Fin stabilizer

Abstract

The invention relates to a gearless fin stabilizer for positionally stabilizing a watercraft. The stabilizer comprises an electric motor as the drive unit and is gearlessly detachably connected to a fin shaft via a coupling.

Description

[0001] Fin stabilizer

[0002] Description

[0003] The invention relates to a fin stabilizer according to the preamble of claim 1.

[0004] Such fin stabilizers are used to stabilize the roll of a watercraft while underway, at anchor or at zero speed and / or to influence the course of the watercraft.

[0005] Fin stabilizers, especially on larger watercraft, are typically electro-hydraulically driven. Purely electrically driven fin stabilizers are rarer and exclusively operate with mechanical gears. Mechanical gears reduce the high speed of the electric motor to the low output speed required to drive the fin stabilizers, and the high output torques required to drive the fin stabilizers can be achieved. Such an electrically driven fin stabilizer with a gear is described in the applicant's German patent application DE 102020208770 A1. An electric motor shown in this known application is a synchronous motor that drives a fin-supporting shaft (fin shaft) by means of a reduction eccentric gear.

[0006] However, mechanical gearboxes require high precision in terms of alignment, component manufacturing, installation tolerances, and protection against external loads. The gearboxes are also heavy and require regular maintenance and replacement because they are susceptible to vibrations and changing loads. Furthermore, mechanical gearboxes themselves transmit vibrations into the foundation, and in inverter-controlled AC motors, leakage currents can also occur in the gearboxes.

[0007] The invention is therefore based on the object of creating a fin stabilizer whose electromechanical drive unit is low-maintenance and noise-reduced compared to known electrically driven fin stabilizers, while requiring less maintenance. This object is achieved by a fin stabilizer having the features of patent claim 1. Advantageous embodiments are set out in subclaims 2 to 11.

[0008] A fin stabilizer according to the invention for roll stabilization of a watercraft has a stabilizer fin and a fin shaft supporting the stabilizer fin. The fin shaft is mounted rotatably about its longitudinal axis via its own bearing. The fin stabilizer has an electric motor for changing the actual angle of attack of the stabilizer fin. The electric motor has a housing that is non-rotatably attached to a section of a hull wall via a foundation. According to the invention, a rotor of the electric motor is connected to the fin shaft via a coupling in a gearless, positive, and / or frictional manner.

[0009] The electric motor drives the fin shaft directly, without mechanical or hydraulic conversion. Eliminating the mechanical transmission simplifies assembly and maintenance compared to conventional electrically driven fin stabilizers. Furthermore, the fin stabilizer according to the invention features a more compact design, quieter operation, and reduced wear. The fin stabilizer according to the invention is more robust against external overloads and vibrations. Due to the low speeds and the absence of pulsation, the noise level is also lower than that of conventional electro-hydraulic fin stabilizers.

[0010] The rotor can be supported via the fin shaft bearing. Mounting the rotor directly via the fin shaft bearing simplifies installation work and avoids misalignments. The electric motor itself then does not have a rotor bearing. The rotor and stator operate without contact.

[0011] The electric motor is preferably a high-torque synchronous motor with a high number of poles. As brushless synchronous motors, such electric motors are dynamic and also allow for high dynamic stabilization requirements, particularly in pre-armature operation. Furthermore, they meet the requirement for extremely low speeds, such as revolutions in the range of less than 10 revolutions per minute (< 10 rpm). The synchronous motor can be designed as a radial or axial design. In an axial design, known as an axial flux motor, flatter designs can be achieved than in a radial design, so that such an electric motor does not protrude as far into the hull as a radial electric motor. It is advantageous if the rotor of the electric motor is designed as a hollow shaft, at least in part, and the coupling is arranged within the hollow shaft.This measure allows the rotor to surround the fin shaft and a particularly space-saving connection between the rotor and the fin shaft is achieved.

[0012] The coupling connecting the electric motor rotor to the fin shaft can be a mechanical clamping set, a gearing, a hydraulic interference fit, or a screw connection. Such couplings are reliable and technically simple to implement.

[0013] In order to secure the stabilizer fin in its current position, i.e. to fix it, the rotor can have a locking device.

[0014] The fin stabilizer preferably has a control and regulation device that determines a target angle of attack (target position) of the stabilizer fin based on measured data such as the current ship's movement, the actual angle of attack of the stabilizer fin, the current position, and / or rotor speed. This so-called superimposed attitude control reliably determines the target position of the stabilizer fin. The control is superimposed because both the attitude of the ship as a whole and the position of the stabilizer fin are used, and the target position is not determined solely based on the ship's attitude or solely based on the position of the stabilizer fin.

[0015] To control the electric motor based on the measured data, the control and regulation device can include power electronics.

[0016] It is also advantageous if the control and regulation system includes a motor encoder that absolutely measures the rotor position over one or more revolutions. Torque and speed control can be achieved using the rotor position and speed.

[0017] The motor encoder can, in particular, be an angle sensor connected to the fin shaft or rotor. The angle sensor can be a so-called multiturn absolute encoder. Alternatively, the angle sensor can also be a singleturn absolute encoder. To save motor encoder data when the fin stabilizer is switched off, the control and regulation device can have a memory unit for storing motor encoder data.

[0018] In the following, a preferred embodiment of the fin stabilizer according to the invention will be explained in more detail using highly simplified figures. Figure 1 shows a schematic section through a first embodiment of a fin stabilizer according to the invention,

[0019] Figure 2: a schematic section through a second embodiment of a fin stabilizer according to the invention, and

[0020] Figure 3: a schematic section through a third embodiment of a fin stabilizer according to the invention.

[0021] The fin stabilizer 1 shown in Figure 1 essentially has an electric motor 2, a coupling 3, a fin shaft 4, a foundation 5 and a stabilizer fin 6. In addition, the fin stabilizer 1 has a fixing device (not shown) for securing the stabilizer fin in its actual angle of attack as well as a control and regulating device (not shown).

[0022] The stabilizer fin 6 is connected to a rotor 7 of the electric motor 2 via the fin shaft 4 and the coupling 3 in a form-fitting, force-fitting, and / or frictional manner. The coupling 3 is, for example, a tension coupling, and the electric motor 2 is, in particular, a high-torque synchronous motor with a high number of poles in a radial design.

[0023] The fin shaft 4 is guided through a coker tube 8 and mounted therein via a bearing 9, 10 for rotation about its longitudinal axis. In the exemplary embodiment shown, the bearing 9, 10 is at least one rolling element bearing 9 and one water-tight plain bearing 10. The rolling element bearing 9 is, for example, a double-row inclined barrel bearing and is arranged away from the water, i.e. close to the coupling 3. The sliding seal 10 is water-tight, i.e. away from the coupling. It prevents seawater from penetrating an unnumbered annular space between the coker tube 16 and the fin shaft 5 and thus protects the rolling element bearing 9 from water. The coker tube 8 itself is guided axially through a support tube 11, which here is designed as a tubular projection 11 that penetrates a section of an outer skin or hull wall 12 on the water side.With its inner fuselage end, the support tube 11 forms the flange-like foundation 5, to which the electric motor 2 is non-rotatably attached via its housing 13. The coker tube 8 is also non-rotatably attached to the foundation 5 via a flange 14.

[0024] The electric motor 2 has a rotating rotor 7 housed in its housing 13 and a rotationally fixed stator surrounding the rotor 7 (see stator windings 15). The rotor 7 and the stator operate without contact, with the rotor 7 being supported exclusively by the fin shaft bearings 9, 10. The electric motor 2 does not have its own rotor bearings, but relies on the fin shaft bearings 9, 10.

[0025] The rotor 8 is designed as a hollow shaft (hollow hub) with a rotor carrier, at the end of which several rotor magnets 16 are arranged. The fin shaft 4 is guided through the hollow-shaft rotor 7 and is mechanically connected via the coupling 3, which is arranged in the space between the fin shaft 4 and the rotor 7. The stator has several stator windings 15 of a simple design. The stator windings 15 are supported by the housing 13, which acts as a stator carrier.

[0026] To secure the fin shaft 4 against axial movements, a mechanical locking unit 17 is arranged at the free end of the fin shaft 4, which keeps axial forces away from the coupling 3.

[0027] The control and regulation unit determines a target angle of attack (target position) of the stabilizer fin 6 based on measurement data such as a current ship movement, the actual angle of attack of the stabilizer fin 6, a current position and / or speed of the rotor 7.

[0028] To control the electric motor 2 to adjust the desired angle of the stabilizer fin 6, the control and regulation unit has a power electronics unit (not shown), which controls the electric motor 2 based on the measured data. To determine the position of the rotor 7, the control and regulation unit has a motor encoder 18. The motor encoder 18 is arranged on the front side of the fin shaft 4 and an angle sensor, exemplified as a multiturn absolute encoder or a single-turn absolute encoder. The motor encoder 18 detects the absolute position of the rotor 7 over at least one revolution.

[0029] In addition to the motor sensor 18, the control and regulating device has a power electronics unit (not shown) for controlling the electric motor 2 based on the measurement data.

[0030] In addition, the control and regulating device comprises a memory unit (not shown) for storing data of the motor encoder 18 when the fin stabilizer 1 is switched off (not energized).

[0031] The control and regulation system operates according to the principle of superimposed control. This means that it receives measured values ​​or measured data that represent the current ship movements, as well as further measured values ​​that represent the current position of the fin, the position, and the speed of the motor rotor. From this measured data, the superimposed control determines the target position of the stabilizer fin 6. The power electronics controls the electric motor 2 accordingly, which moves the stabilizer fin 6 to its new target position via the mechanically coupled fin shaft 4.

[0032] The motor sensor 18 detects the absolute position of the rotor 7 over at least one revolution. The rotor position and rotor speed are required for torque and speed control of the electric motor 2. When the fin stabilizer is switched off, this value is stored in the memory unit.

[0033] Figure 2 shows a second embodiment of a fin stabilizer according to the invention with a high torque synchronous motor with a high number of poles in radial design.

[0034] The only difference from the first embodiment shown in Figure 1 is that the electric motor 2 in the second embodiment is not designed as a single stator, but as a double stator, allowing even higher torques to be achieved. The electric motor 2 in the second embodiment thus has first stator windings, or radially inner stator windings 15a, and second, or radially outer stator windings 15b, between which rotor magnets 16 run.

[0035] The other features of the second embodiment are identical to the features of the first embodiment according to Figure 1, so that repetitive explanations are omitted and reference is made to the explanations for Figure 1.

[0036] Figure 3 shows a third embodiment of a fin stabilizer 1 according to the invention.

[0037] In contrast to the first embodiment shown in Figure 1 and the second embodiment shown in Figure 2, the electric motor 2 in the third embodiment is designed as a high-torque synchronous motor with a high number of poles in an axial design. The electric motor 2 is thus an axial flux motor, with stator windings 15a, 15b oriented orthogonally to the motor rotation axis or fin shaft axis. Stator windings 15a are also referred to here as lower stator windings, and stator windings 15b as upper stator windings. Electromagnets 16 are also arranged horizontally between stator windings 15a, 15b.

[0038] The other features of the third embodiment are the same as in the first and second embodiments, so a repeated explanation is omitted. In particular, the electric motor 2 of the third embodiment, like the previous embodiments, is detachably connected to a fin shaft 4 via a coupling 3 without a gear.

[0039] The invention relates to a gearless fin stabilizer for stabilizing the position of a watercraft, with an electric motor as the drive unit, which is detachably connected to a fin shaft via a coupling. List of reference symbols Fin stabilizer Electric motor Coupling Fin shaft Foundation Stabilizer fin Rotor Coker tube Rolling element bearing Sliding seal Support tube / tubular projection Hull wall Housing Flange of the coker tube Stator a first stator winding (radially inner or upper) b second stator winding (radially outer or lower) Rotor magnet Locking unit Motor encoder

Claims

Patent claims 1. Gearless fin stabilizer for roll stabilization of a watercraft, with a stabilizer fin (6), with a fin shaft (4) carrying the stabilizer fin (6) and rotatably mounted via its own bearing, and with an electric motor (2) for changing an actual angle of attack of the stabilizer fin (6), wherein the electric motor (2) has a housing (13) which is fastened to a section of a hull wall in a rotationally fixed manner via a foundation (5), and wherein a rotor (7) of the electric motor (2) is connected to the fin shaft (4) in a gearless, positive, non-positive and / or frictional manner via a coupling (3).

2. Fin stabilizer according to claim 1, wherein the rotor (7) is mounted via the mounting of the fin shaft (4).

3. Fin stabilizer according to claim 1 or 2, wherein the electric motor (2) is designed as a high torque synchronous motor with a high number of poles.

4. Fin stabilizer according to claim 1, 2 or 3, wherein the rotor (7) of the electric motor (2) is designed at least in sections as a hollow shaft and the coupling (3) is arranged within the hollow shaft.

5. Fin stabilizer according to one of the preceding claims, wherein the coupling (3) connecting the rotor (7) of the electric motor (2) to the fin shaft (4) is a mechanical clamping set, a toothing, a hydraulic press fit or a screw connection.

6. Fin stabilizer according to one of the preceding claims, wherein the rotor (7) of the electric motor (2) has a locking device for locking the stabilizer fin (6).

7. Fin stabilizer according to one of the preceding claims, wherein a control and regulating device is provided which determines a desired position of the stabilizer fin (6) based on measured data such as a current ship movement, the actual angle of attack of the stabilizer fin (6), a current position and / or speed of the rotor (7).

8. Fin stabilizer according to claim 7, wherein the control and regulating device comprises power electronics for controlling the electric motor (2) based on the measurement data.

9. Fin stabilizer according to one of claims 7 or 8, wherein the control and regulating device has a motor sensor (18) which detects the position of the rotor (7) absolutely over at least one revolution.

10. Fin stabilizer according to claim 9, wherein the motor sensor (18) is an angle sensor which is connected to the fin shaft (4) or rotor (7).

11. Fin stabilizer according to one of claims 7 to 10, wherein the control and regulating device comprises a memory unit for storing data of the motor sensor (18) when the fin stabilizer (1) is switched off.

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