COMPRESSOR COUPLING COMPONENT FOR COUPLING A DRIVE SHAFT AND A MOVABLE SPIRAL IN A SCROLL COMPRESSOR

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

[0001]This is a U.S. national phase patent application of PCT/KR2023/014745 filed Sep. 26, 2023, which claims the benefit of and priority to German Patent Application No. 10 2023 124 743.3, filed on Sep. 13, 2023, and German Patent Application No. 10 2022 126 272.3, filed on Oct. 11, 2022, the entire contents of each of which are incorporated herein by reference for all purposes.

TECHNICAL FIELD

[0002]The invention relates to a compressor coupling component with integrally formed counterweight for coupling a drive shaft and a movable spiral of a scroll compressor to transmit a drive torque to the movable spiral. The invention also relates to a scroll compressor for a gaseous fluid, for example a refrigerant, in which such a compressor coupling component is used.

BACKGROUND ART

[0003]The invention is mainly usable in an electrical scroll refrigerant compressor for motor vehicles. A scroll compressor generally has a compressor housing and two interleaving spirals inside the compressor housing. One of the two interleaving spirals is stationary, and the other spiral is movable eccentrically on a circular trajectory, this movable spiral also being referred to as an orbiting spiral or scroll. As a result of the movement of this spiral, the volume of compression chambers formed between the spirals changes cyclically, wherein a gaseous fluid, for example a refrigerant, is sucked in and compressed. The movable spiral is generally moved on a circular trajectory by means of an eccentric drive. The eccentric drive is formed from a drive shaft, which rotates about a rotational axis, and a counterweight, which is connected in a rotationally fixed manner to the drive shaft and thus rotates with the drive shaft.

[0004]In the prior art, a rotatable compressor coupling component with integrally formed counterweight is used to transmit a drive torque from a drive shaft to the movable spiral of the scroll compressor. This means that the eccentric drive comprises at least one drive shaft, which rotates about a rotational axis, and the compressor coupling component, which rotates with the drive shaft and has the counterweight, and that the movable spiral is connected eccentrically to the drive shaft via the compressor coupling component, wherein the axis of the movable spiral and of the drive shaft are offset from one another.

[0005]The compressor coupling component comprises a planar main body as an inner part, through the plane of which the rotational axis about which the compressor coupling component is rotatable runs perpendicularly. This planar main body is also referred to as a shaft extension of the drive shaft and can be connected to the drive shaft via a connecting neck, for example. Furthermore, the compressor coupling component rotating with the drive shaft has the counterweight as an outer part which has an arcuate outer contour and is at least partially in the form of a hollow cylindrical segment. This counterweight is offset to the rear in the axial direction of the rotational axis in relation to the planar main body, and therefore the lateral surface of the hollow cylindrical segment encloses a part of the circumference of the drive shaft in the end region of a shaft shank of the drive shaft.

[0006]For the connection to the compressor coupling component, the drive shaft can have an eccentrically offset connecting neck which is integrally formed, inserted or fastened on the end face of the drive shaft, and the longitudinal axis of which is oriented offset parallel to the longitudinal axis of the drive shaft.

[0007]In particular carbon steel is used as the material for the compressor coupling component. This design is sufficient for previous ranges of use with limited maximum rotation speed.

[0008]The range of use of the compressor coupling component with integrally formed counterweight is limited in rotation speed by the loads occurring during operation owing to the necessary shape. The invention is intended to allow both cost-effective manufacturing processes and materials to be used and the range of use to be extended to higher rotation speeds.

[0009]A compressor coupling component with counterweight is the connecting element which transmits the drive force from the drive shaft into the scroll compression unit. The compressor coupling component comprises a coupling neck with a bore receptacle for a connecting neck of the drive shaft, and a counterweight mass for the partial balancing of the system-induced imbalance of the scroll compression unit.

[0010]Loads during operation generate local stresses on the connection of the sleeve and of the counterweight body, which limits the operating range depending on the material properties and the geometry/proportions of the part. This applies owing to the increase in the operating range of the compressor: The maximum revolution rate should be 11,000 revolutions per minute in comparison with the previous limit of approximately 9000 revolutions per minute.

[0011]Costs are a driving parameter for competitiveness. To offer a significant savings potential, a metal powder forming process is selected. Metal powder alloys have a lower mechanical load capacity owing to a reduced modulus of elasticity and a reduced yield stress. In the standard form of a compressor coupling component, the structural stress occurring during operation limits the operating range of the component.

[0012]Loads during operation generate local stresses on the connection of the coupling neck and of the counterweight body, which limits the operating range depending on the material properties and the geometry or proportions of the part. With reduced mechanical parameters of the sintering alloy and an extended range of operating conditions, the usual shape of the compressor coupling component in the prior art does not have the robustness necessary for operation.

[0013]The driving parameter for the component load and the local stresses is the compressor speed, expressed as rotor rotation speed in revolutions per minute. The maximum speed is increased to up to 11,000 revolutions per minute.

[0014]Under the given operating conditions, the local stresses on the connection of the counterweight body and of the planar main body ensure that the design known from the prior art is unsuitable for the use of a metallic sintering alloy.

SUMMARY

[0015]The object of the invention consists in a design of a compressor coupling component with integrally formed counterweight which is cost-effective to produce, wherein this compressor coupling component should at the same time be suitable for operation at high rotor rotation speeds, that is, up to at least 11,000 revolutions per minute.

[0016]The object is achieved by a compressor coupling component having the features as shown and described herein.

[0017]This compressor coupling component comprises a planar main body with a first, front side and a second, rear side opposite the first side, a cylindrical coupling neck, which is integrally formed on or fastened to the planar main body or inserted into the planar main body, wherein the cylinder axis of the cylindrical coupling neck runs perpendicularly to the plane of the planar main body, and the cylindrical coupling neck protrudes from the planar main body in the axial direction, in relation to the cylinder axis of the coupling neck, on a front side of the planar main body, a counterweight, which is at least partially formed in the shape of a hollow cylindrical segment, has an arcuate outer contour, is integrally formed on an outer region of the planar main body which only partially encloses the cylindrical coupling neck and a neck-surrounding region which runs coaxially with the cylinder axis and completely encloses the coupling neck, and protrudes beyond the planar main body in the axial direction on the rear side of the planar main body.

[0018]According to the invention, the planar main body has opposing outer edge regions which, starting from an arcuate base edge region of the planar main body only partially enclosing the neck-surrounding region, extend as far as ends of the counterweight which oppose each other in the arc direction of the counterweight, and in the outer contour of the planar main body run linearly in the manner of increasingly spaced-apart V-legs.

[0019]The invention therefore proposes a new connection design of the main body, of the coupling neck and of the counterweight. By widening the planar main body in a V shape in comparison with the prior art, the rigidity and robustness of the compressor coupling component is considerably increased.

[0020]This invention makes a much more robust design possible in comparison with the prior art, with a comparable installation space requirement. A compressor coupling component designed in this way can be produced by forming powder metal alloys, for example using a steel powder pressing method, which allows material and costs to be saved in comparison with forging processes. It is estimated that the achievable cost saving is 40% to 60%. The more robust design at the same time allows much higher operating loads resulting from high rotor rotation speeds. As a result, the compressor coupling component produced by a metal powder forming process will be suitable for working under the given load conditions. This means that the compressor coupling component is suitable for operation at rotor rotation speeds of 11,000 revolutions per minute. This compressor coupling component can thus replace a component designed according to the prior art with the same functionality and at much lower costs.

[0021]The connection design according to the invention considerably reduces the local maximum stresses. This is achieved by the connection design according to the invention of the planar main body, of the coupling neck and of the counterweight.

[0022]As a result of the V-shaped widening in comparison with compressor coupling components shaped according to the prior art, not only are the rigidity and robustness of the compressor coupling component considerably increased, but also the widenings obtained are usable for the integration of additional supporting elements. A supporting element or multiple supporting elements can thus be formed in the regions of the planar main body which are adjacent to the outer edge regions running in the manner of V-legs in order to further reinforce the compressor coupling component. According to an advantageous embodiment, the supporting elements are reinforcing ribs of a rib structure which protrudes from the planar main body in the axial direction on the rear side of the planar main body. An embodiment in which the rib structure with the reinforcing ribs extends from the planar main body as far as the counterweight is particularly preferred. Preferably, the rib structure contains two reinforcing ribs as additional supporting elements, which are each adjacent to one of the opposing outer edge regions and extend as far as one of the ends of the counterweight which oppose each other in the arc direction. Advantageously, the reinforcing ribs as additional supporting elements protrude in the axial direction, in relation to the cylinder axis, on the rear side of the planar main body exactly as far as the counterweight protrudes beyond the planar main body on the rear side.

[0023]For the connection to a drive shaft of a scroll compressor, the cylindrical coupling neck advantageously has a receiving bore oriented eccentrically to the cylinder axis.

[0024]A further aspect of the invention therefore relates to a scroll compressor for a gaseous fluid in which the compressor coupling component according to the invention is used as part of an eccentric drive.

[0025]Such a scroll compressor comprises a compressor housing and two interleaving spirals inside the compressor housing, wherein one spiral is stationary, and the other spiral is movable eccentrically on a circular trajectory, and the volume of compression chambers formed between the spirals can be changed cyclically by the movement of the spiral, and the eccentric drive, by means of which the movable spiral is movable on a circular trajectory and which comprises a rotatable drive shaft and the compressor coupling component according to the invention which is rotatable with the drive shaft, wherein the movable spiral is connected eccentrically to the drive shaft via the compressor coupling component.

DESCRIPTION OF DRAWINGS

[0026]Further details, features and advantages of embodiments of the invention can be found in the description of exemplary embodiments below with reference to the associated drawings. In the drawings:

[0027]FIG. 1A: shows a compressor coupling component having a planar main body, a

[0028]counterweight and a coupling neck for coupling a drive shaft and a movable spiral of a scroll compressor, according to the prior art,

[0029]FIG. 1B: shows a schematic diagram of the region of the local maximum stresses in the compressor coupling component during operation,

[0030]FIG. 2: shows a comparative diagram of compressor coupling components shaped

[0031]according to the prior art and a compressor coupling component designed according to an exemplary embodiment of the invention,

[0032]FIG. 3: shows a comparative schematic diagram of compressor coupling components shaped according to the prior art and a compressor coupling component designed according to an exemplary embodiment of the invention in terms of the local maximum stresses in a region of the planar main body,

[0033]FIG. 4: shows a compressor coupling component with indicated widenings,

[0034]FIG. 5A: shows a perspective diagram of the compressor coupling component looking

[0035]towards the front side with the coupling neck,

[0036]FIG. 5B: shows a perspective diagram of the compressor coupling component looking towards the rear side with receiving space for an end of the drive shaft, and

[0037]FIG. 6: shows a bar chart with a comparison of the local maximum stresses for the different compressor coupling components at different rotor rotation speeds.

DESCRIPTION OF AN EMBODIMENT

[0038]FIG. 1A shows a compressor coupling component 1* shaped according to the prior art for coupling a drive shaft (not shown) and a movable spiral of a scroll compressor (not shown). Such a compressor coupling component 1* comprises a planar main body 2*, on or to which a cylindrical coupling neck 3* is integrally formed or fastened or in which the cylindrical coupling neck 3* is inserted, wherein a cylinder axis 4* of the cylindrical coupling neck 3* runs perpendicularly to the plane of the planar main body 2*, and the cylindrical coupling neck 3* protrudes from the planar main body 2* in the axial direction, in relation to the longitudinal axis of the coupling neck 3*, on a first, front side 2a* of the planar main body 2*. Formed by the cylindrical coupling neck 3* is a receiving bore 5* which is oriented eccentrically to the cylinder axis 4* of the cylindrical coupling neck 3* and is designed for receiving a connecting neck (not shown) of the drive shaft (likewise not shown in FIG. 1A). The region of the planar main body 2* which bears directly against the coupling neck 3* and also runs coaxially with the cylinder axis 4* and fully encloses the entire circumference of the coupling neck 3* and of the region bearing directly against the coupling neck shall be referred to below as the neck-surrounding region 6*.

[0039]Furthermore, a counterweight 8* with an arcuate outer contour is integrally formed on an outer region 7* of the planar main body 2* partially enclosing the neck-surrounding region 6* and has the shape of a hollow cylindrical segment, the cylinder axis 9* of which runs parallel to and at a distance from the cylinder axis 4* of the cylindrical coupling neck 3*. The outer region 7* thus connects the neck-surrounding region 6* of the planar main body 2* bearing against the coupling neck 3* to the counterweight 8*. The counterweight 8* also protrudes beyond the planar main body 2* in the axial direction, but predominantly on a second, rear side 2b* of the planar main body 2*, opposite the front side 2a* with the cylindrical coupling neck 3*. Since the counterweight 8* is at least partially in the form of a hollow cylindrical segment, it partially encloses the main body 2* on one side, more precisely the outer region 7* of the main body 2*, and thereby provides a receiving cavity 10* for partially receiving a shaft shank end region of the drive shaft (not shown in FIG. 1A) on the inner side of the hollow cylindrical segment.

[0040]The material used for such a compressor coupling component 1* is in particular carbon steel, wherein the compressor coupling component 1* is generally produced by forging with post-machining of at least some of the component surfaces; this applies in particular to regions of the surface of the planar main body 2*, of the coupling neck 3* and the receiving bore 5* running through the main body 2* and the coupling neck 3*. This design is sufficient for previous ranges of use with limited maximum rotation speed.

[0041]Loads during operation generate local stresses on the connection between the coupling neck 3* and the body of the counterweight 8*, which limits the operating range depending on the material properties and the geometry/proportions of the compressor coupling component 1*. With reduced mechanical parameters of the sintering alloy and an extended range of operating conditions, the usual shape of the compressor coupling component 1* in the prior art does not have the robustness necessary for operation. The driving parameter for the component load and the local stresses is the speed or rotation speed of the compressor, which can be at maximum up to 11,000 revolutions per minute. Under the given operating conditions, the local stresses in the region of the connection of the counterweight 8* to the planar main body 2* ensure that the design known from the prior art is unsuitable for the use of a metallic sintering alloy. FIG. 1B schematically indicates various zones of different degrees of loading of the compressor coupling component 1* at a compressor rotation speed of 11,000 revolutions per minute by means of different shading, and also the region of a local maximum stress 11* on the compressor coupling component 1*, occurring on an edge of the outer region 7* of the planar main body 2*. As already mentioned, the outer region 7* is the region which connects the neck-surrounding region 6* of the planar main body 2* bearing against and completely enclosing the coupling neck 3* to the counterweight 8*

[0042]FIG. 2 contains comparative schematic diagrams of compressor coupling components 1*, 1** shaped according to the prior art, that is, one compressor coupling component 1* produced by a forging process and one compressor coupling component 1** produced by a sintering process with the same design, and of a compressor coupling component 1 designed according to an exemplary embodiment of the invention. In addition, the receiving of a shaft shank end region of the drive shaft 12 in the receiving cavity 10* formed by the inner side of the counterweight 8* is shown by way of example for the compressor coupling component 1*, wherein the position of the rotational axis 13 of the drive shaft 12 is also indicated in the perspective diagrams of the other compressor coupling components 1**, 1, in which can be seen in each case the corresponding receiving space 10**, 10, partially enclosed by the inner side of the counterweight 8**, 8, for the shaft shank end region of the drive shaft 12 and in each case a receiving bore 5**, 5 in the coupling neck 3**, 3 for receiving a connecting neck (not shown), which starts from the shank of the drive shaft 12 and can be integrally formed, inserted or fastened on the end face thereof.

[0043]The compressor coupling component 1 shaped according to an exemplary embodiment of the invention has a planar main body 2, which is shaped such that opposing outer edge regions 14, 15, starting from an arcuate base edge region 16 partially surrounding the neck-surrounding region 6 of the planar main body 2, run linearly in their outer contour in the manner of increasingly spaced-apart V-legs in each case as far as one of the ends of the counterweight 8 which oppose each other in the arc direction. In this way, the area of the planar main body 2 is widened in comparison with the main bodies 2*, 2** of the compressor coupling components 1*, 1** shaped according to the prior art, wherein this widening shall be referred to below simply as V-shaped widening of the planar main body 2. As a result of the V-shaped widening, the rigidity and robustness of the compressor coupling component 1 is considerably increased in comparison with the compressor coupling components 1*, 1** from the prior art.

[0044]FIG. 3 indicates, in a corresponding, comparative schematic diagram, in the different compressor coupling components 1*, 1** and 1, in each case by means of shading, the regions of different degrees of operation-induced loading and the location and size of the region 11*, 11**, 11 of the local maximum stress on the planar main body 2*, 2** and 2. The local maximum stress in the compressor coupling component 1 shaped according to an exemplary embodiment of the invention is much smaller than in the compressor coupling components 1*, 1** from the prior art.

[0045]FIG. 4 contains a comparative diagram which combines a front view of a compressor coupling component 1* designed according to the prior art with a front view of a compressor coupling component 1 shaped according to an exemplary embodiment of the invention. The comparative diagram permits a view of the first, front side 2a*, 2a of the planar main body 2*, 2, an end face of the cylindrical coupling neck 3*, 3 protruding from the front side 2a*, 2a of the planar main body 2*, 2 and having the receiving bore 5*, 5 oriented eccentrically to the cylinder axis 4 thereof, and a front end face 17*, 17 of the cylindrical-segment-shaped counterweight 8* 8 of the respective compressor coupling element 1*, 1. In the combined diagram, the widenings 18, 19 of the planar main body 2 caused by the V-shaped form of the outer edge regions 14, 15 starting from the base edge region 16 are indicated in comparison with the planar main body 2* designed according to the prior art.

[0046]FIG. 5A and FIG. 5B show the compressor coupling component 1 shaped according to an exemplary embodiment of the invention in perspective views, in FIG. 5A looking towards the front side with the coupling neck 3, and in FIG. 5B the compressor coupling component 1 looking towards the rear side with the receiving space 10, partially enclosed by the inner side of the counterweight 8, for the end of a drive shaft (not shown). FIG. 5A shows the front end face of the coupling neck 3 with the front opening of the receiving bore 5 positioned thereon, which is designed for receiving a connecting neck of the drive shaft (not shown), while FIG. 5B shows the rear end face of the coupling neck 3, provided with the opposite, rear opening of the receiving bore 5, wherein the circumference of the coupling neck 3 is fully enclosed on the rear end face of the coupling neck 3 by the neck-surrounding region 6 of the planar main body 2. In the embodiment shown, the coupling neck 3 is inserted into the planar main body 2.

[0047]The neck-surrounding region 6 is visible in FIG. 5A as the region of the planar main body 2 which runs coaxially with the cylinder axis 4 of the cylindrical coupling neck 3 and encloses the entire circumference of the coupling neck 3 at the rear end of the coupling neck 3.

[0048]The planar main body 2 has, starting from an arcuate base edge region 16 of the planar main body 2 partially surrounding the neck-surrounding region 6, opposing outer edge regions 14, 15 which run in their outer contour in the manner of increasingly spaced-apart V-legs as far as the counterweight 8. As a result of the V-shaped widening in comparison with compressor coupling components shaped according to the prior art, not only are the rigidity and robustness of the compressor coupling component 1 considerably increased, but also the widenings obtained are usable for the integration of additional supporting elements 20, such as in the form of two integrated rib structures, which each protrude in the axial direction, in relation to the cylinder axis 4 of the coupling neck 3, on the front side of the planar main body 2, and at the same time extend from the widenings 18, 19 of the planar main body 2 which each bear against the edge regions 14, 15 oriented towards each other in the form of V-legs, as far as the counterweight 8 or extend or merge into the counterweight 8. As can be seen in FIGS. 5A and 5B, the reinforcing ribs as additional supporting elements 20 protrude in the axial direction, in relation to the cylinder axis 4, on the rear side 2b of the planar main body 2 exactly as far as the counterweight 8 protrudes beyond the planar main body 2 on the rear side 2b.

[0049]In the bar chart in FIG. 6, the local maximum stresses for the different compressor coupling components 1*, 1**, 1 are compared at different rotor rotation speeds. The local maximum stresses are indicated in absolute terms in the unit [N/mm2] on one side, and on the other side the chart also permits a relative figure in comparison with the local maximum stress occurring at 8600 revolutions per minute in the forged compressor coupling component 1* shaped according to the prior art as a reference value which corresponds to 100% as shown on the right-hand axis of the chart. As shown in the chart, the connection design according to the invention reduces the local maximum stresses to well below 100%, and thus also to below the maximum permissible operation-induced load of the compressor coupling component 1, at all rotor rotation speeds.