Patent Application
20250153829
The current application claims priority to German Application No. 10 2023 131 258.8, filed Nov. 10, 2023, the contents of which are hereby incorporated by reference.
The present invention relates to a shaft profile for an outboard drive for driving a boat and an outboard drive for driving a boat.
Outboard drives are a known drive means for boats. As a rule, they are attached to the stern of the respective boat via a fastening device, in particular a transom mount. Boats can have different stern shapes. If a flat stern end plate is present, this is also referred to as a “transom”. The transom can be inclined differently with respect to the water surface. It can be perpendicular to the water surface, project obliquely beyond the water surface or be inclined in the direction of the boat interior. Furthermore, the inclination of the transom with respect to the water surface can vary on account of different states, in particular driving and/or loading states, of the boat.
Outboard drives comprise a drive unit which is arranged underwater during operation. Said drive unit comprises a propeller with which propulsion is generated. The drive unit is connected via a shaft to a steering device of the outboard drive, for example a quill, for specifying the steering angle of the drive unit relative to the 0° direction, which corresponds to a bow-stern direction of the boat. The shaft is mounted on the fastening device so as to be rotatable about the steering angle axis of rotation.
It is known to line the shaft with a shaft profile in order to optimize the shaft in a flow-dynamic manner, in particular to reduce the flow resistance and the turbulences, caused by the shaft during travel, of the water flowing around the shaft. The shaft profile therefore serves to reduce the flow resistance during travel through water.
The shaft profile can have an extrusion base body comprising plastic or an extrusion base body comprising a metal alloy. Conventional shaft profiles have a plurality of chambers and a so-called casing tube. The casing tube is a tube extending in the direction of the longitudinal axis of the shaft in the interior of the shaft profile, through which the cylindrical shaft is inserted. The shaft profile is supported on the shaft by the casing tube.
Proceeding from the known prior art, it is an object of the present invention to provide an improved shaft profile for an outboard drive for driving a boat, and an improved outboard drive for driving a boat.
The object is achieved by a shaft profile for an outboard drive for driving a boat having the features of claim 1. Advantageous developments result from the dependent claims, the description and the figures.
Accordingly, a shaft profile for an outboard drive for driving a boat is proposed, comprising a base body extending along a longitudinal axis, wherein the base body comprises a receiving space for receiving a shaft of the outboard drive.
At least three support ribs extending in the direction of the longitudinal axis for radially guiding the shaft are arranged at a distance from one another in the circumferential direction in relation to the longitudinal axis on an inner side, i.e. a radially inner side or wall surface in relation to the longitudinal axis, of the receiving space.
As a result, the proposed shaft profile can be produced very much more easily and in a more material-saving manner in comparison to conventional shaft profiles with a casing tube. This is because instead of the casing tube having a closed annular cross section in relation to the longitudinal axis, the proposed shaft profile has only the support ribs, i.e. significantly less material, which is necessary for forming the guide and the support of the shaft on the shaft profile or vice versa.
Furthermore, a slender design of the shaft profile can be achieved as a result in comparison to conventional shaft profiles with a casing tube. The slender design causes a lower flow resistance and therefore a higher efficiency of the outboard drive.
According to one embodiment, the support ribs can have a rounded shape at their radially inwardly pointing free end.
For example, at least one support rib can have a concave curvature at its free end, i.e. be curved inwardly in relation to the support rib. Alternatively or additionally, at least one support rib can have a convex curvature at its free end, i.e. be curved outwardly in relation to the support rib.
According to one embodiment, the base body can have exactly one chamber, wherein the receiving space is formed in the exactly one chamber. The base body can optionally comprise an outer wall of predetermined wall thickness which is closed in relation to the longitudinal axis in the circumferential direction and encloses the exactly one chamber when viewed perpendicularly to the longitudinal axis. In other words, a cross-sectional shape of the base body can optionally consist of the outer wall of predetermined wall thickness, on the inner side of which the support ribs are formed.
According to one embodiment, the base body can be formed on at least one of its end sides to be connected in a rotationally fixed manner with respect to the longitudinal axis to a component of the outboard drive arranged on this end side, for example a drive unit, for example a pod unit, of the outboard drive.
According to one embodiment, a connecting part, for example an elastic connecting part, for optionally elastically connecting the shaft profile to a component of the outboard drive arranged on this end side can be arranged on at least one of its end sides of the shaft profile with respect to the longitudinal axis, wherein the connecting part optionally provides a seal of the shaft profile.
According to one embodiment, the shaft profile, when viewed perpendicularly to the longitudinal axis, can have a cross-sectional outer contour which is streamlined in a predetermined transverse direction, wherein the cross-sectional outer contour is, for example, teardrop-shaped.
According to one embodiment, the base body can be formed in one piece, i.e. from an uninterrupted material accumulation without connecting points, such as screw connections.
According to one embodiment, the base body can be an extrusion profile comprising plastic, a continuous casting profile comprising a metal alloy or an extruded profile comprising a metal alloy.
According to one embodiment, the shaft profile can comprise a spare rudder section for providing a spare rudder for a boat comprising the outboard drive. In the spare rudder section, the shaft profile can have a predetermined length in the flow direction which makes it possible to generate torques from the medium flowing around which are large enough to provide steering of the boat. In the spare rudder section, a length of the shaft profile, for example of the base body, in the transverse direction can be greater than a length of a connecting section of a drive unit, for example a pod unit, of the outboard drive. The spare rudder section can therefore project in the transverse direction behind the connecting section.
According to one embodiment, the spare rudder section can extend in the direction of the longitudinal axis over the entire shaft profile, optionally over the entire base body. Alternatively, the spare rudder section can extend in the direction of the longitudinal axis over a part of the shaft profile, optionally over a part of the base body.
The shaft profile can comprise a plurality of base body parts. The base body can be formed from a plurality of base body parts. At least one base body part can optionally comprise the spare rudder section.
The abovementioned object is furthermore achieved by an outboard drive for a boat having the features of claim 10. Advantageous developments result from the dependent claims, the description and the figures.
Accordingly, an outboard drive for a boat is proposed, comprising a fastening device for fastening the outboard drive to a boat, and a drive unit which is arranged on the fastening device so as to be rotatable about a steering angle axis of rotation via a shaft.
The outboard drive can comprise a shaft profile according to one of the preceding embodiments which is arranged on the shaft between the fastening unit and the drive unit. Alternatively or additionally, the outboard drive can be configured to be changed between a normal mode and a spare rudder mode.
In the normal mode, a first shaft profile with a first length in the direction of a transverse direction oriented transversely to the steering angle axis of rotation can be arranged between the fastening unit and the drive unit and in the spare rudder mode a second shaft profile with a second length different from the first length can be arranged in the direction of the transverse direction between the fastening unit and the drive unit.
In the normal mode, the (first) shaft profile can be adapted to a connecting section between shaft profile and drive unit. In this way, for example, a particularly low flow resistance can be achieved. In the spare rudder mode, the functionality of a spare rudder can be provided on account of the greater (second) length of the (second) shaft profile. For example, if the main rudder of a boat has been lost or damaged during travel.
The outboard drive can be designed such that the shaft profile can be changed, wherein, for example, a first shaft profile has a first length in the direction of a transverse direction oriented transversely to the steering angle axis of rotation, and a second shaft profile has a second length different from the first length.
The conversion of normal mode and spare rudder mode can take place if the outboard drive is not fastened to the boat, that is to say for example on deck of the boat. The conversion takes place by removing a first shaft profile and attaching a second shaft profile, which for example comprises the spare rudder section, and vice versa.
Exemplary embodiments of the present disclosure are explained in more detail by the following description of the figures. In the figures:
Exemplary embodiments are described below with reference to the figures. In this case, identical, similar or identically acting elements are provided with identical reference symbols in the different figures, and a repeated description of these elements is dispensed with in part in order to avoid redundancies.
The drive unit 3 is fastened to a shaft 10 which is arranged on the fastening unit 7 so as to be rotatable about a steering angle axis of rotation 6. The shaft 10 is connected in a rotationally fixed manner to a steering device 8 which is provided above the fastening unit 7 and which in this case comprises a tiller 9. As a result, the steering angle of the drive unit 3 can be specified via the position of the steering device 8.
A streamlined, thin-walled shaft profile 11 is arranged around the shaft 10.
The shaft profile 11 extends along its longitudinal axis 12, which corresponds to the steering angle axis of rotation 6 or coincides therewith in the correctly assembled state of the outboard drive 1.
In relation to the longitudinal axis 12, the shaft profile 11 has a connecting part 13 on each of its end sides, once to the fastening unit 7 and once to the drive unit 3. According to this optional embodiment, the connecting part 13 to the fastening unit is formed from a solid, that is to say inelastic plastic, and that to the drive unit 3 is an elastic connecting part 13.
It can be seen here that the shaft profile 11 comprises a base body 15 which extends along the longitudinal axis 12 and in which a receiving space 19 for receiving the shaft 10 of the outboard drive 1 is provided.
The base body 15 has exactly one chamber 17, wherein the receiving space 19 is formed in the exactly one chamber 17.
The base body 15 comprises an outer wall 18 of predetermined wall thickness 21 (see
Three support ribs 16 extending in the direction of the longitudinal axis 12 for radially guiding the shaft 10 are arranged on an inner side 22 of the receiving space 19. The support ribs 16 project radially inwardly from the inner side 22 of the outer wall 18 in relation to the longitudinal axis 12, specifically in such a way that their free ends 20 lie on a common pitch circle diameter in relation to the longitudinal axis 12, which pitch circle diameter substantially corresponds to the outer diameter of the shaft 10. As a result, a three-point guide of the shaft 10 on the shaft profile 11 or vice versa is formed in relation to a cross section perpendicularly to the longitudinal axis 12. Each of the support ribs 16 represents a linear guide of the shaft 10 in each case in the direction of the longitudinal axis 12.
The base body 15 is a one-piece extruded profile made from an aluminum alloy.
The shaft profile 11, more precisely the base body 15, when viewed perpendicularly to the longitudinal axis 12, has a cross-sectional outer contour which is streamlined in a transverse direction 14 oriented perpendicularly to the longitudinal axis 12, which transverse direction is oriented parallel to the propeller axis 4 in the assembled state of the outboard drive 1.
At its radially inwardly pointing free end 20, each of the support ribs 16 has a rounded shape. In the present case, the free end 20 is convexly curved, i.e. curved outwardly. As a result, the contact surface between shaft 10 and support ribs 16 is minimized.
Furthermore, the streamlined teardrop shape of the base body 15 can be seen.
It can be seen that the shaft 10 comprises at its lower end a toothing 25 with which it engages in a correspondingly formed toothing 26 on the drive unit 3 in order to be able to transmit torques about the longitudinal axis 12, i.e. about the steering angle axis of rotation 6.
The drive unit 3 comprises a projection 27 which, for example as in the present case, extends at a distance from the longitudinal axis 12 in the direction of the longitudinal axis 12 into the chamber 11. By using the projection 27, torques can be transmitted between the drive unit 3 and the shaft profile 11.
Consequently, the shaft 10 and the shaft profile 11 are connected in a rotationally fixed manner to one another in the assembled state of the outboard drive 1. Alternatively or additionally, shaft 10 and shaft profile 11 can also be connected directly in a rotationally fixed manner to one another.
The elastic connecting part 13 likewise optionally forms a seal of the chamber 11 against an ingress of water.
The outboard drive 1 according to
In the normal mode, the outboard drive 1 comprises the shaft profile 11 from
The shaft profile 11′, more precisely the base body 15 thereof, comprises a spare rudder section 30 for providing a spare rudder for the boat 100 comprising the outboard drive 1.
The spare rudder section 30 comprises a length 31 in the transverse direction 14 which is greater by a predetermined value 32 than that of the shaft 11 from
In the present case, the spare rudder section 30 extends, when viewed in the direction of the longitudinal axis 12, over the entire base body 15, i.e. over the entire length thereof in the direction of the longitudinal axis 12.
Arranged between the lower end face of the base body 15 and the connecting section 28 is a reducing part 34 which compensates for the different lengths 31, 33. The reducing part 34 is designed to connect the shaft profile 11′ and the drive unit 3, more precisely the connecting section 28, in a rotationally fixed manner to one another, so that torques can be transmitted about the longitudinal axis 12, which corresponds to the steering angle axis of rotation 6.
A reducing part 34 (not shown here), which can provide a transition from the upper end side of the shaft profile 11′ to the elastic connecting part 13 (see
Alternatively, the spare rudder section 30 can extend in the direction of the longitudinal axis 12 only over a part of the base body 15.
The shaft profile 11″ comprises a multi-part base body 15 composed of two base body parts 41, 42. Each of the base body parts 41, 42 can be considered as a base body. The shaft profile 11″ can thus be considered to comprise two base bodies (41, 42). The upper first base body part 41 has a length 35 in the transverse direction 14 analogously to the base body 15 of the shaft 11 from
It can be seen that the second base body part 42 is present below the waterline 110 in a correctly fastened state of the outboard drive 1 on the boat 100 (see
A reducing part 34 which connects the abovementioned parts in a rotationally fixed manner and/or seals against the ingress of water can be provided between the base body parts 41, 42. Furthermore, a reducing part 34 which provides a rotationally fixed connection and/or seals against the ingress of water can be provided between the drive unit 3 and the second base body part 42, and/or a further reducing part (not shown here) which optionally seals against the ingress of water can be provided on the upper end side of the first base body 41.
To the extent applicable, all individual features which are illustrated in the exemplary embodiments can be combined with one another and/or replaced without departing from the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2023 131 258.8 | Nov 2023 | DE | national |
