The invention relates to a ship propulsion with a control device to change the direction of action of the propeller thrust.
Known ship propulsions have in an embodiment at least one propulsion and control unit, also indicated as rudder propellers, which is positioned underwater, and which is equipped with one or two propellers and which can be pivoted around a vertical control axis. Through the pivoting of the propulsion vector which is generated by the propeller, a steering function is achieved for the boat. The pivoting happens by means of a steering shaft which is driven by a control device.
It is known to pivot hydraulically the rudder propeller by means of a hydraulic motor. Disadvantages of a hydraulic control device are, on one hand, the large weight, the construction effort and the cost of the hydraulic components. A hydraulic pump is needed to drive the hydraulic motor which is, for itself again, driven by an electric motor or a combustion engine, which presents a disadvantage in regard to the efficiency of the entire system.
An electro motor drive of a rudder propeller is known from WO2005005249A1. Hereby, an electro motor, also named as a servomotor, drives, via a transmission which reduces the rotational speed of the electric motor, the pivoted control shaft of the rudder propeller and swivels here the directivity of the thrust of the rudder propeller around a vertical axis. Through a previous use, the design of the transmission of this electric propulsion is known as a two-step planetary transmission which is, after the electro motor, coaxial positioned to it and drives the pivoted control shaft via a following spur wheel stage. A disadvantage hereby is the respective play of the connected in series planetary gears. Also, this kind of control device requires a strong brake device to avoid an unintended torque of a pivoting propulsion unit which is created through external and internal forces. Furthermore, a control transmission which has two planetary transmission sets, positioned one after the other, has a relatively large overall length and also has a relatively large amount of parts.
The task of the invention is to create a control transmission for a ship propulsion which does not have the disadvantages as in the mentioned state of the art.
A ship propulsion unit comprises at least a transmission unit, fixedly positioned to the ship's hull, and a propulsion unit external to the ship's hull, pivoting around a control axis. Hereby, the propulsion unit is pivoted, by means of a control unit, to set the course of the ship. The control unit comprises of a control motor, which creates the needed mechanical force for pivoting, and a control transmission, which reduces the relatively large rotational speed of the control motor to a required, low angular velocity which is needed for an exact adjustment of the propulsion unit. Also, by means of the control transmission, the torque of the control motor is increased to the required torque which is needed for the pivoting of the propulsion unit. In this invention, the control transmission is designed as a reduced planetary gear transmission which comprises two central gears and a planetary gear carrier with at least two planetary gears. In addition, the reduced planetary gear transmission is positioned coaxial with the control axis.
The control transmission is preferably designed as a reduced planetary gear transmission, and constructed as a Wolfrom-planetary gear set.
In an especially preferred embodiment, a first central gear of the control transmission is torque-proof connected with the transmission unit. The planetary gear carrier, which is driven by the control motor, is hereby active as an input link and a second central gear as the output link, whereby the output link is torque-proof connected with the pivoting propulsion unit.
In an enhancement of the inventive matter, the control transmission has a central passage in which at least one vertical shaft is positioned for the transfer of the drive power to the propulsion unit.
The central gears are preferably designed with an outer gearing.
Also, and in accordance with the invention, it can be provided that the planetary gears have a continuous, common gearing which is designed through a first and a second engagement section of the planetary gear, and that the central gears have a different number of teeth.
Finally, as an advantage it is determined that the drive of the active planetary gear carrier, representing the input link, is designed as a spur gear section with a beveloid-gearing.
In an especially preferred embodiment, the spur gear section which drives the active planetary gear carrier, representing the input link, is designed with a beveloid-gearing.
In an additional embodiment, a preliminary transmission stage is positioned between the control motor and the input link of the control transmission for an additional reduction in the rotational speed of the control motor.
It is also possible that for pivoting of the propulsion unit, in the event of a power failure, an emergency actuation device is provided through which the input link of the control transmission can be pivoted.
In an alternative version which has a configuration with two planetary gears at the planetary gear carrier, an elastic pre-tensioning device is provided for the reduction of a gear backlash between the planetary gears and the central gears.
In an additional embodiment of the invention, the ability to pivot the propulsion unit with reference to the firmly mounted transmission unit is limited to a maximum pivoting angle and a damping device is positioned as a pivoting angle limiter between the transmission unit and the control unit.
Hereafter, the present invention is further explained through the drawings. It shows:
The control transmission 130 comprises of two concentric planetary gear sets, positioned one after the other meaning that the output link of one of the first planetary gear sets is torque-proof connected with the input link of the second planetary gear set. The planetary gear set comprises a sun gear, positioned on a center axis, at least two planetary gear wheels which are rotatably supported on a planetary gear carrier and which mesh with the sun gear, as well as a ring gear which is also positioned centrically with the transmission axis, and its inner gearing also meshes with the planetary gears.
In the control unit 100, in accordance with the state of the art, a sun gear 131 of the first planetary gear set, as the input link of the control transmission 130, is torque-proof connected with the control motor shaft 122 so that the control motor 120 and the control transmission 130 are along the same center axis 121. The center axis 121 extends parallel to the control axis 110. A ring gear 132 is fixed. The sun gear 131, which is driven by the control motor 120, drives the planetary gear wheels 133, which support themselves on the ring gear 132 and hereby drive the planetary gear carrier 134. The output of the first planetary gear set occurs through the planetary gear carrier 134, as the output link. In such selected configuration of the elements of a planetary transmission, the angle velocity of the output link is lower than the that of the input link. The planetary gear carrier 134 and a sun gear 135, of the second planetary transmission, are torque-proof connected with one another. A ring gear 136 of the second planetary gear set is also fixed so that the sun gear 135 drives a planetary gear carrier 138, via several planetary gear wheels 137, whereby the angle velocity, or rotational speed, respectively, is again reduced. The planetary gear carrier 138, as the output link of the control transmission 130, is torque-proof connected with the transmission output shaft 140 which, in a spur wheel stage 160 and by means of an outer gearing 141, meshes with an inner gearing 152. The inner gearing 152 is positioned coaxial with the control axis 110 and is torque-proof connected with the control axis 151.
To steer control the ship, the control motor 120 will be switched on whereby, via the transmission output shaft 140 and the inner gearing 152, the control shaft 151 and thus the propulsion unit 5 are pivoted around the vertical axis 110. The control transmission 130 reduces the rotational speed of the control motor 120 to achieve the required low angle velocity, at the propulsion unit 5, for exact adjustment. In the shown configuration of two planetary transmission sets in series, the total gear ratio of the control transmission 130 corresponds to the product of the singular gear ratios of the planetary transmission sets. An additional reduction of the rotational speed is achieved through the gear ratio of the spur wheel stage 160, between the designed outer gearing 141, at the transmission output shaft 140, and the inner gearing 152.
If the control motor 120 is turned off and the ship is on course, external disturbing forces from the water or internal forces, for instance a radial force component from the propeller thrust, can affect the propulsion unit 5. Under the influence of these forces, the control transmission 130 and thus the control motor 120 can be driven, via the transmission output shaft 140, so that the propulsion unit 5 turns, in an unwanted manner, and the course of the ship changes. For controlling spin of the control unit 100, an additional, actuated brake device 125 is required in the control unit which, in case of a turned off control motor 120, generates a resistance to an interfering torque for the propulsion unit 5 and thereby avoids a movement of the propulsion unit 5.
The invented control device 200 is presented as a schematic in
The control transmission 230 is designed, in accordance with the invention, as a reduced planetary transmission. In the expert language, a reduced planetary gear transmission is meant to be a planetary gear transmission which comprises two central gears and a planetary gear carrier with at least two planetary gear sets, whereby the planetary gears of a first planetary gear set mesh with the first central gear and the planetary gears of the second planetary gear set mesh with the second central gear. The planetary gears of both planetary gear sets are hereby torque-proof connected to a so-called step planetary gear. Embodiments of a reduced planetary gear transmission are, for example, a Wolfrom-planetary gear transmission set or a so-called “Hi-Red” transmission. Such designed transmissions are applied as a so-called actuating gearing and allow the transformation from a high gear ratio to a low one. Here, the described control transmission 230 is designed as a Wolfrom-transmission set. It comprises two central gears which are either designed as sun gears or as ring gears. The design of a first central gear, as a sun gear, and of a second central gear, as a ring gear, is also possible. In addition, the Wolfrom-transmission comprises a planetary gear carrier to which two planetary gear sets are supported whereby, as described above, the planetary gears of a first planetary gear set mesh with the a first central gear and the planetary gears of a second planetary gear set mesh with the second central gear. The planetary gears of the two planetary gear sets rotate around the same shaft and are torque-proof connected with one another to achieve a gear ratio and thus a change in rotation, the central gears and/or the planetary gears, which each are connected to a step planetary gear, need to provide a difference in the number of teeth. If either only the planetary gears or just only the central gears have the same number of teeth, then the difference in the number of teeth, in the different gearings, needs to be equal to the number of planetary gears for each planetary gear set. To achieve functioning mesh conditions, the different gearings have different modifications in their profile. The smaller the difference is in the number of teeth, the larger the gear ratio gets.
Such a designed control transmission 230 has a fixed sun gear 231, as its first central gear, which is fixedly connected with the transmission unit 204 of the ship propulsion. The second central gear is designed as a sun gear 232 which is rotatably positioned around the control axis 210 and which is torque-proof connected with a control shaft 251 and thus with the control unit 205, not shown here. Therefore, the sun gear 232 forms the output link of the control transmission 230. The input link of the control transmission 230 is about by a planetary gear carrier 233, in which carries two planetary gear sets. A first planetary gear set comprises at least two planetary gears 234 and a second planetary gear set comprises at least two planetary gears 236. The planetary gears 234 and 236 are torque-proof linked with one another as a pair and rotate around the same shaft and also mesh, as described above, with the sun gears 231 and 232.
To achieve a gear ratio effect, either at least the sun gears 231 and 232 or the planetary gears of the planetary sets 234 and 236 must have a difference in the number of teeth. It is an advantage, in view of manufacturing and installation space, to design the planetary gears of both planetary gear sets in the advantageous and same manner with regard to the geometry of the gearing, and to design it, as described in
The planetary gear carrier 233, which acts as the input link of the control transmission 230, is driven by means of a spur gear section 260 via an output shaft 242 of the planetary transmission 240, but can also be set in motion by a control motor shaft 222, in case the planetary transmission set 240 has been eliminated. In the described example, the output shaft 242 of the planetary transmission set 240 has an outer geared beveloid gear 241 which meshes with the outer gearing 252 at the planetary gear carrier 233 and which it drives. The beveloid gearing allows tilting of the center axis 221 of the control motor 220, which results in a more favorable installation space of the electric motor 220 and the transmission unit 4. It is theoretically possible to use a regular spur gear, however, in that case the control axis 210 and the center axis 221 need to extend parallel. After the gear ratio of the spur gear section 260 has occurred, the rotational speed is thereafter further reduced in the control transmission 230. The driven planetary gear carrier 233 allows the planetary gears 234, of the first planetary gear set, to support themselves via the sun gear 231 and the planetary gears 236, of the second planetary gear set, to roll on the sun gear 232. The number of teeth and the gearing geometry of the two planetary gear sets are the same, in this embodiment example. If neither sun gears 231 and 232 nor the planetary gears 234 and 236 would have a different number of teeth, the planetary gears 236 would roll around on the sun gear 232 and the sun gear 232 would stand still. Due to the difference in the number of teeth of the sun gears 231 and 232 and/or the difference in the number of teeth of the planetary gears 234 and 236, however, the sun gear 232 turns during a rotation of the planetary gear carrier 233 by the amount of teeth which corresponds to the difference in the number of teeth. A difference in a number of teeth, between both of the sun gears 231 and 232 or the planetary gears 234 and 236, is only possible if they show different profile shifts to create the proper meshing ratios.
An additional specialty of the Wolfrom-transmission is the dependence of the losses of throughput, or the transmission efficiency, respectively, with regard to the throughput direction. If the Wolfrom-gear set is driven via the planetary gear carrier 233, as described, the losses of throughput are significantly lower and, therefore, the transmission efficiency is significantly higher in a drive of the Wolfrom-transmission via the control shaft 251. That characteristic is desired for this application. If interfering torques occur at the steering control 5, the larger throughput losses, at the driven side, increase the resistance against the unwanted torsion of the steering control 5. A brake device 225, positioned at the control motor 220, can therefore be designed for a significantly lower brake torque as compared with the state of the art, described in
At a lower end of the control shaft 251, a control flange 254 is torque-proof connected with the control shaft 251, toward the top, and connected with the control housing 255 of the pivotable drive unit 205, toward the bottom, Thus, the control flange 254 transmits the pivoting motion of the control shaft 251 to turn the drive unit 205 around the control axis 210 when a change in course is desired.
To be able the change the course of a ship, even during a power failure, an emergency actuator 326 is provided which can be turned and, therefore, can be used to drive the planetary gear carrier 333 for steering of the ship. A brake device 325 prevents a shifting of the propulsion unit by interfering torques. If a ship has the control device 300, the brake device 325, due to the application of a Wolfrom transmission as the control transmission 330 or its specialty regarding the different efficiencies at the reversal of the propulsion, respectively, can be designed less powerful and therefore smaller then in the state of the art.
In
Number | Date | Country | Kind |
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10 2008 042 599.0 | Oct 2008 | DE | national |
This application is a National Stage completion of PCT/EP2009/062612 filed Sep. 29, 2009, which claims priority from German patent application serial no. 10 2008 042 599.0 filed Oct. 2, 2008.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP09/62612 | 9/29/2009 | WO | 00 | 4/5/2011 |