment of the refrigerant compressor according to the invention provides that a fixing means designed as a spring element, preferably in the form of a resilient wire clip, is provided, with which the inner element is essentially non-rotatably connected to the stator or other components of the refrigerant compressor. As already described, slight twisting angles of the inner element can be tolerated, which result from the elasticity of the spring element.

The connection to the stator or other - essentially immobile - components of the refrigerant compressor can be direct or indirect, i.e. with the interposition of other elements.

In particular, the spring element ensures a certain mobility of the inner element parallel to the longitudinal axis of the sleeve element. The spring element causes that the inner member is pushed towards the receiving segment to some degree, which tends to reduce the gap width. This is counteracted by a certain pressure of the lubricant in the gap, which pressure depends on various factors. For example, the inner element is pressed away from the inner wall of the receiving segment against the spring force of the spring element, the stronger the thicker the lubricant is or the higher the speed, and the larger the gap width remains the inner element is pressed less strongly away from the inner wall of the receiving segment by the lubricant flowing in the gap against the spring force of the spring element, and the gap width decreases accordingly.

Alternatively, the adjustment can also take place—at least roughly—using the above-described utilization of the buoyancy of the inner element in the lubricant, in which case the fixing means can also be dispensed with entirely if the at least one wing is present. Due to the buoyancy, the inner element is basically pressed in the direction of the receiving segment, which tends to lead to a reduction in the gap width—similar to the embodiment with the spring element described above. This is counteracted by the pressure of the lubricant in the gap, which pressure depends on various factors. For example, the more viscous the lubricant or the higher the speed, the greater the gap width. If the lubricant becomes thinner or the speed decreases, the gap width decreases accordingly.

In particular, fluctuations in the lubricant delivery due to speed fluctuations can be automatically compensated for in the manner described. Such speed fluctuations can be particularly pronounced in compressors with variable Speed and very low moments of inertia of the crankshaft and rotor occur.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be explained in more detail using an exemplary embodiment. The drawings are exemplary and are intended to explain the idea of the invention, but in no way restrict or even conclusively reproduce it.

Fig. 1

ein Innenelement einer Ausführungsform einer erfindungsgemäßen Schmiermittelaufnahme in axonometrischer Ansicht

Fig. 2

eine Schnittansicht der Ausführungsform der erfindungsgemäßen Schmiermittelaufnahme, wobei die Schmiermittelaufnahme auf einer Kurbelwelle eines erfindungsgemäßen Kältemittelkompressors montiert ist

Fig. 3

eine Schnittansicht eines erfindungsgemäßen Kältemittelkompressors mit der Schmiermittelaufnahme aus Fig. 2

It shows:

1

an inner element of an embodiment of a lubricant receptacle according to the invention in an axonometric view

2

a sectional view of the embodiment of the lubricant receiver according to the invention, wherein the lubricant receiver is mounted on a crankshaft of a refrigerant compressor according to the invention

3

a sectional view of a refrigerant compressor according to the invention with the lubricant receptacle 2

WAYS TO CARRY OUT THE INVENTION

1 shows an axonometric view of an inner element 9 of a lubricant receptacle 1 according to the invention. The latter is in an operating state and is attached to a crankshaft 2 of a refrigerant compressor 3 according to the invention in 2 shown in a sectional view.

The lubricant holder 1 is used for the vertical promotion of lubricant, in particular oil 15, from one in one Lubricant sump 26 formed in the bottom area 25 of a compressor housing 18 of the refrigerant compressor 3, see the sectional view of FIG 3 , via the crankshaft 2. The crankshaft 2 has a 2 easily recognizable bore 27, from which the oil 15 can escape via outlet bores 28 to points to be lubricated. For optimal delivery of the oil 15, the bore 27 can be designed to run obliquely to an axis of rotation 29 of the crankshaft 2, as shown in FIG 2 shown.

An electric drive unit 19 with a rotor 20 and a stator 21 is also arranged in the compressor housing 18 , the crankshaft 2 being connected to the rotor 20 in a rotationally fixed manner. Also located in the compressor housing 18 is a piston-cylinder unit 22 which includes a piston 23 which is movably mounted in a cylinder 24 of the piston-cylinder unit 22 and can be driven by the crankshaft 2 to compress refrigerant.

The lubricant holder 1 comprises a sleeve element 4 with a clear cross section 5 delimited by an inner wall 34 which extends along a longitudinal axis 6 of the sleeve element 4 from an upper end 7 to a lower end 8 of the sleeve element 4 . As in 2 As can be seen, the clear cross section 5 at the upper end 7 can serve to accommodate the crankshaft 2 in order to produce a non-rotatable connection between the sleeve element 4 and thus the lubricant receptacle 1 and the crankshaft 2, for example by means of a press fit.

In principle, however, lubricant receptacles 1 according to the invention are also possible in which the lubricant receptacle 1 is non-rotatably connected to the crankshaft 2 via a non-rotatably connected connection between the inner element 9 and the crankshaft 2 .

Furthermore, the lubricant receptacle 1 comprises the inner element 9, which has an outer surface 10 which extends along a longitudinal axis 11 of the inner element 9 from a lower end 12 to an upper end 13 and has a groove 14 in the exemplary embodiment shown. This groove 14 runs spirally in the direction from the lower end 12 to the upper end 13 and extends from the lower end 12 to the upper end 13 of the lateral surface 10. The inner wall 34 has no groove in the illustrated embodiment, although this is possible in principle.

In the operating state of the lubricant receptacle 1, the inner element 9 is arranged with its lateral surface 10 at least in sections - essentially completely in the exemplary embodiment shown - within the clear cross section 5 of the sleeve element 4, more precisely in a receiving segment 33 of the clear cross section 5 provided for receiving. Viewed in the direction from the lower end 8 to the upper end 9 of the sleeve element 4, the lower end 12 of the lateral surface 10 is arranged in front of its upper end 13, ie the sleeve element 4 and the inner element 9 are to a certain extent oriented or aligned in the same way. The sleeve element 4 and the inner element 9 are also designed such that the inner element 9 and the sleeve element 4 can be rotated relative to one another about the longitudinal axis 6 of the sleeve element 4 and/or the longitudinal axis 11 of the inner element 9 . During operation of the refrigerant compressor 3 , this rotation is mediated or generated by the non-rotatable connection of the lubricant receptacle 1 to the crankshaft 2 . In principle, only the relative rotation between the sleeve element 4 and the inner element 9 is important, ie it would be conceivable for the inner element 9 to be driven in rotation and for the sleeve element 4 to be essentially fixed in terms of rotation. In the embodiment shown, due to the non-rotatable connection of the sleeve element 4 with the crankshaft 2 the sleeve element 4 is driven in rotation when the crankshaft 2 rotates, but the inner element 9 does not.

In order to largely avoid rotary movements of the inner element 9, this can be connected to the stator 21 by means of a fixing means, for example. For this purpose, the inner element 9 can be used, as in 1 shown, have a fastening element in the form of an eyelet 16 with which the fixing means can be brought into engagement.

Such as from 2 shows, in the operating state, ie when the inner element 9 is arranged in the sleeve element 4, there is a gap 30 with a gap width 31 between the lateral surface 10 and the inner wall 34, which delimits the clear cross section 5 and thus in particular the receiving segment 33. Accordingly, the oil 15 from the lubricant sump 26 can enter this gap 30 if the inner element 9 and the sleeve element 4 protrude at least in sections into the lubricant sump 26 . The sleeve element 4 projects into the lubricant sump 26, in particular in the area of its lower end 8, and the inner element 9, in particular in the area of the lower end 12 of its lateral surface 10. Due to the viscosity of the oil 15 or the friction between the oil 15 and the sleeve element 4, the Oil 15 upon rotation of the sleeve member 4 a corresponding centrifugal force. This presses the oil 15 in the gap 30 and in particular in the at least one groove 14 in the direction from the lower end 12 to the upper end 13 of the lateral surface 10 and thus in the direction of the crankshaft 2.

In any case, the oil 15 can flow particularly well in the direction of the crankshaft 4 via the groove 14 - regardless of the exact gap width 31. In the exemplary embodiment shown, the bore 27 of the crankshaft 2 with the clear cross section 5 and thus in particular also with the groove 14 is in more fluid Connection so that the oil 15 can get into the bore 27.

On the one hand, the clear cross section 5 tapers at least in the receiving segment 33 in the direction from the lower end 8 to the upper end 7 . On the other hand, the inner element 9 tapers in the area of the lateral surface 10 in the direction from the lower end 12 to the upper end 13 of the lateral surface 10 . Due to the narrowing of the inner element 9 or the receiving segment 33, this can have a large diameter in the area of the lower end 12 of the lateral surface 10, whereby sufficiently large tangential speeds or centrifugal forces (in the gap 30) can be realized even at low speeds in order to ensure reliable delivery of the oil 15 to ensure. On the other hand, the tapering of the inner element 9 or the receiving segment 33 can ensure that in the area of the upper end 13 of the lateral surface 10 there is a substantially continuous transition, i.e. a transition without an abrupt pressure drop, for the oil 15 from the gap 30 into the bore 27 the crankshaft 2 takes place. In the exemplary embodiment shown, this continuous transition is further improved in that the inner element 9 is designed with its taper in such a way that the inner element 9 protrudes into the bore 27, cf. 2 . Accordingly, a disadvantageous reduction in the flow of lubricant can be avoided almost completely.

The shape of the narrowing of the clear cross-section 5 in the receiving segment 33 on the one hand and the shape of the narrowing of the inner element 9 in the area of the lateral surface 10 on the other hand are matched to one another in the exemplary embodiment shown in order to enable an optimal arrangement of the inner element 9 in the sleeve element 4 in the operating state. For this purpose, on the one hand, the clear cross section 5 of the sleeve element 4 is frustoconical, at least in its receiving segment 33 formed, this truncated cone shape being based on a cone with a first opening angle Θ1. On the other hand, the lateral surface 10 of the inner element 9 apart from the at least one groove 14 is designed as the lateral surface of a truncated cone, this truncated cone shape being based on a cone with a second opening angle Θ2. In the exemplary embodiment shown, the above-mentioned matching is further optimized in that the absolute amount of the difference between the first opening angle Θ1 and the second opening angle Θ2 is less than or equal to 10°, preferably less than or equal to 5°, particularly preferably equal to 0°.

In the exemplary embodiment shown, it is further provided that the inner element 9 is movably mounted in relation to the longitudinal axis 6 of the sleeve element 4, i.e. with a directional portion parallel to the longitudinal axis 6. In interaction with the tapering receiving segment 33 and the tapering inner element 9, the gap width 31 can be adjusted in principle, in particular to adapt to operating parameters such as the temperature and/or the viscosity of the oil 15 and/or the speed, in order to achieve an optimal lubricant flow to allow. For example, in the case of oil 15 becoming thinner, the gap width 31 could be reduced in order to bring about increased delivery. The possibility of adjustment is particularly precise in the exemplary embodiment shown due to the above-mentioned truncated cone shapes.

In concrete terms, an automatic adjustment is even provided in the embodiment shown. According to 3 For this purpose, the fixing means is designed as a spring element in the form of a resilient wire clip 32, with which the inner element 9 is essentially non-rotatably connected to the stator 21. Slight twisting angles of the inner element 9, which due to the elasticity of the springy wire clip 32 may arise can be tolerated. In any case, the resilient wire clip 32 causes the inner element 9 to be pressed to a certain extent in the direction of the receiving segment 33 , which tends to lead to a reduction in the gap width 31 . This is counteracted by a certain pressure of the oil 15 in the gap 30, which pressure depends on various factors. For example, the inner element 9 is pushed away from the inner wall 34 of the receiving segment 33 against the spring force of the resilient wire bracket 32, the stronger the more viscous the oil 15 is or the higher the speed, and the larger the gap width 31 remains. If the oil 15 becomes thinner or if the speed drops, the inner element 9 is pressed away less strongly from the inner wall of the receiving segment 33 against the spring force of the resilient wire clip 32 by the oil 15 flowing in the gap 30, and the gap width 31 is reduced accordingly.

REFERENCE LIST

1

lubricant intake

2

crankshaft

3

refrigerant compressor

4

sleeve element

5

Clear cross-section of the sleeve element

6

Longitudinal axis of the sleeve element

7

Upper end of the sleeve element

8th

Lower end of the sleeve element

9

interior element

10

Lateral surface of the inner element

11

Longitudinal axis of the inner element

12

Lower end of the lateral surface

13

Upper end of the lateral surface

14

groove

15

oil

16

eyelet

18

compressor housing

19

Electric drive unit

20

rotor

21

stator

22

Piston-cylinder unit

23

Pistons

24

cylinder

25

floor area

26

lubricant sump

27

bore of the crankshaft

28

exit hole

29

Axis of rotation of the crankshaft

30

gap

31

gap width

32

Springy wire hanger

33

Recording segment of the clear cross-section

34

inner wall

Θ1

First opening angle

Θ2

Second opening angle

Claims (11)

1. Lubricant holder (1) for vertical conveying of lubricant (15) by means of a crankshaft (2) of a coolant compressor (3), comprising a sleeve element (4) having a clear cross-section (5) delimited by an inside wall (34), which clear cross-section extends along a longitudinal axis (6) of the sleeve element (4), from an upper end (7) to a lower end (8) of the sleeve element (4), the lubricant holder (1) furthermore comprising an inner element (9) that has a mantle surface (10) that extends along a longitudinal axis (11) of the inner element (9), from a lower end (12) to an upper end (13), wherein in an operating state of the lubricant holder (1)

   - the inner element (9) is arranged within the clear cross-section (5) of the sleeve element (4) with its mantle surface (10), at least in certain areas,

   - viewed in the direction from the lower end (8) to the upper end (7) of the sleeve element (4), the lower end (12) of the mantle surface (10) is disposed in front of its upper end (13), and

   - the inner element (9) and the sleeve element (4) can be rotated relative to one another about the longitudinal axis (6) of the sleeve element (4) and/or the longitudinal axis (11) of the inner element (9), wherein the clear cross-section (5) narrows from the lower end (8) to the upper end (7) of the sleeve element (4), at least in a holding segment (33) intended for holding the inner element (9), wherein the inner element (9) narrows in the region of the mantle surface (10), from the lower end (12) to the upper end (13) of the mantle surface (10), and wherein the inside wall (34) and/or the mantle surface (10) has/have at least one groove (14) that runs in spiral shape, characterised in that the at least one groove (14) has a varying angle of inclination, which preferably increases from the lower end (12) to the upper end (13) of the mantle surface (10).
2. Lubricant holder (1) according to claim 1, characterised in that the clear cross-section (5) of the sleeve element (4) is configured in the form of a truncated cone, at least in its holding segment (33).
3. Lubricant holder (1) according to one of claims 1 to 2, characterised in that the mantle surface (10) of the inner element (9) is configured as the mantle surface of a truncated cone.
4. Lubricant holder (1) according to claim 3 and to claim 2, characterised in that the truncated-cone shape of the holding segment (33) of the clear cross-section (5) is based on a cone having a first opening angle (Θ1),

   that a truncated-cone shape according to which the mantle surface (10) is configured is based on a cone having a second opening angle (Θ2),

   and that the absolute difference between the first opening angle (Θ1) and the second opening angle (Θ2) is less than or equal to 10°, preferably less than or equal to 5°, particularly preferably equal to 0°.
5. Lubricant holder (1) according to one of claims 1 to 4, characterised in that the inner element (9) has at least one projecting wing and/or a fastening element, preferably an eye (16), for a fixation means, in the region of the lower end (12) of the mantle surface (10).
6. Lubricant holder (1) according to one of claims 1 to 5, characterised in that the inner element (9) is produced from a material, preferably a plastic, having a density that is less than the density of the lubricant (15).
7. Coolant compressor (3) having a compressor housing (18) that can be hermetically encapsulated, an electrical drive unit (19) arranged in a housing interior of the compressor housing (18), comprising a rotor (20) and a stator (21), a crankshaft (2) connected with the rotor (20) in torque-proof manner, as well as a piston/cylinder unit (22) arranged in the housing interior, which piston/cylinder unit comprises a piston (23) movably mounted in a cylinder (24) of the piston/cylinder unit (22), which piston can be driven by the crankshaft (2) for compression of coolant, wherein the coolant compressor (3) has a lubricant holder (1) according to one of claims 1 to 6 that is in the operating state, so as to convey lubricant (15) out of a lubricant sump (26) formed in a bottom region (25) of the compressor housing (18), by way of the crankshaft (2).
8. Coolant compressor (3) according to claim 7, characterised in that the sleeve element (4) of the lubricant holder (1) is connected with the crankshaft (2) in torque-proof manner.
9. Coolant compressor (3) according to one of claims 7 to 8, characterised in that the crankshaft (2) has a bore (27), which bore preferably runs at a slant to an axis of rotation (29) of the crankshaft (2) at least in certain areas, which bore stands in a fluidic connection with the clear cross-section (5) of the sleeve element (4), wherein the inner element (9) projects into the bore (27) .
10. Coolant compressor (3) according to one of claims 7 to 9, characterised in that the inner element (9) can be moved with reference to the longitudinal axis (6) of the sleeve element (4).
11. Coolant compressor (3) according to one of claims 7 to 10, characterised in that a fixation means configured as a spring element, preferably in the form of a resilient wire bracket (32), is provided, with which the inner element (9) is connected with the stator (21) or other components of the coolant compressor (3), essentially in torque-proof manner.

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