Coupling arrangement powertrain marine vessel and land-based vehicle

Abstract

The disclosure concerns a coupling arrangement (8), comprising an input shaft (12) and an output shaft (14), the input and output shafts (12, 14) being aligned along a rotational axis (28), a rotor (30) of an electric machine (6) being arranged concentrically with the rotational axis (28), a sleeve-shaped first piston (36), a sleeve-shaped second piston (38), a first coupling sleeve (40) connected to the first piston (36) and arranged to releasably couple the input shaft (12) to the output shaft (14), a second coupling sleeve (42) connected to the second piston (38) and arranged to releasably couple the rotor (30) of the electric machine (6) to the output shaft (14), and a fixed section (44) arranged between the first and second pistons (36, 38). The first and second pistons are double acting pistons arranged to be displaced in relation to the fixed section.

Description

[0001] Coupling Arrangement Powertrain Marine Vessel and Land-Based

[0002] Vehicle

[0003] TECHNICAL FIELD

[0004] The invention relates to a coupling arrangement for an internal combustion engine and an electric machine. The invention further relates to a powertrain, to a marine vessel comprising a powertrain, and to a land-based vehicle comprising a powertrain.

[0005] BACKGROUND

[0006] Some modern vehicles and / or marine vessels comprise a hybrid power source. Such a hybrid power source can comprise one or more internal combustion engines (ICE) and one or more electric machines. The electric machine may be an electric motor or an electric machine that may operate alternatingly as electric motor or as electric generator.

[0007] An electric motor contributes at least intermittently to a propulsion of the relevant vehicle or marine vessel. When operating as an electric generator, the electric marine charges one or more batteries of the relevant vehicle or marine vessel.

[0008] A powertrain comprising both an ICE and an electric machine comprises a coupling arrangement configured for connecting the ICE and / or the electric machine to an output shaft. The output shaft of the powertrain is connected to propulsive means of the relevant vehicle or marine vessel, such as drive wheels of a vehicle or a propeller of a marine vessel.

[0009] Generally, a coupling arrangement comprises a coupling sleeve arranged to releasably couple two rotatable parts to each other, such as an input shaft to an output shaft. For instance, radially inner splines of the coupling sleeve engage with radially outer splines of the input shaft and with radially outer splines of the output shaft for coupling the input shaft to the output shaft. A shifting fork engages with the coupling sleeve and is moved along an axial direction by an actuator for coupling and uncoupling the input shaft to / from the output shaft.

[0010] Typically, the actuator is arranged radially outside a housing of the coupling arrangement, which means that the shifting fork extends radially through part of the coupling arrangement. This, in turn, means that an axial length of the coupling arrangement must have such length that the axial stroke length applied to the shifting fork by the actuator is provided for.

[0011] SUMMARY It would be advantageous to achieve a coupling arrangement for an internal combustion engine and an electric machine overcoming, or at least alleviating, at least some of the above mentioned drawback related to an axial length of a coupling arrangement. In particular, it would be desirable to provide a compact coupling arrangement for an internal combustion engine and an electric machine. To better address one or more of these concerns, a coupling arrangement, a powertrain, a marine vessel, and a land-based vehicle having the features defined in one or more of the independent claims is / are provided.

[0012] According to an aspect of the invention, there is provided a coupling arrangement for an internal combustion engine and an electric machine. The coupling arrangement comprises an input shaft connectable to the internal combustion engine and an output shaft, the input and output shafts being aligned along a rotational axis and a rotor of the electric machine being arranged concentrically with the rotational axis. The coupling arrangement further comprises a sleeve-shaped first piston arranged concentrically with the rotational axis, a sleeve-shaped second piston arranged concentrically with and radially outside the sleeveshaped first piston, a first coupling sleeve connected to the sleeve-shaped first piston and arranged to releasably couple the input shaft to the output shaft, a second coupling sleeve connected to the sleeve-shaped second piston and arranged to releasably couple the rotor of the electric machine to the output shaft, and a fixed section arranged circumferentially between the sleeve-shaped first and second pistons. The sleeve-shaped first piston is a double acting piston arranged to be hydraulically or pneumatically displaced in relation to the fixed section. The sleeve-shaped second piston is a double acting piston arranged to be hydraulically or pneumatically displaced in relation to the fixed section.

[0013] Since the coupling arrangement comprises the sleeve-shaped first and second pistons arranged concentrically with the rotational axis, the first coupling sleeve arranged to releasably couple the input shaft to the output shaft, and the second coupling sleeve arranged to releasably couple the rotor of the electric machine to the output shaft, and since the sleeve-shaped first piston is a double acting piston and the sleeve-shaped second piston is a double acting piston - the sleeve-shaped first and second pistons form actuators for the respective first and second coupling sleeves, which actuators are suited for being arranged within a housing of the coupling arrangement. Thus, the coupling arrangement is configured for an axial stroke of each of the sleeve-shaped first and second pistons to be accommodated within a housing of the coupling arrangement. Accordingly, the coupling arrangement for an internal combustion engine and an electric machine is configured for being compact. The coupling arrangement for an internal combustion engine, ICE, and an electric machine, EM is herein also simply referred to as the coupling arrangement.

[0014] The coupling arrangement is configured for forming part of a powertrain of a vehicle or a marine vessel.

[0015] For instance, the coupling arrangement may be configured for being arranged between an ICE and a transmission. That is, an output shaft of an ICE is directly or indirectly, such as via a clutch, connectable to the input shaft of the coupling arrangement or the output shaft of the ICE forms the input shaft of the coupling arrangement. The output shaft of the coupling arrangement is directly or indirectly connectable to a transmission.

[0016] In a powertrain of a marine vessel, the output shaft of the coupling arrangement may be connected via a propeller shaft directly to a propeller of the vessel or alternatively, again via a transmission.

[0017] In a powertrain of a land-based vehicle, the output shaft of the coupling arrangement may be connected via a propeller shaft and one or more transmissions to drive wheels of the vehicle.

[0018] The coupling arrangement may form part of a hybrid powertrain, the hybrid powertrain comprising the ICE and the EM.

[0019] The coupling arrangement may comprise the EM. As such the coupling arrangement may be retrofitted in an existing powertrain to provide a hybrid powertrain.

[0020] The EM may operate solely as an electric motor. Alternatively, the EM may operate alternating ly as electric motor or as electric generator.

[0021] When operating as an electric motor, the EM contributes at least partly to a propulsion of the relevant land-based vehicle or marine vessel. When operating as an electric generator, the EM charges one or more batteries of the relevant vehicle or marine vessel. When operating as an electric generator, the EM may be driven by the ICE. A further option, in case of the hybrid power train including the coupling arrangement being installed in a land-based vehicle, the EM may be driven by drive wheels of the powertrain. For instance, when the vehicle is rolling downhill, the drive wheels of the vehicle drive the EM to generate an electric current. Put differently, when the vehicle is rolling downhill, the EM brakes the drive wheels and thereby generates an electric current. Herein an axial direction, an axial extension, or an axial movement is in parallel with the rotational axis of the coupling arrangement. Accordingly, a radial direction, a radial extension, or a radial movement is perpendicularly to the rotational axis.

[0022] As mentioned above, the input shaft is aligned with the output shaft. The rotor of the EM, herein also referred to as the rotor, being arranged concentrically with the rotational axis means that the rotor is positioned around the input shaft and / or the output shaft.

[0023] As mentioned above, the first coupling sleeve is arranged to releasably couple the input shaft to the output shaft. Accordingly, the input shaft can be either in a coupled state, when the input shaft is connected to the output shaft or in an uncoupled state, when the input shaft is not connected to the output shaft.

[0024] Similarly, since the second coupling sleeve is arranged to releasably couple the rotor of the electric machine to the output shaft, the EM can be either in a coupled state, when the EM is connected to the output shaft or in an uncoupled state, when the EM is not connected to the output shaft.

[0025] When the EM is in the uncoupled state, the input shaft and the output shaft are rotatable independently of the EM.

[0026] The input shaft and the EM may both be in their respective coupled states simultaneously. Accordingly, when so, and when arranged in a powertrain, the ICE and the EM drive the output shaft simultaneously.

[0027] The sleeve-shaped first piston may alternatively be referred to as the first piston. The sleeveshaped second piston may alternatively be referred to as the second piston.

[0028] The sleeve-shaped first and second pistons, each have a generally sleeve-like form and as such, enable their arrangement concentrically with the rotational axis and with each other.

[0029] The first and second pistons are displaceable back and forth between axial end positions by hydraulic or pneumatic power. As mentioned above, the first and second pistons are double acting pistons. A double acting piston is displaceable by hydraulic or pneumatic fluid in two opposite directions. This, as opposed to a single acting piston which is displaceable by hydraulic or pneumatic fluid in one single direction and, which in the opposite direction is non-hydraulically or non-pneumatically displaceable, such as by an external force or by a return spring.

[0030] The fixed section arranged circumferentially between the sleeve-shaped first and second pistons is stationary during use of the coupling arrangement. That is, the fixed section does neither rotate around the rotational axis nor is it movable along the axial direction.

[0031] The fixed section is fixed in relation to a housing of the coupling arrangement. The fixed section is directly or indirectly connected to the housing of the coupling arrangement.

[0032] Thus, the first and second pistons are axially displaceable in relation to the fixed section. The first and second pistons are axially movable along the fixed section. Moreover, the first and second pistons are displaceable in relation to the input and out shafts and in relation to the rotor of the EM.

[0033] The fixed section being arranged circumferentially between the first and second pistons means that also the fixed section is arranged concentrically with the rotational axis.

[0034] The first coupling sleeve may be connected to the sleeve-shaped first piston via a first connecting member. Such a first connecting member is short in a radial direction in comparison with a traditional shifting fork extending to outside a housing of a coupling arrangement. Namely, since the first piston is arranged concentrically with the rotational axis, the first piston is arranged close to the rotational axis, which means that there is a comparatively short distance between the first piston and the first coupling sleeve.

[0035] The first coupling sleeve may comprise inner splines arranged to releasably engage with outer splines comprised in the input shaft and in the output shaft, respectively.

[0036] The second coupling sleeve may be connected to the sleeve-shaped second piston via a second connecting member. Such a second connecting member is short in a radial direction in comparison with a traditional shifting fork extending to outside a housing of a coupling arrangement. Namely, since the second piston is arranged concentrically with the rotation axis, the second piston is arranged close to the rotational axis, which means that there is a comparatively short distance between the second piston and the second coupling sleeve.

[0037] The second coupling sleeve may comprise inner splines arranged to releasably engage with outer splines comprised in the output shaft and with outer splines associated with the rotor of the electric machine.

[0038] According to embodiments, a first circumferential chamber and a second circumferential chamber may be formed between the sleeve-shaped first piston and the fixed section. At least one first conduit may fluidly connect to the first circumferential chamber and at least one second conduit may fluidly connect to the second circumferential chamber. In this manner, the first piston may be provided as a double acting piston.

[0039] Hydraulic or pneumatic fluid may be supplied to the first circumferential chamber via the first conduit and may also be expelled therefrom via the first conduit. Hydraulic or pneumatic fluid may be supplied to the second circumferential chamber via the second conduit and may also be expelled therefrom via the second conduit.

[0040] According to embodiments, a third circumferential chamber and a fourth circumferential chamber may be formed between the sleeve-shaped second piston and the fixed section. At least one third conduit may fluidly connect to the third circumferential chamber and at least one fourth conduit may fluidly connect to the fourth circumferential chamber. In this manner, the second piston may be provided as a double acting piston.

[0041] Hydraulic or pneumatic fluid may be supplied to the third circumferential chamber via the third conduit and may also be expelled therefrom via the third conduit. Hydraulic or pneumatic fluid may be supplied to the fourth circumferential chamber via the fourth conduit and may also be expelled therefrom via the fourth conduit.

[0042] According to embodiments, the rotor of the electric machine may be arranged radially outside the output shaft. In this manner, the rotor of the EM may be positioned axially displaced from the first and second coupling sleeves in order for the second coupling sleeve to engage with the rotor of the EM.

[0043] According to some embodiments, the coupling arrangement may comprise the electric machine.

[0044] More specifically, the coupling arrangement may comprise the rotor of the EM and a stator of the EM, the rotor and the stator being arranged within a housing of the coupling arrangement. According to such embodiments, the coupling arrangement may be utilised for modifying an ICE powertrain to a hybrid powertrain. The coupling arrangement may in such case replace a current coupling arrangement of an ICE powertrain. Thus, the compact nature of the present coupling arrangement is beneficial.

[0045] As mentioned above, due to utilising the second sleeve-shaped piston for connecting the electric machine to the output shaft of the coupling arrangement, instead of an actuator arranged radially outside a housing of the coupling arrangement, the compact coupling arrangement is provided. That is, a coupling arrangement that more easily can be fitted into an existing powertrain for replacing a current coupling arrangement e.g., a coupling arrangement between an ICE and a transmission.

[0046] Naturally, also when utilising the coupling arrangement in an initially dedicated hybrid powertrain, the compact nature of the coupling arrangement may be beneficial.

[0047] According to some embodiments, the coupling arrangement may comprise a displacement arrangement configured for displacing the sleeve-shaped second piston from a first axial position in which the second coupling sleeve connects the electric machine to the output shaft to a second axial position in which second coupling sleeve is positioned to disconnect the electric machine from the output shaft. In this manner, an uncoupling of the EM from the output shaft may be provided e.g., in case the second piston would become inoperable.

[0048] For instance, in a hybrid powertrain of a marine vessel such a displacement arrangement may be utilised for manually disconnecting the EM from the output shaft in order to drive the output shaft with the ICE only. This may be a safety measure that prevents an inoperable EM and inoperable second piston from hindering propulsion of the relevant marine vessel.

[0049] For instance, the displacement arrangement may comprise a rotatable ring, which upon being rotated a partial turn about the rotational axis affects the second piston e.g. via at least one cam surface.

[0050] The rotatable ring may be configured to be manually rotated.

[0051] According to embodiments, the displacement arrangement may be further configured for displacing the sleeve-shaped first piston from a first axial position in which the first coupling sleeve is disconnected from the output shaft to a second axial position in which first coupling sleeve is positioned to connect the input shaft to the output shaft. In this manner, the displacement arrangement may be utilised for connecting the input shaft to the output shaft.

[0052] For instance, if in addition to the second piston also the first piston is inoperable, it may be ensured that with the displacement arrangement, the input shaft may be connected to the output shaft. Propulsion by means of the ICE thus, may be ensured in a hybrid powertrain comprising the coupling arrangement.

[0053] According to a further aspect there is provided a powertrain comprising an internal combustion engine, an electric machine, and a coupling arrangement according to any one of aspects and / or embodiments discussed herein, wherein the internal combustion engine is connected to the input shaft of the coupling arrangement.

[0054] According to a further aspect there is provided a marine vessel comprising a powertrain according to any one of aspects and / or embodiments discussed herein.

[0055] According to a further aspect there is provided a land-based vehicle comprising a powertrain according to any one of aspects and / or embodiments discussed herein.

[0056] Further features of, and advantages with, the invention will become apparent when studying the appended claims and the following detailed description.

[0057] BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Various aspects and / or embodiments of the invention, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which:

[0059] Figs. 1a and 1b schematically illustrate powertrains according to embodiments,

[0060] Fig. 2a illustrates a land-based vehicle according to embodiments,

[0061] Fig. 2b illustrates a marine vessel according to embodiments,

[0062] Figs. 4a - 4d illustrate cross sections through a portion of a coupling arrangement, and

[0063] Figs. 5a - 5c illustrate a coupling arrangement according to embodiments.

[0064] DETAILED DESCRIPTION

[0065] Aspects and / or embodiments of the invention will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and / or clarity. Figs. 1a and 1 b schematically illustrate powertrains 2 according to embodiments.

[0066] Each of the powertrains 2 comprises an internal combustion engine, ICE 4, an electric machine, EM 6, and a coupling arrangement 8 according to any one of aspects and / or embodiments discussed herein.

[0067] As shown in Fig. 1a, some embodiments of the powertrain 2 comprise propulsive devices in the form of drive wheels 10 (only one drive wheel 10 is shown). Such embodiments of the powertrain 2 may be comprised in a land-based vehicle as discussed below with reference to Fig. 2a.

[0068] As shown in Fig. 1b, some embodiments of the powertrain 2 comprise a propulsive device in the form of a marine propeller 11 . Such embodiments of the powertrain 2 may be comprised in a marine vessel as discussed below with reference to Fig. 2b.

[0069] The ICE 4 is connected to an input shaft 12 of the coupling arrangement 8. An output shaft 14 of the coupling arrangement 8 connects directly or indirectly to the propulsive devices 10, 11 of the respective powertrains 2.

[0070] The powertrain 2 is a hybrid powertrain since it comprises both the ICE 4 and the EM 6. The powertrain 2 may comprise more than one ICE and / or more than one EM.

[0071] The EM 6 is arranged in connection with the coupling arrangement 8 or alternatively forms part of the coupling arrangement 8.

[0072] A battery 16 supplies electric power to the EM 6. Optionally, if the EM 6 is operable as an electric generator, it may be driven by the ICE 4 or the drive wheels 10 for charging the battery 16.

[0073] Other propulsive device than a marine propeller may be comprised in the powertrain 2 e.g., a propulsive device in the form of a pump-jet, also referred to as hydrojet or water jet, comprising e.g. a ducted propeller, a centrifugal pump, or a mixed flow pump.

[0074] The powertrain 2 may comprise one or more variable or fixed transmissions 20 as indicated in Fig. 1a. The transmissions 20 are arranged for transmitting torque at variable rotational speeds to the drive wheels 10 of the land-based vehicle. In a marine vessel, a propeller shaft 22 of the powertrain 2 may connect the coupling arrangement 8 directly to the marine propeller 11 as shown in Fig. 1b. Optionally, the powertrain 2 may comprise one or more transmissions (not shown).

[0075] The coupling arrangement 8 is discussed further below with reference to Figs. 3 - 5c.

[0076] Fig. 2a illustrates a land-based vehicle 24 according to embodiments.

[0077] The land-based vehicle 24 may be any kind of vehicle configured for land-based propulsion, such as e.g., a bus, a truck, a heavy truck, a car, or a train. In Fig. 2a, the vehicle 24 is illustrated as a heavy load vehicle in the form of a truck.

[0078] The vehicle 24 comprises a powertrain, such as a powertrain 2 discussed above with reference to Fig. 1a and comprising a coupling arrangement 8 according to any one of aspects and / or embodiments discussed herein, such as with reference to Figs. 3 - 5c below.

[0079] Fig. 2b illustrates a marine vessel 26 according to embodiments.

[0080] The marine vessel 26 may be any kind of marine vessel configured for water-based propulsion, such as e.g., a boat, small ship, or other marine vessel propelled by one or more internal combustion engines 4 each having an engine displacement within a range of 4 - 70 litres.

[0081] The marine vessel 26 comprises a powertrain, such as a powertrain 2 discussed above with reference to Fig. 1 b and comprising a coupling arrangement 8 according to any one of aspects and / or embodiments discussed herein, such as with reference to Figs. 3 - 5c below.

[0082] Fig. 3 schematically illustrates a cross section through a portion of a coupling arrangement 8 according to embodiments.

[0083] The coupling arrangement 8 may form part of a powertrain 2 as discussed above with reference to Figs. 1a - 2b. Accordingly, in the following reference is also made to Figs. 1a - 2b.

[0084] The coupling arrangement 8 is for an internal combustion engine 4 and an electric machine

[0085] 6. That is, in use of the coupling arrangement 8, the ICE 4 and / or the EM 6 are coupled to a relevant powertrain 2 in order to provide propulsive power to the powertrain 2. Also, by means of the coupling arrangement 8 the ICE 4 and / or the EM 6 are uncoupled from the powertrain 2.

[0086] The coupling arrangement 8 comprises an input shaft 12 that is connectable to the ICE 4 and an output shaft 14 that is connectable to downstream components of the relevant powertrain. That is, when the coupling arrangement 8 is arranged in a powertrain, the input shaft 12 is connected to the ICE and the output shaft 14 is connected to downstream components of the powertrain. The input and output shafts 12, 14 are aligned along a rotational axis 28.

[0087] A rotor 30 of the electric machine 6 is arranged concentrically with the rotational axis 28. As will be discussed further below, by means of the coupling arrangement 8, the rotor 30 is either coupled to the output shaft 14 or uncoupled from the output shaft 14.

[0088] A stator 32 of the EM 6 is fixed in relation to a housing 34 of the coupling arrangement 8. The stator 32 may be directly or indirectly connected to the housing 34.

[0089] The coupling arrangement 8 may comprise the EM 6.

[0090] The coupling arrangement 8 further comprises a sleeve-shaped first piston 36 arranged concentrically with the rotational axis 28 and a sleeve-shaped second piston 38 arranged concentrically with the first piston 36 and the rotational axis 28 as well as radially outside the sleeve-shaped first piston 36.

[0091] The coupling arrangement 8 further comprises a first coupling sleeve 40 connected to the first piston 36 and a second coupling sleeve 42 connected to the second piston 38. The first coupling sleeve 40 is arranged to releasably couple the input shaft 12 to the output shaft 14. The second coupling sleeve 42 is arranged to releasably couple the rotor 30 of the EM 6 to the output shaft 14.

[0092] Moreover, the coupling arrangement 8 comprises a fixed section 44 arranged circumferentially between the first and second pistons 36, 38. Accordingly, also the fixed section 44 arranged concentrically with the rotational axis 28.

[0093] The fixed section 44 is directly or indirectly connected to the housing 34.

[0094] The fixed section 44 may comprise one or more parts. In the positions of the first piston 36 and the first coupling sleeve 40 shown in Fig. 3, the input shaft 12 is coupled to the output shaft 14 via the first coupling sleeve 36 and in the positions of the second piston 38 and the second coupling sleeve 42, the rotor 30 of the EM 6 is uncoupled from the output shaft 14.

[0095] Thus, in the position shown in Fig. 3, the input shaft 12 is in a coupled state i.e., when the input shaft 12 is connected to the output shaft 14. Conversely, in an uncoupled state, the input shaft 12 is not connected to the output shaft 14.

[0096] In the position shown in Fig. 3, the rotor 30 in an uncoupled state i.e., when the rotor 30 is not connected to the output shaft 14. Conversely, in a coupled state, the rotor 30 of the EM 6 is coupled to the output shaft 14.

[0097] The input and output shafts 12, 14, the rotor 30, as well as the first and second coupling sleeves 40, 42, are rotatable about the rotational axis 28.

[0098] The fixed section 44 is stationary in relation to the housing 34 of the coupling arrangement 8.

[0099] The first and second pistons 36, 38 do not rotate about the rotational axis 28 but are movable between respective end positions along an axial direction i.e., in a parallel with the rotational axis 28.

[0100] Each of the first and second pistons 36, 38 is a double acting piston arranged to be hydraulically or pneumatically displaced in relation to the fixed section 44. The displacements of the first and second pistons 36, 38 are along the axial direction.

[0101] Thus, the first and second pistons 36, 38 form actuators for the first and second coupling sleeves 40, 42. Since these actuators are sleeve-shaped and arranged concentrically with the rotational axis 28 and with each other, they are devised for being arranged within the housing 34 of the coupling arrangement 8. Moreover, each of the first and second pistons 36, 38 is arranged within a radial extension of the rotor 30 of the EM 6. At least one of the pistons 36, 38 may also overlap in an axial direction with the rotor 30.

[0102] Accordingly, the coupling arrangement 8 is configured for an axial stroke of the actuators in the form of the first and second pistons 36, 38 to be accommodated within the housing 34. The coupling arrangement 8 is therefore compact. One or more first connecting members 46 connect the first piston 36 with the first coupling sleeve 40. Since the first piston 36 is arranged concentrically with the rotational axis 28 and within the housing 34, such one or more first connecting members 46 may be kept short. Similarly, one or more second connecting members 48 connect the second piston 38 with the second coupling sleeve 42. Since the second piston 38 is arranged concentrically with the rotational axis 28 and within the housing 34, such one or more second connecting members 48 may be kept short. However, since the second piston 38 is arranged radially outside the first piston 36, the one or more second connecting members 48 may be longer than the one or more first connecting members 46.

[0103] In these embodiments, the one or more first and second connecting members 46, 48 are fixedly connected to the respective first and second pistons 36, 38 while they are slidably connected with the first and second coupling sleeves 40, 42 to permit a relative rotation between the first and second connecting members 46, 48 and the first and second coupling sleeves 40, 42. Alternative arrangements for relative rotation between the first and / or second connecting members and / or the first and / or second coupling sleeves may be provided.

[0104] The first and second coupling sleeves 40, 42 comprise radially arranged inner splines configured to engage with radially outer splines. The input shaft 12, the output shaft 14, and a portion of the rotor 30 comprise radially outer splines configured to engage with the inner splines of the first and second coupling sleeves 40, 42. Such inner and outer splines are commonly known and thus, not specifically shown in Fig. 3.

[0105] Figs. 4a - 4d illustrate cross sections through a portion of the coupling arrangement 8 discussed above with reference to Figs. 1a - 3. Accordingly, in the following reference is also made to Figs. 1a - 3.

[0106] A first circumferential chamber 50 and a second circumferential chamber 52 are formed between the sleeve-shaped first piston 36 and the fixed section 44. At least one first conduit 54 fluidly connects to the first circumferential chamber 50 and at least one second conduit 56 fluidly connects to the second circumferential chamber 52.

[0107] Via the at least one first conduit 54, hydraulic or pneumatic fluid is supplied to, and conducted from, the first circumferential chamber 50. Similarly, via the at least one second conduit 56 hydraulic or pneumatic fluid is supplied to, and conducted from, second first circumferential chamber 52. Thus, the first piston 36 is configured as a double acting piston. It is movable back and forth between axial end positions by hydraulic or pneumatic fluid being supplied to either the first or the second circumferential chamber 50, 52.

[0108] In Figs. 4a - 4d, the first piston 36 is in an end position provided by hydraulic or pneumatic fluid having been supplied to the first circumferential chamber 50 via the first conduit 54. The volume of the first circumferential chamber 50 has thus, increase while displacing the first piston 36 to the illustrated end position. During the displacement of the first piston 36 towards the illustrated end position, hydraulic or pneumatic fluid is expelled from the second circumferential chamber 52 via the second conduit 56 as the volume of the second circumferential chamber 52 decreases. In a corresponding manner, during displacement of the first piston 36 towards its opposite end position, hydraulic or pneumatic fluid is supplied to the second circumferential chamber 52, the volume of which increases, while hydraulic or pneumatic fluid is expelled from the first circumferential chamber 50, the volume of which decreases.

[0109] According to embodiments, such as the illustrated embodiments, a portion of the at least one first conduit extends through the fixed section 44 to the first circumferential chamber 50, and a portion of the at least one second conduit 56 extends through the fixed section 44 to the second circumferential chamber 52. In this manner, the first and second conduits 54, 56 leading to the respect at least one first and second circumferential chambers 50, 52 may be conveniently provided.

[0110] A third circumferential chamber 58 and a fourth circumferential chamber 60 are formed between the sleeve-shaped second piston 38 and the fixed section 44. At least one third conduit 62 fluidly connects to the third circumferential chamber 58 and at least one fourth conduit 64 fluidly connects to the fourth circumferential chamber 60.

[0111] Via the at least one third conduit 62, hydraulic or pneumatic fluid is supplied to, and conducted from, the third circumferential chamber 58. Via the at least one fourth conduit 64, hydraulic or pneumatic fluid may be supplied to, and conducted from, the fourth circumferential chamber 60.

[0112] In Figs. 4a - 4d, the second piston 38 is in an end position provided by hydraulic or pneumatic fluid having been supplied to the third circumferential chamber 58 via the third conduit 62. The volume of the third circumferential chamber 58 has thus, increase while displacing the second piston 38 to the illustrated end position. During the displacement of the second piston 38 towards the illustrated end position, hydraulic or pneumatic fluid is expelled from the fourth circumferential chamber 60 via the fourth conduit 64 as the volume of the second circumferential chamber 52 decreases. In a corresponding manner, during displacement of the second piston 38 towards its opposite end position, hydraulic or pneumatic fluid is supplied to the fourth circumferential chamber 60, the volume of which increases, while hydraulic or pneumatic fluid is expelled from the third circumferential chamber 58, the volume of which decreases.

[0113] According to embodiments, such as the illustrated embodiments, a portion of the at least one third conduit 62 extends through the fixed section 44 to the third circumferential chamber 58, and a portion of the fourth conduit 64 extends through the fixed section 44 to the fourth circumferential chamber 60. In this manner, the third and fourth conduits 62, 64 leading to the respect at least one third and fourth circumferential chambers 58, 60 may be conveniently provided.

[0114] Generally, the first and second pistons 36, 38 are positioned adjacent to the fixed section 44.

[0115] The first, second, third, and fourth circumferential chambers 50, 52, 58, 60 may extend at least partially circumferentially along the fixed section 44. Alternatively, one or more of these circumferential chambers 50, 52, 58, 60 may be formed by a number of separate respectively interconnected chambers positioned circumferentially along the fixed section 44.

[0116] The first, second, third, and fourth circumferential chambers 50, 52, 58, 60 are sealed against the fixed section 44 e.g., with O-rings.

[0117] A non-shown control arrangement controls the flow of hydraulic or pneumatic fluid via the first, second, third, and fourth conduits 54, 56, 62, 64 to and from the respective first, second, third, and fourth circumferential chambers 50, 52, 58, 50 for controlling the movement of the first and second pistons 36, 38 between their respective two axial end positions. Consequently, the control arrangement controls the positions of the first and second couplings sleeves and the coupling and uncoupling of the input shaft 12 and the EM 6 to the output shaft 14.

[0118] Figs. 5a - 5c illustrate a coupling arrangement 8 according to embodiments. Fig. 5a show a cross section through part of the coupling arrangement 8. Fig. 5b shows a partial cross section through a portion of the coupling arrangement 8. Fig. 5c shows a displacement arrangement 66 of the coupling arrangement 8.

[0119] The coupling arrangement 8 of these embodiments resembles in much the coupling arrangement 8 discussed above with reference to Figs. 3 - 4d. Accordingly, in the following mainly the differences will be discussed.

[0120] Again, the coupling arrangement comprises an input shaft 12, an output shaft 14, the input and output shafts 12, 14 being aligned along a rotational axis 28, a rotor 30 of an electric machine 6, a sleeve-shaped first piston 36, a sleeve-shaped second piston 38, a first coupling sleeve 40 connected to the first piston 36, a second coupling sleeve 42 connected to the second piston 38, and a fixed section 44 arranged circumferentially between the first and second pistons 36, 38. Again, each of the first and second pistons 36, 38 is a double acting piston arranged to be hydraulically or pneumatically displaced in relation to the fixed section 44.

[0121] In these embodiments, the coupling arrangement 8 comprises a displacement arrangement 66. The displacement arrangement 66 is configured for displacing the sleeve-shaped second piston 38 from a first axial position in which the second coupling sleeve 42 connects the electric machine 6 to the output shaft 14 to a second axial position in which second coupling sleeve 38 is positioned to disconnect the electric machine 6 from the output shaft 14.

[0122] Specifically, in the first axial position, the second coupling sleeve 42 connects the rotor 30 of the EM 6 to the output shaft 14 and in the second axial position, the rotor 30 of the EM 6 is disconnected from the output shaft 14.

[0123] Accordingly, the displacement arrangement 66 is configured for uncoupling the EM 6 from the output shaft 14. The displacement arrangement 66 thus, may be utilised for emergency uncoupling of the EM 6 in case hydraulic or pneumatic fluid cannot be supplied to the second piston 38 or if the second piston 38 would become inoperable for other reasons.

[0124] Thus, during use of the coupling arrangement 8 in a powertrain, due to the coupling arrangement 8 comprising the displacement arrangement 66, it may be ensured that the EM 6 does not hinder propulsion by the ICE via the input shaft 12 to the output shaft 14 in case the second piston 38 should become inoperable.

[0125] In Figs. 5a and 5b, the second piston 38 is shown in its second axial position. Moreover, the displacement arrangement 66 may be further configured for displacing the sleeve-shaped first piston 36 from a first axial position in which the first coupling sleeve 40 is disconnected from the output shaft 14 to a second axial position in which first coupling sleeve 40 is positioned to connect the input shaft 12 to the output shaft 14.

[0126] Thus, the displacement arrangement 66 may be utilised not only for uncoupling of the EM 6 but also for engaging the input shaft 12 with the output shaft 14. The displacement arrangement 66 thus, may be utilised for emergency coupling of the input shaft 12, and a thereto connected ICE of a powertrain, to the output shaft 14 in case hydraulic or pneumatic fluid cannot be supplied to the first piston 36 or if the first piston 36 would become inoperable for other reasons.

[0127] In Figs. 5a and 5b, the first piston 36 is shown in its second axial position.

[0128] In the illustrated embodiments, the displacement arrangement 66 comprises a rotatable ring 68 arranged concentrically with the rotational axis 28 and a cam follower 70 extending in parallel with the rotational axis 28. The rotatable ring 68 comprises a cam surface 72. The cam follower 70, at a first end portion 74 thereof, abuts against the cam surface 72. The cam follower 70, at a second end portion 76 thereof, is configured to engage with the sleeveshaped second piston 38.

[0129] In this manner, as indicated in Fig. 5c, by partial rotation of the rotatable ring 68 for the first end portion 74 of the cam follower 70 to follow the cam surface 72, the cam follower 70 is displaced in parallel with the rotational axis 28 and thus, together with the cam follower 70 its second end portion 76 is displace in parallel with the rotational axis 28. Since the second end portion 76 is configured to engage with the second piston 38, the second piston 38 is displaced from its first end position to its second end position. The rotation of the rotatable ring 68 and the displacement of the second end portion 76 of the cam follower 70 are indicated with arrows in Fig. 5c.

[0130] With reference e.g., to the lower portion of Fig. 5b, the second end portion 76 and the second piston 38 are shown separated from each other i.e. , as when the displacement arrangement 66 is in a rotational position ready for displacing the second piston 38. The second piston 38 however, is in its second axial position e.g., having been brought into the second axial position by hydraulic or pneumatic actuation. On the other hand, with the second piston 38 in its first axial position, the second end portion 76 of the cam follower will abut, and thus, engage with the second piston 38, for displacement thereof into the second axial position by means of the displacement arrangement 66, should so be required.

[0131] In a similar manner, the second end portion 76 of the cam follower 70 may be configured to engage with the first piston 36 for displacing it from its first axial position to its second axial position.

[0132] The first axial position / s from which the displacement arrangement 66 displaces the first and / or second pistons 36, 38 and the second axial position / s, to which the displacement arrangement 66 displaces the first and / or second pistons 36, 38 may correspond to the first and second end positions that the first and second pistons 36, 38 reach by supply of hydraulically or pneumatically fluid to the first, second, third, and fourth circumferential chambers 50, 52, 58, 60.

[0133] The cam surface 72 is an axial surface of the rotatable ring 68. That is, the cam surface 72 faces in a axial direction of the coupling arrangement 8.

[0134] In this manner, the first end portion 74 of the cam follower 70 will abut against the axial surface, which entails that the cam surface 72 and the first end portion 74 of the cam follower 70 are subjected to axial forces, which are transferred to the second piston 38 and / or the first piston 36 for axial displacement thereof. This may be beneficial from a load distribution point of view, since any substantial bending stress may be avoided in the cam follower 70.

[0135] According to embodiments, such as the illustrated embodiments, the cam follower 70 is guided in the fixed section 44. In this manner, it may be ensured that the cam follower 70 is movable along a straight path. A separate part dedicated for guiding the cam follower 70 is not required. Instead, the fixed section 40 is utilised.

[0136] According to embodiments, such as the illustrated embodiments, the rotatable ring 68 is positioned axially along the fixed section 44. In this manner, the cam follower 70 may extend through the fixed section 44 for its first end portion 74 to about against the cam surface 72 of the rotatable ring 68.

[0137] According to embodiments, such as the illustrated embodiments, the rotatable ring 68 is journaled in the fixed section 44. In this manner, it may be ensured that the rotatable ring 68 will be rotatable concentrically about the rotational axis 28. In the illustrated embodiments, the displacement arrangement 66 comprises three cam followers 70 circumferentially evenly distributed along the rotatable ring 68. Each of the cam followers 70 is guided in the fixed section 44.

[0138] In the illustrated embodiments, also, a second rotatable ring 68’ is provided, concentrically with the rotatable ring 68. Thus, six cam surfaces 72, 72’ are provided for each of the first end portions 74 of the cam followers 70 to abut against two cam surfaces 72, 72’. The six cam surfaces 72, 72’ are provided in pairs, one cam surface 72, 72’ of each pair provided on one each of the rotatable rings 68, 68’. Accordingly, the first end portion 74 of the cam follower 70 will abut against both cam surfaces 72, 72’ of a pair of cam surfaces 72, 72’. With the cam follower 70 extending between the two rotatable rings 68, 68’, bending stress may thus, be avoided in the cam follower 70.

[0139] The two rotatable rings 68, 68’ are linked together such that they are simultaneously rotatable.

[0140] In order to provide manual actuation of the displacement arrangement 66, according to some embodiments, the displacement arrangement 66 may comprise an actuating rod 78 extending in parallel with a tangent of the rotatable ring 68. The actuating rod 78 may be pivotably connected to the rotatable ring 68. A pulling or pushing movement of the actuating rod 78 rotates the rotatable ring 68 about the rotational axis 28 causing the cam follower 70 to follow the cam surface 72 and displace the sleeve-shaped second piston 38 towards its second axial position.

[0141] The rotation about the rotational axis 28 actuated by pulling or pushing at the actuating rod 78 may be a partial rotation about the rotational axis 28 such as, a partial rotation corresponding to a circumferential length of the cam surface 72.

[0142] To increase leverage, the actuating rod 78 may be connected to the rotatable ring 68 via a lever 80. The actuating rod 78 is indirectly pivotably connected to the rotatable ring 68 at a pivot point 82 between the lever 80 and the actuating rod 78.

[0143] In use of the coupling arrangement 8, the actuating rod 78 extends from the coupling arrangement such that an end portion of the actuating rod 78 is graspable by a user for pulling and / or pushing at the actuating rod 78. The coupling arrangement 8 is suitable for forming part of a hybrid powertrain of a marine vessel. The displacement arrangement 66 may be utilised for manually disconnecting the EM 6 from the output shaft 14 in order to drive the output shaft 14 with the ICE only. Also, the displacement arrangement 66 may be utilised for manually connecting the input shaft 12 with the output shaft 14. Thus, propulsive power may be maintained via the ICE for the relevant marine vessel in case the EM 6 or the first and / or second pistons 36, 38 should malfunction.

[0144] Also, in a land-based vehicle, the coupling arrangement 8 may form part of a hybrid powertrain. Again, the displacement arrangement 66 may be utilised for manually disconnecting the EM 6 from the output shaft 14 in order to drive the output shaft 14 via the input shaft 12 with the ICE only.

[0145] It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the invention, as defined by the appended claims.

Claims

CLAIMS1 . A coupling arrangement (8) for an internal combustion engine (4) and an electric machine (6), comprising an input shaft (12) connectable to the internal combustion engine (4) and an output shaft (14), the input and output shafts (12, 14) being aligned along a rotational axis (28) and a rotor (30) of the electric machine (6) being arranged concentrically with the rotational axis (28), the coupling arrangement (8) further comprising a sleeve-shaped first piston (36) arranged concentrically with the rotational axis (28), a sleeve-shaped second piston (38) arranged concentrically with, and radially outside, the sleeve-shaped first piston (36), a first coupling sleeve (40) connected to the sleeveshaped first piston (36) and arranged to releasably couple the input shaft (12) to the output shaft (14), a second coupling sleeve (42) connected to the sleeve-shaped second piston (38) and arranged to releasably couple the rotor (30) of the electric machine (6) to the output shaft (14), and a fixed section (44) arranged circumferentially between the sleeve-shaped first and second pistons (36, 38), wherein the sleeve-shaped first piston (36) is a double acting piston arranged to be hydraulically or pneumatically displaced in relation to the fixed section (44), and wherein the sleeve-shaped second piston (38) is a double acting piston arranged to be hydraulically or pneumatically displaced in relation to the fixed section (44).

2. The coupling arrangement (8) according to claim 1 , wherein a first circumferential chamber (50) and a second circumferential chamber (52) are formed between the sleeve-shaped first piston (36) and the fixed section (44), and wherein at least one first conduit (54) fluidly connects to the first circumferential chamber (50) and at least one second conduit (56) fluidly connects to the second circumferential chamber (52).

3. The coupling arrangement (8) according to claim 2, wherein a portion of the at least one first conduit (54) extends through the fixed section (44) to the first circumferential chamber (50), and wherein a portion of the at least one second conduit (56) extends through the fixed section (44) to the second circumferential chamber (52).

4. The coupling arrangement (8) according to any one of the preceding claims, wherein a third circumferential chamber (58) and a fourth circumferential chamber (60) are formed between the sleeve-shaped second piston (38) and the fixed section (44), and wherein at least one third conduit (62) fluidly connects to the third circumferential chamber (58) and at least one fourth conduit (64) fluidly connects to the fourth circumferential chamber (60).

5. The coupling arrangement (8) according to claim 4, wherein a portion of the at least one third conduit (62) extends through the fixed section (44) to the third circumferential chamber (58), and wherein a portion of the fourth conduit (64) extends through the fixed section (44) to the fourth circumferential chamber (60).

6. The coupling arrangement (8) according to any one of the preceding claims, comprising a displacement arrangement (66) configured for displacing the sleeve-shaped second piston (38) from a first axial position in which the second coupling sleeve (42) connects the electric machine (6) to the output shaft (14) to a second axial position in which second coupling sleeve (42) is positioned to disconnect the electric machine (6) from the output shaft (14).

7. The coupling arrangement (8) according to claim 6, wherein the displacement arrangement (66) comprises a rotatable ring (68) arranged concentrically with the rotational axis (28) and a cam follower (70) extending in parallel with the rotational axis (28), wherein the rotatable ring (68) comprises a cam surface (72), wherein the cam follower (70), at a first end portion (74) thereof, abuts against the cam surface (72), and wherein the cam follower (70), at a second end portion (76) thereof, is configured to engage with the sleeve-shaped second piston (38).

8. The coupling arrangement (8) according to claim 7, wherein the cam surface (72) is an axial surface of the rotatable ring (68).

9. The coupling arrangement (8) according to claim 7 or 8, wherein the cam follower (70) is guided in the fixed section (44).

10. The coupling arrangement (8) according to any one of claims 7 - 9, wherein the rotatable ring (68) is positioned axially along the fixed section (44).11 . The coupling arrangement (8) according to claim 10, wherein the rotatable ring (68) is journaled in the fixed section (44).

12. The coupling arrangement (8) according to any one of claims 7 - 11 , wherein the displacement arrangement (66) comprises an actuating rod (78) extending in parallel with a tangent of the rotatable ring (68), wherein the actuating rod (78) is pivotably connected to the rotatable ring (68), and wherein a pulling or pushing movement of the actuating rod (78) rotates the rotatable ring (68) about the rotational axis (28) causing the cam follower (70) to follow the cam surface (72) and displace the sleeve-shaped second piston (38) towards its second axial position.

13. The coupling arrangement (8) according to any one of claims 6 - 12, wherein the displacement arrangement (66) is further configured for displacing the sleeve-shaped first piston (36) from a first axial position in which the first coupling sleeve (40) is disconnected from the output shaft (14) to a second axial position in which first coupling sleeve (40) is positioned to connect the input shaft (12) to the output shaft (14).

14. A powertrain (2) comprising an internal combustion engine (4), an electric machine (6), and a coupling arrangement (8) according to any one of the preceding claims, wherein the internal combustion engine (4) is connected to the input shaft (12) of the coupling arrangement (8).

15. A marine vessel (26) comprising a powertrain (2) according to claim 14.

16. A land-based vehicle (24) comprising a powertrain (2) according to claim 14.

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