Patent Application
20150158572
The present disclosure relates to a transmission system, and more particularly, to a transmission system of a pod system for a marine vessel.
Many marine vessels employ transmission systems to transmit power from an engine or a motor to one or more propellers. The transmission systems may have rotating components mounted on shafts, for example, a pump or one or more gears mounted on the shaft. Typically, these shafts may be partially or completely positioned rotatably within a housing with the help of bearings.
For example, U.S. Pat. No. 5,509,863 (hereinafter referred to as '863 patent) discloses a transmission for boats, comprising an input shaft, a reversing mechanism and an output shaft. The reversing mechanism is comprised of two bevel gears freely rotatably mounted on an intermediate shaft and engaged with a bevel gear on the input shaft. The bevel gears each cooperate with an individual clutch respectively, by which one of the bevel gears can be locked to the intermediate shaft. The clutches are compressible by a piston that moves in a cylinder which in turn communicates with a hydraulic pump driven by one of the input and intermediate shafts. The output shaft is driven by a bevel gear having a recess in which one of the clutches is partially received.
In cases such as the '863 patent, rotating components of the hydraulic pump are disposed towards one end of the input shaft while the bearings are disposed towards another end of the shaft. Such an arrangement may affect the stability of the input shaft during operation since the load exerted by the operation of the pump and the support offered by the bearings is concentrated at the ends of the input shaft respectively. Thus, a relative arrangement of the rotating components and the bearings on the input shaft may influence various constructional and operational parameters of the transmission system. Therefore, there is a need to evaluate the arrangement of the rotating components with respect to the bearings on the input shaft and improve an overall stability and performance of the transmission system.
In one aspect of the present disclosure, a transmission system includes a housing, an input shaft, a first bearing, a second bearing, and a hydraulic pump. The housing defines a hydraulic circuit therein. The input shaft is rotatably disposed within the housing. The first bearing and the second bearing are mounted on the input shaft, and are spaced apart from each other along a longitudinal axis of the input shaft. The hydraulic pump is disposed between the first bearing and the second bearing. Further, the hydraulic pump is in fluid communication with the hydraulic circuit.
In another aspect, the present disclosure provides a pod system for a marine vessel. The pod system includes an engine having an output shaft, and a transmission system. The transmission system includes a housing, an input shaft, a first bearing, a second bearing, and a hydraulic pump. The housing defines a hydraulic circuit therein. The input shaft is coupled to the output shaft of the engine and rotatably disposed within the housing. The first bearing and the second bearing are mounted on the input shaft, and are spaced apart from each other along a longitudinal axis of the input shaft. The hydraulic pump is disposed between the first bearing and the second bearing. Further, the hydraulic pump is in fluid communication with the hydraulic circuit.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.
The present disclosure relates to a transmission system, and more particularly, to a transmission system of a pod system for a marine vessel.
The pod system 102 includes an engine 106 (shown schematically) having an output shaft 108, and a transmission system 110 coupled to the output shaft 108. Although the present disclosure discloses the engine 106, any type of prime mover commonly known in the art may be used in place of the engine 106 depending on the requirements of a specific application.
The transmission system 110 includes an upper housing 112, a lower housing 114, and an intermediary housing 116 disposed between the upper housing 112 and the lower housing 114. The upper housing 112 and the intermediary housing 116 may be rigidly coupled to each other by means of fasteners commonly known in the art. The lower housing 114 may be rotatably coupled to the intermediary housing 116 such that the lower housing 114 may be rotatable relative to the upper housing 112 and the intermediary housing 116 about a longitudinal axis X-X′ as will be disclosed hereinafter.
The transmission system 110 further includes a steering assembly 131 associated with the steering kingpin 126. The steering assembly 131 may include a steering motor 133, a steering shaft 135, and one or more gear wheels 137. The steering shaft 135 may be powered by the steering motor 133. The gear wheels 137 may be disposed between the steering shaft 135 and the steering kingpin 126 such that the gear wheels 137 may be configured to transmit steering torque from the steering shaft 135 to the steering kingpin 126. Therefore, the steering kingpin 126 may be configured to rotate relative to the intermediary housing 116 and the upper housing 112 about the longitudinal axis X-X′ (as indicated by curved arrow AA). In this manner, the propellers 104 located on the lower housing 114 may be configured to change direction about the longitudinal axis X-X′ to accomplish steering of the marine vessel 100 (Referring to
The upper housing 112 includes a first power transmission shaft 118 rotatably supported by bearings 174, 176 disposed therebetween. The bearings 174, 176 disclosed herein may be, for example, needle bearings or tapered roller bearings. Further, the first power transmission shaft 118 is configured to extend beyond the bearing 176 such that the first power transmission shaft 118 passes through a sleeve 139 disposed in an opening 141 of the steering kingpin 126.
Furthermore, the transmission system 110 includes a first clutch pack 166 and a second clutch pack 168 rotatably disposed about the first power transmission shaft 118 by bearings 178, 180 respectively. The bearings 178, 180 disclosed herein may be, for example, needle bearings or tapered roller bearings. The transmission system 110 further includes a pair of clutch pistons 162, 164 i.e. a first clutch piston 162 and a second clutch piston 164 associated with the first clutch pack 166 and the second clutch pack 168 respectively.
The transmission system 110 further includes an input shaft 136 disposed within the upper housing 112. The input shaft 136 extends along a longitudinal axis Y-Y′ which is disposed laterally with respect to the longitudinal axis X-X′ of the first power transmission shaft 118. The input shaft 136 is configured to be driven by the output shaft 108 of the engine 106. The input shaft 136 includes a first gear component 154 mounted at an end 156 thereof.
Further, the transmission system 110 includes a second gear component 158 and a third gear component 160 rigidly mounted on the first power transmission shaft 118. As illustrated in
The transmission system 110 may further include one or more solenoids 151 (not visible in
As shown in
The lower housing 114 includes a second power transmission shaft 122 rotatably supported by bearings 124, 132 disposed therebetween. Further, the second power transmission shaft 122 is configured to extend beyond the bearing 124 and rigidly couple with the first power transmission shaft 118 via the sleeve 139. The bearings 174, 176 disposed between the first power transmission shaft 118 and the upper housing 112, and the bearings 124, 132 disposed between the second power transmission shaft 122 and the lower housing 114 are configured to provide support to the first and second power transmission shafts 118, 122 from torque loads during operation of the transmission system 110.
Furthermore, the lower housing 114 includes a third power transmission shaft 143 rotatably supported by bearings 134a, 134b disposed therebetween. The second and third power transmission shafts 122, 143 have intermeshing gears 147a, 147b mounted thereon. The gears 147a, 147b transfer power from the second power transmission shaft 122 to the third power transmission shaft 143 during operation of the transmission system 110 such that the third power transmission shaft 143 may be configured to drive a propeller shaft 149 via a bi-directional gear assembly 145 mounted thereon, for example, a pair of opposing bevel gears mounted on the propeller shaft 149.
Therefore, referring to
Referring to
The primary hydraulic pump 142 is disposed about the input shaft 136 and located between the first bearing 138 and the second bearing 140. The primary hydraulic pump 142 includes a first rotor 144 rigidly mounted on the input shaft 136, and a second rotor 146 disposed within the upper housing 112. The second rotor 146 may be configured to co-act with the first rotor 144 to pump a hydraulic fluid therein. In an embodiment, the primary hydraulic pump 142 may be a gerotor pump. The hydraulic fluid disclosed herein may be, for example, oil. For ease in understanding the present disclosure, reference to the hydraulic fluid will be hereinafter made to as “oil”. However, oil disclosed herein is merely exemplary in nature and hence, non-limiting of this disclosure. Any liquid commonly known in the art may be used as the hydraulic fluid of the present disclosure.
The first bearing 138 and the second bearing 140 disposed on either side of the primary hydraulic pump 142 are configured to support the input shaft 136 within the upper housing 112. In an embodiment, the first bearing 138 and the second bearing 140 may be tapered roller bearings such that the first bearing 138 and the second bearing 140 are configured to distribute therebetween, a torque load and/or a bending load in the input shaft 136 during operation of the primary hydraulic pump 142. In an embodiment as shown in
The primary hydraulic pump 142 is configured to pressurize and supply oil for operation and/or lubrication of various components of the transmission system 110. Turning back to
In an embodiment as shown in
The hydraulic circuit 148 disclosed herein may extend into the first power transmission shaft 118 to define a first input line 170, and a second input line 172 therein. As shown in
Many marine vessels employ transmission systems to transmit power from an engine to one or more propellers. The transmission systems may have rotating components mounted on shafts, for example, a pump or one or more gears mounted on the shaft. Typically, these shafts may be partially or completely positioned rotatably within a housing with the help of bearings. However, in some cases, the rotating components may be located towards one end of the shaft while the bearings are located towards another end of the shaft. An overall arrangement of the rotating components and the bearings on the shafts may influence various constructional and operational parameters of the transmission system.
With reference to the transmission system 110 of the present disclosure, the first bearing 138 and the second bearing 140 are spaced apart from each other along the longitudinal axis Y-Y′ of the input shaft 136. Thereafter, the primary hydraulic pump 142 is disposed between the first bearing 138 and the second bearing 140 with the pre-determined first and second distances D1, D2 respectively.
A person having ordinary skill in the art will acknowledge that during operation of the transmission system 110, the first rotor 144 and the second rotor 146 of the primary hydraulic pump 142 may encounter forces while co-acting relative to each other to pump the oil. These forces may be transmitted to the input shaft 136 rotatably supported within the housing by the first and second bearings 138, 140. A positioning of the first and second bearings 138, 140 at the pre-determined first and second distances D1, D2 from the primary hydraulic pump 142 may distribute operating loads substantially evenly along the input shaft 136 such that the input shaft 136 rotates about the longitudinal axis Y-Y′. Therefore, the relative arrangement of the primary hydraulic pump 142, the first bearing 138, and the second bearing 140 may offer more stability to the input shaft 136 during operation of the primary hydraulic pump 142 and may help to increase a service life of the first and second bearings 138, 140.
Further, the configuration of the second and third gear components 158, 160 with the pocket 161 therebetween, and the subsequent arrangement of the first and second clutch packs 166, 168 within the pocket 161 impart compactness to the transmission system 110. Therefore, the transmission system 110 is rendered with a construction that occupies minimal space while performing the required functions in the pod system 102.
While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machine, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.
