ES2232791T3 - MOTOR SYSTEM FOR WATER VEHICLES. - Google Patents

Abstract

The length ratio (x/L) between the actual distance (x) from the nose of the propeller casing mounting shaft profle and the total length (L) of the shaft profile is related to the thickness ratio (t/tmax) between the actual profile thickness (t) and maximum profile thickness (tmax) in the following way : 0.05/0.44, 0.1/0.62, 0.15/0.76, 0.2/0.84. 0.25/0.91 and 0.3/0.96 (length ratio/thickness ratio). The propeller device is used to provide propulsion and preferably also to correct the thrust direction of the marine craft, preferably from -10 to +10 deg. The drive device has a casing (4) which is suspended beneath the underside (1) of the hull so that it has an essentially horizontal position. A propeller is provided outside the casing at one end and inside the casing are at least some of the propeller drive parts. The casing is joined to the hull via a shaft with a vertical length axis (5), the bottom end being fixed to the casing and the top end preferably being connected to the hull so that it is pivotable about its length axis. The shaft has a support vane cross-section profile (6), ie with a rounded nose at its front end, following which the profile increases to a maximum thickness before tapering to a point at its front end.

Description

Drive system for water vehicles.

The present invention refers to a driving system for water vehicles, which can be used to drive the water vehicle, but, in certain cases, it also serves to vary the direction of the water vehicle's progress and for its government, having thought about the invention especially for a course change of approximately ± 10 ° with respect to the main direction of travel. The drive system has a housing that is arranged as a wafer, with the longitudinal axis essentially horizontal, under the hull of the water vehicle, outside said water vehicle. A drive motor or elements of an engine can be found in the underwater housing. The drive motor can be, for example, an electric motor according to DE-19,648,417, and it can also be a gear mechanism that is part of a motor, for example according to DE-4,440,738, which transmits the driving power from an engine located inside the water vehicle. The drive motor, or part thereof, is connected through a drive shaft with at least one propeller disposed at one end of the housing, outside of said housing. There may also be, in certain cases, a shared drive shaft between both ends of the housing, to drive at least one propeller disposed outside each end of the housing. To place the underwater carcass in the hull of the water vehicle, a tajamar with the vertical longitudinal axis is used, whose lower end is fixed to the underwater carcass, while the upper end is attached to the hull of the water vehicle. The junction between the upper end of the tajamar and the hull of the water vehicle is shaped in a known manner, the tajamar can oscillate or rotate respectively around its longitudinal axis, whereby it is possible to change the direction of the impulse generated with at least one propeller , so that the driving system not only serves to advance the water vehicle but also to determine the direction of travel of the same. The aforementioned tajamar, arranged between the underwater housing and the hull of the water vehicle, has a cross section approximately in the form of a support wing, to offer the minimum possible resistance to flowing water and to give it a laminar way, that is to say with the least possible training of
turbulence

The present invention now deals with the conformation of the aforementioned tajamar, preferably for a oscillating drive fundamentally all around, to water vehicles with a speed above approximately 24 knots, such that the danger of cavitation in the tajamar and in the at least one propeller is reduced, staying reduced pressure oscillations while oscillations of drive and turning moment are transmitted with the most value reduced possible to the whole structure.

These driving systems, which include a electric motor arranged in an underwater housing, have a virtually unlimited power spectrum. Therefore can be used on boats with high speed demands, such as for example Ro-Ro ships and passenger ships. The current trend in these ships is that they reach speeds of 24 knots and above. For such applications there are special requirements for the arrangement of the propellers and all the installation, including the tajamar between the underwater housing and the Water vehicle helmet.

Unlike a driven boat conventionally, with a rudder independent of the drive system to correct the course, in an oscillating drive system, such as the described above, the course correction is done through a called PoD, the motor system having the function of the organ of drive and government. When governing a water vehicle by such an installation, to keep the course, but also to correct this course, they occur under conditions of Normal boat operation rudder angles of ± 10º. Given this provision of the drive system against the current a through tangential components, in the output current of the helix radial changes of the PoD occur at different angles of creep in the tajamar, being an object of the invention to propose measures that take into account the high speeds of the ship and the relatively large adjustment angles in the profile of the tajamar, to avoid cavitation and dissolution of the current, since the geometries of the tajamar used until now They cannot meet these requirements.

This is based on the knowledge that the output current of a water vehicle, especially also of a ship, it is due to a reduction in the speed of creep A similar effect appears in the front areas and behind, respectively, the tajamar of a drive system with housing Submarine shaped boat. The current also slows down in the area behind the tajamar of the housing. Both fields of Pressure overlap.

In areas where there are more slowdowns due to the clear displacement of the work point of the propeller, cavitation appears. It may cause damage to erosion on the propeller blade. The level of pressure oscillations increases clearly. At the same time, the appearance of large velocity gradients is the cause of drive oscillations and turning moment, which are transmitted to the structure. So special on ships with high requirements (eg passenger) no high oscillation values in pressure or pressure are accepted cavitation The present invention must also take these problems.

With the invention it is possible to use radios relatively large at the entrance edge in each section of the the tajamar profile of the housing and a creep of shake-free current across a large angle area of profile adjustment. Strong accelerations and spikes are avoided. local depression The danger of cavitation is reduced. The risk of landslides are reduced thanks to a moderate increase in pressure in the direction of the rear edge of the profile. The relationship between the local thickness and the maximum thickness should not be less than indicated in the table, according to the invention, given below. A relationship between the maximum thickness and the length of the order profile from 0.23 to 0.30 constitutes a convenient compromise. The danger of Cavitation is reduced without increasing the resistance of the cutwater.

T / tmax thickness distribution:

       \ dotable {\ tabskip \ tabcolsep \ hfil # \ hfil \ + \ hfil # \ hfil \ + \ hfil # \ hfil \ tabskip0ptplus1fil \ dddarstrut \ cr} {
  x / L \ + \ hskip2cm \ + t / tmax \ cr 0,05 \ + \ +
0.44 \ cr 0.10 \ + \ + 0.62 \ cr 0.15 \ + \ + 0.76 \ cr 0.20 \ + \ + 0.84 \ cr
0.25 \ + \ + 0.91 \ cr 0.30 \ + \ +
0.96 \ cr}
    

In another configuration of the invention, it deals with of the problem of avoiding an additional slowdown of the current at through the tajamar of the underwater housing. For this purpose, it is chosen a relatively large distance from the generation plane of the propeller (the circle of the propeller tips) to the edge front and back, respectively, of the tajamar profile. This is determined taking into account the distribution of charges in the propeller.

For reasons of cavitation the propeller is discharged in the area of the cube and the outer section. Sections (0.5 - 0.9 r / R) have a greater distance to the plane of the propeller. How consequence of the greater local load in these sections of the blade, a reduction in current leads to faster cavitation in that place. In the following table, according to another conformation of the invention, the minimum necessary distance is indicated, according to the invention, depending on the diameter of the propeller.

Distance of the propeller planes to the axis:

       \ dotable {\ tabskip \ tabcolsep \ hfil # \ hfil \ + \ hfil # \ hfil \ + \ hfil # \ hfil \ tabskip0ptplus1fil \ dddarstrut \ cr} {
  r / R \ + \ hskip2cm \ + s / D \ cr 0.5 \ + \ + 0.20 \ cr
0.6 \ + \ + 0.23 \ cr 0.7 \ + \ + 0.25 \ cr 0.8 \ + \ + 0.27 \ cr 0.9 \ + \ +
0.29 \ cr 1.0 \ + \ +
0.30 \ cr}
    

The parameters, according to the invention, used in both tables presented and cited in the claims, appear in the only drawing.

It represents a driving system according to the invention, but as is known. At the bottom 1 of the hull 2 of a water vehicle is mounted, at its upper end, the chopping board 2 of an underwater casing 4. The connection between the upper end of the tajamar and the hull of the water vehicle can be rigid, but preferably it is shaped rotating, in a known manner, so that the chopping board 3 and the housing 4 can oscillate continuously, that is 360 °, around the longitudinal axis 5 of the chopping board of the housing 3. The profile of the chopping board has been drawn as a polygonal contour 6. The lower end of the tajamar 3 is rigidly connected to the underwater housing 4. In a known manner, it houses a drive motor, which is preferably an electric motor, powered by energy through cables that cross the tajamar 3 and penetrate into the interior of the helmet. But inside the underwater shell as a nozzle 4, a distributor gear mechanism can also be found, the input of which is fed with the energy from an engine disposed within the hull 2 of the water vehicle by means of a drive shaft that passes through the chopping board 3. In both cases, a drive shaft is rotated that rotates around the longitudinal axis 7 of the underwater housing 4, which exits at one or both ends of said underwater housing and that has a propeller attached to the protruding end of the housing, or else minus a propeller 8, 9, at each of the protruding ends of the underwater housing 4. The propeller or propellers serve to propel the water vehicle, especially a ship, so that by rotating the shaft and the housing around the axis 5, in the direction of the jet of flowing water, allows to vary the course of the water vehicle. The indicated parameters that characterize the invention are the
following:

       \ dotable {\ tabskip \ tabcolsep # \ hfil \ + # \ hfil \ + # \ hfil \ tabskip0ptplus1fil \ dddarstrut \ cr} {
 tmax \ + = \ + \ begin {minipage} [t] {140mm} the maximum thickness of the
profile of the supporting wing, as indicated by the contour
6 and section of axis 3, whose front edge and rear edge
they have a concave curved shape; \ end {minipage} \ cr t \ + = \ + el
current profile thickness in the chosen areas; \ cr x \ + = \ +
 \ begin {minipage} [t] {140mm} the distance of the chosen area from
the nose-shaped end of the profile in the main sense of
the forward march; \ end {minipage} \ cr L \ + = \ + the length
profile total; \ cr s \ + = \ + the distance from the main plane of
the P.E. of the circle of the tips of the chosen area of the
axis; \ cr r \ + = \ + the distance of the chosen area of the axis from the
axis of rotation of the propeller; \ cr R \ + = \ + the radius of the circle of
propeller tips \ cr D \ + = \ + the diameter of the circle of
tips of the
propeller. \ cr}
    

In short, the problem of the invention can Describe as follows.

For water vehicle / boat speeds greater than 24 knots, certain particularities are required in the conformation of the motor system. They are due to performance requirements for a lower level of oscillations of pressure and a lower acoustic load. At the same time they are avoided installation damage due to erosive cavitation in the Tajamar and the propellers. The measures according to the invention offer the possibility of operating motor systems in this range of speeds considering these requirements. The possibility that it is possible to use bigger radios in the entrance song of the tajamar guarantees a flow of current without shaking through of a wide angle of adjustment. Tajamar profiles present a maximum thickness / length ratio of 0.3. So you get one certain minimum resistance between the plane of the propeller and the cutwater.

Claims (2)

1. Device to drive a water vehicle and preferably also to correct the direction of travel of the water vehicle, preferably on the order of ± 10º, approximately, so that the drive device presents a housing that is arranged as a wafer, with the shaft essentially horizontal longitudinal, under the vehicle's hull aquatic, turning a propeller at one end in the surrounding water outside the housing, while inside the housing there are at least elements of the propeller drive system, and it is joined by a tajamar, which essentially has an axis longitudinal longitudinal, to the hull of the water vehicle, so that the lower end of the tajamar is fixed to the underwater housing, while the upper end is attached to the vehicle's helmet aquatic, preferably rotatably around its axis longitudinal, having the cross section of the tajamar approximately the shape of a supporting wing, that is, shape in the front end in the direction of current regulation a rounded nose, and then increase the thickness of the profile until it becomes, after a maximum thickness, a tip final, characterized by the fact that starting with the nose of the profile, the ratio of the longitudinal ratio (x / L) between the distance current (x) of the profile nose and the entire profile length (L) on the one hand and the thickness ratio (t / tmax) between the thickness current profile (t) and the maximum profile thickness (tmax) is as follow: T / tmax thickness distribution:

         \ dotable {\ tabskip \ tabcolsep \ hfil # \ hfil \ + \ hfil # \ hfil \ + \ hfil # \ hfil \ tabskip0ptplus1fil \ dddarstrut \ cr} {
  x / L \ + \ hskip2cm \ + t / tmax \ cr 0,05 \ + \ +
0.44 \ cr 0.10 \ + \ + 0.62 \ cr 0.15 \ + \ + 0.76 \ cr 0.20 \ + \ + 0.84 \ cr
0.25 \ + \ + 0.91 \ cr 0.30 \ + \ +
0.96 \ cr}
      

2. Device to drive a water vehicle according to claim 1, characterized by the fact that the ratio ratio (r / R) between the current diameter of the propeller (r) and the maximum diameter of the propeller (R) on the one hand, and the proportion (s / D) between the distance (s) of the circle of the propeller tips from the front edge of the tajamar and the maximum diameter (D) of the propeller on the other hand, is like follow: Distance of the propeller planes to the axis:

         \ dotable {\ tabskip \ tabcolsep \ hfil # \ hfil \ + \ hfil # \ hfil \ + \ hfil # \ hfil \ tabskip0ptplus1fil \ dddarstrut \ cr} {
  r / R \ + \ hskip2cm \ + s / D \ cr 0.5 \ + \ + 0.20 \ cr
0.6 \ + \ + 0.23 \ cr 0.7 \ + \ + 0.25 \ cr 0.8 \ + \ + 0.27 \ cr 0.9 \ + \ +
0.29 \ cr 1.0 \ + \ +
0.30 \ cr}