PROPULSION APPARATUS FOR SHIP

Abstract

This propulsion apparatus for a ship includes an upper case supported by a hull, a lower case pivotably supported by the upper case, a screw disposed in an area submerged in external water in the lower case and configured to generate propulsion power, a feeding flow channel configured to feed a fluid to the lower case from the upper case via relatively pivoting sliding parts of the upper case and the lower case, and a returning flow channel configured to return the fluid to the upper case from the lower case via the sliding parts, an annular space is provided between the sliding part on the side of the upper case and the sliding part on the side of the lower case and the annular space is partitioned into a first arc-shaped passage and a second arc-shaped passage by a plurality of partition walls, any one of the first arc-shaped passage and the second arc-shaped passage is in communication with the feeding flow channel, and the other of the first arc-shaped passage and the second arc-shaped passage is in communication with the returning flow channel.

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority based on Japanese Patent Application No. 2022-156768, filed Sep. 29, 2022, the content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a propulsion apparatus for a ship.

Description of Related Art

An outboard motor, an inboard-outdrive engine, a POD type propulsion apparatus, and the like are known as propulsion apparatus for ships. As such a propulsion apparatus, an apparatus in which an upper case supported on the side of the hull and a lower case pivotably supported on the upper case are provided and a screw is attached to a rear part of the lower case is known (for example, see Japanese Utility Model Publication No. S61-66095).

In the propulsion apparatus disclosed in Japanese Utility Model Publication No. S61-66095, the upper case is supported by the ship, and a hydraulic motor configured to rotate the screw is installed in the lower case pivotably supported by the upper case. A lower region of the lower case where the screw is placed is submerged in external water such as seawater, fresh water, or the like. A pivot angle of the lower case with the upper case is manipulated by power of a steering motor disposed in the upper case. The propulsion apparatus changes the direction of the screw to control the direction in which the ship advances.

In addition, the propulsion apparatus disclosed in Japanese Utility Model Publication No. S61-66095 feeds a working liquid from a hydraulic circuit on the side of the upper case to the hydraulic motor configured to drive the screw, and returns the working liquid that actuates the hydraulic motor to the hydraulic circuit on the side of the upper case again. A feeding flow channel and a returning flow channel connected to the hydraulic motor are connected to an upper case-side passage and a lower case-side passage through two sets of hydraulic rotation bearings disposed between the upper case and the lower case. The hydraulic rotation bearings constitute an annular space provided in an annular sliding part of the upper case and the lower case as a main element. That is, the hydraulic rotation bearings provide the annular space in a contact part between the upper case and the lower case, the upper case-side passage and the lower case-side passage are connected through the annular space, and thus the upper case-side passage and the lower case-side passage can be maintained in a normally connected state regardless of a pivot position of the lower case.

SUMMARY OF THE INVENTION

However, in the propulsion apparatus disclosed in Japanese Utility Model Publication No. S61-66095, since the feeding flow channel and the returning flow channel are provided between the upper case and the lower case, it is necessary to provide two stages of annular spaces (hydraulic rotation bearings) in the contact part between the upper case and the lower case. For this reason, a connecting passage for connecting the upper case-side passage and the lower case-side passage occupies a large area of the sliding parts of the upper case and lower case, and tends to cause the size of the entire apparatus to increase.

In particular, if there are multiple types (multiple systems) of flow channels through which a fluid flows in the upper case and the lower case, the number of annular spaces (hydraulic rotation bearings) provided in the sliding part will further increase, and the overall size of the apparatus will tend to increase.

Here, an aspect of the present invention is directed to providing a propulsion apparatus for a ship in which a plurality of connecting passages can be disposed in sliding parts of an upper case and a lower case while an increase in size of the apparatus is suppressed.

In order to accomplish the above-mentioned purposes, a propulsion apparatus for a ship according to an aspect of the present invention employs the following configurations.

(1) An aspect of the present invention is a propulsion apparatus for a ship including an upper case (for example, a motor case part (12U) of an embodiment) supported by a hull; a lower case (for example, a gear case part (12L) of the embodiment) pivotably supported by the upper case; a screw (for example, a screw (10) of the embodiment) disposed in an area submerged in external water in the lower case and configured to generate propulsion power; a feeding flow channel (for example, a feeding flow channel (FP) of the embodiment) configured to feed a fluid to the lower case from the upper case via relatively pivoting sliding parts of the upper case and the lower case; and a returning flow channel (for example, a returning flow channel (RP) of the embodiment) configured to return the fluid to the upper case from the lower case via the sliding parts, an annular space (for example, an annular space (49) of the embodiment) being provided between the sliding part on the side of the upper case and the sliding part on the side of the lower case and the annular space being partitioned into a first arc-shaped passage (for example, a first arc-shaped passage (51) of the embodiment) and a second arc-shaped passage (for example, a second arc-shaped passage (52) of the embodiment) by a plurality of partition walls (for example, partition walls (50) of the embodiment), any one of the first arc-shaped passage and the second arc-shaped passage being in communication with the feeding flow channel, and the other of the first arc-shaped passage and the second arc-shaped passage being in communication with the returning flow channel.

According to the aspect of the above-mentioned (1), the fluid in the feeding flow channel flows toward the lower case from the side of the upper case via one of the first arc-shaped passage and the second arc-shaped passage in the annular space. In addition, the fluid in the returning flow channel flows toward the upper case from the side of the lower case via the other of the first arc-shaped passage and the second arc-shaped passage.

(2) In the aspect of the above-mentioned (1), a plurality of pairs of the feeding flow channels and the returning flow channels may be provided, the sliding parts may be disposed on facing cylindrical surfaces of the upper case and the lower case, and the plurality of annular spaces corresponding to the pairs of the feeding flow channels and the returning flow channels may be arranged on the cylindrical surface in an axial direction.

According to the aspect of the above-mentioned (2), even when the plurality of pairs of the feeding flow channels and the returning flow channels are provided, since the annular spaces corresponding to each pair are arranged on the cylindrical surface in the axial direction, the plurality of connecting passages (the first arc-shaped passage and the second arc-shaped passage) can be compactly disposed in the sliding parts of the upper case and the lower case.

(3) In the aspect of the above-mentioned (2), two sets of the feeding flow channels and the returning flow channels may be provided, lubricating oil that lubricates the inside of the upper case may flow through the annular space disposed in the vicinity of the upper case of the cylindrical surface, and a coolant that cools heat-generating parts disposed inside or outside the upper case may flow through the annular space disposed in the vicinity of the lower case of the cylindrical surface.

According to the aspect of the above-mentioned (3), since the annular space (the first arc-shaped passage and the second arc-shaped passage) through which lubricating oil flows is disposed in the vicinity of the upper case, even if the lubricating oil flowing through the annular space leaks toward the upper case, there is no adverse effect due to the leakage of the fluid into the upper case.

(4) In the aspect of the above-mentioned (1), the annular space may be surrounded by an annular groove (for example, an annular groove (28) of the embodiment) formed in one of the lower case and the upper case and a closing wall (for example, an inner circumferential surface of a fitting hole (23) of the embodiment) provided on the other, a case-side passage (for example, a first shaft passage (29) and a second shaft passage (32) of the embodiment) connected to each of the first arc-shaped passage and the second arc-shaped passage may be formed in the one of the lower case and the upper case in which the annular groove is formed, a communication port (for example, a first communication port (27) and a second communication port (36) of the embodiment) facing each of the first arc-shaped passage and the second arc-shaped passage may be formed in the closing wall, and another case-side passage (for example, a first bottom wall passage (25c) and a second bottom wall passage (35a) of the embodiment) in communication with each of the first arc-shaped passage and the second arc-shaped passage through the communication port may be formed in the other of the lower case and the upper case having the closing wall.

According to the aspect of the above-mentioned (4), since each communication port formed in the closing wall is in communication with the first arc-shaped passage and the second arc-shaped passage, it becomes possible to feed the fluid toward the lower case from the side of the upper case and return the fluid toward the upper case from the side of the lower case. In this configuration, with a simple structure that is easy to manufacture, it is possible to realize a passage connection in the sliding parts using the first arc-shaped passage and the second arc-shaped passage.

(5) In the aspect of the above-mentioned (4), the annular space may be partitioned into two arc-shaped passages with a center angle of about 180° by a pair of partition walls, one of the passage may be the first arc-shaped passage and the other passage may be the second arc-shaped passage, and each of the communication ports may always be in communication with any one of the first arc-shaped passage and the second arc-shaped passage when a pivot angle of the lower case with respect to the upper case is within a range of substantially 90° from a central position in one direction and another direction.

According to the aspect of the above-mentioned (5), the lower case can keep the case-side passage of the upper case and the case-side passage of the lower case in a connected state using the first arc-shaped passage and the second arc-shaped passage within a pivoting range of substantially 90° from the central position in one direction and another direction. For this reason, the direction of in which the ship advances can be freely changed by pivoting the lower case from the central position in an appropriate direction within the range of approximately 90°.

Further, when the ship moves backwards, the direction of rearward progression can also be freely changed by driving the screw in the opposite direction and changing the pivot angle of the lower case.

(6) In the aspect of the above-mentioned (5), the communication port facing the first arc-shaped passage and the communication port facing the second arc-shaped passage may be disposed to be offset in a widthwise direction crossing a circumferential direction of the annular space, and the pair of partition walls may be formed in shapes in which partition regions in the annular space are offset in the circumferential direction on one side and the other side in the widthwise direction. According to the aspect of the above-mentioned (6), when the lower case is pivoted 90° in either one direction or another direction from the central position, a part of one partition wall can be prevented from climbing over the communication port arranged on one side in the widthwise direction of the annular space. In addition, at that time, a part of the other partition wall can be prevented from climbing over the communication port arranged on the other side in the widthwise direction of the annular space. As a result, the one communication port is kept in communication with the first arc-shaped passage, and the other communication port is kept in communication with the second arc-shaped passage.

Accordingly, when this configuration is employed, fluid circulation through the first arc-shaped passage and the second arc-shaped passage can be allowed even when the lower case is pivoted 90° from the central position in either one direction or another direction. Accordingly, when this configuration is employed, it is possible to pivot the lower case 90° from the central position and move the ship sideways.

(7) In the aspect of the above-mentioned (6), the pair of partition walls may be formed in crank shapes when seen from an end surface in a protrusion direction facing the closing wall.

According to the aspect of the above-mentioned (7), when the lower case is pivoted 90° from the central position in either one direction or another direction, part of the crank shape of the end surface of one partition wall does not climb over one communication port, and the communication port is kept in communication with the first arc-shaped passage. In addition, here, the other part of the crank shape of the end surface of the other partition wall does not climb over the other communication port, and the communication port is kept in communication with the second arc-shaped passage.

(8) In the aspect of the above-mentioned (6), the pair of partition walls may be formed in inclination shapes in which a shape seen from an end surface in a protrusion direction facing the closing wall is inclined from one side toward the other side in the widthwise direction on one side in the circumferential direction.

According to the aspect of the above-mentioned (8), when the lower case is pivoted 90° from the central position in either one direction or another direction, part of the inclination shape of the end surface of one partition wall does not climb over one communication port, and the communication port is kept in communication with the first arc-shaped passage. In addition, here, the other part of the inclination shape of the end surface of the other partition wall does not climb over the other communication port, and the communication port is kept in communication with the second arc-shaped passage.

(9) In the aspect of the above-mentioned (5), the lower case may be set not to pivot 90° or more in one direction and another direction about the central position with respect to the upper case.

According to the aspect of the above-mentioned (9), since the lower case is not pivoted 90° or more from the central position, the communication port in communication with the first arc-shaped passage and the communication port in communication with the second arc-shaped passage can eliminate the inconvenience of communicating with the opposite arc-shaped passages.

In the propulsion apparatus for a ship according to the aspect of the present invention, one annular space disposed in the sliding part is partitioned by the partition walls to constitute the first arc-shaped passage and the second arc-shaped passage, and the fluid in the feeding flow channel and the fluid in the returning flow channel flow to the first arc-shaped passage and the second arc-shaped passage, respectively. For this reason, the plurality of passages configured to connect the upper case-side passage and the lower case-side passage do not occupy a large area of the sliding parts of the upper case and the lower case. Accordingly, when the propulsion apparatus for a ship according to the aspect of the present invention is employed, the plurality of connecting passages can be disposed in the sliding parts of the upper case and the lower case while an increase in size of the apparatus is suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional side view of an electric outboard motor (propulsion apparatus) of a first embodiment.

FIG. 2 is an enlarged view showing a cross-sectional portion of FIG. 1.

FIG. 3 is a longitudinal cross-sectional view at another position in FIG. 2 of the electric outboard motor (propulsion apparatus) of the first embodiment.

FIG. 4 is a longitudinal cross-sectional view at another position in FIG. 2 and FIG. 3 of the electric outboard motor (propulsion apparatus) of the first embodiment.

FIG. 5 is an enlarged view of a portion V in FIG. 2.

FIG. 6 is a cross-sectional view corresponding to a cross section VI-VI in FIG. 5.

FIG. 7 is a cross-sectional view, like FIG. 6, showing an actuation state during pivotal movement of a gear case part (lower case).

FIG. 8 is an exploded side view of the electric outboard motor (propulsion apparatus) of the first embodiment.

FIG. 9 is a cross-sectional view, like FIG. 5, showing an electric outboard motor (propulsion apparatus) of a second embodiment.

FIG. 10 is a side view of a member on the side of the gear case part corresponding to an arrow X in FIG. 9.

FIG. 11 is a side view of a member on the side of the gear case part corresponding to an arrow XI in FIG. 9.

FIG. 12 is a side view of an electric outboard motor (propulsion apparatus) of a third embodiment corresponding to FIG. 10.

FIG. 13 is a side view of the electric outboard motor (propulsion apparatus) of the third embodiment corresponding to FIG. 11.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

Further, an arrow FR pointing to a front side in a propulsion direction of a propulsion apparatus is marked at appropriate places in the drawings. In addition, in the embodiments as described below, the same components are designated by the same reference signs, and overlapping descriptions thereof may be partially omitted.

First Embodiment

A propulsion apparatus for a ship of the embodiment is an electric outboard motor 1 driven by an electric motor 11.

FIG. 1 is a side view showing a partial longitudinal cross section of the electric outboard motor 1 of the embodiment, and FIG. 2 is an enlarged view of a longitudinal cross-sectional portion of FIG. 1.

The electric outboard motor 1 can be attached to a stern board (transom board) of a rear part of the hull (not shown). The electric outboard motor 1 includes a screw 10 submerged in water of the sea, rivers, lakes, or the like (hereinafter, referred to as “external water w”), to generate propulsion power, the electric motor 11 (driving source) configured to rotate the screw 10, and an outboard motor case 12 configured to accommodate drive-related parts including the electric motor 11 therein. The outboard motor case 12 is supported by a frame member (not shown). The frame member is pivotably supported by the rear part of the hull about a tilt shaft (not shown) in an upward/downward direction.

Regarding the electric outboard motor 1, when the screw 10 is submerged in the external water w, a side facing vertically upward is called “upper” and a side facing vertically downward is called “lower.” In addition, in particular, unless otherwise specified, a direction in which the electric outboard motor 1 moves under the propulsion power of the screw 10 is called “forward” and a direction opposite to the direction in which the electric outboard motor 1 moves is called “rearward.”

The outboard motor case 12 includes a motor case part 12U configured to accommodate the electric motor 11, and a gear case part 12L configured to accommodate a power transmission mechanism 13. The power transmission mechanism 13 is a speed reduction mechanism including a plurality of gears, which reduces rotation of an output shaft 11a of the electric motor 11 at a predetermined reduction ratio and transmits the reduced rotation to the screw 10. The motor case part 12U is attached to the rear part of the hull, and the gear case part 12L is pivotably connected to (supported by) a lower side of the motor case part 12U. The gear case part 12L is pivotable about a rotation center axis c1 that is coaxial with the output shaft 11a of the electric motor 11.

In the embodiment, the motor case part 12U constitutes an upper case in the propulsion apparatus, and the gear case part 12L constitutes a lower case in the propulsion apparatus.

In addition, the gear case part 12L is pivoted by a motor for pivotal movement (not shown) disposed in the motor case part 12U within a predetermined angle range. The screw 10 supported by the gear case part 12L rotates together with the gear case part 12L around the rotation center axis c1. The electric outboard motor 1 can change a propulsion direction by changing an orientation of the screw 10 using the motor.

The screw 10 is integrally pivotably supported by a screw shaft 10a passing through a rear wall of the gear case part 12L forward and rearward. The screw shaft 10a is connected to the power transmission mechanism 13 in the gear case part 12L. The screw 10 is disposed behind a lower end of the gear case part 12L. The screw 10 receives rotational power of the electric motor 11 and generates propulsion power through rotation in the external water w.

A part of the gear case part 12L that constitutes a lower region of the outboard motor case 12 is submerged in the external water w together with the screw 10 during marine navigation of the ship.

A control unit 40 including a driving circuit of the electric motor 11 is disposed on an outer surface of the motor case part 12U on the side of the rear part. In the control unit 40, heat generating parts such as the driving circuit and the like of the electric motor 11 are disposed inside the outer case. The heat generating parts inside the control unit 40 are cooled by coolant flowing through a circulation flow channel 70 (see FIG. 8), which will be described below.

Further, a battery (not shown) that is an electric power supply of the electric motor 11 or the like is disposed in the motor case part 12U or the hull.

In addition, a liquid coolant storage part 15 configured to store liquid coolant 2 and a pump apparatus 31 configured to suction up the liquid coolant 2 in the liquid coolant storage part 15 to flow to a circulation flow channel 24 for the liquid coolant 2 are disposed inside the motor case part 12U. The liquid coolant 2 stored in the liquid coolant storage part 15 may be (lubricating oil) containing a lubricating ingredient. The liquid coolant 2 (lubricating oil) can lubricate mechanical parts by being supplied to the mechanical parts in the motor case part 12U. The pump apparatus 31 is driven by, for example, the output shaft 11a of the electric motor 11. The pump apparatus 31 may employ various types such as a trochoid type, a centrifugal type, a gear type, or the like, as long as the liquid coolant 2 suctioned up from the liquid coolant storage part 15 is sent to the circulation flow channel 24.

The circulation flow channel 24 sends the liquid coolant 2 suctioned up from the liquid coolant storage part 15 by the pump apparatus 31 toward the gear case part 12L, and cools the liquid coolant 2 through heat exchange with the external water w on the side of the gear case part 12L. Then, the circulation flow channel 24 returns the liquid coolant 2 cooled on the side of the gear case part 12L toward the motor case part 12U again, and discharges the liquid coolant 2 to a heat generating part 11b of the electric motor 11. Accordingly, the heat generating part 11b is cooled by the liquid coolant 2. Here, the liquid coolant 2 discharged to the heat generating part 11b is dropped downward and stored in the liquid coolant storage part 15. The liquid coolant 2 stored in the liquid coolant storage part 15 is sent to the circulation flow channel 24 by the pump apparatus 31 again.

The heat generating part 11b of the electric motor 11 is, for example, a motor case configured to cover a coil or a stator from an outer side. However, the heat generating part 11b may be a rotor or a coil itself according to a structure of the electric motor 11.

The gear case part 12L includes a hollow case main body 12La configured to accommodate the power transmission mechanism 13 therein, a rearward extension part 12Lb extending rearward from the case main body 12La, and an anti-cavitation plate 45 continuous with an outer circumferential part of the case main body 12La and a lower surface of the rearward extension part 12Lb. The anti-cavitation plate 45 is formed in a substantially horizontal plate shape wider than the case main body 12La or the rearward extension part 12Lb. The anti-cavitation plate 45 extends approximately the same width from the outer side of the case main body 12La to approximately the same position as the rear end portion of the rearward extension part 12Lb.

The anti-cavitation plate 45 is disposed to cover the screw 10 from above. The screw 10 is disposed to protrude rearward from a rear wall of the case main body 12La on the side of a lower portion. The anti-cavitation plate 45 has at least a lower surface submerged in the external water w during marine navigation of the ship. The anti-cavitation plate 45 prevents entrainment of air (occurrence of cavitation) by the screw 10 when the screw 10 rotates in the external water w.

A meandering fine flow channel (not shown) is formed almost entirely inside the anti-cavitation plate 45. The liquid coolant 2 in the circulation flow channel 24 fed from the motor case part 12U flows through a partial region (for example, a right half region) in the anti-cavitation plate 45. A flow channel for liquid coolant in the anti-cavitation plate 45 performs heat exchange with the external water in contact with the outer surface of the liquid coolant 2 when the liquid coolant 2 flows therethrough. The liquid coolant 2 flowing through the flow channel is cooled by heat exchange with the external water.

In addition, the coolant in the circulation flow channel 70 (see FIG. 8) fed from the motor case part 12U flows through the remaining region (for example, a left half region) in the anti-cavitation plate 45. The flow channel for coolant in the anti-cavitation plate 45 performs heat exchange with the external water in contact with the outer surface of the coolant when the coolant flows therethrough. The coolant flowing through the flow channel is cooled by performing heat exchange with the external water.

As shown in FIG. 2, a substantially cylindrical power transmission shaft 16 is disposed in the motor case part 12U coaxially with the rotation center axis c1. The power transmission shaft 16 is rotatably supported by the motor case part 12U via a bearing 17. The power transmission shaft 16 is a member configured to transmit rotation of the motor for pivotal movement (not shown) to the gear case part 12L, and an outer gear 19 meshed with a driving gear 18 on the side of the motor is provided on an outer circumferential surface on the side of an upper end.

The power transmission shaft 16 is formed in a stepped cylindrical shape. That is, an upper region of the power transmission shaft 16 is formed in a cylindrical shape with a large diameter, and a lower region is formed in a cylindrical shape with a diameter smaller than that of the upper region. The power transmission shaft 16 has a cylindrical part 16a with a large diameter on the side of the upper part, which is supported by the motor case part 12U via the bearing 17. A cylindrical part 16b with a small diameter on the side of the lower part of the power transmission shaft 16 is connected coaxially with the gear case part 12L. In addition, an inner circumferential surface on the side of the upper part of the cylindrical part 16b with a small diameter rotatably supports the output shaft 11a via a bearing 20. Further, a seal member 21 configured to liquid-tightly seal the upper and lower spaces (a space in the motor case part 12U and a space in the gear case part 12L) is provided between the inner circumferential surface on the side of the lower part of the cylindrical part 16b with a small diameter and the output shaft 11a.

A substantially cylindrical connecting tube 22 is connected integrally with the upper part of the case main body 12La of the gear case part 12L. A fitting hole 23 into which the connecting tube 22 on the side of the gear case part 12L is pivotably fitted is formed at a center of a bottom wall of the motor case part 12U. An inner circumferential surface of the fitting hole 23 and an outer circumferential surface of the connecting tube 22 constitute relatively pivoting sliding parts of the upper case (the motor case part 12U) and the lower case (the gear case part 12L). Further, the gear case part 12L is restricted in the axial direction with respect to the motor case part 12U by appropriate restriction means.

In addition, the inner circumferential surface of the fitting hole 23 and the outer circumferential surface of the connecting tube 22 constitute facing cylindrical surfaces of the upper case (the motor case part 12U) and the lower case (the gear case part 12L). The sliding parts that are relatively pivoted are provided on the cylindrical surfaces, respectively.

The cylindrical part 16b of the power transmission shaft 16 on the side of the lower part is connected to the inner circumferential surface of the connecting tube 22 by spline fitting. Accordingly, the case main body 12La of the gear case part 12L is pivoted integrally with the power transmission shaft 16 via the connecting tube 22. Accordingly, the gear case part 12L supported by the motor case part 12U can be pivoted about the rotation center axis c1 by a driving force of the motor for pivotal movement.

Next, the circulation flow channel 24 through which the liquid coolant 2 circulates between the heat generating part 11b of the electric motor 11 and the anti-cavitation plate 45 that is a heat exchange part will be described.

FIG. 3 is a longitudinal cross-sectional view of the electric outboard motor 1 at another position in FIG. 2 around the rotation center axis c1. FIG. 4 is a longitudinal cross-sectional view of the electric outboard motor 1 at another position in FIG. 2 and FIG. 3 around the rotation center axis c1. In addition, FIG. 5 is an enlarged view of a portion V in FIG. 2, and FIG. 6 and FIG. 7 are cross-sectional views corresponding to a cross section VI-VI in FIG. 5.

As shown in FIG. 3, a suction passage 25a extending toward a bottom part of the liquid coolant storage part 15 is connected to a suction part of the pump apparatus 31. A strainer 26 is connected to an end portion of the suction passage 25a. In addition, as shown in FIG. 2, a discharge passage 25b in communication with a first bottom wall passage 25c of a bottom wall of the motor case part 12U is connected to a discharge part of the pump apparatus 31. As shown in FIG. 5, the first bottom wall passage 25c extends inward along the bottom wall of the motor case part 12U in the radial direction, and an end portion on an inner side in the radial direction is open in the inner circumferential surface (peripheral surface, sliding part) of the fitting hole 23. The end portion of the first bottom wall passage 25c that opens in the inner circumferential surface of the fitting hole 23 constitutes a first communication port 27 (communication port) configured to bring the first bottom wall passage 25c in communication with a first arc-shaped passage 51, which will be described below.

As shown in FIG. 6, annular grooves 28 partitioned into two arc-shaped grooves by a pair of partition walls 50 are provided in the outer circumferential surface of the connecting tube 22 on the side of the gear case part 12L at a height position facing the first communication port 27. The annular grooves 28 constitute an annular space 49 partitioned by the pair of partition walls 50 by fitting the connecting tube 22 into the fitting hole 23 on the side of the motor case part 12U. The annular space 49 is separated into the first arc-shaped passage 51 and a second arc-shaped passage 52 by being partitioned by the pair of partition walls 50. The pair of partition walls 50 project into the annular grooves 28 at two positions 180° apart in the circumferential direction. The circumferences of the first arc-shaped passage 51 and the second arc-shaped passage 52 have the same length.

In the embodiment, the inner circumferential surface of the fitting hole 23 constitutes a closing wall that constitutes the annular space 49 together with the annular grooves 28.

A first shaft passage 29 connected to a flow channel on an upstream side in the anti-cavitation plate 45 is formed in the connecting tube 22 of the gear case part 12L and the circumferential wall of the case main body 12La. The upper part of the first shaft passage 29 is in communication with the first arc-shaped passage 51 via a connecting hole 30. As shown in FIG. 6, the connecting hole 30 is in communication with the first arc-shaped passage 51 at a substantially central position in the circumferential direction.

In addition, as shown in FIG. 4, a second shaft passage 32 connected to a flow channel on a downstream side in the anti-cavitation plate 45 is formed in the connecting tube 22 of the gear case part 12L and the circumferential wall of the case main body 12La. The second shaft passage 32 is formed at a position (for example, a position spaced 180° around the rotation center axis c1) spaced apart from the first shaft passage 29 in the circumferential wall of the connecting tube 22 and the case main body 12La. The upper part of the second shaft passage 32 is in communication with the second arc-shaped passage 52 by a connecting hole 33. As shown in FIG. 6, the connecting hole 33 is in communication with the second arc-shaped passage 52 at a substantially central position in the circumferential direction.

In addition, a second bottom wall passage 35a extending along the bottom wall in the radial direction is formed in the bottom wall of the motor case part 12U. An end portion of the second bottom wall passage 35a on an inner side in the radial direction opens in the inner circumferential surface (peripheral surface, sliding part) of the fitting hole 23. An end portion of the second bottom wall passage 35a that opens in the inner circumferential surface of the fitting hole 23 constitutes a second communication port 36 (communication port) configured to bring the second bottom wall passage 35a in communication with the second arc-shaped passage 52. The second communication port 36 opens at the same height position as the annular grooves 28 in the outer circumferential surface of the connecting tube 22.

As shown in FIG. 4, an introduction passage 35b configured to introduce the liquid coolant 2 to the vicinity of the heat generating part 11b of the electric motor 11 is connected to the second bottom wall passage 35a. The liquid coolant 2 introduced into the introduction passage 35b after heat exchange (cooling) by the anti-cavitation plate 45 is injected to the heat generating part 11b from a circumferential region of the electric motor 11. Accordingly, the heat generating part 11b is cooled by the liquid coolant 2 that is sufficiently cooled.

Incidentally, the circulation flow channel 24 of the liquid coolant 2 includes a feeding flow channel FP configured to feed the liquid coolant 2 (fluid) to the gear case part 12L from the motor case part 12U, and a returning flow channel RP configured to return a liquid coolant (fluid) to the motor case part 12U from the gear case part 12L.

The feeding flow channel FP is constituted by the discharge passage 25b, the first bottom wall passage 25c, the first shaft passage 29, and the like, and the returning flow channel RP is constituted by the second shaft passage 32, the second bottom wall passage 35a, the introduction passage 35b, and the like. The liquid coolant 2 in the feeding flow channel FP flows toward the gear case part 12L (toward the anti-cavitation plate 45) from the side of the motor case part 12U via the relatively pivoting sliding parts of the motor case part 12U and the gear case part 12L. The liquid coolant in the returning flow channel RP is returned toward the motor case part 12U from the side of the gear case part 12L (the side of the anti-cavitation plate 45) via the same sliding part of the motor case part 12U and the gear case part 12L.

The first arc-shaped passage 51 and the second arc-shaped passage 52 are disposed in the sliding part of the motor case part 12U and the gear case part 12L at the same height position in the axial direction as described above. Then, the first arc-shaped passage 51 connects the case-side passage (the first bottom wall passage 25c) on the side of the motor case part 12U and the case-side passage (the first shaft passage 29) on the side of the gear case part 12L in the feeding flow channel FP. In addition, the second arc-shaped passage 52 connects the case-side passage (the second shaft passage 32) on the side of the gear case part 12L and the case-side passage (the second bottom wall passage 35a) on the side of the motor case part 12U in the returning flow channel RP.

FIG. 6 shows a connected state of the feeding flow channel FP and the returning flow channel RP when a pivot position of the gear case part 12L with respect to the motor case part 12U is a central position (a pivot position where the screw 10 is directed toward a rear side of the hull).

In this state, the first arc-shaped passage 51 is in communication with the first communication port 27 at an arc-shaped central position of the passage, and the second arc-shaped passage 52 is in communication with the second communication port 36 at an arc-shaped central position of the passage.

FIG. 7(A) shows a connected state of the feeding flow channel FP and the returning flow channel RP when the gear case part 12L is pivoted in one direction from the central position shown in FIG. 6, and FIG. 7(B) shows a connected state of the feeding flow channel FP and the returning flow channel RP when the gear case part 12L is pivoted in the other direction from the central position shown in FIG. 6.

In the state of FIG. 7(A), the first arc-shaped passage 51 and the second arc-shaped passage 52 are displaced by a predetermined angle counterclockwise in the drawings from the central position shown in FIG. 6. Here, the first arc-shaped passage 51 is in communication with the first communication port 27 at a position biased toward one end from the arc-shaped central position of the passage, and the second arc-shaped passage 52 is similarly in communication with the second communication port 36 at a position biased toward the one end from the arc-shaped central position of the passage.

In the state of FIG. 7(B), the first arc-shaped passage 51 and the second arc-shaped passage 52 are displaced by a predetermined angle clockwise in the drawings from the central position shown in FIG. 6. Here, the first arc-shaped passage 51 is in communication with the first communication port 27 at a position biased toward the other end from the arc-shaped central position of the passage, and the second arc-shaped passage 52 is similarly in communication with the second communication port 36 at a position biased toward the other end from the arc-shaped central position of the passage.

Accordingly, the electric outboard motor 1 can maintain the upper and lower case-side passages of the feeding flow channel FP and the returning flow channel RP in the connected state even when the gear case part 12L is pivoted in any direction with respect to the motor case part 12U.

Here, in the electric outboard motor 1 of the embodiment, when the gear case part 12L (lower case) is pivoted about the central position with respect to the motor case part 12U (upper case) in one direction and the other direction more than 90°, the first arc-shaped passage 51 is in communication with the second communication port 36, and the second arc-shaped passage 52 is in communication with the first communication port 27. Here, the liquid coolant 2 flows to the second shaft passage 32 from the first communication port 27 via the second arc-shaped passage 52 on the side of the feeding flow channel FP, and flows to the second communication port 36 from the first shaft passage 29 via the first arc-shaped passage 51 in the returning flow channel RP. That is, in the anti-cavitation plate 45 on the side of the gear case part 12L (lower case), the liquid coolant 2 flows with the inflow side and the outflow side reversed. Here, although the direction of the flow of the liquid coolant 2 is reversed on the anti-cavitation plate 45, heat exchange can be performed between the liquid coolant 2 and the external water was normal.

FIG. 8 is an exploded side view of the electric outboard motor 1 showing the circulation flow channel 70 of the coolant that cools instruments in the control unit 40.

As shown in FIG. 8, the circulation flow channel 70 includes a reservoir tank 75 configured to store coolant, and a pump apparatus 76 configured to supply the coolant in the reservoir tank 75 to the instruments in the control unit 40. The suction part of the pump apparatus 76 is connected to a returning port 41 provided in the motor case part 12U, and the discharge part of the pump apparatus 76 is connected to an inflow port 40a provided in the control unit 40.

An outflow port 40b of the control unit 40 is connected to the feeding flow channel FP configured to flow the coolant (fluid) from the motor case part 12U to the gear case part 12L. The coolant flowing into the gear case part 12L through the feeding flow channel FP flows into the flow channel for coolant in the anti-cavitation plate 45. In addition, the returning port 41 of the motor case part 12U is connected to the returning flow channel RP configured to return the coolant to the motor case part 12U from the gear case part 12L. The returning flow channel RP is connected to a discharge side of the flow channel for coolant in the anti-cavitation plate 45. The coolant heat-exchanged with the external water w on the anti-cavitation plate 45 is returned to the reservoir tank 75 through the returning flow channel RP.

As shown in FIG. 2 to FIG. 5, a connecting structure including the first arc-shaped passage 51A and the second arc-shaped passage 52A like the above-mentioned circulation flow channel 24 for liquid coolant is disposed between the fitting hole 23 that is the sliding part on the side of the motor case part 12U and the outer circumferential surface of the connecting tube 22 that is the sliding part on the side of the gear case part 12L. That is, the first arc-shaped passage 51A and the second arc-shaped passage 52A are formed by partitioning the annular spaces 49A of the circumferential region of the connecting tube 22 using a pair of partition walls (not shown). The annular spaces 49 that form the first arc-shaped passage 51A and the second arc-shaped passage 52A are arranged on a lower side of the annular spaces 49A of the circulation flow channel 24 for liquid coolant in the circumferential region of the connecting tube 22. The two annular spaces 49 and 49A for liquid coolant and for coolant are arranged in the axial direction of the outer circumferential surface (cylindrical surface) of the connecting tube 22.

In addition, annular seal members s1, s2 and s3 configured to prevent a leakage of the liquid coolant 2 or the coolant from the annular spaces 49 and 49A are disposed in the sliding part between the fitting hole 23 and the connecting tube 22. The seal member s1 is disposed on an outer edge portion above the annular space 49 on the side of the upper part, and the seal member s3 is disposed on an outer edge portion below the annular space 49A on the side of the lower part. The seal member s2 is disposed at an intermediate position of the upper and lower annular spaces 49 and 49A.

As described above, in the electric outboard motor 1 (the propulsion apparatus for a ship) of the embodiment, the annular space 49 (49A) is provided between the sliding part on the side of the motor case part 12U and the sliding part on the side of the gear case part 12L, and the annular space 49 (49A) is partitioned into the first arc-shaped passage 51 (51A) and the second arc-shaped passage 52 (52A) by the plurality of partition walls 50. Then, the first arc-shaped passage 51 (51A) is in communication with the feeding flow channel FP, and the second arc-shaped passage 52 (52A) is in communication with the returning flow channel RP. For this reason, an annular space disposed between the sliding part on the side of the motor case part 12U and the sliding part on the side of the gear case part 12L is partitioned into the first arc-shaped passage 51 (51A) and the second arc-shaped passage 52 (52A) and used. Accordingly, a plurality of passages configured to connect the passage on the side of the motor case part 12U (the side of the upper case) and the passage on the side of the gear case part 12L (the side of the lower case) do not occupy much of the sliding parts of both the case parts.

Accordingly, when the electric outboard motor 1 of the embodiment is employed, the plurality of connecting passages can be disposed in the sliding parts of the motor case part 12U (upper case) and the gear case part 12L (lower case) while an increase in size of the apparatus is suppressed.

In addition, the electric outboard motor 1 of the embodiment includes the plurality of circulation flow channels 24 and 70, and the annular spaces 49 and 49A corresponding to the plurality of circulation flow channels 24 and 70 are arranged in the axial direction between the inner circumferential surface (cylindrical surface) of the fitting hole 23 on the side of the motor case part 12U and the outer circumferential surface (cylindrical surface) of the connecting tube 22 on the side of the gear case part 12L. For this reason, even if there are multiple pairs of the feeding flow channels FP and the returning flow channels RP bridging between the motor case part 12U and the gear case part 12L, the plurality of connecting passages that allows pivotal movement of the gear case part 12L can be placed compactly in the sliding parts of the motor case part 12U and the gear case part 12L.

While two pairs of the feeding flow channels FP and the returning flow channels RP bridging between the motor case part 12U and the gear case part 12L are provided in the embodiment, three or more pairs of the feeding flow channels FP and the returning flow channels RP may be provided. Even in this case, the annular spaces corresponding to the pairs are arranged in the axial direction between the inner circumferential surface (cylindrical surface) of the fitting hole 23 and the outer circumferential surface (cylindrical surface) of the connecting tube 22, and thus, the plurality of connecting passages can be disposed compactly in the sliding parts.

In addition, in the electric outboard motor 1 of the embodiment, two pairs of the feeding flow channels FP and the returning flow channels RP are provided, and the liquid coolant (lubricating oil) containing the lubricating ingredient flows to the annular spaces 49 (the first arc-shaped passage 51 and the second arc-shaped passage 52) disposed in the vicinity of the upper part of the outer circumferential surface (cylindrical surface) of the connecting tube 22. In addition, the coolant containing no lubricating ingredient flows to the annular spaces 49A (the first arc-shaped passage 51A and the second arc-shaped passage 52A) disposed in the vicinity of the lower part of the outer circumferential surface (cylindrical surface) of the connecting tube 22. For this reason, meanwhile, even when the liquid coolant 2 (lubricating oil) containing the lubricating ingredient is leaked toward the motor case part 12U from the annular spaces 49 (the first arc-shaped passage 51 and the second arc-shaped passage 52), there is no adverse effect of the liquid coolant leakage into the motor case part 12U. That is, since the side of the bottom part in the motor case part 12U is the liquid coolant storage part 15, even when the liquid coolant 2 in the annular spaces 49 (the first arc-shaped passage 51 and the second arc-shaped passage 52) is leaked into the motor case part 12U, problems such as mixing of fluids with different ingredients do not occur.

In addition, in the electric outboard motor 1 of the embodiment, the annular spaces 49 and 49A are surrounded by the annular grooves 28 formed in the connecting tube 22, and the inner circumferential surface (closing wall) of the fitting hole 23 on the side of the motor case part 12U. Then, the first shaft passage 29 or the second shaft passage 32 (the case-side passage) connected to the first arc-shaped passages 51 and 51A and the second arc-shaped passages 52 and 52A is formed on the side of the gear case part 12L that is the connecting tube 22, and the first communication ports 27 and 27A and the second communication ports 36 and 36A facing the first arc-shaped passages 51 and 51A and the second arc-shaped passages 52 and 52A are formed in the inner circumferential surface (closing wall) of the fitting hole 23. In the electric outboard motor 1 of the embodiment, the first communication ports 27 and 27A and the second communication ports 36 and 36A formed in the inner circumferential surface (closing wall) of the fitting hole 23 are in communication with the first arc-shaped passages 51 and 51A and the second arc-shaped passages 52 and 52A, and thus, the liquid coolant or the coolant can be fed toward the gear case part 12L from the side of the motor case part 12U and the liquid coolant or the coolant can be returned toward the motor case part 12U from the side of the gear case part 12L.

When the configuration is employed, with a simple configuration that is easy to manufacture, it is possible to realize passage connections in the sliding parts using the first arc-shaped passages 51 and 51A and the second arc-shaped passages 52 and 52A.

Further, in the electric outboard motor 1 of the embodiment, the annular spaces 49 and 49A are partitioned into the first arc-shaped passages 51 and 51A and the second arc-shaped passages 52 and 52A by the pair of partition walls 50 at a center angle of about 180°. Then, the first communication ports 27 and 27A and the second communication ports 36 and 36A are in communication with any one of the first arc-shaped passages 51 and 51A and the second arc-shaped passages 52 and 52A except for the positions where the pivot angle of the gear case part 12L is pivoted 90° from the central position in one direction and the other direction. For this reason, a direction of advance of the ship can be freely changed.

In the electric outboard motor 1 of the embodiment, while the pivoting range of the gear case part 12L (lower case) with respect to the motor case part 12U (upper case) is not particularly limited, the gear case part 12L (lower case) can also be set not to be pivoted 90° or more in one direction and the other direction about the central position with respect to the motor case part 12U (upper case). That is, the pivoting range from the central position of the gear case part 12L may be set within a pivoting range of approximately 90° but not reaching 90° in one direction and the other direction.

In this case, the communication port (the first communication ports 27 and 27A) in communication with the first arc-shaped passages 51 and 51A and the communication port (the second communication ports 36 and 36A) in communication with the second arc-shaped passages 52 and 52A can be in communication with opposite arc-shaped passages to prevent the liquid coolant 2 flowing through the anti-cavitation plate 45 from suddenly changing the direction thereof.

Further, when the ship is advanced toward the rear side, by driving the screw 10 in the opposite direction and changing the pivot angle of the gear case part 12L, the direction of advance to the rear side of the ship can also be changed freely.

Second Embodiment

FIG. 9 is a cross-sectional view of an electric outboard motor 101 (a propulsion apparatus) of the embodiment like in FIG. 5 of the first embodiment. FIG. 10 is a side view of a connecting tube 122 corresponding to an arrow X in FIG. 9, and FIG. 11 is a side view of the connecting tube 122 corresponding to an arrow XI in FIG. 9.

The electric outboard motor 101 of this embodiment has the same overall basic configuration as the above-mentioned first embodiment. In the electric outboard motor 1 of the first embodiment, at the pivot position with a pivot angle of 90° of the gear case part 12L about the central position, circulation of the liquid coolant 2 between the motor case part 12U and the gear case part 12L stops. For this reason, in the electric outboard motor 1 of the first embodiment, the use was limited to the 90° angle position. On the other hand, the electric outboard motor 101 of this embodiment adopts a structure that allows the maximum pivot angle of the gear case part 12L centered on the central position to be 90° or more. Specifically, internal structures of the upper and lower annular spaces 49 and 49A and arrangement of the first communication ports 27 and 27A and the second communication ports 36 and 36A facing each of the annular spaces 49 and 49A are changed from those in the first embodiment. These changes are almost the same as the annular space 49 on the upper side and as the annular space 49A on the lower side. For this reason, hereinafter, only the annular space 49 on the upper side will be described in detail.

The annular grooves 28 arranged in the axial direction are formed in the outer circumferential part of the connecting tube 122 on the side of the gear case part 12L, and the annular groove 28 on the upper side forms the annular space 49 together with the inner circumferential surface of the fitting hole 23 on the side of the motor case part 12U. A pair of partition walls 150 project from the annular grooves 28 at positions spaced 180° in the circumferential direction. The inside of the annular space 49 is partitioned into the first arc-shaped passage 51 and the second arc-shaped passage 52 by the pair of partition walls 150. While this configuration is similar to that of the first embodiment, the shape of the partition wall 150 is different from that of the first embodiment.

Each of the partition walls 150 has a crank shape when viewed from an end surface in the protrusion direction facing the inner circumferential surface (closing wall) of the fitting hole 23. That is, each of the partition walls 150 has a shape in which the partition region in the annular space 49 is offset in the upward/downward direction (a widthwise direction crossing the circumferential direction of the annular space 49) on one side and the other side in the circumferential direction.

On the other hand, as shown in FIG. 10, the first communication port 27 facing the first arc-shaped passage 51 in the annular space 49 is disposed at a position offset upward by a predetermined distance d with respect to a central position of the annular space 49 in the widthwise direction. In addition, as shown in FIG. 11, the second communication port 36 facing the second arc-shaped passage 52 in the annular space 49 is disposed at a position offset downward by a predetermined distance d with respect to the central position of the annular space 49 in the widthwise direction.

In the electric outboard motor 1 of the embodiment configured as described above, even when the gear case part 12L is pivoted 90° or more from the central position in either one direction or the other direction, the upper region of the partition wall 150 on one side does not cross over the first communication port 27 disposed in the vicinity of the upper part of the annular space 49. Here, the lower region of the partition wall 150 on the other side does not cross over the second communication port 36 disposed in the vicinity of the lower part of the annular space 49. Accordingly, even when the gear case part 12L is pivoted 90° or more from the central position in either one direction or the other direction, the first communication port 27 is kept in communication with the first arc-shaped passage 51, and the second communication port 36 is kept in communication with the second arc-shaped passage 52.

In addition, since the annular space 49 on the lower side have the same structure as the upper side, even if the gear case part 12L is rotated 90° in either one direction or the other direction from the central position, the first communication port 27A is kept in communication with the first arc-shaped passage 51A, and the second communication port 36A is kept in communication with the second arc-shaped passage 52A.

As described above, since the electric outboard motor 101 of the embodiment has the same basic configuration as the first embodiment, the same effects as in the above-mentioned first embodiment can be obtained.

In addition, the electric outboard motor 101 of the embodiment can allow circulation of the fluid through the first arc-shaped passages 51 and 51A and the second arc-shaped passages 52 and 52A even when the gear case part 12L is pivoted 90° or more from the central position in either one direction or the other direction.

Accordingly, when the electric outboard motor 101 of the embodiment is employed, it is also possible to rotate the gear case part 12L 90° from the central position to make the ship move sideways.

Third Embodiment

FIG. 12 is a side view of an electric outboard motor of the embodiment corresponding to FIG. 10 of the second embodiment, and FIG. 13 is a side view corresponding to FIG. 11 of the second embodiment.

The embodiment has substantially the same configuration as the second embodiment. While each of the partition walls 150 has the crank shape when seen in the protrusion end direction in the second embodiment, a shape of each of partition walls 250 when seen in a protrusion end direction in the embodiment is an inclination shape inclined from one side toward the other side in the widthwise direction of the annular grooves 28 on one side in the circumferential direction. Even in this case of the embodiment, each of the partition walls 250 has a shape in which a partition region in the annular space 49 is offset in the circumferential direction on one side and the other side in the upward/downward direction (a widthwise direction crossing the circumferential direction of the annular space 49).

As shown in FIG. 12, the first communication port 27 facing the first arc-shaped passage 51 in the annular space 49 is disposed at a position offset upward with respect to the central position of the annular space 49 in the widthwise direction. As shown in FIG. 13, the second communication port 36 facing the second arc-shaped passage 52 in the annular space 49 is disposed at a position offset downward by a predetermined distance d with respect to the central position of the annular space 49 in the widthwise direction.

Even in this case of the embodiment, the same effects as in the second embodiment can be obtained.

The present invention is not limited to the above-mentioned embodiments, and various design changes may be made without departing from the spirit of the present invention.

For example, while a type of the propulsion apparatus is the electric outboard motor in each of the embodiments, the propulsion apparatus is not limited to the electric outboard motor and the propulsion apparatus may have a screw driven by an engine or a hydraulic motor. In addition, the propulsion apparatus is not limited to the outboard motor, but may be an inboard-outdrive engine, a POD type propulsion apparatus, or the like.

Further, while the characteristic structure of the present invention is adopted for the circulation flow channel through which the lubricating oil flows and the circulation flow channel through which the coolant flows in the above-mentioned embodiments, the fluid flow channel to be handled is not limited to this. For example, when handling the hydraulic device on the side of the lower case, it is also possible to apply the characteristic structure of the present invention to the flow channel for working liquid that actuates the hydraulic device.

In addition, while the liquid coolant and the coolant flow through the circulation flow channels in the above-mentioned embodiments, the fluid flowing through the circulation flow channel is not limited thereto. The fluid, if asked, may be a working liquid, a gas, or the like, for actuating the actuator.

Further, while the annular groove is formed in the sliding part on the side of the lower case (the gear case part 12L) to form the annular space partitioned by the partition walls in the above-mentioned embodiment, the annular groove may be formed in the sliding part on the side of the upper case (the motor case part 12U). In addition, the annular grooves may be formed in both the sliding surface on the side of the upper case (the motor case part 12U) and the sliding surface on the side of the lower case (the gear case part 12L).

In addition, while the pair of (two) partition walls that partition the annular space into the first arc-shaped passage and the second arc-shaped passage are provided in the above-mentioned embodiment, the number of the partition walls is not limited to two as long as the number of the partition walls can partition the annular space into at least the first arc-shaped passage and the second arc-shaped passage. The number of the partition walls may be three or more.

In addition, in the above-mentioned embodiments, the first arc-shaped passage and the second arc-shaped passage (the annular space partitioned by the partition walls) are formed between the cylindrical sliding parts of the upper case (the motor case part 12U) and the lower case (the gear case part 12L). However, the sliding parts that form the first arc-shaped passage and the second arc-shaped passage are not limited thereto. For example, the first arc-shaped passage and the second arc-shaped passage may be formed in flat sliding parts that are in contact with each other in the axial direction of the upper case and the lower case (a direction along the rotation center axis c1).

BRIEF DESCRIPTION OF THE REFERENCE SYMBOLS

• • 1: Electric outboard motor (propulsion apparatus)
  • 10: Screw
  • 12U: Motor case part (upper case)
  • 12L: Gear case part (lower case)
  • 25 c: First bottom wall passage (another case-side passage)
  • 27, 27A: First communication port (communication port)
  • 28: Annular groove
  • 29: first shaft passage (case-side passage)
  • 32: Second shaft passage (case-side passage)
  • 35 a: Second outer wall passage (another case-side passage)
  • 36, 36A: Second communication port (communication port)
  • 49, 49A: Annular space
  • 50, 150, 250: Partition wall
  • 51, 51A: First arc-shaped passage
  • 52, 52A: Second arc-shaped passage
  • FP: Feeding flow channel
  • RP: Returning flow channel

Claims

1. A propulsion apparatus for a ship comprising: an upper case supported by a hull;a lower case pivotably supported by the upper case;a screw disposed in an area submerged in external water in the lower case and configured to generate propulsion power;a feeding flow channel configured to feed a fluid to the lower case from the upper case via relatively pivoting sliding parts of the upper case and the lower case; anda returning flow channel configured to return the fluid to the upper case from the lower case via the sliding parts,wherein an annular space is provided between the sliding part on the side of the upper case and the sliding part on the side of the lower case and the annular space is partitioned into a first arc-shaped passage and a second arc-shaped passage by a plurality of partition walls,any one of the first arc-shaped passage and the second arc-shaped passage is in communication with the feeding flow channel, andthe other of the first arc-shaped passage and the second arc-shaped passage is in communication with the returning flow channel.

2. The propulsion apparatus for a ship according to claim 1, wherein a plurality of pairs of the feeding flow channels and the returning flow channels are provided, the sliding parts are disposed on facing cylindrical surfaces of the upper case and the lower case, andthe plurality of annular spaces corresponding to the pairs of the feeding flow channels and the returning flow channels are arranged on the cylindrical surface in an axial direction.

3. The propulsion apparatus for a ship according to claim 2, wherein two sets of the feeding flow channels and the returning flow channels are provided, lubricating oil that lubricates the inside of the upper case flows through the annular space disposed in the vicinity of the upper case of the cylindrical surface, anda coolant that cools heat-generating parts disposed inside or outside the upper case flows through the annular space disposed in the vicinity of the lower case of the cylindrical surface.

4. The propulsion apparatus for a ship according to claim 1, wherein the annular space is surrounded by an annular groove formed in one of the lower case and the upper case and a closing wall provided on the other, a case-side passage connected to each of the first arc-shaped passage and the second arc-shaped passage is formed in the one of the lower case and the upper case in which the annular groove is formed,a communication port facing each of the first arc-shaped passage and the second arc-shaped passage is formed in the closing wall, andanother case-side passage in communication with each of the first arc-shaped passage and the second arc-shaped passage through the communication port is formed in the other of the lower case and the upper case having the closing wall.

5. The propulsion apparatus for a ship according to claim 4, wherein the annular space is partitioned into two arc-shaped passages with a center angle of about 180° by a pair of partition walls, one of the passages being the first arc-shaped passage and the other being the second arc-shaped passage, and each of the communication ports is always in communication with one of the first arc-shaped passage and the second arc-shaped passage when a pivot angle of the lower case with respect to the upper case is within a range of substantially 90° from a central position in one direction and another direction.

6. The propulsion apparatus for a ship according to claim 5, wherein the communication port facing the first arc-shaped passage and the communication port facing the second arc-shaped passage are disposed to be offset in a widthwise direction crossing a circumferential direction of the annular space, and the pair of partition walls are formed in shapes in which partition regions in the annular space are offset in the circumferential direction on one side and the other side in the widthwise direction.

7. The propulsion apparatus for a ship according to claim 6, wherein the pair of partition walls are formed in crank shapes when seen from an end surface in a protrusion direction facing the closing wall.

8. The propulsion apparatus for a ship according to claim 6, wherein the pair of partition walls are formed in inclination shapes in which a shape seen from an end surface in a protrusion direction facing the closing wall is inclined from one side toward the other side in the widthwise direction on one side in the circumferential direction.

9. The propulsion apparatus for a ship according to claim 5, wherein the lower case is set not to pivot 90° or more in one direction and another direction about the central position with respect to the upper case.