Conveyor unit

Abstract

Conveyor unit with a drive shaft (1) and a rotor (2) rotatably arranged in a housing (3) driven by the drive shaft (1), wherein the drive shaft (1) forms an inclined sliding plane (1) that interacts with the rotor (2).1) having a rotor (2) with its rotor axis (5) that allows the rotor (2) to wobble about a drive axis (6) of the drive shaft (1), wherein the rotor (2) has a toothing (9) on its end face facing away from the drive shaft (1) which meshes with a toothing (10) formed on the housing (3), wherein working spaces (11) are formed between the toothing (9) of the rotor (2) and the toothing (10) of the housing (3), characterized in that the drive shaft (1) is surrounded by a stator (15), that magnets (16) are provided on the drive shaft (1) which interact magnetically with the stator (15), and that the magnets (16) are arranged off-center on the drive shaft (1) with respect to the stator (15) and in the direction of the drive axis (6) such that the drive shaft (1) is pressed against the rotor (2) with a predetermined magnetic force.

Description

State of the art The invention relates to a conveying unit according to the preamble of the main claim. A conveying unit is already known from DE 10 2010 040 758 A1 and DE 10 2008 013 991 A1, comprising a drive shaft and a rotor rotatably arranged in a housing and driven by the drive shaft. The drive shaft has an inclined sliding plane that interacts with the rotor, causing the rotor to wobble about a drive axis of the drive shaft. The rotor has teeth on its end face facing away from the drive shaft, which mesh with teeth formed on a housing of the conveying unit. Working spaces are formed between the teeth of the rotor and the teeth of the housing, which can be filled via an inlet and emptied via an outlet. A disadvantage is that the conveying unit has a comparatively large axial length, since the drive of the conveying unit is arranged at an end of the drive shaft facing away from the rotor. Furthermore, a conveying unit is known from DE 10 2007 022 418 A1, which has a power rotor with integrated permanent magnets. Advantages of the invention In contrast, the conveying unit according to the invention, with the characterizing features of the main claim, has the advantage that the axial length of the conveying unit is significantly reduced by surrounding the drive shaft with a stator and providing magnets on the drive shaft that interact magnetically with the stator. In the design according to the invention, the drive shaft is configured as the armature of an electric machine. The function of the armature is thus integrated into the drive shaft. The number of components required is therefore reduced. According to the invention, the magnets on the drive shaft are arranged off-center with respect to the stator and in the direction of the drive axis such that the drive shaft is pressed against the rotor with a predetermined magnetic force. This ensures that the drive shaft and rotor are constantly pressed against the teeth of the housing with a constant magnetic force. As a result, the conveyor unit starts more easily when the electric motor is switched on. In other words, the drive shaft and rotor can be turned more easily when the electric motor is switched on. The measures listed in the dependent claims enable advantageous further development and improvements of the conveying unit specified in the main claim. It is particularly advantageous if the drive shaft has at least one pocket or recess for receiving the magnets, as this allows the magnets to be integrated flush with the drive shaft, i.e., not protruding. It is also advantageous if the magnets are permanent magnets, since in this way a permanently excited electrical machine is formed. According to an advantageous embodiment, the drive shaft in the area of ​​the magnets is encased by a cylinder, since the magnets are thus encapsulated and protected from the fluid of the conveying unit. It is very advantageous if a shaft bearing is provided on each end face of the stator for supporting the drive shaft, as the drive shaft is thus precisely supported. It is also advantageous if the shaft bearings are designed as plain bearings, since plain bearings are particularly robust and cost-effective to implement. Furthermore, it is advantageous if the shaft bearings are provided on a disc-shaped or ring-shaped component. It is also advantageous if the shaft bearings are injection-molded onto the stator with a plastic, as this allows for particularly cost-effective production of the shaft bearings and integrates the function of the shaft bearing into the injection-molded plastic. drawing An embodiment of the invention is shown in simplified form in the drawing and explained in more detail in the following description. Description of the exemplary embodiment The drawing shows a cross-section of a conveying unit according to the invention. The conveying unit, for example a pump or a compressor, comprises a drive shaft 1 that drives a rotor 2, which is rotatably mounted in a housing 3. The drive shaft 1 has, at its end facing the rotor 2, an inclined sliding plane 1.1 that interacts with the rotor 2. This inclined sliding plane is formed, for example, on a shoulder 4 of the drive shaft 1 and causes the rotor 2 to wobble about a drive axis 6 of the drive shaft 1 with its rotor axis 5. The rotor 2 has, on its side facing the drive shaft 1, a sliding surface 2.1 that interacts with the inclined sliding plane 1.1, and on its end face facing away from the drive shaft 1, a toothed section 9 that meshes with the toothed section 10 formed on the housing 3. Between the toothing 9 of the rotor 2 and the toothing 10 of the housing 3, working spaces 11 are formed, which can be filled via an inlet 12 of the conveying unit and emptied via an outlet 13 of the conveying unit.The toothing 9 of the rotor 2 and the toothing 10 of the housing 3 are, for example, designed as cycloidal toothing, but can also be a different type of toothing. The conveying unit operates on the displacement principle, so that the fluid is drawn into the working chambers 11 via the inlet 12 and expelled from these chambers at increased pressure via the outlet 13. The drive shaft 1 has a through-channel 14 to transport fluid from the inlet 12 into the working chambers 11 or from these chambers to the outlet 13. Which opening 12, 13 of the conveying unit is the inlet or outlet depends on the direction of rotation of the rotor. According to the invention, the drive shaft 1 is at least partially surrounded by a stator 15, and magnets 16 are provided on the drive shaft 1, which interact magnetically with the stator 15. With this embodiment, the drive shaft 1 forms the armature of an electric machine, thereby shortening the axial length, i.e., in the direction of the drive axis 6. Unlike the invention, the magnets 16 can be arranged centrally with respect to the stator 15 and in the direction of the drive axis 6. According to the invention, the magnets 16 are arranged off-center on the drive shaft 1 with respect to the stator 15 and in the direction of the drive axis 6 such that the drive shaft 1 is pressed against the rotor 2 with a predetermined magnetic force. For this purpose, the magnets 16 are arranged on the drive shaft 1 offset from a central arrangement with respect to the stator 15 in the direction away from the rotor 2. The stator 15, for example, is formed by a stack of stacked sheet metal lamellae made of so-called electrical steel. The drive shaft 1, for example, has at least one pocket or recess, or at least one shoulder 17, for receiving the magnets 16. The pocket or recess 16 can be open or closed radially outward with respect to the drive axis 6. The magnets 16 are permanent magnets to form a permanent magnet electric machine. The magnets 16 can be individual magnets or formed on a single ring in which magnetic powder is embedded. For example, the magnet ring can be made of a plastic base material in which the magnetic powder is distributed. The drive shaft 1 can be covered in the area of ​​the magnets 16 by a cup-shaped or cylindrical casing 18, which can also be a coating. The casing 18 is made of plastic, for example, and protects the magnets 16 from the fluid of the conveying unit and / or secures them in the at least one pocket or recess 17. According to the exemplary embodiment, a shaft bearing 20 or a receptacle for a shaft bearing 20 is provided on each end face of the stator 15. The shaft bearing 20 is, for example, designed as a plain bearing. The shaft bearings 20 are each provided on a disk-shaped or ring-shaped component 19, which, for example, abuts the end faces of the stator 15. The component 19 can be directly tapered to the stator 15. The component 19 has a through-opening 21 for the drive shaft 1. The shaft bearing 20 can be arranged in the through-opening 21 as a separate component, for example, as a plain bearing bushing. However, the through-opening 21 can also itself form the plain bearing. The stator 15 has stator teeth 24 on its inner side facing the drive shaft 1, each of which is fitted with a stator winding 25, with stator slots 26 formed between the stator teeth 25. The stator slots 26 can be filled with plastic, for example, such that the components 19 are integrally connected to one another by the plastic. Coil formers 27 are provided on the stator teeth 25, for example, which receive the stator winding 25 and electrically insulate it from the stator 15. The sections of the stator winding 25 protruding from the stator slots 26 are, for example, also overmolded with plastic and thus protected against corrosion, whereby this overmolding and the component 19, which is, for example, overmolded onto the stator 15, can be manufactured in one piece in an injection molding process. The plastic can also be provided section by section on the outer circumference of the stator 15, for example as a web 30, and connect the disc-shaped or ring-shaped components 19 to each other. The housing 3 comprises a hollow cylindrical or pot-shaped housing section 3.1, which is closed at its end face by at least one cover 3.2, 3.3. According to the exemplary embodiment, the housing 3 is hollow cylindrical and closed at its end face by a cover 3.2, 3.3. One of the covers 3.2, 3.3 could also be configured as the bottom of a pot-shaped housing section 3.1.

Claims

Conveyor unit with a drive shaft (1) and a rotor (2) rotatably arranged in a housing (3) driven by the drive shaft (1), wherein the drive shaft (1) forms an inclined sliding plane (1) that interacts with the rotor (2).1) having a rotor (2) with its rotor axis (5) which causes the rotor (2) to wobble about a drive axis (6) of the drive shaft (1), wherein the rotor (2) has a toothing (9) on its end face facing away from the drive shaft (1) which meshes with a toothing (10) formed on the housing (3), wherein working spaces (11) are formed between the toothing (9) of the rotor (2) and the toothing (10) of the housing (3), characterized in that the drive shaft (1) is surrounded by a stator (15), that magnets (16) are provided on the drive shaft (1) which interact magnetically with the stator (15), and that the magnets (16) are arranged off-center on the drive shaft (1) with respect to the stator (15) and in the direction of the drive axis (6) such that the drive shaft (1) is pressed against the rotor (2) with a predetermined magnetic force. Conveyor unit according to claim 1, characterized in that the drive shaft has at least one pocket or recess (17) for receiving the magnets (16). Conveyor unit according to claim 1, characterized in that the magnets (16) are arranged centrally on the drive shaft (1) with respect to the stator (15) and in the direction of the drive axis (6). Conveyor unit according to claim 1, characterized in that the magnets (16) are arranged offset on the drive shaft (1) in a direction away from the rotor (2) relative to an arrangement centered with respect to the stator (15). Conveyor unit according to one of the preceding claims, characterized in that the magnets (16) are permanent magnets. Conveyor unit according to one of the preceding claims, characterized in that the drive shaft (1) is covered by a sheath (18) in the area of ​​the magnets (16). Conveyor unit according to one of the preceding claims, characterized in that a shaft bearing (20) for supporting the drive shaft (1) is provided on each end face of the stator (15). Conveyor unit according to claim 7, characterized in that the shaft bearings (20) are designed as sliding bearings. Conveyor unit according to claim 7, characterized in that the shaft bearings (20) are provided on a disc-shaped or ring-shaped component (19). Conveyor unit according to one of the preceding claims, characterized in that the stator (15) has stator teeth (24) on its inner side facing the drive shaft (1), on each of which a stator winding (25) is provided, wherein stator grooves (26) are formed between the stator teeth (24). Conveyor unit according to one of the preceding claims, characterized in that the housing (3) has a cylindrical or pot-shaped housing section (3.1) which is closed at its end face by at least one cover (3.2, 3.3).

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