EP3245126B1 - Swimming and diving aid - Google Patents

Description

The invention relates to swimming and diving aid with a vehicle body on which a user hangs up or sets up, with a arranged in the vehicle body flow channel in which a driven by an electric motor propeller with radially outward attached to a base portion of the propeller propeller blades, wherein the electric motor has a fixed motor stator and a rotating rotor spatially associated with the motor stator.

Such swimming and diving are from the DE 10 2004 049 615 B4 known. They have a handle assembly to which a user can hold while he rests with a portion of his upper body on the top of the vehicle body of the vessel. Within the vehicle body, a flow channel is arranged, in which a propeller is housed. The propeller is powered by an electric motor powered by batteries. For this purpose, the propeller is connected via a drive shaft to the electric motor. The electric motor is held in a receiving housing, which is guided to the propeller. The drive shaft is guided via a sealing cassette from the receiving housing to the propeller. The thus waterproof running Recording housing with the electric motor can be arranged in a flooded area of water in the vehicle body of the swimming and diving aid and so give its heat loss to the passing water. For this purpose, it is provided that the propeller, the electric motor and an associated control unit are designed as underwater drive unit and arranged in the flow channel.

With such an arrangement, the advantages of the compact construction and the good efficiency achieved by the cooling are counteracted by the disadvantage that the electric motor is arranged in the flow channel and thus not insignificantly influences the flow of the water. This is especially true for high-performance electric motors, which apply a high torque for rapid acceleration of the swimming and diving aid and must be transmitted to the propeller via the drive shaft, which has a comparatively small diameter and thus a short lever arm in the transmission area. The flow channel must therefore be dimensioned sufficiently large to compensate for the shading caused by the electric motor. This affects the size of the swimming and diving aid.

In the DE 10 2013 100 544 A1 Therefore, a watercraft is proposed, in which a propeller is arranged in a flow channel. In a vehicle body of the vessel, a flooding space is provided, which is filled in the swimming and diving operation via water passage openings with water. The electric motor and associated accumulators are disposed in the flooding space and are thus cooled efficiently without affecting the flow in the flow channel. The energy transfer from the electric motor to the propeller takes place via a drive shaft guided in an enveloping tube, which is guided out of the flooding space into the flow channel. The electric motor is thus taken out of the flow region of the flow channel, but is still cooled by the heat-conducting contact with the water in the flooding chamber.

A disadvantage of this arrangement is the weight increase of the watercraft by the required, extended drive shaft, which in particular the transport of the sports equipment outside the water severely impaired. The increased mass inertia of the drive shaft influences the dynamics of the drive, which must be compensated by a correspondingly more powerful electric motor under the disadvantage of increased energy consumption. Another disadvantage arises from the performance-reducing disturbance of the flow in the flow channel through the drive shaft passed through and by the interruption in the otherwise smooth running wall of the flow channel in the area where the drive shaft is guided in the flow channel.

It is an object of the invention to provide a swimming and diving aid, which has a low weight at a high driving dynamics.

The object of the invention is solved by the features of claim 1. This creates a high torque that is transmitted to the propeller. Due to the high torque rapid changes in the rotational speed of the propeller can be effected, which allows a high driving dynamics of the swimming and diving aid.

According to a particularly preferred embodiment variant of the invention, it can be provided that the outer ends of at least part of the propeller blades are connected to a propeller ring and that the rotor is arranged on the propeller ring and / or that the outer ends of at least a portion of the propeller blades with an annular Rotor housing are connected and that the rotor is arranged in the rotor housing. The driving force is thus transmitted over several propeller blades, whereby the mechanical load of the individual propeller blades is significantly reduced. This makes it possible to transfer very high driving forces to the propeller. The centrifugal forces of the rotor are transmitted to the propeller ring or the rotor housing. Lifting forces acting on opposite areas of the propeller ring or the rotor housing on each other, so that the propeller blades are not loaded on train. This increases the life expectancy of the propeller blades. The propeller ring can represent the inner bottom of the rotor housing. When using a rotor housing, the rotor is protected from water.

A simple and cost-effective production can be achieved in that the propeller ring and / or the rotor housing are integrally formed on the propeller. The propeller can be manufactured together with the propeller ring or the rotor housing in one operation.

A simple and safe construction of the electric motor can be achieved in that the rotor has a plurality of arranged in the direction of rotation of the rotor permanent magnet and / or that the motor stator has a plurality of circumferentially the circular path on which the rotor moves, arranged electromagnet. Due to the structure of the rotor with permanent magnets, no current has to be transferred to the rotor. This eliminates a water-protected power supply on rotating components. By using a large number of permanent magnets and electromagnets, a high number of pole pairs is achieved. Thereby, an electric motor with a high torque is obtained.

It is advantageously provided that in the flow direction of the water after the propeller, a flow stator is arranged with Statorflügeln that the flow stator via the Statorflügel is directly or indirectly fixed to the wall of the flow channel and / or that directly or indirectly with the outer ends of at least one part the stator blade is connected to a stator housing for receiving the motor stator. The stator vanes are oriented so that the rotation of the water is converted into a linear motion. As a result, the stored energy in the rotation of the water for driving the swimming and diving aid can be obtained. By fixing the flow stator to the flow channel, it is stationarily positioned in the flow channel. He also does not change his position at high flow velocities of the water in the flow channel. The stator is preferably circumferentially to a circular path on which the rotor moves, arranged. In this case, the stator is to be arranged stationary. Both requirements can be met easily by a stator connected to the stator stator.

A simple and cost-effective production can be achieved in that the stator housing of the electric motor is integrally formed on the flow stator. The flow stator and the stator housing of the electric motor can be produced in one step.

In order to achieve a desired drive of the swimming and diving aid, a corresponding volume of water must be accelerated to a sufficient speed. This requires a sufficiently large flow cross section. In order to achieve a sufficiently large flow cross section, it can be provided that the rotor and / or the motor stator are arranged in a lateral recess of the flow channel. The electric motor is thus arranged outside the main flow of the guided in the flow channel water. Thus, compared to a structure in which the electric motor is disposed within the flow channel, the cross section of the flow channel can be reduced. Since the flow channel occupies a substantial proportion of the vehicle body, so the entire swimming and diving aid can be built compactly with undiminished drive power.

A simple and resilient bearing of the propeller can be achieved in that the propeller is axially fixed to a rotatably mounted shaft disposed within the flow channel.

According to a preferred embodiment of the invention, it can be provided that the shaft is designed as a hollow shaft and / or that the shaft is made of a carbon fiber reinforced plastic. By carrying out the shaft as a hollow shaft, a reduction in weight can be achieved without significant stability losses and stiffness losses of the shaft. Carbon fiber reinforced plastics (CFRP) have a much lower level than metal shafts Density at the same time a very high rigidity. Therefore, a lighter shaft made of CFRP can be used for the rotatable mounting of the propeller and for transmitting a thrust force from the propeller to the vehicle body of the swimming and diving aid. The swimming and diving aid can be worn more easily outside the water. The lower inertia of the motor shaft caused by the lower mass leads to increased dynamics of the swimming and diving aid at the same, provided by the electric motor power, which is a significant advantage for the use of swimming and diving aid as a water sports equipment. This is especially true because the installable power of the electric motor used and the storage capacity of the associated energy storage are limited in a portable water sports equipment.

Preferably, it may be provided that in the flow direction of the water flowing in the flow channel water in front of the propeller, a centering device is arranged with a base and attached centering and that the centering device via the centering is determined directly or indirectly on the wall of the flow channel. The propeller can be rotatably fixed to the stationary held centering. The Zentrierstreben are so streamlined shaped that they oppose the passing water low flow resistance.

High forces act on the propeller, which also act on the propeller transversely to the axis of rotation due to the water flowing turbulently in the flow channel. In order to be able to intercept these forces safely and still allow a smooth rotation of the propeller, it can be provided that in each case a bearing is arranged on the centering device and on the flow stator, in which the shaft is mounted. Due to the two-sided storage swinging and bending of the shaft can be avoided. As a result, the radial position of the propeller is securely fixed. This makes it possible to provide only a small gap between the rotor and the stator mounted radially outside the rotor. By this measure, an electric motor with a high efficiency is obtained. Collisions between the rotor and the stator or between the rotor housing and the stator can be safely avoided.

In order to store the shaft permanently smoothly, it can be provided that within the base of the centering a first bearing housing is formed, that in the first bearing housing, the front bearing is held and that the first bearing housing with a removable Anströmkappe is watertight sealed against the flow channel. The front bearing is thus protected from moisture. In case of required maintenance, the front bearing can be easily reached by removing the inflow cap.

A permanently smooth running bearing of the shaft can furthermore be achieved by forming a further bearing housing within the stator base of the flow stator such that the rear bearing is held in the further bearing housing and that the further bearing housing is sealed watertight with a removable bearing retaining ring. The rear bearing is protected from moisture. In case of required maintenance, the rear bearing can be easily achieved by removing the bearing retainer.

The swimming and diving aid serves as a water sports device. For this purpose, it must be designed so that a user can not be injured on the device. To avoid that a user engages in the running propeller, it may be provided that the Eingreifschutz is arranged with integrally formed Eingreifschutz struts that the Eingreifschutz struts are directly or indirectly fixed to the wall of the flow channel and that preferably a base body of the Eingreifschutzes is connected to the flow stator. The Eingreifschutz struts are designed so that they affect the flow of water as little as possible, but prevent the intervention in the flow channel. If the base body of the engagement protection connected to the flow stator, this can also be supported against the flow channel. This leads to a further stabilization of the position of the rear bearing of the shaft and thus the radial Positin of the propeller.

According to a particularly preferred embodiment variant of the invention it can be provided that at least from the electric motor with the rotor housing and the stator housing, the centering device, the Anströmkappe, the flow stator and the propeller with the shaft and the bearings an underwater drive unit is formed. The underwater drive unit can be installed as a module pre-assembled in the flow channel. As a result, the installation of the swimming and diving aid is significantly simplified, whereby the manufacturing costs are reduced.

Fig. 1

in perspektivischer Seitenansicht von hinten eine Schwimm- und Tauchhilfe,

Fig. 2

die in Figur 1 gezeigte Schwimm- und Tauchhilfe in perspektivischer Ansicht von unten,

Fig. 3

in einer seitlichen Schnittdarstellung die Schwimm- und Tauchhilfe im Bereich eines geöffnet dargestellten Strömungskanals,

Fig. 4

in einer seitlichen Schnittdarstellung die Schwimm- und Tauchhilfe mit einer ebenfalls im Schnitt dargestellten Unterwasser-Antriebs-Einheit,

Fig. 5

einen Ausschnitt der in Figur 4 gezeigten Schnittdarstellung im Bereich eines Propellers,

Fig. 6

einen Ausschnitt der in Figur 4 gezeigten Schnittdarstellung in einem vorderen Lagerbereich und

Fig. 7

einen Ausschnitt der in Figur 4 gezeigten Schnittdarstellung in einem hinteren Lagerbereich.

The invention will be explained in more detail below with reference to an embodiment shown in the drawings. Show it:

Fig. 1

in perspective side view from behind a swimming and diving aid,

Fig. 2

in the FIG. 1 shown swimming and diving aid in a perspective view from below,

Fig. 3

in a side sectional view of the swimming and diving aid in the region of a flow channel shown open,

Fig. 4

in a side sectional view of the swimming and diving aid with a likewise shown in section underwater drive unit,

Fig. 5

a section of in FIG. 4 shown sectional view in the area of a propeller,

Fig. 6

a section of in FIG. 4 shown sectional view in a front storage area and

Fig. 7

a section of in FIG. 4 shown sectional view in a rear storage area.

FIG. 1 shows in perspective side view from behind a swimming and diving aid 10. The swimming and diving aid 10 has a vehicle body 11. The vehicle body 11 is composed of an upper part 11.6 and a lower part 11.4. The upper part 11.6 is equipped with two handles 16, which are arranged on both sides of the vehicle body 11. At these handles 16, a user can hold on and control the swimming and diving aid 10 with attached to the handles 16 16.1 controls. In particular, the engine power of the swimming and diving aid 10 can be varied here. The user, who holds on to the handles 16, lies with his upper body on a support surface 11.3 in the area behind a display 13 on the upper part 11.6. On the bearing surface 11.3 a bracket 11.7 is attached to attach a belt system with which the user can garter on the swimming and diving aid 10. In front of the bearing surface 11.3, a shutter 12 is arranged for a charging socket shown behind it. About the charging socket 11 accumulators can be charged in the vehicle body.

Laterally on the vehicle body 11 carrying handles 11.2 are arranged, where the swimming and diving aid 10 can be worn outside the water.

In the direction of travel in front of the display 13 and between the two handles 16 a removable cover 14 is attached to the vehicle body 11. The cover 14 covers a mounting area, not shown, of the swimming and diving aid 10. The side vents 15.1 are provided in the cover 15, which provided with a provided in the vehicle body 11, in FIG. 3 shown flooding space 17 are connected.

In the area of the bugs 11.1 water inlet openings 15.2 are provided, through which water can flow into the flooding chamber 17. The flooding chamber 17 can be vented via the vents 15.1 of the cover 14. Due to the flooding space 17 filled with water, the buoyancy of the floating and diving aid 10 adjusted so that a given buoyancy force is maintained, so that both a swimming and a dive operation is possible. At the rear 11.5 of the swimming and diving aid 10 covered by fins water outlet openings 15.3 are mounted, which are also in communication with the flooding chamber 17. The flooding chamber 17 is, as soon as the swimming and diving aid 10 is placed in the water, flooded with water, which penetrates through the water inlet openings 15.2 and 15.3 water outlet openings. As soon as the swimming and diving aid 10 moves into the driving operation, a flow is generated in the flooding chamber 17. The water enters through the water inlet openings 15.2 in the flooding chamber 17 a. It flows through the flooding chamber 17 and flows around it in the flooding space 17 held electrical components, such as required for driving the swimming and diving aid 10 required accumulators. The water absorbs the power loss of the electrical components and cools them. After flowing through the flooding chamber 17, the water leaves through the water outlet openings 15.3, which are arranged symmetrically on both sides of a jet outlet 26 of a flow channel 20. In the flow channel 20, an engagement protection 70 is arranged at the end, which prevents the user from engaging in the flow channel 20.

FIG. 2 shows the in FIG. 1 shown swimming and diving aid (10) in a perspective view from below.

At the bow 11.1 of the vehicle body 11 are in FIG. 1 to recognize shown water inlet openings. Laterally on the lower part 11.4 of the vehicle body 11 lateral flooding openings 17.1 are provided. In the front region of the lower part 11.4 further lower flooding openings 17.2 are introduced from below, which are covered by integrally formed on the vehicle body 11 ribs. In the middle of the lower part 11.4, a left and a right inlet opening 21.1, 21.2 of the flow channel 20 are arranged. The inflow openings 21.1, 21.2 are separated by a guide element 22.1. In the area of the inlet openings 21.1, 21.2 protection struts 22.2, 22.3 are arranged.

The flooding openings 17.1, 17.2 are like the water inlet openings 15.2 with the in FIG. 3 shown flooding space 17 connected. If the swimming and diving aid 10 is left to water, this flows through the flooding openings 17.1, 17.2 and the water inlet openings 15.2 in the flooding chamber 17 and thus provides the desired buoyancy of the swimming and diving aid 10 a. If the swimming and diving aid 10 is removed from the water, the water from the flooding chamber 17 through the flooding openings 17.1, 17.2 and the water inlet openings 15.2 run out of the flooding chamber 17, whereby the swimming and diving aid 10 loses significant weight and thus easily portable becomes.

By a arranged in the flow channel 20, in FIG. 3 shown propeller 50, water is sucked through the inlet openings 21.1, 21.2 and through the flow channel 20 to the in FIG. 1 shown beam exit 26 accelerates. This results in the propulsion of the swimming and diving aid. The guide element 22. 1 and the protective struts 22. 2, 22. 3 prevent larger foreign substances from being sucked in or the user gripping the running propeller 50. Furthermore, the guide element 22.1 and the ribs arranged in front while driving stabilizing effect on the swimming and diving aid 10th

FIG. 3 shows in a side sectional view of the swimming and diving aid 10 in the region of an open flow channel shown 20. The cut surface extends in the direction of travel right and parallel to a central longitudinal surface of the swimming and diving aid 10th

The flow channel 20 is guided within the vehicle body 11 swinging from the bottom to the stern of the swimming and diving aid 10. Toward the inlet openings 21.1, 21.2, the flow channel 20 is formed by a left front flow channel half shell 23 in the direction of travel and a right front flow channel half shell 24. The flow channel half-shells 23, 24 are fitted to each other and connected by means of connecting elements. Thus, a front flow channel portion is formed with a smooth surface. In the direction of travel in front of the flow channel 20 is a part of the flooding chamber 17th shown, which also includes the space around the flow channel 20 at the rear of the swimming and diving aid 10 partially.

In the flow channel 20 is an underwater drive unit with a propeller 50 with an associated electric motor 110, arranged in the flow direction in front of the propeller 50 centering device 40 with a plug-mounted on the centering device 40 on-flow cap 30, one arranged in the flow direction downstream of the propeller 50 Flow stator 60 and the subsequent Eingreifschutz 70 arranged with an attached end cap 80.

The engagement protection 70 is arranged in the region of a jet outlet pipe 25. The jet outlet pipe 25 is arranged downstream of the flow stator 60 in the flow direction. It forms the flow channel 20 between the flow stator 60 and the jet outlet 26.

Surrounding the jet exit 26, a closing ring 19 and a connecting ring 18 form the connection from the jet outlet pipe 25 to the vehicle body 11.

The propeller 50 has a base part 52 on which radially projecting outward propeller blades 54 are integrally formed. The propeller blades 54 are aligned obliquely to the base part 52, so that they suck in a water in the present embodiment, clockwise rotation of the propeller 50 from the inlet openings 21.1, 21.2 and eject from the jet outlet 26.

To drive the propeller 50, this is connected to a rotor 112 of the electric motor 110. The rotor 112 is indirectly coupled to the outer ends of the propeller blades 54 of the propeller 50. Upon rotation of the propeller 50, the rotor 112 moves in a circular orbit about the propeller 50. A motor stator 111 of the electric motor 110 is arranged around this circular path.

The driving force is generated between the motor stator 111 and the rotor 112. The transmission of the driving force to the propeller 50 occurs from the rotor 112 the ends of the propeller blades 54. Thus, the force is applied to a very large radius, resulting in a high torque. As a result, can be realized at a given power of the electric motor 110 very fast speed changes of the propeller 50 and thus speed changes the swimming and diving aid 10.

The motor stator 111 and the rotor 112 are arranged laterally of the flow cross section of the flow channel 20 predetermined by the flow channel half shells 23, 24, the outer diameter of the circular path of the propeller blades and the jet outlet tube 25. Thus, the electric motor 110 is not in the range of the main flow of the accelerated in the flow channel 20 and thus does not affect the available flow cross section and thus the flow of water. The flow channel 20 can thus be performed at the same volume flow through the flow channel 20 with a smaller diameter compared to an arrangement in which a conventionally acting on a drive shaft electric motor 110 is provided in the flow channel 20. As a result, the entire design of the swimming and diving aid 10 can be made more compact.

The centering device 40 has a streamlined base 41, with the likewise streamlined configured, radially outwardly aligned centering struts 42 are connected. The centering device 40 is fixed to the centering struts 42 on the flow channel half-shells 23, 24. Contrary to the direction of flow, the flow cap 30 is attached to the base 41 of the centering device 40. The inflow cap 30 also has a streamlined running inflow surface 31 which merges steplessly into the surface of the base 41. Toward the propeller 50, the diameter of the base 41 is adapted to the diameter of the base part 52 of the propeller 50. This shaping of the inflow cap 30, the base 41 of the centering device 40 and the base part 52 of the propeller 50, a low flow resistance for the water flowing through the flow channel 20 is achieved.

The flow stator 60 has a stator base 61 on which radially outwardly directed stator vanes 65 are arranged. The stator vanes 65 are indirectly connected to the flow channel 20 at the end. The flow stator 60 is thus arranged stationarily in the flow channel 20.

The stator vanes 65 are made bent along the flow direction of the water. The propeller 50 facing ends of the stator vanes 65 are bent by a predetermined angle against the direction of rotation of the propeller 50. The ends of the stator vanes 65 facing away from the propeller 50, however, run approximately parallel to the axis of rotation of the propeller 50. The water leaves the propeller 50 on a helical path. Due to the shape of the stator vanes 65, the flow stator 60 counteracts the rotation of the water flowing through the flow channel 18, so that the water after the flow stator 60 flows as free of rotation as possible to the jet outlet 26. The rotational energy of the water is thereby converted into a linear kinetic energy and thus serves to drive the swimming and diving aid 10th

Preferably, the diameter of the stator base 61 corresponds at least approximately to the diameter of the base part 52 of the propeller 50. Thus, a low flow resistance in the transition of the water from the propeller 50 to the flow stator 60 is achieved.

The Eingreifschutz 70 is connected via radially arranged Eingreifschutz struts 72 with the jet outlet pipe 25 of the flow channel 20. Thus, the engagement protection 70 is fixedly positioned in the flow channel 20. The Eingreifschutz struts 72 are designed streamlined. At their inner ends they are connected to a base body 71 of the Eingreifschutzes 70. The base body 71 has a streamlined contour. Towards the flow stator 60, the diameter of the base body 71 corresponds at least approximately to the diameter of the stator base 61 of the flow stator 60. Thus, a low flow resistance is achieved when the water flows from the flow stator 60 to the engagement protection 70. Toward the jet outlet 26, the diameter of the base body 71 tapers. Here, its outer surface follows preferably spaced apart the course of the surface of the jet outlet tube 25. The distance between the surfaces of the base body 71 and the jet outlet tube 25 limits the flow cross-section of the passing water. The flow cross-section is selected by the shape of the base body 71 and the jet outlet pipe 25 that a high volume flow is made possible by a sufficiently large cross-section, but at the same time by a small cross-section a high flow velocity of the water to the jet outlet 26 is enforced.

At the end, the base body 71 of the engagement guard 70 is closed by the end cap 80. Into the end cap 80, a cap opening 81 is inserted. Through the cap opening 81, water can flow out of the base body 71 designed as a hollow body.

FIG. 4 shows in a side sectional view of the swimming and diving aid 10 with a likewise shown in section underwater drive unit.

Unlike the in FIG. 3 shown illustration runs in FIG. 4 the cutting surface along a central longitudinal surface of the swimming and diving aid, so that the components of the underwater drive unit are shown in section.

The propeller 50 is mounted on a shaft 90 as more closely attached FIG. 5 is described. At the centering device 40, a first bearing housing 45 is attached. The shaft 90 is rotatably supported in the first bearing housing 45. This is detailed in FIG. 6 shown. On the flow stator 60, a second bearing housing 63 is attached. The shaft 90 is rotatably supported in the second bearing housing 63. The second bearing housing is enlarged in FIG. 7 shown.

The base body 71 of the engagement protection 70 is designed as a hollow body. Through the cap opening 81 of the end cap 80, which is likewise designed as a hollow body, water can flow in and out of the base body 71.

The illustrated left front flow channel half-shell 23 has along the central longitudinal surface of the flow channel 20, a left joint rail 23.1 and mounting lugs 23.2. Mounted is the in FIG. 3 shown right front flow channel half-shell 24 defined with its edge in the left guide rail 23.1 and the two flow channel half-shell 24 are firmly connected by suitable fastening means, preferably with guided through the mounting eyelets 23.2 screws. In the left joint rail 23.1, a sealing material may be introduced.

FIG. 5 shows a section of the in FIG. 4 shown sectional view in the area of the propeller 50.

The shaft 90 is designed as a hollow shaft. Advantageously, the shaft 90 is made of a carbon fiber reinforced plastic (CFRP). The shaft is divided into a center region 91, a front shaft bearing section 93 oriented counter to the flow direction of the water, and a rear shaft bearing section 94 opposite the front shaft bearing section 93.

In the front shaft bearing portion 93, the shaft 90 is mounted with a front bearing 101. The front bearing 101 is designed as angular contact ball bearings. The front bearing 101 is held by a lock nut 100 within the first bearing housing 45 of the centering device 40, as closer FIG. 6 is described.

In the rear shaft bearing portion 94, the shaft 90 is mounted with a rear bearing 104. The rear bearing 104 is designed as a deep groove ball bearing.

In the center region 91 of the shaft 90 of the propeller is fixed with an inner cylinder 51 on the shaft 90. Preferably, the inner cylinder 51 is glued to the shaft 90. To the inner cylinder 51 propeller struts 53 are formed. The propeller struts 53 are partially aligned transversely and partially parallel to the central longitudinal axis of the shaft 90. At their outer ends, the propeller struts 53 are connected to the base part 52 of the propeller 50. Advantageous are the propeller struts integrally formed on the base part 52. The propeller struts 53 thus form a rigid connection between the inner cylinder 51 and the base part 52 of the propeller 50. Between the inner cylinder 51 and the base part 52, a hub region is formed as a cavity. The hub region is divided by the transverse to the central longitudinal axis of the shaft 90 aligned propeller struts 53 in a front, the centering device 40 facing and a rear, the flow stator 60 facing chamber. In these transverse propeller struts 53 not shown breakthroughs are introduced. With rotating propeller 50, water is transported from the front chamber to the rear chamber through the openings.

On the base part 52, a front connecting inner step 52.1 is formed on its edge facing the centering device 40 and a rear connecting inner step 52.2 is formed on the opposite edge. On the outer periphery of the base part 52, the propeller blades 54 are fixed. Preferably, the propeller blades 54 are integrally formed on the base part 52. At their outer ends, the propeller blades 54 are connected via a connecting region 54. 1 to a propeller ring 55 which extends at a distance from the base part 52. The propeller ring 55 is thus arranged rotationally symmetrical about the axis of rotation of the shaft 90. On the propeller ring 55 is directed radially outwardly a rotor housing front wall 56 is formed. Preferably, the inner cylinder 51, the propeller braces 53, the base part 52, the propeller blades 54, the propeller ring 55, and the rotor housing front wall 56 are made in one piece.

The stator base 61 of the flow stator 60 is connected to the second bearing housing 63 via a connecting member 62. In the embodiment shown, the connecting element 62 is funnel-shaped. Not shown, the connecting element 62 through openings, through which water from the rear chamber of the hub portion in the interior of the base body 71 of the Eingreifschutzes 70 can escape. Oriented towards the propeller 50, a front terminal outer 61.1 is integrally formed on the stator base 61. The front terminal outer stage 61.1 slightly overlaps the rear terminal inner stage of the base part 52 of the propeller 50. For this purpose, the stator base 61 at least approximately the same outer diameter as the base part 52 of the propeller 50. Opposite to the front connection outer stage 61.1, a rear connection outer stage 61.2 is integrally formed on the stator base 61. At the stator base 61, the stator vanes 65 are fixed. The stator vanes 65 are preferably integrally formed on the stator base 61. The stator vanes 65 are aligned radially with respect to the stator base 61, as is already the case FIG. 3 was presented. At their outer ends, the stator vanes 65 are connected to a stator outer ring 66. The stator outer ring 66 is arranged circumferentially to the axis of rotation of the propeller 50. With its edge facing the propeller 50, the stator outer ring 66 terminates at a small distance in front of the edge of the propeller ring 55. On the outer surface of the stator outer ring 66, a rear housing wall 67 is integrally formed. The section in the illustration shown extends through a reinforced region of the housing wall 67, in which a threaded bore 67.1 is introduced for receiving a screw 116. Such reinforced areas with threaded holes 67.1 are provided spaced along the housing wall 67. In between, the housing wall 67 is made thin-walled. To the housing wall 67, a housing cover 68 is integrally formed, which radially overlaps the propeller ring 55. In the front side of the housing cover 68 threaded receptacles 68.1 for receiving screws 116 are introduced.

Preferably, the second bearing housing 63, the connecting element 62, the stator base 61, the stator vanes 65, the stator outer ring 66, the rear housing wall 67 and the housing cover 68 are made in one piece.

The jet outlet pipe 25 is fastened to the housing wall 67 by means of the screws 116. For this purpose, a radially aligned flange 25.1 is formed on the jet outlet pipe 25, in which holes 67 for carrying out the screws 116 are precisely made to the threaded holes 67.1 of the housing wall.

The base body 71 of the engagement protection 70 has, at its end facing the flow stator 60, a step-shaped stator connection region 71.1. The stator terminal portion 71.1 is inserted into the rear terminal outer stage 61.2 of the stator base 61, so that a circumferential connector arises. Between the stator terminal portion 71.1 and the rear terminal outer stage 61.2, a fourth sealing ring 123 is provided. The fourth sealing ring 123 seals the interior of the base body 71 with respect to the flow channel 20.

The centering device 40 is arranged in the flow direction in front of the propeller 50. The rotationally symmetrical base 41 of the centering device 40 has the same outer diameter as the base part 52 in its transition region to the base part 52 of the propeller 50. This leads to a low flow resistance for the passing water. Towards the inflow cap 30, the outer diameter of the base 41 tapers along a concave curve. Towards the propeller 50, the base 41 has a connecting step 41. The connecting step 41.1 covers the rear connecting internal step 52.2 of the base part 52 of the propeller 50 at a small radial distance. The centering struts 42 are fastened radially aligned on the base 41. The centering struts 42 are preferably integrally formed on the base 41. The centering struts 42 are narrow in their tangential to the base 41 extending extension. In this way, they counteract the flow of water through a low flow resistance. In their axial orientation, the centering struts 42 cover over half the length of the base 41. Their front edge, which opposes the inflowing water, drops with increasing radial distance from the base in the flow direction of the water. This measure also reduces the flow resistance for the passing water. At the outer end of the Zentrierstreben 42 a Zentrieraußenring 43 is attached. The centering outer ring 43 is preferably integrally connected to the centering struts 42. At the Zentrieraußenring 43 a radially outwardly oriented front housing wall 44 is fixed, in particular integrally formed. The front housing wall 44 extends in its outer diameter up to the housing cover 68, on whose end face it rests. In the housing wall 44 mounting holes 44.1 are provided. The mounting holes 44.1 are arranged congruent to the threaded receptacles 68.1 of the housing cover 68. The housing wall 44 and the housing cover 68 are fixedly connected to screws 116 guided through the mounting bores 44.1 and screwed into the threaded receptacles 68.1.

On the outer surface of the Zentrieraußenrings 43 a detent 43.1 is formed. The detent 43.1 is executed in the present embodiment as circumferentially formed to the centering outer ring 43 bead. However, it can also be provided around the Zentrieraußenring 43 spaced, hemispherical locking lugs 43.1 provided. The centering device 40 is inserted with its centering outer ring 43 into the flow channel 20 formed by the flow channel half shells 23, 24. In this case, the centering outer ring 43 is inserted so far into the flow channel 20 until the flow channel half shells 23, 24 abut the front housing wall 44 at the end or are arranged directly in front of it. In this position, the detent 43.1 engages in a circumferentially introduced into the flow channel half shells 23, 24 locking receptacle. The centering device 40 is anchored so firmly in the flow channel 20.

Inwardly directed, the first bearing housing 45 is integrally formed on the base 41 of the centering device 40. The first bearing housing 45 is attached to the flow of the water opposite end of the base 41 via a first sealing portion 45.1. The first bearing housing 45 has a cup-shaped contour, wherein the connection to the base 41 takes place at the pot edge. The first bearing housing 45 is arranged aligned in the flow direction of the water in the cavity formed by the base 41. The space between the first bearing housing 45 and the base 41 is filled by a potting compound 47. Thus, no water can accumulate in this area. The inflow cap 30 is attached to the base 41 in the first sealing region 45.1.

Through the housing cover 68, the rear housing wall 67 and the front housing wall 44, a motor housing 117 of the electric motor 110 is formed. Toward the flow channel 20, the motor housing 117 is delimited by the stator outer ring 66, the propeller ring 55 and the centering outer ring 43. The motor housing 117 is thus arranged radially outside of the predetermined by the diameter of the flow channel 20 flow cross section of the flowing in the flow channel 20 water. The radially outer region of the motor housing 117 is separated by a Statorgehäusedeckel 113.1. The separated area forms a stator housing 113. In the stator housing 113, the motor stator 111 of the Electric motor 110 arranged. The motor stator 111 is formed of a predetermined number of electromagnets. These are arranged at predetermined regular or irregular intervals 113 along the annular stator housing 113. Each solenoid is associated with at least one coil 111.1. Advantageously, the cavities of the stator housing 113 are encapsulated with a potting compound. The motor stator 111 is thus cast in the potting compound.

Within the motor housing 117, a rotor housing 114 is formed by the propeller ring 55, the rotor housing front wall 56 and a rotor housing cover 114.1. The rotor housing cover 114.1 is arranged radially outwardly spaced from the propeller ring 55. On one side of the rotor housing cover 114.1 abuts the rotor housing front wall 56 at. Within the rotor housing 114, the rotor 112 of the electric motor 110 is fixed. The rotor 114 is formed by a predetermined number of permanent magnets 112.1. These are arranged at predetermined regular or irregular intervals 113 along the annular rotor housing 114. The rotor 114 or the permanent magnets 112.1 are cast in a casting compound introduced into the rotor housing 114. As a result, the rotor 114 or the permanent magnets 112.1 are connected to the rotor housing 114. The rotor housing cover 114.1 is also fixed with the potting compound. Between the Statorgehäusedeckel 113.1 and the rotor housing cover 114.1 an air gap 115 is formed.

The electric motor 110 corresponds in its design to a ring or torque motor. The electric motor 110 is designed as internal runs. Since the rotor 112 is disposed radially far apart from the axis of rotation of the electric motor 110, a high torque can be generated by this design and transmitted to the propeller 50. Furthermore, the torque can be increased by a high number of pole pairs with a corresponding number of electromagnets and permanent magnets 112.1. Thus, rapid changes in the speed of the propeller 50 and thus rapid and dynamic changes in the speed of the swimming and diving aid 10 can be achieved.

The motor housing 117 is advantageously located outside the flow cross section of the water defined by the flow channel 20 and the diameter of the propeller blades 54. As a result, the available flow cross-section is not reduced by the electric motor 110 with the advantages already described.

The motor housing 117 is not sealed from the flow channel 20. Between the propeller ring 55 and the stator outer ring 66 and the centering outer ring 43, a gap is formed in each case through which water can flow into the motor housing 117. The motor stator 111 and the rotor 112 are sealed within the stator housing 113 and the rotor housing 114 from the incoming water. By passing water, the heat loss of the electric motor 110 is efficiently dissipated. This leads to a high efficiency of the electric motor 110. The motor stator 111 and the rotor 112 are protected in particular by the respectively provided potting compound from the penetrating water. The potting compound also forms a thermal bridge with good thermal conduction properties, so that the energy loss of the electric motor 110 can be discharged efficiently via the potting compound to the surrounding water.

The shaft 90 is advantageously mounted on both sides of the propeller 50. As a result, high lateral forces transmitted to the propeller 50 due to the passing water can be safely absorbed. A bending of the shaft 90 or vibrations of the shaft 90 and the propeller 50 can be avoided. As a result, the air gap 115 formed between the motor stator 111 and the rotor 112 can be kept constant. This leads to a high level of smoothness. Furthermore, the driving force is not affected by fluctuating widths of the air gap 115. A collision of the rotor housing 114 with the stator housing 113 is reliably avoided.

The fact that the shaft 90 is designed as a hollow shaft, weight can be saved without the rigidity of the shaft 90 is significantly affected. A light weight is for a portable water sports equipment as the present swimming and diving aid a significant advantage. The weight will continue reduced by the fact that the shaft consists of a carbon fiber reinforced plastic (CFRP).

CFRP has the advantage of significantly reduced weight and very high rigidity compared to materials traditionally used to produce shafts 90, such as steel. Compared to steel, a shaft 90 made of CFRP has a significantly lower tendency to oscillate, resulting in improved concentricity and lower noise. Furthermore, the lower weight and the reduced vibration lead to a reduction of the load of the bearings 101, 104, with which the shaft 90 is rotatably mounted about its central longitudinal axis, whereby the wear of the bearings 101, 104 is reduced and thus their life is increased. The inertial mass of the shaft 90 made of CFK is significantly reduced compared to a shaft 90 made of steel, resulting in a higher dynamics at desired changes in the rotational speed of the shaft 90 and thus the propeller 50 results. At the same time, the energy consumption for accelerating the shaft 90 decreases with the propeller 50, which leads to an extension of the operating life of the powered by batteries swimming and diving aid 10.

In order to increase the rigidity of the shaft 90, it can be constructed in multiple layers. An inner layer, in which carbon fiber mats with different orientation of the carbon fibers within the plastic matrix are arranged, is followed by a layer of aligned carbon fibers. These are preferably designed as high-modulus carbon fibers which have a very high modulus of elasticity of, for example,> 400,000N / mm ² in the fiber direction. In the present embodiment, the high modulus carbon fibers are oriented substantially in the direction of the longitudinal extent of the shaft 90 so as to increase the tensile strength and flexural rigidity of the shaft 90. Alternatively or additionally, a CFRP layer with high-modulus carbon fibers arranged transversely to the longitudinal extent of the shaft 90 can also be provided. In this arrangement, the additional carbon fibers increase the torsional rigidity of the shaft 90.

The surface of the shaft 90 is partially over-turned, ground or polished. Through these post-treatment steps becomes an exact rotationally symmetric Contour of the shaft 90 obtained, which leads to a good concentricity. Cracks in the surface are removed, thus avoiding or at least reducing notch stresses that form at the crack ends under mechanical stress. This reduces the probability of breakage of the shaft 90 and its load capacity increases. In order to avoid that the carbon fibers are injured in the post-processing, the shaft has on the outside a final plastic layer which contains no carbon fibers.

Due to the partially transverse and partially parallel to the central longitudinal axis of the shaft 90 aligned propeller struts 53 a rigid and highly resilient connection between the inner cylinder 51 and the base part 52 of the propeller 50 is achieved.

The inner cylinder 51, the propeller struts 53, the base part 52, the propeller blades 54, the propeller ring 55 and the rotor housing front wall 56 are preferably a one-piece component. This may be made of plastic, for example. The propeller 50 with the associated assemblies can be manufactured so inexpensively in one production step.

Alternatively, the propeller 50 with the associated assemblies inner cylinder 51, propeller struts 53, base member 52, propeller blade 54, propeller ring 55 and rotor housing front wall 56 may be made entirely or partially of metal.

The centering device 40 and the flow stator 60 are fixedly connected to the flow channel 20. Thereby, the position of the front and the second bearing housing 45, 63 and thus the position of the bearings 101, 104 of the shaft 90 is fixed and fixed. This ensures correct positioning of the propeller 50 within the flow channel 20. The fixed connection between the centering device 40, the propeller 50 and the flow stator 60 and the motor housing 117 formed therein with the stator housing 113 and the rotor housing 114, the moving parts of the underwater drive unit are firmly aligned with each other. Exposing vibrations and shocks, such as those in regular operation of the swimming pool and Diving aid 10 often occur, can be compensated. In particular, small distances between movable and fixed components can be provided. Thus, in particular, the air gap 115 between the rotor 112 and the motor stator 111 can be made narrow, resulting in a high power transmission and high efficiency of the electric motor 110.

FIG. 6 shows a section of the in FIG. 4 shown sectional view in a front storage area.

The front bearing area is encompassed by the first bearing housing 45. The first bearing housing 45 is integrally formed on the base 41 of the centering device 40. Starting from the first sealing area 45.1 directed towards the inflow cap 30, a cylindrical section 45.3 leading into the interior of the base 41 follows. At the cylindrical portion 45.3, a front bearing holder 46 connects with respect to the cylindrical portion 45.3 slightly reduced diameter. By a subsequent further reduction of the diameter of the first bearing housing 45, a second sealing region 45.2 is formed. At the second sealing portion 45.2 a radially inwardly oriented first system 48 is formed.

The shaft 90 is inserted with its front shaft bearing portion 93 from the side of the second sealing portion 45.2 in the first bearing housing 45. On the shaft 90, a propeller stop 92 is integrally formed, against which the inner cylinder 51 of the propeller 50 is applied. The end of the diameter of the front shaft bearing portion 93 of the shaft 90 is reduced. On this reduced in diameter area a bearing seat 95 is attached. The bearing seat 95 is made of metal and in particular connected by gluing with the shaft 90. Toward the shaft 90, the bearing seat 95 has a bearing stop 95.1 projecting radially outward.

On the bearing seat 95, a front bearing 101 is pushed. The front bearing 101 is designed as angular contact ball bearings. It rests with its inner ring on the bearing stop 95.1 of the bearing seat 95. The outer ring of the front bearing 101 lies with its outer surface on the front bearing holder 46 of the first bearing housing 45. The outer ring of the front bearing 101 is held by the lock nut 100, which is fixed inside in the cylindrical portion of the first bearing housing 45. For this purpose, the outer ring rests against a first outer ring abutment 101.1 formed on the locking nut 100.

In the second sealing region 45.2 of the first bearing housing 45, a front radial sealing region 102 is formed. For this purpose, a front radial shaft sealing ring 102.1 is arranged between the second sealing region 45.2 and the front shaft bearing section 93 of the shaft 90. Towards the propeller 50, the front radial shaft sealing ring 102. 1 is held by the inward-facing first abutment 48 of the bearing housing 45. Opposite the front radial shaft seal 102.1 is held by a first retaining ring 102.2. The first retaining ring 102. 2 is clamped in a groove in the first bearing housing 45.

The inflow cap 30 has the first bearing housing 45 toward a connection piece 32. In the connecting piece 32 sealing ring receivers 33 are introduced. In the sealing ring receivers 33 are sealing rings 120, 121 inserted. The inflow cap 30 is inserted with the connecting piece 32 in the first sealing region 45.1 of the centering device 40. The sealing rings 120, 121 prevent water from entering the interior of the inflow cap 30 and the first bearing housing 45 from the flow channel 20.

By the front bearing 101, the shaft 90 is easily rotatably supported at its front shaft bearing portion 93. By the bearing seat 95 with the bearing stop 95.1, the lock nut 100 with the first outer ring abutment 100.1 and the front bearing holder 46, the front bearing 101 is held securely. The lock nut 100 allows adjusting the game, with which the front bearing 101 is held axially. Toward the shaft 90, the area of the front bearing 101 is sealed by the front radial shaft seal. On the side of the inflow cap 30, the seal between the first sealing region 45.1 of the centering device 40 and the connecting piece 32 of the inflow cap 30 takes place through the sealing rings 120, 121 arranged there Bearing 101 is thus protected from moisture penetration. In addition, the cavities in the shaft 90 and the front bearing 101 are filled with grease and thus additionally protected from moisture.

The repulsive force of the water is transmitted via the propeller 50 from the inner cylinder 51 of the propeller 50 to the shaft 90. The shaft 90 transmits this force via the bearing seat 95 on the inner ring of the front bearing 101. Within this designed as angular contact ball bearing front bearing 101, the force is transmitted via the bearing balls on the outer ring of the front bearing 101. From there, the force enters via the lock nut 100 on the centering device 40 and from there to the flow channel 20 and the vehicle body 11 of the swimming and diving aid 10th

The metal bearing seat 95 prevents the surface of the CFK made shaft 90 from being damaged at the high forces to be transmitted.

FIG. 7 shows a section of the in FIG. 4 shown sectional view in a rear storage area.

The second bearing housing 63 is integrally formed on the connecting element 62 of the flow stator 60. Starting from its tail 11.5 of the swimming and diving aid 10 facing the end of the second bearing housing 63 is formed by a fourth Abdichtbereich 63.2, a rear bearing holder 64, a third Abdichtbereich 63.2 and a second system 63.3.

The fourth sealing region 63.2 and the rear bearing holder 64 form a region of the second bearing housing 63 that radially surrounds the axis of rotation of the shaft 90. The third sealing region 63.1 is reduced in its diameter. The second system 63.3 is aligned radially inwardly formed on the end of the third Abdichtbereichs 63.1.

The shaft 90 is inserted with its rear shaft bearing portion 94 through the third sealing portion 63.1 in the second bearing housing 63. Between the third Sealing region 63.1 and the shaft 90, a rear radial shaft seal 103.1 is arranged. The rear radial shaft seal 103.1 is held toward the propeller 50 by the radially projecting second abutment 63.3 of the bearing housing 63 and opposite by a second locking ring 106 in its axial position. Through the radial shaft sealing ring 103.1, the shaft 90 and the third sealing region 63.1, a rear radial sealing region 103 is formed.

The rear bearing 104 is disposed between the rear shaft bearing portion 94 and the rear bearing holder 64 of the second bearing housing 63. In this case, the rear bearing 104 rests with its inner ring on the rear shaft bearing portion 94 and with its outer ring on the rear bearing holder 64. The rear bearing 104 is designed as a single-row deep groove ball bearings. Towards the rear 11.5 of the swimming and diving aid 10 toward the rear bearing 104 is held axially by a rear bearing retainer 105. For this purpose, on the rear bearing retainer 105, a second outer ring thrust bearing 105.1 aligned with the rear bearing 104 is formed. The outer ring of the rear bearing 104 abuts against this outer ring abutment 105.1.

The outer periphery of the rear bearing retainer 105 is formed by an annular positioning portion 105.2 which abuts against the inner surface of the fourth sealing portion 63.2 of the second bearing housing 63. Between the annular positioning portion 105.2 and the fourth sealing portion 63.2, two sealing rings 124, 125 are arranged. The sealing rings 124, 125 are for this purpose in grooves, which are introduced into the fourth sealing 63.2 inserted. The rear bearing retainer 105 is inserted in the fourth sealing portion 63.2. Following the rear bearing retainer 105, a third retaining ring 107 is provided. The rear bearing retainer 105 is thus held in position.

The rear radial shaft seal 103. 1 prevents water from penetrating along the shaft 90 into the second bearing housing 63. By the rear bearing retainer 105 and the peripheral sealing rings 124, 125, the second bearing housing 63 is also sealed. The rear bearing 104 is thus protected from moisture. In addition, the cavities in the shaft and in the area the rear bearing 104 filled with grease and thus additionally protected from moisture.

For assembly, the shaft 90 is inserted into the second bearing housing 63, the rear radial shaft seal 103.1 plugged and secured with the second locking ring 106. Subsequently, the rear bearing 104 is attached and the rear bearing retainer inserted. Finally, the third retaining ring 107 is clamped in the groove provided. The storage area is thus easy to assemble. By the inserted rear bearing retainer 105, the rear bearing 104 and the rear radial shaft seal 103.1 can be easily reached for maintenance purposes.

Claims (13)

1. A swimming and diving aid (10) with a vehicle hull (11) and handles (16) on an upper part (11.6) of the vehicle hull (11) which a user holds on to while he rests with the upper part of his body on the upper part (11.6), with a flow channel (20) which is arranged in the vehicle hull (11) and which accommodates a propeller (50), driven by an electric motor (10), with radially outwardly directed propeller blades (54) mounted on a base part (52) of the propeller (50), wherein the electric motor (10) has a rigidly arranged motor stator (111) and a rotating rotor (112) which is spatially assigned to the motor stator (111),
   characterised in that
   the rotor (112) of the electric motor (10) is coupled to at least one outer end of at least one propeller blade (54),
   the motor stator (111) is arranged circumferentially at least partially around the rotor (112),
   a flow stator (60) with stator vanes (65) is arranged downstream of the propeller (50) in the flow direction of the water,
   the flow stator (60) is fixed to the wall of the flow channel (20) via the stator vanes (65), and/or
   a stator housing (113) for receiving the motor stator (111) is connected to the outer ends of at least part of the stator vanes (65),
   on the side of the flow stator (60) facing away from the propeller (50), an engagement protection (70), with engagement protection struts (72) formed thereon, is arranged, the engagement protection struts (72) are fixed to the wall of the flow channel (20), and
   a base body (71) of the engagement protection (70) is preferably connected to the flow stator (60).
2. The swimming and diving aid (10) according to claim 1,
   characterised in that
   the outer ends of at least one part of the propeller blades (54) are connected to a propeller ring (56), and that the rotor (112) is arranged on the propeller ring (56), and/or that the outer ends of at least one part of the propeller blades (54) are connected to an annular rotor housing (114), and that the rotor (112) is arranged in the rotor housing (114).
3. The swimming and diving aid (10) according to claim 2,
   characterised in that
   the propeller ring (56) and/or the rotor housing (114) are moulded as one piece on the propeller (50).
4. The swimming and diving aid (10) according to any one of claims 1 to 3,
   characterised in that
   the rotor (112) has a plurality of permanent magnets (112.1) arranged in the rotational direction of the rotor (112), and/or that the motor stator (111) has a plurality of electromagnets (111.1) arranged circumferential to the circular path on which the rotor (112) moves.
5. The swimming and diving aid (10) according to any one of claims 1 to 4,
   characterised in that
   the stator housing (113) of the electric motor (110) is moulded as one piece on the flow stator (60).
6. The swimming and diving aid (10) according to any one of claims 1 to 5,
   characterised in that
   the rotor (112) and/or the motor stator (111) are arranged in a lateral recess of the flow channel (20).
7. The swimming and diving aid (10) according to any one of claims 1 to 6,
   characterised in that
   the propeller (50) is axially fixed on a rotatably mounted shaft (90) arranged within the flow channel (20).
8. The swimming and diving aid (10) according to claim 7,
   characterised in that
   the shaft (90) is designed as a hollow shaft, and/or that the shaft (90) is manufactured from a carbon fibre reinforced plastic material.
9. The swimming and diving aid (10) according to any one of claims 1 to 8,
   characterised in that
   a centring device (40) with a base (41) and centring bars (42) applied thereon is arranged upstream of the propeller (50) in the flow direction of the water flowing in the flow channel (20), and that the centring device (40) is directly or indirectly attached to the wall of the flow channel (20) via the centring bars (42).
10. The swimming and diving aid (10) according to claim 9,
    characterised in that
    a bearing (101, 104), in which the shaft (90) is mounted, is respectively arranged on the centring device (40) and on the flow stator (60).
11. The swimming and diving aid (10) according to claim 9,
    characterised in that
    a first bearing housing (45) is designed within the base (41) of the centring device (40), that the front bearing (101) is held in the first bearing housing (45), and that the first bearing housing (45) is closed water-tight with respect to the flow channel (20) using a removable inflow cap (30).
12. The swimming and diving aid (10) according to claim 10 or 11,
    characterised in that
    an additional bearing housing (63) is designed within the stator base (61) of the flow stator (60), that the rear bearing (101) is held in the additional bearing housing (63), and that the additional bearing housing (63) is closed water-tight using a removable bearing support ring (105).
13. The swimming and diving aid (10) according to any one of claims 1 to 12,
    characterised in that
    an underwater drive unit is formed at least from the electric motor (110) with the rotor housing (114) and the stator housing (113), the centring device (40), the inflow cap (30), the flow stator (60), and the propeller (50) with the shaft (90) and the bearings (101, 104).

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