Propulsion device and moving body

Abstract

This propulsion device is provided with: a cylindrical part disposed such that the axis thereof extends in a front-rear direction under the water surface, and forming a flow path; a shaft part disposed inside the cylindrical part and extending in the axial direction; a propeller which is attached to the shaft part, has a plurality of propeller blades that extends in the radial direction of the axis in the flow path and that are arranged in the circumferential direction of the axis, and which is able to rotate around the axis; a plurality of struts which are provided in the flow path on at least one of the front side and the rear side with respect to the propeller, extend in the radial direction and are arranged in the circumferential direction, and supports the shaft part. The plurality of struts extend in a vertical direction and are disposed symmetrical with respect to a line of symmetry that passes through the axis. Among angular intervals between the struts, at least one angular interval is different from the angular interval between the other struts, and at least one strut is disposed on each side in the vertical direction with respect to a horizontal plane that extends in the horizontal direction so as to pass through the axis line.

Description

Technical Field

[0001] The present disclosure relates to a propulsion device and a moving body.

[0002] Priority is claimed on Japanese Patent Application No. 2023-084458, filed May 23, 2023, the content of which is incorporated herein by reference.Background Art

[0003] PTL 1 discloses a propulsion device with a nozzle attached to a ship or the like. In the propulsion device, struts that support a propeller shaft are provided in front of and behind the propeller blade. A plurality of struts are provided side by side in a circumferential direction around the propeller shaft so that angular intervals are uniform. The propeller shaft is stably supported by the plurality of struts arranged at equal intervals.Citation ListPatent Literature

[0004] [PTL 1] U.S. Patent No. 9821896Summary of InventionTechnical Problem

[0005] However, in a propulsion device of PTL 1, fluid resistance increases as the number of struts increases. Therefore, there is a concern that efficiency of the propulsion device is decreased. In addition, in a case where, during rotation of a propeller, a region in which the propeller blade and the strut overlap simultaneously is large, fluctuation of thrust is significant. Therefore, the number of struts is determined in consideration of the number of propeller blades. Further, it is necessary to consider a strength of the propulsion device, and a degree of freedom in design is greatly limited.

[0006] The present disclosure has been made to solve the above-described problem, and an object thereof is to provide a propulsion device and a moving body capable of improving a degree of freedom in design.Solution to Problem

[0007] In order to solve the above-described problem, a propulsion device comprising: a tubular portion disposed below a water surface such that an axis line extends in a front-rear direction and forming a flow passage in which a front side is an upstream side and a rear side is a downstream side; a shaft portion disposed inside the tubular portion and extending in a direction of the axis line; a propeller mounted on the shaft portion, having a plurality of propeller blades extending in a radial direction of the axis line in the flow passage and arranged in a circumferential direction of the axis line, and being rotatable around the axis line; a plurality of struts provided in the flow passage at at least one of a front side and a rear side with respect to the propeller, extending in the radial direction and arranged in the circumferential direction, and supporting the shaft portion; wherein the plurality of struts are arranged to be symmetrical with respect to a symmetry line that extends in a vertical direction and passes through the axis line, at least one angular interval among angular intervals between the struts is different from the angular intervals between the other struts, and, at least one of the struts is arranged on each of both sides in the vertical direction with respect to a horizontal plane extending in a horizontal direction through the axis line.

[0008] A moving body according to the present disclosure comprises the propulsion device and is movable in at least one of on water or underwater.Advantageous Effects of Invention

[0009] According to a propulsion device and a moving body of the present disclosure, a degree of freedom in design can be improved.Brief Description of Drawings

[0010] FIG. 1 is a schematic view showing a schematic configuration of a moving body according to a first embodiment of the present disclosure. FIG. 2 is a schematic view showing a propulsion device according to the first embodiment of the present disclosure as viewed from a left side. FIG. 3 is a schematic view showing an arrangement of propeller blades according to the first embodiment of the present disclosure as viewed from a front side. FIG. 4 is a schematic view showing an arrangement of struts according to the first embodiment of the present disclosure as viewed from a front side. FIG. 5 is a schematic view showing another example of the configuration of the struts according to the first embodiment of the present disclosure as viewed from the front side. FIG. 6 is a schematic view showing an arrangement of struts according to a second embodiment of the present disclosure as viewed from a front side. FIG. 7 is a schematic view showing an arrangement of struts according to a third embodiment of the present disclosure as viewed from a front side. FIG. 8 is a schematic view showing a propulsion device according to a fourth embodiment of the present disclosure as viewed from a left side. FIG. 9 is a schematic view showing an arrangement of front struts according to the fourth embodiment of the present disclosure. FIG. 10 is a schematic view showing an arrangement of rear struts according to the fourth embodiment of the present disclosure. FIG. 11 is a schematic view showing a schematic configuration of a moving body according to a modification example of the present disclosure. FIG. 12 is a schematic view showing a propulsion device according to the modification example of the present disclosure as viewed from a left side. FIG. 13 is a schematic view showing a propulsion device according to the modification example of the present disclosure as viewed from a left side. FIG. 14 is a schematic view showing an arrangement of struts according to a modification example of the present disclosure as viewed from a front side. FIG. 15 is a schematic view showing an arrangement of struts according to a modification example of the present disclosure as viewed from a front side. Description of Embodiments <First Embodiment>(Configuration of Moving body)

[0011] Hereinafter, a moving body 1 according to the embodiment of the present disclosure will be described with reference to FIGs. 1 to 4.

[0012] As shown in FIG. 1, the moving body 1 according to the present embodiment is a ship 1a that can move on water. The ship 1a includes a hull 2 and a propulsion device 10.(Hull)

[0013] The hull 2 is a box-shaped structure formed to float on a water surface W. The hull 2 extends in one direction along a horizontal plane. The hull 2 includes a bow 3, a stern 4, and a ship bottom 5. The bow 3 is a portion on one side in a longitudinal direction of the hull 2. The stern 4 is a portion on the other side in the longitudinal direction of the hull 2. The ship bottom 5 constitutes a lower portion of the hull 2. The ship bottom 5 extends in the longitudinal direction of the hull 2 to connect the bow 3 and the stern 4.

[0014] Hereinafter, a vertical direction will be simply referred to as "vertical direction Dv". A direction along the longitudinal direction of the hull 2 is referred to as a front-rear direction Ds, and a direction along a ship width direction of the hull 2 is referred to as a left-right direction Dw. A reference sign "Dvu" is assigned to an upper side, and a reference sign "Dvd" is assigned to a lower side. A reference sign "Dsf" is assigned to a front side, and a reference sign "Dsb" is assigned to a rear side. A reference sign "Dwr" is assigned to a right side, and a reference sign "Dwl" is assigned to a left side.(Propulsion Device)

[0015] The propulsion device 10 is attached to the ship bottom 5. A location at which the propulsion device 10 is installed is not limited to the ship bottom 5. For example, in a case in which the ship 1a is a motorboat, the propulsion device 10 may be provided as a part of an outboard motor mounted on the stern 4. As shown in FIG. 2, the propulsion device 10 comprises a tubular portion 11, a fixing device 12, a shaft portion 13, a propeller 20, a hub 14, and a strut 15.(Tubular Portion)

[0016] The tubular portion 11 is generally called a nozzle or a duct. The tubular portion 11 of the present embodiment is formed in a cylindrical shape. The tubular portion 11 is disposed such that an axis line O extends in the front-rear direction Ds below the water surface W. The tubular portion 11 forms a flow passage F in which the front side Dsf is an upstream side and the rear side Dsb is a downstream side.

[0017] Hereinafter, the axis line O of the tubular portion 11 is simply referred to as an "axis line O", the radial direction of the axis line O is simply referred to as a "radial direction", and the circumferential direction of the axis line O is simply referred to as a "circumferential direction". In addition, unless otherwise specified, the axis line O direction is the same as the front-rear direction Ds and orthogonal to the vertical direction Dv and the width direction Dw.(Fixing Device)

[0018] The fixing device 12 fixes the tubular portion 11 to the hull 2. The fixing device 12 includes a vertical shaft 12a extending downward from the hull bottom 5. The vertical shaft 12a connects the ship bottom 5 and the tubular portion 11. The vertical shaft 12a is provided to be rotatable with respect to the hull 2. By rotating the vertical shaft 12a, the tubular portion 11 can pivot to the left and right.

[0019] The vertical shaft 12a may be fixed to the hull 2.(Shaft Portion)

[0020] The shaft portion 13 is disposed inside the tubular portion 11. The shaft portion 13 is formed in a columnar shape extending in one direction along the axis line O.(Propeller)

[0021] The propeller 20 is mounted on the shaft portion 13 and is attached to be rotatable around the axis line O. In the present embodiment, one propeller 20 is disposed in the tubular portion 11. The propeller 20 includes a propeller hub 21 and a propeller blade 22. The propeller hub 21 is an annular member into which the shaft portion 13 is inserted. The propeller blade 22 extends from the propeller hub 21 to a radially outer side in the flow passage F. The plurality of propeller blades 22 are arranged in the circumferential direction. For example, in the present embodiment, as shown in FIG. 3, six propeller blades 22 are provided.(Hub)

[0022] The hub 14 is provided at an end portion of the shaft portion 13 on the front side Dsf in the axis line O direction. The plurality of struts 15 are provided on the hub 14.(Strut)

[0023] The struts 15 are provided on the front side Dsf of the propeller 20 in the flow passage F. The struts 15 extend radially from the hub 14 and are connected to the tubular portion 11. The plurality of struts 15 are arranged in the circumferential direction. The struts 15 support the shaft portion 13 via the hub 14.

[0024] A posture of the strut 15 can be appropriately selected. However, it is desirable that the struts 15 are disposed to be inclined in the front-rear direction Ds in a direction opposite to the rotation of the propeller 20. By disposing the struts 15 in an inclined manner, a swirling flow in a direction that cancels out the swirling flow generated by the propeller 20 is imparted to the flow inside the tubular portion 11 by the struts 15. The struts 15 may be disposed to be inclined in the front-rear direction Ds in the same direction as the rotation of the propeller 20, or may be disposed to be along the front-rear direction Ds.(Disposition of Struts)

[0025] The plurality of struts 15 are provided according to the following three rules.

[0026] First, the plurality of struts 15 are disposed to be symmetric with respect to a symmetric line L1 that extends in the vertical direction Dv and passes through the axis line O (first condition).

[0027] Second, at least one angular interval of the struts 15 is different from another angular interval between the struts 15 (second condition).

[0028] Third, at least one strut 15 is disposed on both sides in the vertical direction Dv with respect to the horizontal plane HS that extends in the horizontal direction to pass through the axis line O (third condition).

[0029] The number and disposition of the struts 15 can be appropriately changed as long as the rules (first condition, second condition, and third condition) are satisfied.

[0030] In addition to satisfying the three rules, in the present embodiment, the disposition of the struts 15 is determined according to the following rule as one of design guidelines.

[0031] Here, a plurality of division lines L2 that extend in the radial direction and equally divide a region around the axis line O into an odd number in the circumferential direction is considered from the front-rear direction Ds. One division line L2 of the plurality of division lines L2 is set on the symmetric line L1. The division line L2 set to match the symmetric line L1 is used as a reference (0 degrees) for setting the other plurality of division lines L2. Further, the plurality of division lines L2 are set to be symmetric with respect to the symmetric line L1.

[0032] The number of division lines L2 is set according to the number of struts 15.

[0033] For example, in a case in which the number of struts 15 is N (natural number), the number of division lines L2 is (N × 2 - 1). The number of division lines L2 (N × 2 - 1) is different from the number of propeller blades 22. Here, in a case in which an angular interval between the division lines L2 is θ1 degrees, θ 1 = 360 / N × 2 − 1 is established.

[0034] Each of the N struts 15 is disposed at any one of (N × 2 - 1) division lines L2 as viewed from the front-rear direction Ds. In the present embodiment, each strut 15 is disposed such that a center line extending in the radial direction of the strut 15 matches the division line L2 as viewed in the axis line O direction. In this case, for an angular interval between adjacent struts 15, the angular interval between the struts 15 is any of N' × 360 / (N × 2 - 1) degrees where N' is 1 or more and less than N. Accordingly, in the present embodiment, the plurality of struts 15 are disposed such that the angular intervals between the struts 15 are not uniform.

[0035] Hereinafter, a case in which N' is 1 for an angular interval between one set of adjacent struts and N' is 2 for angular intervals between other adjacent struts will be described as a representative.

[0036] Each of the N struts 15 is disposed at any one of (N × 2 - 1) division lines L2 as viewed from the front-rear direction Ds. In this case, only one angular interval (Hereinafter, this angular interval may be referred to as a first angular interval.) among the angular intervals between the adjacent struts 15 is set to θ1=360 / (N×2-1) degrees, and the angular interval (Hereinafter, this angular interval may be referred to as a second angular interval.) between the remaining struts 15 is set to θ2=2×θ1=2×360 / (N×2-1) degrees. Accordingly, in the present embodiment, the plurality of struts 15 are disposed such that only one angular interval among the angular intervals between the struts 15 is different from the angular intervals between the other struts 15.

[0037] In the present embodiment, as shown in FIG. 4, N=3 struts 15 are provided. In this case, the number of division lines L2 is N × 2 - 1 = 5. In addition, the first angular interval θ1 is θ1 = 360 / (N × 2 - 1) = 72 degrees, and the second angular interval θ2 is θ2 = 2 × θ1 = 2 × 360 / (N × 2 - 1) = 144 degrees. In FIG. 4, the propeller 20 is not shown.

[0038] In this case, one of the five division lines L2 is set on the symmetric line L1 extending in the vertical direction Dv. In the example shown in the drawing, the one division line L2 on the symmetric line L1 is positioned above the horizontal plane HS passing through the axis line O. The strut 15 is disposed on the division line L2 set in this manner such that the first angular interval θ1 and the second angular interval θ2 are satisfied.

[0039] The plurality of struts 15 and the division lines L2 may be inverted in the vertical direction Dv with the axis line O as a reference. In this case, the one division line L2 on the symmetric line L1 is positioned below the horizontal plane HS passing through the axis line O.

[0040] In addition, as described above, in the present embodiment, three struts 15 are provided for the six propeller blades 22. That is, in the present embodiment, the propulsion device 10 is designed so that the number of the propeller blades 22 and the number of the struts 15 have a common divisor. However, in a case where the number of the struts 15 is N, the propulsion device 10 is designed such that the number of the propeller blades 22 and the number (N × 2 - 1) of the division lines L2 are relatively prime.(Effects)

[0041] The propulsion device 10 of the present embodiment can exhibit the following effects.

[0042] In the present embodiment, the propulsion device 10 comprises the tubular portion 11, the shaft portion 13, the propeller 20, and the plurality of struts 15. The tubular portion 11 is disposed such that the axis line O extends in the front-rear direction Ds below the water surface W, and forms a flow passage F with the front side Dsf as an upstream side and the rear side Dsb as a downstream side. The shaft portion 13 is disposed inside the tubular portion 11 and extends in the axis line O direction. The propeller 20 is mounted on the shaft portion 13, has a plurality of propeller blades 22 that extend in the radial direction of the axis line O in the flow passage F and are arranged in the circumferential direction of the axis line O, and is rotatable around the axis line O. The plurality of struts 15 are provided on the front side Dsf of the propeller 20 in the flow passage F, extend in the radial direction, are arranged in the circumferential direction, and support the shaft portion 13. The plurality of struts 15 are disposed symmetrically with respect to the symmetry line L1 extending in the vertical direction Dv (first condition). Further, at least one of the angular intervals between the struts 15 is different from the angular interval between the other struts 15 (second condition). Further, at least one strut 15 is disposed on both sides in the vertical direction Dv with respect to the horizontal plane HS that extends in the horizontal direction to pass through the axis line O (third condition).

[0043] In the present embodiment, the plurality of struts 15 are disposed symmetrically with respect to the symmetry line L1 extending in the vertical direction Dv. Accordingly, it is possible to suppress a left-right bias of force caused in the strut 15 during the turning. Therefore, since the force generated in the strut 15 during the pivot is the same on the left and right sides, a bias of a water flow load to one of the left or right side is suppressed, and the turning performance can be sufficiently secured.

[0044] During the rotation of the propeller 20, the flow speed of the flow flowing into the propeller blade 22 is reduced due to the overlap between the strut 15 and the propeller blade 22, and the thrust fluctuates. In the present embodiment, at least one of the angular intervals between the struts 15 is different from the angular interval between the other struts 15. Accordingly, it is possible to reduce a region in which the plurality of struts 15 and the plurality of propeller blades 22 overlap each other. Therefore, the fluctuation of the thrust can be reduced. Further, the efficiency of the propeller 20 can be further improved.

[0045] Further, at least one strut 15 is disposed on both sides in the vertical direction Dv with respect to the horizontal plane HS that extends in the horizontal direction to pass through the axis line O. Accordingly, the shaft portion 13 can be supported from both sides of the vertical direction Dv by the strut 15. Therefore, the strength of the propulsion device 10 can be improved.

[0046] Therefore, according to the present embodiment, even in a case where the number of struts 15 is freely set, the propulsion device 10 can sufficiently exhibit the required function. That is, the design freedom can be improved. For example, the number of struts 15 can be freely determined from the viewpoint of strength regardless of the structure such as the number of propeller blades 22. Therefore, the disposition of the strut 15 according to the present embodiment can be applied to any propeller 20, and thus the degree of freedom in design can be improved. Therefore, the fluctuation of the thrust can be suppressed while the number of struts 15 is minimized to ensure the strength. Since the number of struts 15 is not unnecessarily increased, the resistance of the struts 15 can also be reduced.

[0047] In the present embodiment, each of the N struts 15 is disposed at any one of (N × 2 - 1) division lines L2 that divide the region around the axis line O in the circumferential direction into equal parts. The angular interval between the struts 15 is any of N' × 360 / (N × 2 - 1) degrees when N' is equal to or greater than 1 and less than N.

[0048] According to the present embodiment, since the struts 15 can be disposed based on the division line L2, the positioning of the struts 15 becomes easy. Therefore, the propulsion device 10 can be easily designed.

[0049] In the present embodiment, a case has been described as a representative example in which only one angular interval of the angular intervals between the struts 15 is different from the other angular intervals between the struts 15.

[0050] With such a disposition, the disposition conditions (the first condition, the second condition, and the third condition) of the strut 15 can be easily satisfied. Therefore, the design efficiency can be improved. Since the number of locations where the angular intervals are different can be suppressed to one, the flow rate between the struts 15 is easily controlled.

[0051] In the present embodiment, each of the N struts 15 is disposed at any one of (N × 2 - 1) division lines L2 that divide the region around the axis line O in the circumferential direction into equal parts. One angular interval of the angular intervals between the struts 15 is θ1 = 360 / (N × 2 - 1) degrees, and all the remaining angular intervals between the struts 15 are θ2 = 2 × 360 / (N × 2 - 1) degrees.

[0052] According to the present embodiment, the disposition conditions of the struts 15 can be satisfied merely by setting the division line L2 and disposing the struts 15 on the division line L2. That is, it is possible to easily implement the disposition of the struts 15 in which only one angular interval of the angular intervals between the struts 15 is different from the other angular intervals between the struts 15. Therefore, the manufacturing efficiency can be further improved.

[0053] In the present embodiment, the number of division lines L2 (N × 2 - 1) is different from the number of the propeller blades 22.

[0054] According to the present embodiment, the region in which the division line L2 and the propeller blade 22 overlap with each other simultaneously can be reduced. Since the strut 15 is disposed on the division line L2, the region in which the strut 15 and the propeller blade 22 overlap each other at once can be reduced. Therefore, the fluctuation of the thrust can be further reduced. Therefore, the struts 15 can be disposed more effectively.

[0055] In the present embodiment, the number of the propeller blades 22 and the number of the struts 15 may also have a common divisor (however, the propulsion device 10 is designed such that the number of the propeller blades 22 and the number of the division lines L2 (N × 2 - 1) are relatively prime to each other when the number of the struts 15 is denoted by N).

[0056] According to the present embodiment, compared with the case where the number of propeller blades 22 and the number of struts 15 are limited to having no common divisor (in a case where the number of the propeller blades 22 and the number of the struts 15 are relatively prime to each other), there are more options for the number and arrangement of the propeller blades 22 and the struts 15. Therefore, the degree of freedom in design can be further improved.

[0057] In addition, since the number of the division lines L2 (N × 2 - 1) and the number of the propeller blades 22 are relatively prime to each other, the number of the division lines L2 overlapping with the propeller blades 22 can be suppressed to one. Since the strut 15 is disposed on the division line L2, the number of the struts 15 that overlap with the propeller blade 22 at once can be suppressed to one. Therefore, the fluctuation of the thrust can be further reduced.

[0058] In the first embodiment, the case where N=3 struts 15 are provided has been described, but the present disclosure is not limited to this.

[0059] For example, as shown in FIG. 5, the number of the struts 15 may be N = 5. In this case, the number of the division lines L2 is N × 2 - 1 = 9. In addition, the first angular interval θ1 is θ1 = 360 / (N × 2 - 1) = 40 degrees, and the second angular interval θ2 is θ2 = 2 × θ1 = 2 × 360 / (N × 2 - 1) = 80 degrees.

[0060] In this case, one of the nine division lines L2 is set on the symmetric line L1 extending in the vertical direction Dv. In the example shown in the drawing, the one division line L2 on the symmetric line L1 is positioned above the horizontal plane HS passing through the axis line O. The strut 15 is disposed on the division line L2 set in this manner such that the first angular interval θ1 and the second angular interval θ2 are satisfied.

[0061] The plurality of struts 15 and the division lines L2 may be inverted in the vertical direction Dv with the axis line O as a reference. In this case, the one division line L2 on the symmetric line L1 is positioned below the horizontal plane HS passing through the axis line O.

[0062] In the present modification example, five struts 15 are provided for six propeller blades 22. That is, in the present modification example, the number of the propeller blades 22 and the number of the struts 15 do not have a common divisor. In addition, in a case where the number of the struts 15 is denoted by N, the propulsion device 10 is designed so that the number of the propeller blades 22 are different from the number of the division lines L2 (N × 2 - 1).<Second Embodiment>

[0063] Next, the second embodiment will be described with reference to FIG. 6. The same configurations as those of the above-described embodiment will be designated by the same reference numerals and names, and will not be described in detail. The configurations that will not be described below are the same as those of the above-described embodiment.

[0064] In the propulsion device 110 of the present embodiment, as shown in FIG. 6, the number of the struts 15 is N = 4. FIG. 6 is a diagram corresponding to FIG. 4 of the first embodiment. In FIG. 6, the propeller 20 is not shown.

[0065] In the present embodiment, a plurality of the division lines L2 are set by the same rule as that of the first embodiment, and the struts 15 are disposed on the division lines L2.

[0066] That is, the number of the division lines L2 is set to N × 2 - 1 = 7. In addition, the first angular interval θ1 is θ1 = 360 / (N × 2 - 1) ≈ 51.4 degrees, and the second angular interval θ2 is θ2 = 2 × θ1 = 2 × 360 / (N × 2 - 1) = 102.8 degrees.

[0067] In this case, one of the seven division lines L2 is set on the symmetrical line L1 extending in the vertical direction Dv. In the example shown in the drawing, the one division line L2 on the symmetrical line L1 is located below the horizontal plane HS passing through the axis line O. The strut 15 is disposed on the division line L2 set in this manner such that the first angular interval θ1 and the second angular interval θ2 are satisfied.(Effects)

[0068] The propulsion device 110 of the present embodiment can exhibit the following effects.

[0069] In the present embodiment, the number of the struts 15 is N = 4.

[0070] In the propeller 20, the number of the propeller blades 22 is often 3 to 6. In a case where the number of the propeller blades 22 is typically 3 to 6, it is suitable for securing strength and thrust to set the number of the struts 15 to four and to dispose the struts 15 on the seven division lines L2 as in the present embodiment. Therefore, the present embodiment can be applied to a large number of the propellers 20, and the universality can be achieved.

[0071] Here, for example, it is assumed that six propeller blades 22 are equally (at equal intervals) provided in the circumferential direction for one propulsion device 110. At this time, in a case where three struts are equally provided in the circumferential direction, three propeller blades 22 of the six propeller blades 22 overlap the struts simultaneously during the driving of the propeller 20, and the thrust fluctuates greatly. In a case where four struts are equally provided in the circumferential direction, in a case where the propeller 20 is driven, two propeller blades 22 of the six propeller blades 22 overlap the struts simultaneously, but the number of struts that overlap the propeller blades 22 simultaneously can be reduced as compared with a case where three struts are equally provided in the circumferential direction, and the fluctuation of the thrust can also be suppressed. Further, as in the present embodiment, by disposing four struts 15 unequally in the circumferential direction and disposing one angular interval of the angular intervals between the struts 15 to be different from the other angular intervals between the struts 15, it is possible to suppress the number of the struts 15 overlapping the propeller blades 22 at a time to 1 during the driving of the propeller 20. As a result, the fluctuation of the thrust can be further suppressed.

[0072] Further, it is easy to dispose the plurality of struts 15 symmetrically to the left and right with respect to the symmetric line L1 extending in the vertical direction Dv. Therefore, the present embodiment is suitable from the viewpoint of the structural design because it is easy to design to suppress the left-right bias of the force generated in the strut 15 during the pivot.<Third Embodiment>

[0073] Next, the third embodiment will be described with reference to FIG. 7. The same configurations as those of the above-described embodiment will be designated by the same reference numerals and names, and will not be described in detail. The configurations that will not be described below are the same as those of the above-described embodiment.

[0074] In the propulsion device 210 of the present embodiment, as shown in FIG. 7, in a case where M ≥ N (where M is a natural number), (M × 2 - 1) division lines L2 are set for the N struts 15. The (M × 2 - 1) division lines L2 divide the region around the axis line O in the circumferential direction, as in the first embodiment. The angular interval θ1 between the division lines L2 is θ1 = 360 / (M × 2 - 1) degrees. Each of the N struts 15 is disposed at any of the (M × 2 - 1) division lines L2.

[0075] FIG. 7 shows a case where N = 4 and M = 6, the struts 15 are N = 4 and the division lines L2 are (M × 2 - 1) = 11. The four struts 15 are disposed on the eleven division lines L2 such that the first condition, the second condition, and the third condition are satisfied.

[0076] In the example shown in the drawing, only the two upper struts 15 are disposed such that one division line L2 is positioned between the two struts 15, and the other struts 15 are disposed such that two division lines L2 are positioned between the two struts 15. Therefore, the angular interval (third angular interval) θ3 between the two upper struts 15 is θ3 = 2 × 360 / (M × 2 - 1) = 2 × θ1 ≈ 2 × 32.7 ≈ 65.4 degrees, and the angular interval (fourth angular interval) θ4 between the other struts 15 is θ4 = 3 × 360 / (M × 2 - 1) = 3 × θ1 ≈ 3 × 32.7 ≈ 98.1 degrees.(Effects)

[0077] The propulsion device 210 of the present embodiment can exhibit the following effects.

[0078] In the present embodiment, in a case where M ≥ N, and the N struts 15 are disposed on any of (M × 2 - 1) division lines L2 that equally divide the region around the axis line O in the circumferential direction.

[0079] According to the present embodiment, since the number of options for the number and disposition of the struts 15 becomes large, the degree of freedom of the disposition of the struts 15 can be further increased. For example, in a case where the strength of the propulsion device 10 is insufficient, the number of struts 15 can be increased to improve the strength of the propulsion device 10. In this case, since the number of struts 15 is increased by an even number with respect to the symmetric line L1 that extends in the vertical direction Dv and passes through the axis line O, the left-right symmetry of the struts 15 is not impaired.<Fourth Embodiment>

[0080] Next, the fourth embodiment will be described with reference to FIGs. 8 to 10. The same configurations as those of the above-described embodiment will be designated by the same reference numerals and names, and will not be described in detail. The configurations that will not be described below are the same as those of the above-described embodiment.

[0081] In the propulsion device 310 of the present embodiment, as shown in FIG. 8, the propulsion device 310 is designed with a double structure having two propellers 20 provided side by side in the front-rear direction Ds. The two propellers 20 are provided to be rotatable in opposite directions.

[0082] The number of propeller blades 22 of the two propellers 20 can be appropriately selected. For example, in a case where the number of propeller blades 22 of the propeller 20 on the front side Dsf is defined as X and the number of propeller blades 22 on the rear side Dsb is defined as Y, for example, eight patterns of (X, Y) = (3, 4), (3, 5), (4, 5), (5, 6), (4, 3), (5, 3), (5, 4), and (6, 5) are assumed as the combinations of (X, Y). By setting the number of the propeller blades 22 of each propeller in this way, the number of the front and rear propeller blades 22 simultaneously overlapping each other is reduced, which is effective in reducing the fluctuation of the thrust.

[0083] The struts 15 are provided for the two propellers 20 designed as described above as follows.

[0084] The struts 15 are provided on the front side Dsf and the rear side Dsb with respect to the two propellers. As shown in FIGs. 9 and 10, the disposition of the plurality of struts 15 on the rear side Dsb is a disposition obtained by inverting the disposition of the plurality of struts 15 on the front side Dsf in the vertical direction.

[0085] Hereinafter, among the struts 15, the strut 15 on the front side Dsf of the propeller 20 will be referred to as a front strut 15a, and the strut 15 on the rear side Dsb will be referred to as a rear strut 15b.

[0086] First, the disposition of the front strut 15a will be described.

[0087] The front struts 15a are provided in, for example, four, as shown in FIG. 9. In the present embodiment, the plurality of division lines L2 are set according to the same rule as in the first embodiment, and the front strut 15a is disposed on the division lines L2.

[0088] That is, the number of the division lines L2 is set to N × 2 - 1 = 7. In addition, the first angular interval θ1 is θ1 = 360 / (N × 2 - 1) ≈ 51.4 degrees, and the second angular interval θ2 is θ2 = 2 × θ1 = 2 × 360 / (N × 2 - 1) = 102.8 degrees.

[0089] In this case, one of the seven division lines L2 is set on the symmetrical line L1 extending in the vertical direction Dv. In the example shown in the drawing, the one division line L2 on the symmetrical line L1 is located below the horizontal plane HS passing through the axis line O. The front strut 15a is disposed on the division lines L2 set in this way such that the first angular interval θ1 and the second angular interval θ2 are satisfied.

[0090] The posture of the front strut 15a can be appropriately selected. For example, the front strut 15a is disposed to be inclined with respect to the front-rear direction Ds. Due to the inclination of the front strut 15a, a swirling flow flows into the propeller 20.

[0091] Subsequently, the disposition of the rear strut 15b will be described.

[0092] The rear struts 15b are provided, for example, four in number as shown in FIG. 10, the same number as the front struts 15a. In the present embodiment, a plurality of division lines L2 are set according to the same rule as in the first embodiment, and the rear struts 15b are disposed on the division lines L2.

[0093] That is, the number of the division lines L2 is set to N × 2 - 1 = 7. In addition, the first angular interval θ1 is θ1 = 360 / (N × 2 - 1) ≈ 51.4 degrees, and the second angular interval θ2 is θ2 = 2 × θ1 = 2 × 360 / (N × 2 - 1) ≈ 102.8 degrees.

[0094] In this case, one of the seven division lines L2 is set on the symmetrical line L1 extending in the vertical direction Dv. In the example shown in the drawing, the one division line L2 on the symmetric line L1 is positioned above the horizontal plane HS passing through the axis line O. The rear strut 15b is disposed on the division line L2 set in this way so as to satisfy the first angular interval θ1 and the second angular interval θ2.

[0095] The posture of the rear strut 15b can be appropriately selected. For example, the rear strut 15b is disposed along the front-rear direction Ds. As a result, swirling flow discharged from the propeller 20 is deflected to the straight flow in the front-rear direction Ds.(Effects)

[0096] The propulsion device 310 of the present embodiment can exhibit the following effects.

[0097] In the present embodiment, two propellers 20 are provided side by side in the front-rear direction Ds. The two propellers 20 are provided to rotate in opposite directions. The struts 15 are provided on the front side Dsf and the rear side Dsb with respect to the two propellers 20, and the disposition of the plurality of struts 15 on the rear side Dsb is a disposition obtained by inverting the disposition of the plurality of struts 15 on the front side Dsf in a vertical direction.

[0098] Since the two propellers 20 rotate in opposite directions, the swirling flow discharged from the propeller 20 on the front side Dsf can be canceled by the propeller 20 on the rear side Dsb. Therefore, by inclining the strut 15 on the front side Dsf (front side strut 15a) pivot in the front-rear direction Ds, it is not necessary to impart the swirling flow to the water flow. Thus, the disposition of the strut 15 can be designed by considering only the required strength. Therefore, the degree of freedom in design can be further improved.

[0099] In addition, in a case where the struts 15 are disposed in front of and behind the two propellers 20 arranged in the front-rear direction Ds, it is necessary to determine the number and disposition of the struts 15 by considering the structure of the two propellers 20 in order to sufficiently exhibit the function of the required propulsion device 10, and the study of the number and disposition of the struts 15 is complicated. However, as in the present embodiment, by disposing the propeller 20 on the rear side Dsb by inverting the disposition of the propeller 20 on the front side Dsf, the disposition conditions of each of the struts 15 in front of and behind the propeller 20 can be easily satisfied. Therefore, the manufacturing efficiency can be improved.(Other Embodiments)

[0100] The embodiments of the present disclosure have been described in detail with reference to the drawings hereinbefore. However, the specific configuration is not limited to the embodiments, and includes design changes and the like within a scope not departing from the gist of the present disclosure.

[0101] In the above-described embodiment, the moving body 1 is a ship 1a that moves on the water, but the present disclosure is not limited thereto. For example, as shown in FIG. 11, the moving body 1 may be an ocean research vessel 1b that can move in underwater. In addition, the moving body 1 on which the propulsion device 10 is mounted may be designed to be movable in both on the water and underwater.

[0102] In the above-described embodiment, the case has been described in which the six propeller blades 22 are provided for one propeller 20, but the present disclosure is not limited thereto. The number of the propeller blades 22 can be appropriately changed, and for example, two, three, four, five, seven, eight, or more propeller blades 22 may be provided.

[0103] In the first embodiment, the case has been described in which the number of struts 15 is three or five, and the number of division lines L2 is five or nine. In the second embodiment, the case has been described in which the number of struts 15 is four, and the number of division lines L2 is seven. In the third embodiment, the case has been described in which the number of struts 15 is four, and the number of division lines L2 is 11. However, the present disclosure is not limited thereto. The number of struts 15 and the number of division lines L2 can be appropriately changed.

[0104] In the above-described embodiment, the case has been described in which the strut 15 is provided on the front side Dsf of the propeller 20 in the flow passage F, but the present disclosure is not limited thereto. As shown in FIG. 12, the strut 15 may be provided on the rear side Dsb of the propeller 20 in the flow passage F. In a case in which the strut 15 is disposed on the rear side Dsb of the propeller 20, the strut 15 is disposed along the front-rear direction Ds, and turns swirling flow discharged from the propeller 20 into the direct current in the front-rear direction Ds. As a result, the thrust is generated by the strut 15 on the rear side Dsb, and the thrust of the entire propulsion devices 10, 110, and 210 is increased.

[0105] In addition, as shown in FIG. 13, the strut 15 may be provided on both the front side Dsf and the rear side Dsb of the propeller 20 in the flow passage F.

[0106] In the above-described embodiment, each strut 15 is disposed such that a center line extending in the radial direction of the strut 15 coincides with the division line L2 as viewed in the axial direction O of the axis line O, but the present disclosure is not limited thereto. Since the strut 15 has a thickness in the circumferential direction, at least a part of the strut 15 may be positioned on the division line L2 as viewed in the axial direction O of the axis line O, and it may be said that the "strut 15 is disposed on the division line L2". That is, the angular interval between the struts 15 may be slightly shifted with respect to the angular interval between the corresponding division lines L2.

[0107] In the above-described embodiment, the case where the strut 15 is disposed on the division line L2 has been described, but the present disclosure is not limited thereto. In a case where the disposition of the strut 15 satisfies the first condition, the second condition, and the third condition, the strut 15 may not be disposed on the division line L2. For example, as shown in FIG. 14, as viewed in the front-rear direction Ds, some struts 15 of the plurality of struts 15 may be disposed at positions shifted from the division line L2. In the example of FIG. 14, the strut 15 is disposed at positions of 0 degrees, about 135 degrees, and about 225 degrees with respect to the division lines L2 at 0 degrees, 72 degrees, 144 degrees, 216 degrees, 288 degrees, and 360 degrees.

[0108] In the above-described embodiment, the case where only one angular interval of the angular intervals between the struts 15 is different from the angular intervals between the other struts 15 has been described, but the present disclosure is not limited thereto. In a case where the disposition of the strut 15 satisfies the first condition, the second condition, and the third condition, for example, as shown in FIG. 15, as viewed in the front-rear direction Ds, a plurality of angular intervals (θ1 × 2 degrees) of the angular intervals between the struts 15 may be different from the angular intervals (θ1 degrees) between the other struts 15.<Additional Notes>

[0109] The propulsion devices 10, 110, 210, 310 and the moving body 1 according to each of the embodiments are understood as follows.

[0110] (1) A propulsion device 10, 110, 210, 310 according to a first aspect includes a tubular portion 11 disposed below a water surface W such that an axis line O extends in a front-rear direction Ds and forming a flow passage F in which a front side Dsf is an upstream side and a rear side Dsb is a downstream side; a shaft portion 13 disposed inside the tubular portion 11 and extending in a direction of the axis line O; a propeller 20 mounted on the shaft portion 13, having a plurality of propeller blades 22 extending in a radial direction of the axis line O in the flow passage F and arranged in a circumferential direction of the axis line O, and being rotatable around the axis line O; a plurality of struts 15 provided in the flow passage F at at least one of a front side Dsf and a rear side Dsb with respect to the propeller 20, extending in the radial direction and arranged in the circumferential direction, and supporting the shaft portion 13; in which the plurality of struts 15 are arranged to be symmetrical with respect to a symmetry line L1 that extends in a vertical direction Dv and passes through the axis line O, at least one angular interval among the angular intervals between the struts 15 is different from the angular interval between the struts 15, at least one of the struts 15 is arranged on each of both sides in the vertical direction Dv with respect to a horizontal plane HS extending in a horizontal direction through the axis line O.

[0111] In the present aspect, the plurality of struts 15 are disposed to be symmetrical with respect to the symmetric line L1 that extends in the vertical direction Dv. Accordingly, it is possible to suppress a left-right bias of force caused in the strut 15 during the pivot.

[0112] During the rotation of the propeller 20, the flow speed of the flow flowing into the propeller blade 22 is reduced due to the overlap between the strut 15 and the propeller blade 22, and the thrust is fluctuated. In the present aspect, at least one of the angular intervals between the struts 15 is different from the angular interval between the other struts 15. Accordingly, it is possible to reduce a region in which the plurality of struts 15 and the plurality of propeller blades 22 overlap each other. Therefore, the fluctuation of the thrust can be reduced. Further, the efficiency of the propeller 20 can be further improved.

[0113] Further, at least one strut 15 is disposed on both sides in the vertical direction Dv with respect to the horizontal plane HS that extends in the horizontal direction to pass through the axis line O. Accordingly, the shaft portion 13 can be supported from both sides of the vertical direction Dv by the strut 15. Therefore, the strength of the propulsion devices 10, 110, 210, 310 can be improved.

[0114] Therefore, according to the present aspect, even in a case where the number of struts 15 is freely set, the propulsion device 10, 110, 210, 310 can sufficiently exhibit the required function. That is, the design freedom can be improved. For example, the number of struts 15 can be freely determined from the viewpoint of strength regardless of the structure such as the number of propeller blades 22.

[0115] (2) The propulsion devices 10, 110, 210, 310 according to the second aspect are the propulsion devices 10, 110, 210, 310 according to the first aspect, in which only one angular interval among the angular intervals between the struts 15 is different from the angular interval between the other struts 15.

[0116] According to the present aspect, the disposition condition of the strut 15 according to the first aspect can be easily satisfied. Since the number of locations where the angular intervals are different can be suppressed to one, the flow rate between the struts 15 is easily controlled.

[0117] (3) The propulsion devices 10, 110 according to the third aspect are the propulsion devices 10, 110, 210 according to the first or second aspect, in which each of N struts 15 is arranged on any one of (N × 2 - 1) division lines L2 that equally divide a region around the axis line O in the circumferential direction, and angular intervals between the struts 15 are any of N' × 360 / (N × 2 - 1) degrees, where N' is greater than or equal to 1 and less than N.

[0118] According to the present aspect, since the struts 15 can be disposed based on the division line L2, the positioning of the struts 15 becomes easy.

[0119] (4) The propulsion devices 10, 110 according to the fourth aspect are the propulsion devices 10 and 110 according to the third aspect, in which the number of the division lines L2 (N × 2 - 1) and the number of the propeller blades 22 are relatively prime to each other.

[0120] According to the present aspect, the number of division lines L2 overlapping with the propeller blades 22 can be limited to one. Since the strut 15 is disposed on the division line L2, the number of the struts 15 that overlap with the propeller blade 22 at once can be suppressed to one. Therefore, the fluctuation of the thrust can be further reduced.

[0121] (5) The propulsion devices 10, 110 according to the fifth aspect are the propulsion devices 10, 110, 210 according to the third or fourth aspect, in which the number of the division lines L2 (N × 2 - 1) is different from the number of the propeller blades 22.

[0122] According to the present aspect, the region in which the division line L2 and the propeller blade 22 overlap simultaneously each other can be reduced. Since the strut 15 is disposed on the division line L2, the region in which the strut 15 and the propeller blade 22 overlap each other at once can be reduced. Therefore, the fluctuation of the thrust can be further reduced.

[0123] (6) The propulsion device 110 according to the sixth aspect is the propulsion device 110 according to any one of the third to fifth aspects, in which the number of the struts 15 is N = 4.

[0124] In the propeller 20, the number of the propeller blades 22 is often 3 to 6. In a case where the most common number of the propeller blades 22 is 3 to 6, it is suitable for securing strength and thrust to set the number of the struts 15 to four and to dispose the struts 15 on the seven division lines L2 as in the present aspect. Therefore, the present aspect can be applied to a large number of the propellers 20, and the universality can be achieved. Further, it is easy to dispose the plurality of struts 15 symmetrically to the left and right with respect to the symmetric line L1 extending in the vertical direction Dv. Therefore, the present aspect is suitable from the viewpoint of the structural design because it is easy to design to suppress the left-right bias of the force generated in the strut 15 during turning.

[0125] (7) The propulsion device 210 according to the seventh aspect is the propulsion device 210 according to the first or second aspect, in which in a case where M ≥ N, each of the N struts 15 is arranged on any one of (M × 2 - 1) division lines L2 that equally divide a region around the axis line O in the circumferential direction.

[0126] According to the present aspect, since the number of options for the number and disposition of the struts 15 becomes large, the degree of freedom of the disposition of the struts 15 can be further increased.

[0127] (8) The propulsion device 310 according to the eighth aspect is the propulsion device 310 according to any one of the first to seventh aspects, in which the propeller 20 is provided as two propellers 20 provided side by side in the front-rear direction Ds, the two propellers 20 are provided to rotate in opposite directions to each other, a plurality of the struts 15 are provided on each of a front side Dsf and a rear side Dsb of the two propellers 20, and the arrangement of the plurality of struts 15 on the rear side Dsb is a disposition in which the disposition of the plurality of struts 15 on the front side Dsf is reversed in a vertical direction.

[0128] Since the two propellers 20 rotate in opposite directions, the swirling flow discharged from the propeller 20 on the front side Dsf can be canceled by the propeller 20 on the rear side Dsb. Therefore, by inclining the strut 15 on the front side Dsf in the front-rear direction Ds, it is not necessary to impart the swirling flow to the water flow, so that the disposition of the strut 15 can be designed by considering only the required strength. Therefore, the degree of freedom in design can be further improved.

[0129] In addition, in a case where the struts 15 are disposed in front of and behind the two propellers 20 that are arranged in the front-rear direction Ds, the number and the disposition of the struts 15 need to be determined in consideration of the structure of the two propellers 20, and the consideration of the number and the disposition of the struts 15 is complicated. However, as in the present aspect, by disposing the propeller 20 on the rear side Dsb by inverting the disposition of the propeller 20 on the front side Dsf, it is possible to easily satisfy the disposition condition of each of the struts 15 in front of and behind the propeller 20.

[0130] (9) The propulsion device 10, 110, 210, 310 according to the ninth aspect is the propulsion device 10, 110, 210, 310 according to any one of the first to eighth aspects, in which the number of the propeller blades 22 and the number of the struts 15 have a common divisor.

[0131] According to the present aspect, compared with the case where the number of propeller blades 22 and the number of struts 15 are limited to having no common divisor, there are more options for the number and arrangement of the propeller blades 22 and the struts 15.

[0132] (10) The moving body 1 according to the tenth aspect includes the propulsion device 10, 110, 210, 310 according to any one of the first to ninth aspects, in which the moving body is movable in at least one of on water or underwater.

[0133] Examples of the moving body 1 include the above-described ship 1a, an ocean research vessel 1b, and the like.Industrial Applicability

[0134] According to a propulsion device and a moving body of the present disclosure, a degree of freedom in design can be improved. Reference Signs List

[0135] 1: moving body 1a: ship 2: hull 3: bow 4: stern 5: ship bottom 10: propulsion device 11: tubular portion 12: fixing device 12a: vertical axis 13: shaft portion 20: propeller 21: propeller hub 22: propeller blade 14: hub 15: strut Dv: vertical direction Dvu: upper side Dvd: lower side Ds: front-rear direction Dsf: front side Dsb: rear side Dw: width direction Dwr: right side Dwl: left side F: flow passage HS: horizontal plane L1: symmetry line L2: division line O: axis line W: water surface θ1: angular interval (first angular interval) θ2: angular interval (second angular interval) 110: propulsion device 210: propulsion device θ3: angular interval (third angular interval) θ4: angular interval (fourth angular interval) 310: propulsion device 15a: front strut 15b: rear strut 1b: ocean research vessel

Claims

1. A propulsion device comprising: a tubular portion disposed below a water surface such that an axis line extends in a front-rear direction and forming a flow passage in which a front side is an upstream side and a rear side is a downstream side; a shaft portion disposed inside the tubular portion and extending in a direction of the axis line; a propeller mounted on the shaft portion, having a plurality of propeller blades extending in a radial direction of the axis line in the flow passage and arranged in a circumferential direction of the axis line, and being rotatable around the axis line; and a plurality of struts provided in the flow passage at at least one of a front side and a rear side with respect to the propeller, extending in the radial direction and arranged in the circumferential direction, and supporting the shaft portion; wherein the plurality of struts are disposed to be symmetrical with respect to a symmetry line that extends in a vertical direction and passes through the axis line, at least one angular interval among angular intervals between the struts is different from the angular intervals between the other struts, and at least one of the struts is disposed on each of both sides in the vertical direction with respect to a horizontal plane extending in a horizontal direction through the axis line.

2. The propulsion device according to claim 1, wherein only one angular interval among the angular intervals between the struts is different from the angular intervals between the other struts.

3. The propulsion device according to claim 1 or 2, wherein each of N struts is disposed on any of (N × 2 - 1) division lines that equally divide a region around the axis line in the circumferential direction, and an angular interval between the struts is any of N' × 360 / (N × 2 - 1) degrees, where N' is greater than or equal to 1 and less than N.

4. The propulsion device according to claim 3, wherein the number of the division lines (N × 2 - 1) and the number of the propeller blades are relatively prime.

5. The propulsion device according to claim 3, wherein the number of the division lines (N × 2 - 1) is different from the number of the propeller blades.

6. The propulsion device according to claim 3, wherein the number of the struts is N = 4.

7. The propulsion device according to claim 1 or 2, wherein in a case where M ≥ N, each of the N struts is disposed on any one of (M × 2 - 1) division lines that equally divide a region around the axis line in the circumferential direction.

8. The propulsion device according to claim 1 or 2, wherein two propellers are provided side by side in the front-rear direction, the two propellers are provided to rotate in opposite directions to each other, a plurality of the struts are provided on each of a front side and a rear side of the two propellers, and the disposition of the plurality of struts on the rear side is a disposition in which the disposition of the plurality of struts on the front side is reversed in the vertical direction.

9. The propulsion device according to claim 1 or 2, wherein the number of the propeller blades and the number of the struts have a common divisor.

10. A moving body comprising: the propulsion device according to claim 1 or 2, wherein the moving body is movable in at least one of on water or underwater.

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