Pump

Abstract

Pump, in particular for conveying a medium, with a conveying area (10) comprising a rotatable rotor (1) and a stator (2) for receiving the rotor (1), wherein the rotor (1) has a screw geometry (5) and the stator (2) has a cavity (13) with a geometry substantially corresponding to the screw geometry (5), and wherein the conveying area (10) has an inlet (11) on one side and an outlet (12) for the medium on the other side, and with a drive (14) for rotating the rotor (1), wherein the drive (14) interacts with the rotor (1) via a gearbox (15), characterized in that the gearbox (15) is a planetary gearbox.

Description

[0001] The invention relates to a pump according to claim 1.

[0002] Such a pump is used to pump a medium. For example, the pump can be used as a dosing pump for supplying and / or dosing liquid detergent in a washing machine or dishwasher.

[0003] Such a pump has a delivery area that includes a rotatable rotor and a stator for holding the rotor. The rotor has a screw geometry and the stator has a cavity with a geometry that essentially corresponds to the screw geometry. In other words, the rotor has the shape of a screw, while the shape of the cavity in the stator is essentially correspondingly screw-shaped. The delivery area has an inlet on one side and an outlet for the medium on the other side. Finally, the pump also includes a drive for rotating the rotor, wherein the drive interacts with the rotor via a gear. The known pump in the type of an eccentric screw pump is large and therefore not suitable for small installation spaces and / or confined spaces.

[0004] The invention is based on the object of further developing the pump in the form of an eccentric screw pump in such a way that it is designed to be compact. In particular, the eccentric screw pump should be suitable for use in small installation spaces and / or in confined spaces.

[0005] This object is achieved in a generic pump by the characterizing features of claim 1.

[0006] The pump according to the invention is characterized by the fact that the gear mechanism is a planetary gear. This creates a compact eccentric screw pump whose operating principle advantageously ensures a constant flow and / or pressure build-up for the medium. This also favors the use of the pump according to the invention in household appliances. Further embodiments of the invention are the subject of the dependent claims.

[0007] To protect the pump from external influences, a housing can be provided to accommodate the stator and / or rotor and / or gear unit. For a more efficient drive, the drive can be an electric motor. For a more compact design, the drive can be mounted laterally and / or as an extension of the housing.

[0008] The housing can enclose the stator in a compact manner. Preferably, the housing can be approximately cylindrical. Expediently, the stator can be designed in the manner of a cylindrical extension. The housing can have a receptacle for the gear, wherein a cover can be arranged on one side of the receptacle. The cavity in the stator can in turn be connected to the other side of the receptacle. Furthermore, the outlet can be arranged at the transition between the cavity and the receptacle, in particular protruding laterally from the housing. Advantageously, this makes it possible to create an essentially one-piece housing for the pump with a small space requirement.

[0009] As already mentioned, a compact planetary gear unit is provided as the transmission for the pump. Such a transmission unit can comprise at least one planetary gear and a planetary gear carrier on which the planetary gear is arranged, as well as a ring gear. In a particularly reliable manner, three planetary gears can be provided. The planetary gear, in turn, can be rotatably mounted on a bearing journal on the planetary gear carrier.

[0010] In a simple manner, the planetary gear carrier can be operatively connected to the drive for moving the planetary gear carrier. For compactness, the planetary gear carrier can have external gearing. The planetary gear carrier can, in turn, be movable by the drive via a drive pinion that engages the external gearing. The drive pinion can expediently be arranged on an output shaft of the electric motor. Finally, an opening can be provided in the housing, particularly in the cover, for the engagement of the drive pinion with the external gearing of the planetary gear carrier.

[0011] The ring gear can be fixedly arranged in the housing. In a functionally reliable design, the planetary gear can be designed as a gear, and the ring gear can have internal teeth for interaction with the planetary gear. In particular, the interaction can occur in such a way that a rolling movement of the planetary gear in the ring gear can be effected by the movement of the planetary gear carrier. Furthermore, for the sake of compactness, one of the planetary gears can be arranged as a rotor spur gear on the rotor to rotate the rotor.

[0012] Finally, the rotational axis of the rotor spur gear can be arranged eccentrically to the rotational axis of the rotor's screw geometry. This is done in such a way that the axial offset between the rotor spur gear and the screw geometry causes a rolling action of the rotor in the stator cavity. In this case, the rotational movement of the rotor is superimposed on a linear up and / or down movement of the screw geometry to convey the medium.

[0013] To increase operational reliability, the gearbox and / or the drive can be separated from the conveying area by means of a sealing unit, so that penetration of the medium into the gearbox and / or the drive is prevented. The sealing unit can comprise a sealing disc and at least one shaft seal. The sealing disc can be movable in the ring gear by the rolling movement of the rotor spur gear. The sealing disc can expediently be eccentrically shaped such that the sealing disc corresponds to the eccentricity of the movement of the rotor. The rotor can be rotatably mounted in the sealing disc in a functionally reliable manner by means of a ball bearing. Furthermore, one shaft seal can be provided to seal the rotation of the sealing disc relative to the stator. Finally, a further shaft seal can be provided between the rotor and the sealing disc to seal the rotational movement of the rotor about its axis of rotation.

[0014] The following can be stated for a particularly preferred embodiment of the pump according to the invention.

[0015] Household appliances, such as coffee machines, washing machines, and the like, require pumps to pump media such as water, detergent, etc. However, today's household appliances are increasingly designed to be space-saving, which means that the space for the required technology within the appliance's housing is becoming increasingly smaller.

[0016] Therefore, there is a need for a compact, short-profile eccentric screw pump. This eccentric screw pump should operate with an efficient and quiet drive for the precise and / or highly repeatable delivery of various media, such as water, detergent, etc. At the same time, the necessary pressure build-up should be ensured.

[0017] Progressing cavity pumps currently available on the market generally have a very long design. This is due, on the one hand, to the pump's operating principle, as the conveying distance must be correspondingly long depending on the fluid and / or pressure. Another reason for the long design is the power transmission from the motor to the pump's rotor. In common progressing cavity pumps, this power transmission is achieved via a long drive shaft or a universal joint.

[0018] The eccentric screw pump according to the invention essentially consists of the conveying section, consisting of the screw geometries of the rotor and stator, and a drive unit consisting of a gear transmission with a special sealing unit that separates the conveying section from the drive unit. The compact design is achieved in particular by a transmission consisting of a spur gear, hereinafter referred to as the rotor spur gear, and a ring gear. The rotor spur gear is connected to the pump rotor. The rotor is designed as a screw geometry. The rotational axis of the rotor spur gear is shifted by the amount x relative to the rotational axis of the screw geometry in the manner of an eccentricity. Analogous to a planetary gear, the rotor spur gear of the rotor functions as a planet in a ring gear.

[0019] The drive, or rather the rotary motion, of the rotor spur gear as a planet is initiated by a planet gear carrier. Rotating the planet gear carrier results in a rolling motion of the rotor spur gear in the ring gear. Due to the axial offset x between the rotor spur gear and the worm gear geometry of the rotor, as well as the special size ratio of the rotor spur gear to the ring gear, the rotary motion is superimposed with a linear up and / or down motion. Thus, the worm gear geometry of the rotor describes a hypocycloid curve, which in this special case is a straight line, namely a Cardan circle. The aforementioned superposition of rotary motion with linear motion leads to a rolling motion of the rotor in the stator, which describes the operating principle of the eccentric screw pump.

[0020] To ensure the use of the progressing cavity pump in the food industry, for example, the drive unit is separated from the conveying section, i.e. the rolling area from the rotor to the stator, by a sealing unit consisting of a sealing disc and two shaft seals. Since the rotor moves eccentrically in the area of ​​the sealing disc, the sealing disc is also eccentrically shaped to compensate for the rotor's eccentricity. The rotor moves clockwise on a circular path through the planet gear carrier, while rotating counterclockwise due to the rolling process between the rotor spur gear and the ring gear. Thus, the direction of rotation of the circular path on which the rotor spur gear moves and the direction of rotation of the rotor around its own axis are opposite. This is comparable to the rotating planet in the ring gear of a planetary gear.The rotation of the rotor around its own axis is sealed with a small shaft seal between the rotor and the sealing disc. The rotation of the sealing disc is sealed with a larger shaft seal to the stator housing. This principle allows the pump to be sealed using simple sealing elements, such as radial shaft seals, O-rings, quad rings, or similar.

[0021] The result is a compact progressive cavity pump with a gear-based drive unit that is separate from the pumped medium. In conventional progressive cavity pumps, the rotary motion is generated by an up and / or down movement through friction between the rotor and stator. To achieve this up and / or down movement, a relatively long drive shaft or cardan joint is required. In the invention, however, the space-intensive power transmission via a drive shaft or cardan joint is replaced by a compact gear, which also determines the rotor's movement.

[0022] The advantages achieved by the invention are, in particular, that the pump has a compact design. Furthermore, the respective pumped media can be easily and completely separated from the drive unit.

[0023] An embodiment of the invention with various developments and refinements is shown in the drawings and is described in more detail below. Fig. 1 an exploded view of the pump, Fig. 2 a longitudinal section through the pump Fig. 1, Fig. 3 a cross section along the line 3 -3 in Fig. 2, Fig. 4 a cross section along the line 4-4 in Fig. 2 and Fig. 5 the pump off Fig. 1 in a partially cutaway view.

[0024] In Fig. 1 shows an exploded view of a pump 30 for conveying a medium. The pump 30 serves, for example, as a dosing pump for supplying liquid detergent in a washing machine or a dishwasher. The pump 30 has a conveying region 10, wherein the conveying region 10 has an inlet 11 on one side and an outlet 12 for the medium on the other side. The conveying region 10 comprises a rotatable rotor 1 and a stator 2 for receiving the rotor 1. The rotor 1 has a screw geometry 5 in that it is formed in the shape of a screw. The stator 2, in turn, has a cavity 13 with a geometry essentially corresponding to the screw geometry 5, whereby the shape of the cavity 13 in the stator 2 is essentially correspondingly screw-shaped.

[0025] Furthermore, a Fig. 2, a drive 14 is provided for rotating the rotor 1, wherein the drive 14 preferably consists of an electric motor. The drive 14 interacts with the rotor 1 via a gear 15. A housing 16 is provided to accommodate the stator 2 and / or the rotor 1 and / or the gear 15. The drive 14 is arranged as an extension of the housing 16, as can be seen from FIG. Fig. 2. According to another version, which is shown in Fig. 5, the drive 14 is located on the side of the housing 16.

[0026] How to proceed based on Fig. 1, the housing 16 is approximately cylindrical in shape. The housing 16 encloses the stator 2, which is also designed in the manner of a cylindrical projection. Furthermore, the housing 16 has a receptacle 26 for the gear 15. A cover 27 is arranged on one side of the receptacle 26, so that the housing 16 is closed off laterally. The cavity 13 in the stator 2 is adjacent to the other side of the receptacle 26. Finally, the outlet 12 is arranged at the transition 28 between the cavity 13 and the receptacle 26. The outlet 12 protrudes laterally from the housing 16.

[0027] The transmission 15 is a planetary gear transmission. The transmission 15 has at least one planetary gear 3 and a planetary gear carrier 6, on which the planetary gear 3 is arranged, as well as a ring gear 4. In particular, the transmission 15 has three planetary gears 3, 17, 17' arranged on the planetary gear carrier 6, as can be seen from Fig. 3. As can be seen from Fig. 4, the planet gear 3, 17, 17' is rotatably arranged on a bearing journal 18 on the planet gear carrier 6.

[0028] The planet carrier 6 is positioned according to Fig. 2 in operative connection with the drive 14 to move the planet carrier 6. As further in Fig. 5, the planetary gear carrier 6 has an external toothing 19, so that the planetary gear carrier 6 is movable by the drive 14 by means of a drive pinion 20, which engages in the external toothing 19. The drive pinion 20 is arranged on the output shaft 21 of the electric motor 14. For the engagement of the drive pinion 20 in the external toothing 19 of the planetary gear carrier 6, a Fig. 1 visible opening 22 is provided in the housing 16, more precisely in the cover 27.

[0029] The ring gear 4 is fixedly arranged in the housing 16. The planet gear 3, 17, 17' is designed as a gear, and the ring gear 4 has an internal toothing 23 for interaction with the planet gear 3, 17, 17', such that a rolling movement of the planet gear 3, 17, 17' in the ring gear 4 can be effected by movement of the planet gear carrier 6. Furthermore, one planet gear 3 is arranged as a rotor spur gear on the rotor 1 for rotating the rotor 1.

[0030] How to continue Fig. As can be seen in Figure 1, the rotational axis of the rotor spur gear 3 is arranged eccentrically to the rotational axis of the screw geometry 5 of the rotor 1. This creates an axial offset between the rotor spur gear 3 and the screw geometry 5, which causes a rolling action of the rotor 1 in the cavity 13 of the stator 2. As a result, the rotational movement of the rotor 1 is superimposed with a linear up and / or down movement of the screw geometry 5 for conveying the medium, so that the pump 30 operates as an eccentric screw pump.

[0031] As shown by Fig. As can be seen in Figure 2, the gear unit 15 is separated from the conveying area 10 by a sealing unit 24 located in the housing 16, so that penetration of the medium into the gear unit 15 is prevented. Of course, this also separates the drive unit 14 from the conveying area 10, so that interference with the drive unit 14 by the medium is also excluded. According to Fig.1, the sealing unit 24 comprises a sealing disk 7 and at least one shaft sealing ring 8, preferably two shaft sealing rings 8, 9. The sealing disk 7 is movable by the rolling movement of the rotor spur gear 3 in the ring gear 4. Furthermore, the sealing disk 7 is eccentrically shaped such that the sealing disk 7 corresponds to the eccentricity of the movement of the rotor 1. The rotor 1 is in turn rotatably mounted in the sealing disk 7 by means of a ball bearing 25. The one, larger shaft sealing ring 9 is provided to seal the rotation of the sealing disk 7 relative to the stator 2. The other, smaller shaft sealing ring 8 is provided between the rotor 1 and the sealing disk 7 to seal the rotational movement of the rotor 1 about its axis of rotation.

[0032] The invention is not limited to the described and illustrated embodiment. Rather, it also encompasses all expert developments within the scope of the invention defined by the patent claims. Thus, the pump 30 can be used not only in washing machines and / or dishwashers, but also in other appliances in which, due to the ambient conditions, only small installation spaces are permitted and / or space is limited. In particular, the compact design of the eccentric screw pump according to the invention, combined with the advantages of its operating principle, namely constant flow and / or pressure buildup, is suitable for use in household appliances, especially coffee machines. Reference symbol list: 1 rotor 2 Stator 3 Planetary gear / rotor spur gear 4 ring gear 5 Screw geometry (of the rotor) 6 planetary gear carriers 7 Sealing washer 8 Shaft seal 9 (additional) shaft seal 10 Funding area 11 Entrance 12 Outlet 13 Cavity (in the stator) 14 Drive / Electric motor 15 gearboxes 16 housings 17.17' planetary gear 18 bearing journals (on planetary gear carrier) 19 External gearing (on planetary gear carrier) 20 drive pinions 21 Output shaft (from drive) 22 Opening (in the housing) 23 Internal gearing (of ring gear) 24 Sealing unit 25 ball bearings 26 Mounting (for gearbox in the housing) 27 lids 28 Transition (between receptacle and cavity) 30 pump

Claims

[1] Pump, in particular for conveying a medium, with a conveying area (10) comprising a rotatable rotor (1) and a stator (2) for receiving the rotor (1), wherein the rotor (1) has a screw geometry (5) and the stator (2) has a cavity (13) with a geometry substantially corresponding to the screw geometry (5), and wherein the conveying area (10) has an inlet (11) on one side and an outlet (12) for the medium on the other side, and with a drive (14) for rotating the rotor (1), wherein the drive (14) interacts with the rotor (1) via a gear (15), characterized by that the gear (15) is a planetary gear. [2] Pump according to claim 1, characterized bythat a housing (16) is provided for receiving the stator (2) and / or the rotor (1) and / or the gear (15), that preferably the drive (14) consists of an electric motor, and that further preferably the drive (14) is arranged laterally and / or in extension to the housing (16). [3] Pump according to claim 1 or 2, characterized bythat the preferably approximately cylindrically designed housing (16) comprises the stator (2), which is designed in particular in the manner of a cylindrical extension, that the housing (16) preferably has a receptacle (26) for the gear (15), that further preferably a cover (27) is arranged on one side of the receptacle (26), that even more preferably the cavity (13) in the stator (2) adjoins the other side of the receptacle (26), and that even more preferably the outlet (12) is arranged at the transition (28) between the cavity (13) and the receptacle (26), in particular projecting laterally from the housing (16). [4] Pump according to claim 1, 2 or 3, characterized bythat the transmission (15) has at least one planetary gear (3), in particular three planetary gears (3, 17, 17'), and a planetary gear carrier (6) on which the planetary gear (3, 17, 17') is arranged, as well as a ring gear (4), and that preferably the planetary gear (3, 17, 17') is rotatably arranged on a bearing journal (18) on the planetary gear carrier (6). [5] Pump according to one of claims 1 to 4, characterized bythat the planet gear carrier (6) is operatively connected to the drive (14) for moving the planet gear carrier (6), that preferably the planet gear carrier (6) has an external toothing (19), that further preferably the planet gear carrier (6) is movable by the drive (14) by means of a drive pinion (20) which engages in the external toothing (19), that even more preferably the drive pinion (20) is arranged on an output shaft (21) of the electric motor (14), and that even more preferably an opening (22) is provided in the housing (16), in particular in the cover (27), for the engagement of the drive pinion (20) in the external toothing (19) of the planet gear carrier (6). [6] Pump according to one of claims 1 to 5, characterized bythat the ring gear (4) is arranged in a fixed manner in the housing (16), that preferably the planet gear (3, 17, 17') is designed as a gear and the ring gear (4) has an internal toothing (23) for interacting with the planet gear (3, 17, 17'), in particular in such a way that a rolling movement of the planet gear (3, 17, 17') in the ring gear (4) can be brought about by movement of the planet gear carrier (6), and that further preferably one planet gear (3) is arranged as a rotor spur gear on the rotor (1) for rotating the rotor (1). [7] Pump according to one of claims 1 to 6, characterized bythat the rotational axis of the rotor spur gear (3) is arranged eccentrically to the rotational axis of the screw geometry (5) of the rotor (1), such that a rolling process of the rotor (1) in the cavity (13) of the stator (2) can be effected by the axial offset between the rotor spur gear (3) and the screw geometry (5), wherein the rotary movement of the rotor (1) is superimposed with a rectilinear up and / or down movement of the screw geometry (5) for conveying the medium. [8] Pump according to one of claims 1 to 7, characterized by that the gear (15) and / or the drive (14) are separated from the conveying area (10) by means of a sealing unit (24) such that penetration of the medium into the gear (15) and / or into the drive (14) is prevented. [9] Pump according to one of claims 1 to 8, characterized bythat the sealing unit (24) comprises a sealing disc (7) and at least one shaft sealing ring (8, 9), that preferably the sealing disc (7) is movable by the rolling movement of the rotor spur gear (3) in the ring gear (4), wherein in particular the sealing disc (7) is formed eccentrically such that the sealing disc (7) corresponds to the eccentricity of the movement of the rotor (1), and that further preferably the rotor (1) is rotatably mounted in the sealing disc (7) by means of a ball bearing (25). [10] Pump according to one of claims 1 to 9, characterized by that one shaft sealing ring (9) is provided for sealing the rotation of the sealing disc (7) relative to the stator (2), and that preferably a further shaft sealing ring (8) is provided between the rotor (1) and the sealing disc (7) for sealing the rotational movement of the rotor (1) about its axis of rotation.

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