JP2010254293A - Marine propulsion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a marine propulsion device of a tandem counter-rotating system which is miniaturized, has a high flexibility of layout at the stern, and can provide superior propulsion performance and high steering effect. <P>SOLUTION: This marine propulsion device includes a first propeller 4 at the stern and a turnable pod propulsion device 5 having a second propeller 6. The first propeller and the second propeller form a counter-rotating propeller. The second propeller of the pod propulsion device is formed cylindrically, and the cross sectional shape thereof is within a blade type duct 20. The propulsion effect of the device by the counter-rotation due to the boosting effect in the duct is increased, and the superior propulsion performance is developed by the straightening action of the duct and a thrust during the straight movement. During the turning, a high steering effect can be provided by a steering function by the duct which receives a flow from the first propeller and a thrust force by the second propeller and the duct. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a marine vessel having a first propeller attached to a hull and a pod propulsion device having a second propeller that is pivotally attached to the outside of the hull and constitutes a counter-rotating system. The present invention relates to a propulsion device (tandem type counter rotating system).

  Recently, in order to improve the propulsion efficiency of a ship, a counter-rotating system is used for an electric propulsion ship or the like. As shown in FIG. 5A, the single propeller generates both a rotational flow and an axial flow behind the propeller 100, but only the axial flow contributes to the propulsion. The energy of the rotating flow shown does not contribute to the propulsion. However, as shown in FIG. 5B, in the counter rotating propeller, the rotation directions of the front propeller 201 and the rear propeller 202 are opposite, and the energy of the rotational flow of the front propeller 201 is recovered by the rear propeller 202 to be It is possible to improve propulsion efficiency by rectifying the directional flow, eliminating energy loss due to the rotating flow, and leaving only the axial flow B behind.

  Further, as shown in FIG. 6, as a marine propulsion device, a tandem type dual propulsion device in which a front propeller 301 is provided at the stern of the hull 300 and a pod propulsion device 302 is arranged in tandem behind the front propeller 301 outside the stern of the hull 300. Inversion systems are known. Here, the front propeller 301 is attached to a drive shaft 303 connected to a drive device (engine or electric motor) (not shown) inside the hull 300. The pod propulsion device 302 includes a strut 306 that is pivotally mounted around a vertical axis on a platform 305 provided at the bottom of the stern of the hull 300, a casing 307 that is attached to the lower end of the strut 306, It has a rear propeller 308 that is attached to the front end of the casing 307 and arranged to face the front propeller 301. The rear propeller 308 constitutes the front propeller 301 and a counter-rotating propeller. An electric motor 309 for the pod propulsion device 302 is arranged inside the stern of the hull 300, and is further illustrated inside the strut 306 and the casing 307 via the drive shaft 310 and the gear box 311 on the platform 305. The rear propeller 308 can be driven via a transmission mechanism that does not.

  In the tandem type counter-rotating system shown in FIG. 6, the rear pod propulsion device 302 also has a role as a rudder for the ship. Although the pod propulsion device tends to be enlarged by providing a large ladder 312 or the like, it is described in the following Patent Document 1 or 2 in order to cope with a case where it is difficult to satisfy the required rudder area only with the pod propulsion device. Thus, a technique for providing an auxiliary rudder has also been proposed.

JP 2004-182096 A JP 2006-2119026 A

  As described above, in the tandem type counter-rotating system shown in FIG. 6, the rear pod propulsion device 302 also has a role as a rudder of the ship, and as shown in FIG. In many cases, it is necessary to increase the size of the struts 306 or the like in order to secure the rudder area. In such a case, the strength needs to be improved along with the increase in size, and the cost increases.

  Further, as shown in FIG. 7, when the pod propulsion device 302 is enlarged to secure the rudder area, the space for placing the pod propulsion device 302 has to be secured more widely outside the bottom of the ship bottom, so that the position of the ship bottom increases. As a result, the inside of the ship becomes narrower, and the distance from the position of the forward propeller 301 to the rear end of the stern becomes longer, and the space of the stern part of the ship is reduced as a whole. As a result, the degree of freedom in the layout of the devices is reduced.

  Even if an auxiliary rudder is provided when it is difficult to satisfy the rudder area only with the pod propulsion device as disclosed in the above-mentioned patent document, a space for providing the auxiliary rudder mechanism is also necessary. There will be no change in the layout.

  The present invention aims to solve the above-described conventional problems, and has a compact configuration as a whole, and can provide a sufficient free space at the stern of the hull, thus providing a high degree of freedom in layout and its cargo loading. Marine propulsion with a tandem type counter-rotating system that can increase the amount, can exhibit excellent propulsion performance when going straight, and has a high rudder effect when turning, and can exhibit a stable rudder effect especially from low speed range to operation speed The object is to provide a device.

The marine propulsion device described in claim 1 is:
A first propeller provided at the stern of the hull;
A second propeller that constitutes the first propeller and the contra-rotating propeller is disposed outside the stern of the hull so as to face the first propeller, and has a pivot axis parallel to the vertical direction as a center. A pod propulsion device attached to the hull so that it can turn,
In a marine propulsion device having
The pod propulsion device has a cylindrical shape in which the second propeller is housed inside and has openings in the front and rear, and has a duct having a wing shape in cross section parallel to the water flow. It is said.

The marine propulsion device according to claim 2 is the marine propulsion device according to claim 1,
The pod propulsion device includes a strut attached to a bottom of a stern of a hull so as to be rotatable about the turning axis, and a second propeller attached to a front end of the strut attached to a lower end of the strut. A casing with
A rudder fin is provided on at least one of the rear end portion of the strut and the bottom surface of the casing.

The marine propulsion device according to claim 3 is the marine propulsion device according to claim 1 or 2,
The propeller diameter of the second propeller is set in a range of 86% to 100% of the propeller diameter of the first propeller.

The marine propulsion device described in claim 4 is the marine propulsion device according to any one of claims 1 to 3,
The distance between the first propeller and the second propeller is set in the range of 45% to 80% of the propeller diameter of the first propeller.

According to the marine propulsion device described in claim 1.
Since the duct can be used as the rudder area, the propulsion unit itself becomes compact, and sufficient free space can be secured above the stern of the hull that supports the marine propulsion device. You can increase the volume. Further, the propulsion effect by the double reversal is further improved by the speed increasing effect in the duct, and excellent propulsion performance can be exhibited by the rectifying action and thrust of the duct when going straight. In addition, a high rudder effect can be obtained by utilizing the rudder function by the duct that receives the flow from the first propeller in front of the turn and the propulsive force by the second propeller and duct at the rear.

  In particular, in the low speed range, the water flow hitting the duct is slow and the rudder function is small, but the thrust of the duct is large, so that the effect as a rudder is obtained. Although the duct thrust is small at high speed, the rudder function can be satisfied because the water flow hitting the duct is sufficiently fast. In other words, the rudder function using the water flow hitting the duct and the duct thrust complement each other, and a stable rudder effect can be exhibited from the low speed range to the operation speed.

  According to the marine propulsion device described in claim 2, in the effect by the marine propulsion device according to claim 1, the rudder function is further improved by providing a rudder fin at the rear end portion of the strut of the pod propulsion device. In addition, this structure also makes it possible to reduce the configuration of the entire apparatus while increasing the rudder area and to secure an empty space at the stern of the hull. Further, if a rudder fin is provided on the bottom surface of the pod propulsion device, the rudder function can be improved, and the rudder fin also serves as a reinforcing material for supporting the duct. If the rudder fins are provided on both, the rudder function can be further improved as compared with the case where the rudder fins are provided only on one side.

  According to the marine propulsion device described in claim 3, in the effect of the marine propulsion device according to claim 1 or 2, all the wake flow by the front first propeller flows into the duct at the time of straight traveling. The flow velocity difference between the two is increased, and the thrust force forward increases due to the pressure difference caused by the difference, resulting in an effect of increasing the propulsion device efficiency.

  According to the marine propulsion device described in claim 4, in the effect of the marine propulsion device according to any one of claims 1 to 3, the distance between the first propeller and the second propeller is set to the first propeller. Since it can be freely set within the range of 45% to 80% of the propeller diameter of the propeller, the layout of each part of the apparatus becomes convenient and the effect of increasing the degree of freedom of design is obtained.

1 is a front view of a marine propulsion device according to a first embodiment of the present invention. It is a front view of the modification of 1st Embodiment of this invention. It is a front view of the ship propulsion apparatus which is 2nd Embodiment of this invention. It is a front view of the ship propulsion apparatus which is 3rd Embodiment of this invention. (A) is a perspective view illustrating the energy of propulsion by a rotating flow of a single propeller, and (b) is a perspective view illustrating the energy of propulsion by a counter rotating propeller. It is a front view of the ship propulsion device of the conventional tandem type counter-rotating system. It is a front view at the time of increasing the rudder area in the marine propulsion device of the conventional tandem type counter-rotating system. It is a figure explaining the effect | action when turning the rudder in the ship propulsion apparatus which is embodiment of this invention. In the ship propulsion apparatus which is 5th Embodiment of this invention, it is a figure which shows the code | symbol which shows the dimension of each part, and its setting conditions. In the marine propulsion apparatus which is 5th Embodiment of this invention, it is a figure which shows the experimental result which investigated the relationship between a propeller load degree and propeller efficiency, using the ratio of the front propeller diameter with respect to a rear propeller diameter as a parameter. In the marine propulsion apparatus which is 5th Embodiment of this invention, it is a figure which shows the experimental result which investigated the relationship between the propeller load degree and propeller efficiency, using the ratio of the propeller diameter of the front propeller with respect to the space | interval of the front and rear propellers as a parameter. .

1. First embodiment (FIG. 1)
A marine propulsion device 1 according to the present embodiment shown in FIG. 1 has a first propeller 4 disposed on the stern 3 of a hull 2 and a pod propulsion having a second propeller 6 behind the first propeller 4. A tandem type counter-rotating system in which a device 5 is arranged and a counter-rotating propeller is constituted by the first and second propellers 4 and 6.

  A first propeller 4 that is a forward propeller is attached to a drive shaft 7 that is connected to a drive device (engine or electric motor) (not shown) inside the hull 2. The pod propulsion device 5 is mounted on a platform 8 provided at the bottom of the stern 3 of the hull 2 so as to be pivotable about a vertical axis, and is provided so as to protrude into a space below the stern 3. A strut 9, a casing 10 that is a casing attached to the lower end of the strut 9, and a rear second attached to the front end of the casing 10 and disposed opposite to the front first propeller 4. It has a propeller 6. An electric motor (not shown) for the pod propulsion device 5 is arranged inside the stern 3 of the hull 2, and further inside the strut 9 and the casing 10 via the drive shaft 11 and the gear box 12 on the platform 8. The second propeller 6 can be driven in the opposite direction to the first propeller 4 via a transmission mechanism (not shown).

  In the present embodiment, the pod propulsion device 5 is provided with a duct 20 that houses the second propeller 6. The duct 20 has an opening at the front and rear, and has a cylindrical shape in which the second propeller 6 is housed, and a cross-sectional shape in a cross section S parallel to the water flow is an airfoil. When traveling straight, as shown in FIG. 8A, a pressure difference is generated inside and outside the duct 20 due to the speed increase in the duct 20 by the second propeller 6, and the forward direction is caused by a relatively high pressure applied to the outer surface of the duct 20. A propulsive force is generated in the duct 20 by the component force. When turning, the duct 20 functions as a rudder by receiving the water flow from the first propeller 4 as shown in FIGS. 8B and 8C, and the thrust of the pod propulsion device 5 itself is reduced. By using it together, the rudder effect is further improved.

  The pod propulsion device 5 can be rotated 360 degrees in any direction around a vertical rotation axis together with the struts 9 and can be fixed at a desired rotation angle. The second propeller 6 in the duct 20 is a duct. The propeller can be stably rotated in the flow rectified by 20.

According to the marine propulsion device 1 of the present embodiment, the following effects are obtained.
(1) Since the duct 20 can be used as a rudder area by providing the duct 20 in the pod propulsion device 5 having the second propeller 6, the structure is more compact than a conventional pod propulsion device with a rudder. The propulsion device 1 has a compact configuration as a whole. When traveling straight, excellent propulsion performance can be exhibited by the rectifying action and thrust of the duct 20 as shown in FIG. 8A, and when turning, as shown in FIGS. 8B and 8C. Further, by utilizing the rudder function by the duct 20 that receives the flow from the first propeller 4 at the front and the propulsive force by the second propeller 6 and the duct 20 itself at the rear, a high rudder effect is exhibited.

  (2) In the low speed range (for example, 8 knots or less), as shown in FIG. 8 (b), the water flow hitting the duct 20 is slow and the rudder function is small, but the thrust of the duct 20 is large. Effects can be obtained. In a high speed region (for example, 14 knots or more), the thrust of the duct 20 is small as shown in FIG. 8C, but a sufficient rudder function is obtained because the water flow hitting the duct 20 is sufficiently fast. That is, the rudder function using the water flow hitting the duct 20 and the thrust of the duct 20 itself complement each other, and a stable rudder effect can be exhibited from the low speed range to the operation speed.

  (3) By changing the shape of the airfoil cross section S in the cross section of the duct 20 parallel to the water flow according to the ship operating speed and purpose of use, the above (1) and (2) are more effective. Is obtained.

  (4) Due to the speed increasing effect in the duct 20, the propulsion effect by the double reversal is further improved. That is, the flow velocity of the water flowing into the duct 20 is improved by the water flow of the first propeller 4 in the front, thereby improving the thrust by the nozzle, and the swirling flow by the first propeller 4 in the front is Since the rectification is effected by the rectification effect of the second propeller 6, the propulsion effect is further enhanced.

  (5) Since the pod propulsion device 5 has become compact, there is room in the upper part of the stern 3 of the hull 2 that supports the marine propulsion device 1, and the degree of freedom in layout of equipment and the like increases. The load can also be increased.

  As described above, according to the marine propulsion device 1 of the present example, the compact marine propulsion device 1 that can satisfy the propulsion performance by the rectifying action and the propulsive force of the duct 20 itself while satisfying the necessary rudder function is provided. can do.

  Further, according to the marine propulsion device 1 of the tandem type counter-rotating system according to the present example, since the pod propulsion device 5 with the duct 20 is used, the marine propulsion device 1 is used particularly in a ship that requires a propulsive force in a low speed range. It is effective to do it, and it will be highly effective if it is used on a large ship. That is, since a large thrust can be generated by the second propeller 6 with the duct 20 and the first propeller 4 at the front, the duct 20 is suitable for a tanker, a cement ship or the like. Of course, even when applied to a large ship, not only a sufficient thrust can be obtained in the low speed range, but also the necessary rudder function can be sufficiently satisfied as described above.

  Further, as described above, the marine propulsion device 1 of the present example using the pod propulsion device 5 provided with the duct 20 is compact and has a margin in the space of the stern 3 of the marine vessel. The electric motor 21 is vertically arranged in the space in the stern 3 of the ship, and the output shaft of the electric motor is aligned with the vertical drive shaft (not shown) in the strut 9 of the pod propulsion device 5. Since they can be connected in a state where they are connected, the degree of freedom in layout of equipment and the like in the ship is increased, and the amount of cargo load can be increased.

2. Second Embodiment (FIG. 3)
In the configuration of the first embodiment, when the rudder function is insufficient only with the strut 9 and the duct 20, the rear end of the strut 9 is parallel to the strut 9 in the same plane as the strut 9 as shown in FIG. 3. By attaching the rudder fins 22 as described above, the area serving as the rudder can be expanded to further enhance the rudder function. Further, the structure in which the rudder fin 22 is attached to the rear end portion of the strut 9 as described above is still a compact configuration as the marine propulsion device 1, and sufficient free space is secured in the stern 3 of the hull 2. What can be done is the same as in the first embodiment.

3. Third embodiment (FIG. 4)
In the configuration of the first embodiment, when the rudder function is insufficient with only the strut 9 and the duct 20, the bottom surface of the casing of the pod propulsion device 5 is parallel to the strut 9 in the same plane as the strut 9 as shown in FIG. 4. By attaching the rudder fins 23, the area serving as a rudder can be expanded and the rudder function can be further enhanced. In this case, since the lower rudder fin 23 reinforces the connection state between the duct 20 and the casing 10, the rigidity of the entire apparatus is increased, and the strength is improved.
Further, both the rudder fins 22 of the second embodiment (FIG. 3) and the rudder fins 23 of the third embodiment (FIG. 4) may be installed to further improve the rudder function.

  The rudder fins 22 and 23 of the second and third embodiments described above are substantially quadrangular in the drawing, but the shape is not limited to this, and various shapes can be used to provide a necessary rudder function.

4). Fourth Embodiment In the second and third embodiments, the rudder fins 22 and 23 are fixed to the pod propulsion device 5, but a movable rudder fin capable of swinging in a desired necessary direction is provided in the pod propulsion device 5. For example, by moving the rudder fin in accordance with the state of the flow field, a rectifying effect at the time of propulsion can be obtained, and fine adjustment can be made with respect to the operation of the marine propulsion device 1 with respect to the flow field. Can be demonstrated.

5). Fifth Embodiment As described above, the present invention relates to a marine propulsion device in which a counter rotating system is configured by a front first propeller and a second propeller of a rear pod propulsion device. It is one of the features that is stored in a duct having a predetermined shape. The present inventor conducted various experiments aiming at further improvement of the propulsion device efficiency in the present invention having such a basic configuration, and as a result, as described below, more preferable conditions related to the configuration of the present invention were set. I came to find it.

  First, according to the first experiment by the present inventors, the propulsion device efficiency of the marine propulsion device according to the present invention has a non-linear correlation between the dimensional ratio between the propeller diameters of the two front and rear propellers. Yes, if the dimensional ratio exceeds a certain limit, the increase rate of the propulsion efficiency with respect to the change in the dimensional ratio increases, but in the region below the limit, the increase rate of the propulsion efficiency with respect to the change in the dimensional ratio is very small, It has proved advantageous to take a dimensional ratio above a certain limit in order to obtain high propulsion efficiency. Specifically, as shown in FIG. 9, the propeller diameter d ′ of the second propeller 6 is set to be in the range of 86% to 100% of the propeller diameter d of the first propeller 4. Preferred for obtaining high propulsion efficiency.

In the marine propulsion device according to the present invention, the inventors drive the marine propulsion device while fixing one propeller diameter of the first propeller 4 and the second propeller 6 and appropriately changing the other propeller diameter. The first experiment was conducted, and the relationship between the propeller load degree _CT and the propulsion unit efficiency η was examined. Here, the propeller load degree _CT and the propulsion device efficiency η are defined as in the following equations (1) and (2).
C _T = (8 / π) × (K _T / J ² ) (1)
η = (J · K _T ) / (2π · K _Q ) (2)
Here, _KT is a thrust coefficient, J is a forward rate, and _KQ is a torque coefficient.

FIG. 10 shows a graph of a first experiment result by the present inventors.
In this experiment, the ratio d ′ / d of the propeller diameter d ′ of the second propeller 6 to the propeller diameter d of the first propeller 4 is changed, and the relationship between the propeller load C _T and the propulsion efficiency η is examined. It was. As a result, the propeller efficiency η in the first case where the ratio is set from 86% to 100% is compared with the second case where the ratio is set from 70% to 82%. It showed a significant height over the entire range of C _T. Note that in FIG. 10, are also shown experimental results of the first propeller alone, in this case, unless the propeller load of C _T is small, over substantially the entire range of the propeller load of C _T, In the present invention, the propeller efficiency was low even when the ratio was set from 70% to 82%.

As described above, if the propeller diameter d ′ of the second propeller 6 is set within the range of at least 86% to 100% of the propeller diameter d of the first propeller 4 based on the results of this experiment, it is less than at least 82%. compared with the case where the set, over a wide range of propeller loads degree C _T, high propeller efficiency η than expected value that is obtained has been found from the results in the region of less than 82%.

That, d '= (0.86~1.0) satisfies the × d, higher propeller efficiency η can be obtained over a wide range of propeller loads degree C _T.

  Next, according to a second experiment by the present inventors, it has been found that there is a predetermined front-to-back distance range in which the propulsion efficiency does not decrease with respect to the axial distance between the first and second propellers. did. Conventionally, in the tandem type counter-rotating system as in the present invention, if the distance between the front propeller and the rear propeller is increased, the wake energy of the front propeller is dissipated, so that the counter-rotating effect is caused. The energy recovery effect is considered to be low, and this idea has been established as general technical common sense. For this reason, this is a preconception, and it has become common sense to arrange the two propellers as close as possible, which makes the layout of each part of the marine propulsion device inconvenient and has a low degree of freedom in design. .

FIG. 11 shows a graph of the second experiment result by the present inventors.
In this experiment, the distance x between the first and second propellers 4 and 6 is changed by changing the ratio x / d of the first propeller 6 to the propeller diameter d, and the propeller load degree _CT and the propulsion efficiency η are respectively set. I investigated the relationship. As a result, when the ratio was set between 45% and 80%, the value of the propulsion device efficiency η hardly changed. Considering conventional common sense, if the above ratio is increased from 45% to 80%, the distance between the two front and rear propellers will increase, so the propulsion efficiency η should decrease accordingly. However, in fact, such a phenomenon was not observed, and a result contrary to the conventional common sense that there was no great difference in setting any value was obtained.

Thus, from this experimental result, the distance x between the first and second propellers 4 and 6 is within the range of at least 0.45 to 0.8 in the ratio x / d to the propeller diameter d of the first propeller 6. It is set to a fixed propeller efficiency η over a wide range of propeller loads degree C _T that are guaranteed found.

That is, 0.45 be determined with x in a range satisfying × d ≦ x ≦ 0.8 × d , since the propeller efficiency η over a wide range of propeller load of C _T is substantially constant, this X can be freely determined within the range, so that the layout of each part of the marine propulsion device can be freely performed and the degree of freedom in design can be improved.

DESCRIPTION OF SYMBOLS 1 ... Marine propulsion apparatus 2 ... Hull 3 ... Stern 4 ... 1st propeller 5 ... Pod propulsion apparatus 6 ... 2nd propeller 9 ... Strut 10 ... Casing 20 ... Duct 22, 23 ... Rudder fin S ... Cross section of duct

Claims (4)

A first propeller provided at the stern of the hull;
A second propeller that constitutes the first propeller and the contra-rotating propeller is disposed outside the stern of the hull so as to face the first propeller, and has a pivot axis parallel to the vertical direction as a center. A pod propulsion device attached to the hull so that it can turn,
In a marine propulsion device having
The pod propulsion device has a cylindrical shape in which the second propeller is housed inside and has openings in the front and rear, and has a duct having a wing shape in cross section parallel to the water flow. A marine propulsion device. The pod propulsion device includes a strut attached to a bottom of a stern of a hull so as to be rotatable about the turning axis, and a second propeller attached to a front end of the strut attached to a lower end of the strut. A casing with
The marine propulsion device according to claim 1, wherein a rudder fin is provided on at least one of a rear end portion of the strut and a bottom surface of the casing. 3. The marine propulsion device according to claim 1, wherein a propeller diameter of the second propeller is set in a range of 86% to 100% of a propeller diameter of the first propeller. 4. The distance between the first propeller and the second propeller is set in a range of 45% to 80% of a propeller diameter of the first propeller. The marine propulsion device according to one.

Images