Marine gearbox and drive arrangement for a marine propulsion system

Description

[0001] The invention relates to a marine transmission according to the type defined in the preamble of claim 1 and a drive arrangement for a marine propulsion system according to the preamble of claim 8.

[0002] EP 1 123 865 A1 discloses a marine transmission comprising a drive shaft for connection to a drive motor, an intermediate shaft, and an output shaft for driving a propeller. Furthermore, the document describes the possibility of coupling an additional motor to the intermediate shaft. Additional drives on a marine transmission are also referred to as PTI (Power Take In).

[0003] From JP 2017 013715 A, a marine transmission according to the preamble of claim 1 is also known.

[0004] The present invention is based on the object of further improving such a marine transmission and a corresponding drive assembly with an auxiliary drive. In particular, this should enable broad applicability, a compact design, and the lowest possible installation effort for the drive assembly.

[0005] These objects are achieved by a marine transmission having the features of claim 1 and by a drive arrangement having the features of claim 6. Advantageous further embodiments of the invention are specified in the respective dependent claims.

[0006] Accordingly, a marine transmission is proposed that comprises a main drive shaft, a first intermediate shaft, and an output shaft. The main drive shaft can be connected to a main drive motor. At least one propeller can be driven via the output shaft. Furthermore, a connection for an auxiliary drive is provided on the marine transmission. According to the invention, the marine transmission comprises an electric motor as an auxiliary drive, as well as a second intermediate shaft and a planetary gear. The electric motor can be connected to the second intermediate shaft of the marine transmission via the planetary gear.

[0007] The planetary gear is required to reduce the relatively high speeds of the electric motor to speeds at which a propeller shaft can be driven via an intermediate shaft and the gear ratios of a conventional marine gearbox. In this way, conventional basic gearboxes of marine gearboxes can be used and upgraded with an additional drive. With the help of the planetary gear, a high gear ratio can be achieved between the electric motor and the intermediate shaft of the marine gearbox with a relatively small installation space requirement. This in turn enables the use of a high-speed electric motor as the electric machine. A high-speed electric motor also has relatively small dimensions in relation to its power. Consequently, a marine gearbox can be used for a hybrid drive, i.e.with an internal combustion engine as the main propulsion engine and an electric motor as the auxiliary drive, which advantageously requires little installation space. In particular, compared to conventional propulsion arrangements in ships, in which an internal combustion engine is used as the auxiliary drive, the proposed marine transmission with the electric motor requires considerably less installation space.

[0008] The term "connectable" means that the components mentioned in this context can be connected to one another in such a way that torque and rotational movement can be transmitted via this connection. The components do not have to be permanently or permanently connected to one another. Instead, they can be separably connected to one another, for example, via a switchable clutch, as explained in more detail below for a preferred embodiment.

[0009] According to the invention, an output gear arranged on the output shaft engages with a first drive pinion, a second drive pinion, and a third drive pinion. The first drive pinion is connectable to the main drive shaft via a first powershift clutch. The second drive pinion is connectable to the first intermediate shaft via a second powershift clutch, and the third drive pinion is connected in a rotationally fixed manner to the second intermediate shaft. The output gear is thus connectable to the electric machine via the third drive pinion and the second intermediate shaft.

[0010] Consequently, the propeller can be driven by the electric motor via the second intermediate shaft, the third drive pinion, and the output gear. The first and second powershift clutches can, for example, each be designed as a multi-disk friction clutch or as a multi-disk clutch with an inner disk carrier and an outer disk carrier.

[0011] The outer plate carrier of the first powershift clutch can serve as an input element and be rigidly connected to the main drive shaft, while the inner plate carrier of the first powershift clutch is rigidly connected to the first drive pinion. The inner plate carrier of the first powershift clutch can also be designed as a single piece with the first drive pinion. The outer plate carriers of the first and second powershift clutches can each have external teeth that mesh with one another, so that the outer plate carrier of the second powershift clutch is continuously driven via the outer plate carrier of the first powershift clutch. The outer plate carrier of the second powershift clutch can be designed as a single piece with the first intermediate shaft, and the inner plate carrier of the second powershift clutch can be designed as a single piece with the second drive pinion.The third drive pinion can be constructed in one piece with the second intermediate shaft. "Integral construction" means that the components are each manufactured from a single blank. The design variants mentioned in this paragraph advantageously reduce the number of components and the required installation space. This avoids adverse manufacturing tolerances during the production and assembly of the individual parts.

[0012] In practice, marine transmissions are frequently used in which an output gear arranged on an output shaft engages with a plurality of drive pinions, and drive power is selectively transmitted to the output shaft via one of the drive pinions. The above-mentioned arrangement of the components mentioned therefore enables simple integration of the present invention into existing marine propulsion systems and the use of proven components. This also allows a large number of identical parts to be used, which leads to cost advantages. This advantage can be exploited even more effectively if the first drive pinion, the second drive pinion, and the third drive pinion have the same number of teeth, according to a further preferred embodiment. The three drive pinions mentioned can therefore, in particular, also be designed identically.This means that the gear ratio when driving from one of the three drive pinions to the output shaft is always the same.

[0013] Furthermore, the marine transmission can have a switchable clutch via which the third drive pinion can be connected to the electric machine. This advantageously allows different operating modes for operating the proposed marine transmission or drive arrangement. Operating modes are possible in which the electric machine is coupled to the output shaft of the marine transmission, and other operating modes in which the electric machine is decoupled from the output shaft. For example, a purely electric drive can be implemented in which the ship is driven exclusively by the electric machine. In addition, the output shaft can also be driven solely by the main propulsion motor or by the main propulsion motor and the electric machine simultaneously. To achieve this, the switchable clutch is provided in the drive arrangement, with which the electric machine can be coupled and uncoupled.The arrangement of the switchable clutch in the marine transmission allows for a compact design of the drive assembly. The switchable clutch is also preferably designed to be power-shiftable, for example, in the form of a friction disc clutch. However, a non-power-shiftable, positive-locking clutch is also conceivable, in which the speeds during coupling can be synchronized via the speed control of the electric motor. A positive-locking clutch can be designed more compactly than a friction clutch.

[0014] It is also conceivable to place a means for connecting and disconnecting the electric motor at a different location in the drive train, for example, at the planetary gear. However, the preferred arrangement of a switchable clutch in the marine transmission, particularly adjacent to the third drive pinion, allows as many components of the drive train as possible to remain stationary with the electric motor when the electric motor is not in use, eliminating the need to accelerate and decelerate. This allows for energy savings.

[0015] To further increase the gear ratio in the electric machine's drive train, a spur gear stage is arranged between the planetary gear and the second intermediate shaft. This allows the electric machine to operate at particularly high speeds. As explained above, higher speeds of the electric machine allow for compact dimensions of the electric machine relative to its output power.

[0016] The compact dimensions of the electric machine lead to a further advantage, namely its low weight, or rather its low mass. This in turn allows the electric machine to be flange-mounted directly onto the marine gearbox. For this option, it is preferably provided that the marine gearbox has a housing, and that the housing has a flange for fastening the electric machine. This eliminates the need for additional fastening elements or foundations for the electric machine in the ship's hull. This allows a marine gearbox according to the invention with an additional drive to be retrofitted into an existing ship without having to make any changes to the hull. The marine gearbox can be completely assembled with the electric machine and installed as a single unit in a ship's hull. This simplifies installation work.The flange mentioned can, for example, be arranged on a partial housing of the planetary gear if the planetary gear is designed as a separate unit, as explained further below.

[0017] According to another preferred embodiment, the planetary gear unit and / or the spur gear stage can each be designed as a separate structural unit. This means that a base gear unit and the planetary gear unit or the spur gear stage, which are designed as separate structural units, each have their own sub-housing. The sub-housings together form the housing of the marine gear unit.

[0018] The basic transmission can, for example, comprise the main drive shaft, a first and a second intermediate shaft, two powershift clutches and an output shaft as well as a sub-housing with bearings for the aforementioned components. The design with separate components enables a so-called modular concept or design. Identical components, such as the basic transmission and its sub-housing, can be used for various applications in various combinations with the other separate components. In the present case, for example, an identical sub-housing of the basic transmission with the main drive shaft, at least a first intermediate shaft and an output shaft can be used for applications with and without the aforementioned electric motor. This enables higher quantities of identically usable components and consequently cost savings.If the planetary gear unit is designed as a separate unit, its design can be adapted to different types of electrical machines without having to modify the basic gear unit. For example, a planetary gear unit can have one or more planetary gear sets, allowing for different gear ratio ranges and / or a reversal of rotation direction for different applications.

[0019] Finally, the present invention comprises a drive arrangement for a marine propulsion system with a main propulsion engine and a marine transmission configured according to one of the embodiments described above. In addition to its function as an auxiliary drive, the electric machine can also be used as a generator, for example, by being driven by the main propulsion engine via the marine transmission.

[0020] In the following, the invention and its advantages are explained in more detail with reference to the embodiment shown in the attached figure.

[0021] The Fig. 1 a schematic representation of a drive arrangement according to the invention with a marine transmission.

[0022] The Fig. 1The drive arrangement shown comprises a marine transmission 1 with a main drive shaft 3, which is connected to a main drive motor 2 via a non-switchable clutch 19. The main drive shaft 3 is arranged coaxially with an output shaft of the main drive motor 2. The non-switchable clutch 19 can essentially consist of two screw flanges screwed together, which are rigidly fastened to the respective associated shaft end. The main drive motor 2 is typically designed as an internal combustion engine and serves as the drive source for the propulsion of an associated vessel during the majority of the travel time. The marine transmission 1 further comprises a first intermediate shaft 4, a second intermediate shaft 5 and an output shaft 6, which in the present embodiment are all arranged parallel to the main drive shaft 3. A propeller shaft 20 with a propeller 21 fastened thereto can be driven via the output shaft 6.For this purpose, the output shaft 6 is connected to the propeller shaft 20 via a non-switchable coupling 22.

[0023] An output gear 14 arranged on the output shaft 6 is continuously engaged with a first drive pinion 11, a second drive pinion 12, and a third drive pinion 13. The first drive pinion 11 is connectable to the main drive shaft 3 via a first powershift clutch 15. The second drive pinion 12 is connectable to the first intermediate shaft 4 via a second powershift clutch 16. In the present embodiment, the first and second powershift clutches 15 and 16 are identical.

[0024] The third drive pinion 13 is connected in a rotationally fixed manner to the second intermediate shaft 5. In this example, the third drive pinion 13 is rigidly connected to the second intermediate shaft 5. The first, second, and third drive pinions 11, 12, 13 are all identical in this embodiment, thereby reducing their manufacturing costs.

[0025] An electric motor 7 is provided on the marine transmission 1 as an auxiliary drive. The electric motor 7 is connectable to the second intermediate shaft 5 of the marine transmission 1 via a planetary gear 8. A spur gear stage 9 is arranged between the planetary gear 8 and the second intermediate shaft 5, thereby realizing an even higher transmission ratio between the electric motor 7 and the output shaft 6.

[0026] The marine transmission 1 further comprises a switchable clutch 10, via which the third drive pinion 13 can be connected to the electric machine 7. The switchable clutch 10 can be controlled by a control unit. This allows the auxiliary drive train to be coupled and uncoupled from the electric machine 7 as needed or according to the desired operating mode. The switchable clutch 10 is arranged in the housing 17 of the marine transmission 1, directly adjacent to the third drive pinion 13. The arrangement of the switchable clutch 10 directly adjacent to the third drive pinion 13 offers a further advantage. In operating modes in which the electric machine 7 is decoupled from the output shaft 6, all other components of the auxiliary drive train, for example the planetary gear 8 and the spur gear stage 9, can be stationary. This contributes to energy-saving operation.

[0027] The planetary gear unit 8 and the spur gear stage 9 are each designed as separate units. This means that the base gear unit, the planetary gear unit 8, and the spur gear stage 9 each have their own sub-housing 24, 25, and 26, respectively. This allows other drive arrangements to be created with identical components, for example, without the spur gear stage 9. In this case, the sub-housing 24 of the planetary gear unit 8 can be flanged directly to the sub-housing 26 of the base gear unit.

[0028] The housing 17 of the marine transmission 1 accordingly comprises all sub-housings 24, 25 and 26. In other embodiments, the basic transmission can also be arranged together with the planetary transmission 8 and the spur gear stage 9 in a common housing 17.

[0029] A flange 18 for securing the electric machine 7 is provided on the sub-housing 24 of the planetary gear. However, this flange is not used in the present embodiment for flanging the electric machine 7. Instead, the electric machine 7 is arranged at a distance from the planetary gear 8 and connected to it via a non-switchable clutch 23. Reference symbol

[0030] 1 Drive arrangement 2 Main drive motor 3 Main drive shaft 4 First intermediate shaft 5 Second intermediate shaft 6 Output shaft 7 Electric machine 8 Planetary gear 9 Spur gear stage 10 Switchable clutch 11 First drive pinion 12 Second drive pinion 13 Third drive pinion 14 Output gear 15 First powershift clutch 16 Second powershift clutch 17 Housing 18 Flange 19 Non-switchable clutch 20 Propeller shaft 21 Propeller 22 Non-switchable clutch 23 Non-switchable clutch 24 Sub-housing 25 Sub-housing 26 Sub-housing

Claims

1. Marine transmission having a housing (17), having a main drive shaft (3), which is connectable to a main drive motor (2), having a first intermediate shaft (4), having a second intermediate shaft (5) and having an output shaft (6), via which at least one propeller (21) is drivable, wherein an output gearwheel (14) arranged on the output shaft (6) is in engagement with a first drive pinion (11), with a second drive pinion (12) and with a third drive pinion (13), wherein the first drive pinion (11) is connectable to the main drive shaft (3) via a first power-shiftable clutch (15), wherein the second drive pinion (12) is connectable to the first intermediate shaft (4) via a second power-shiftable clutch (16), wherein the third drive pinion (13) is connected to the second intermediate shaft (5) in a manner resistant to torsion, and wherein the marine transmission (1) comprises an electric machine (7) as an auxiliary drive; characterized in that the marine transmission (1) comprises a planetary transmission (8), in that the electric machine (7) is connectable via the planetary transmission (8) to the second intermediate shaft (5) of the marine transmission (1), in that a spur gear stage (9) is arranged between the planetary transmission (8) and the second intermediate shaft (5), and in that the electric machine (7) is located outside the housing (17).

2. Marine transmission according to Claim 1, characterized in that the first drive pinion (11), the second drive pinion (12) and the third drive pinion (13) have the same number of teeth.

3. Marine transmission according to Claim 1 or 2, characterized in that the marine transmission (1) has a shiftable clutch (10), via which the third drive pinion (13) is connectable to the electric machine (7).

4. Marine transmission according to any one of the preceding claims, characterized in that the planetary transmission (8) and / or the spur gear stage (9) are / is designed in each case as a separate constructional unit.

5. Marine transmission according to any one of the preceding claims, characterized in that the marine transmission (1) has a housing (17), and in that the housing (17) has a flange (18) for the securing of the electric machine (7).

6. Drive arrangement for a marine drive having a main drive motor (2) and having a marine transmission (1), which is designed according to any one of the preceding claims.