Lubricant receptacle for a refrigerant compressor

Abstract

A lubricant holder for vertical conveying of lubricant using a crankshaft of a coolant compressor includes a sleeve element having a clear cross-section delimited by an inside wall, which cross-section extends along a longitudinal axis, from an upper end to a lower end, an inner element that has a mantle surface that extends along a longitudinal axis of the inner element, from a lower end to an upper end, wherein in an operating state the inner element is arranged within the clear cross-section with its mantle surface, at least in certain areas. At least one groove of the inside wall and/or of the mantle surface, which groove runs in spiral shape, has a varying angle of inclination, which preferably increases from the lower end to the upper end of the mantle surface.

Claims

1. A lubricant holder for vertical conveying of lubricant by means of a crankshaft of a coolant compressor, comprising a sleeve element having a clear cross-section delimited by an inside wall, which clear cross-section extends along a longitudinal axis of the sleeve element, from an upper end to a lower end of the sleeve element, the lubricant holder furthermore comprising an inner element that has a mantle 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 holder the inner element is arranged within the clear cross-section of the sleeve element with its mantle surface, at least in certain areas, viewed in the direction from the lower end to the upper end of the sleeve element, the lower end of the mantle surface is disposed in front of its upper end, 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, wherein the clear cross-section narrows from the lower end to the upper end of the sleeve element, at least in a holding segment intended for holding the inner element, wherein the inner element narrows in the region of the mantle surface, from the lower end to the upper end of the mantle surface, and wherein the inside wall and/or the mantle surface has/have at least one groove that runs in spiral shape, wherein the at least one groove has a varying angle of inclination.

2. The lubricant holder according to claim 1, wherein the clear cross-section of the sleeve element is configured in the form of a truncated cone, at least in its holding segment.

3. The lubricant holder according to claim 2, wherein the truncated-cone shape of the holding segment of the clear cross-section is based on a first cone having a first opening angle, wherein the mantle surface of the inner element is configured as the mantle surface of a truncated cone based on a second cone having a second opening angle, and wherein the absolute difference between the first opening angle and the second opening angle is less than or equal to 10°.

4. The lubricant holder according to claim 1, wherein the mantle surface of the inner element is configured as the mantle surface of a truncated cone.

5. The lubricant holder according to claim 1, wherein the inner element has at least one projecting wing and/or a fastening element for a fixation means, in the region of the lower end of the mantle surface.

6. The lubricant holder according to claim 1, wherein the inner element is produced from a material having a density that is less than the density of the lubricant.

7. A coolant compressor having a compressor housing that can be hermetically encapsulated, an electrical drive unit arranged in a housing interior of the compressor housing, comprising a rotor and a stator, a crankshaft connected with the rotor in torque-proof manner, as well as a piston/cylinder unit arranged in the housing interior, which unit comprises a piston movably mounted in a cylinder of the piston/cylinder unit, which piston can be driven by the crankshaft for compression of coolant, wherein the coolant compressor has the lubricant holder according to claim 1 that is in the operating state, so as to convey lubricant out of a lubricant sump formed in a bottom region of the compressor housing, by way of the crankshaft.

8. The coolant compressor according to claim 7, wherein the sleeve element of the lubricant holder is connected with the crankshaft in torque-proof manner.

9. The coolant compressor according to claim 7, wherein the crankshaft has a bore, which bore stands in a fluidic connection with the clear cross-section of the sleeve element, wherein the inner element projects into the bore.

10. The coolant compressor according to claim 7, wherein the inner element can be moved with reference to the longitudinal axis of the sleeve element.

11. The coolant compressor according to claim 7, wherein a fixation means configured as a spring element is provided, with which the inner element is connected with the stator or other components of the coolant compressor, essentially in torque-proof manner.

12. The lubricant holder according to claim 1, wherein the at least one groove has a varying angle of inclination, which increases from the lower end to the upper end of the mantle surface.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention will now be explained in greater detail using an exemplary embodiment. The drawings are meant as examples and are supposed to explain the idea of the invention, but by no means to restrict it or to conclusively represent it.

(2) In this regard, the figures show:

(3) FIG. 1 an inner element of an embodiment of a lubricant holder according to the invention, in an axonometric view,

(4) FIG. 2 a sectional view of the embodiment of the lubricant holder according to the invention, wherein the lubricant holder is mounted on a crankshaft of a coolant compressor according to the invention,

(5) FIG. 3 a sectional view of a coolant compressor according to the invention, with the lubricant holder from FIG. 2.

WAYS TO IMPLEMENT THE INVENTION

(6) FIG. 1 shows an axonometric view of an inner element 9 of a lubricant holder 1 according to the invention. The latter is shown in an operating state and fastened to a crankshaft 2 of a coolant compressor 3 according to the invention in FIG. 2, in a sectional view.

(7) The lubricant holder 1 serves for vertical conveying of lubricant, in particular oil 15, from a lubricant sump 26 formed in a bottom region 25 of a compressor housing 18 of the coolant compressor 3, see also the sectional view of FIG. 3, by way of the crankshaft 2. For this purpose, the crankshaft 2 has a bore 27 that can be seen well in FIG. 2, from which bore the oil 15 can exit to locations to be lubricated, by way of exit bores 28. For optimal conveying of the oil 15, the bore 27 can be structured to run at a slant to an axis of rotation 29 of the crankshaft 2, as shown in FIG. 2.

(8) Furthermore, an electrical drive unit 19 having a rotor 20 and a stator 21 is arranged in the compressor housing 18, wherein the crankshaft 2 is connected with the rotor 20 in torque-proof manner. Furthermore, a piston/cylinder unit 22 is situated in the compressor housing 18, which unit comprises a piston 23 mounted so as to move in a cylinder 24 of the piston/cylinder unit 22, which piston can be driven by the crankshaft 2 for compression of coolant.

(9) The lubricant holder 1 comprises a sleeve element 4 having a clear cross-section 5 delimited by an inside wall 34, which 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. As can be seen in FIG. 2, the clear cross-section 5 can serve to hold the crankshaft 2 at the upper end 7, for example so as to produce a torque-proof connection between the sleeve element 4 and thereby the lubricant holder 1 and the crankshaft 2, for example by means of a press fit.

(10) Fundamentally, however, lubricant holders 1 according to the invention are also possible, in which a torque-proof connection of the lubricant holder 1 with the crankshaft 2 takes place by way of a torque-proof connection between the inner element 9 and the crankshaft 2.

(11) Furthermore, the lubricant holder 1 comprises the inner element 9, which 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, and has a groove 14 in the exemplary embodiment shown. This groove 14 runs in spiral shape, 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 mantle surface 10. According to the invention, the groove 14 has a varying inclination angle, which preferably increases from the lower end 12 to the upper end 13 of the mantle surface 10. In the exemplary embodiment shown, the inside wall 34 does not have a groove, although this is fundamentally possible.

(12) In the operating state of the lubricant holder 1, the inner element 9 is arranged, with its mantle surface 10, at least in certain areas—in the exemplary embodiment shown, essentially completely—within the clear cross-section 5 of the sleeve element 4, more precisely in a holding segment 33 of the clear cross-section 5, intended for holding. In this regard, 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 mantle surface 10 is arranged in front of its upper ends 13, in other words the sleeve element 4 and the inner element 9 are oriented or aligned in the same way, as it were. Furthermore, the sleeve element 4 and the inner element 9 are designed in such a manner 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. This rotation is imparted or produced, during operation of the coolant compressor, by means of the torque-proof connection of the lubricant holder 1 with the crankshaft 2. Fundamentally, the only important thing is the relative rotation between the sleeve element 4 and the inner element 9, in other words it would be conceivable that the inner element 9 is driven to rotate and the sleeve element 4 is essentially fixed in place rotationally. In the exemplary embodiment shown, the sleeve element 4 is driven to rotate due to the torque-proof connection of the sleeve element 4 with the crankshaft 2 when the crankshaft 2 rotates, but the inner element 9 is not.

(13) In order to prevent rotational movements of the inner element 9 to a great extent, this element can be connected with the stator 21, for example, by means of a fixation means. For this purpose, the inner element 9 can have a fastening element in the form of an eye 16, with which the fixation means can be brought into engagement, as shown in FIG. 1.

(14) As is evident from FIG. 2, for example, a gap 30 having a gap width 31 between the mantle surface 10 and the inside wall 34 occurs in the operating state, i.e. in the case of placement of the inner element 9 in the sleeve element 4; the inside wall delimits the clear cross-section 5 and thereby, in particular, the holding segment 33. Accordingly, the oil 15 can enter into this gap 30 from the lubricant sump 26 when the inner element 9 and the sleeve element 4 project into the lubricant sump 26 at least in certain areas. In this regard, the sleeve element 4 projects into the lubricant sump 26 in the region of its lower end 8, in particular, and the inner element 9 projects into it in the region of the lower end 12 of its mantle surface 10, in particular. Due to the viscosity of the oil 15 or the friction between the oil 15 and the sleeve element 4, a corresponding centrifugal force acts on the oil 15 when the sleeve element 4 rotates. This force 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 mantle surface 10, and thereby in the direction of the crankshaft 2.

(15) In each case, the oil 15 can flow particularly well in the direction of the crankshaft 2 by way of the groove 14—independent of the precise gap width 31. In the exemplary embodiment shown, the bore 27 of the crankshaft 2 stands in a fluidic connection with the clear cross-section 5 and thereby, in particular, also with the groove 14, so that the oil 15 can get all the way into the bore 27.

(16) On the one hand, the clear cross-section 5 narrows, according to the invention, at least in the holding segment 33, in the direction from the lower end 8 to the upper end 7. On the other hand, according to the invention the inner element 9 narrows in the region of the mantle surface 10, in the direction from the lower end 12 to the upper end 13 of the mantle surface 10. Due to the narrowing of the inner element 9 or of the holding segment 33, the latter can have a large diameter in the region of the lower end 12 of the mantle surface 10, and thereby sufficiently great tangential speeds or centrifugal forces (in the gap 30) are implemented even at low speeds of rotation, so as to guarantee reliable conveying of the oil 15.

(17) On the other hand, it can be ensured, by means of the narrowing of the inner element 9 or of the holding segment 33, that an essentially continuous transition, i.e. a transition without an abrupt pressure drop, occurs for the oil 15 from the gap 30 into the bore 27 of the crankshaft 2 in the region of the upper end of the mantle surface 10. In the exemplary embodiment shown, this continuous transition is further improved in that the inner element 9 with its narrowing is designed in such a manner that the inner element 9 projects into the bore 27, see FIG. 2. Accordingly, disadvantageous reduction of the lubricant flow can be prevented practically entirely.

(18) The shape of the narrowing of the clear cross-section 5 in the holding segment 33, on the one hand, and the shape of the narrowing of the inner element 9 in the region of the mantle surface 10, on the other hand, are coordinated with one another, in the exemplary embodiment shown, so as to allow optimal placement of the inner element 9 in the sleeve element 4 in the operating state. For this purpose, 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, on the one hand, wherein this truncated-cone shape is based on a cone having a first opening angle θ1. On the other hand, the mantle surface 10 of the inner element 9, with the exception of the at least one groove 14, is configured as the mantle surface of a truncated cone, wherein this truncated-cone shape is based on a cone having a second opening angle θ2. The coordination mentioned above is further optimized, in the case of the exemplary embodiment shown, 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°.

(19) In the exemplary embodiment shown, it is furthermore provided that the inner element 9, with reference to the longitudinal axis 6 of the sleeve element 4, i.e. with a direction component parallel to the longitudinal axis 6, is mounted in movable manner. In interplay with the narrowing holding segment 33 and the narrowing inner element 9, the gap width 31 can be fundamentally adjusted in this way, in particular for adaptation to operating parameters such as, for example, the temperature and/or the viscosity of the oil 15 and/or the speed of rotation, so as to allow an optimal lubricant flow. For example, the gap width 31 could be reduced in the case of an oil 15 that becomes thinner, so as to bring about increased conveying. The adjustment possibility is particularly precise in the case of the exemplary embodiment shown, due to the aforementioned truncated-cone shapes.

(20) In concrete terms, in the embodiment shown automatic adjustment is actually provided. According to FIG. 3, the fixation means is formed, for this purpose, as a spring element in the form of a resilient wire bracket 32, with which the inner element 9 is connected with the stator 21 in essentially torque-proof manner. Slight angles of twist of the inner element 9, which might occur as the result of the elasticity of the resilient wire bracket 32, can be tolerated in this regard. In any case, the resilient wire bracket 32 brings about the result that the inner element 9 is pressed in the direction of the holding segment 33 up to a certain degree, and this tends to reduce the gap width 31. A certain pressure of the oil 15 in the gap 30 counteracts this; this pressure depends on various factors. For example, the inner element 9 is pressed away from the inside wall 34 of the holding segment 33, counter to the spring force of the resilient wire bracket 32, all the more strongly, the more viscous the oil 15 is or the greater the speed of rotation is, and the gap width 31 remains all the greater. If the oil 15 becomes thinner or if the speed of rotation drops, the inner element 9 is pressed away from the inside wall of the holding segment 33, counter to the spring force of the resilient wire bracket 32, all the less strongly, by the oil 15 that flows in the gap 30, and the gap width 31 is reduced accordingly.

REFERENCE SYMBOL LIST

(21) 1 lubricant holder 2 crankshaft 3 coolant 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 8 lower end of the sleeve element 9 inner element 10 mantle surface of the inner element 11 longitudinal axis of the inner element 12 lower end of the mantle surface 13 upper end of the mantle surface 14 groove 15 oil 16 eye 18 compressor housing 19 electrical drive unit 20 rotor 21 stator 22 piston/cylinder unit 23 piston 24 cylinder 25 bottom region 26 lubricant sump 27 bore of the crankshaft 28 exit bore 29 axis of rotation of the crankshaft 30 gap 31 gap width 32 resilient wire bracket 33 holding segment of the clear cross-section 34 inside wall θ1 first opening angle θ2 second opening angle