PROPULSION DEVICE FOR WATER-SURFACE MOVABLE BODY

Abstract

A propulsion device for a water-surface movable body includes an upper case, a propulsion motor accommodated in the upper case, a lower case supported by the upper case so as to turn around a turning axis, a propulsor supported by the lower case, a steering motor accommodated in the upper case, and a steering deceleration mechanism configured to decelerate rotation of the steering motor. The steering deceleration mechanism includes a gear shaft arranged in parallel with an output shaft of the steering motor, an output shaft gear arranged coaxially with the output shaft of the steering motor, a ring gear arranged coaxially with the turning axis, and deceleration gears interposed between the output shaft gear and the ring gear. At least one of the deceleration gears is arranged higher than the output shaft gear in a state where the turning axis extends in a vertical direction.

Claims

1. A propulsion device for a water-surface movable body, comprising: an upper case supported by a hull of the water-surface movable body; a propulsion motor accommodated in the upper case; a lower case supported by the upper case so as to turn around a turning axis; a propulsor supported by the lower case and configured to rotate around a propulsion axis by a driving force of the propulsion motor; a steering motor accommodated in the upper case; and a steering deceleration mechanism provided on a steering force transmission path from the steering motor to the lower case and configured to decelerate rotation of the steering motor, wherein the steering deceleration mechanism includes: at least one gear shaft arranged in parallel with an output shaft of the steering motor; an output shaft gear arranged coaxially with the output shaft of the steering motor; a ring gear arranged coaxially with the turning axis; and a plurality of deceleration gears provided on the at least one gear shaft and interposed between the output shaft gear and the ring gear on the steering force transmission path, and at least one of the plurality of deceleration gears is arranged higher than the output shaft gear in a state where the turning axis extends in a vertical direction.

2. The propulsion device for the water-surface movable body according to claim 1, wherein the at least one gear shaft is arranged within a lateral dimension of the ring gear in a plan view.

3. The propulsion device for the water-surface movable body according to claim 1, wherein a contour of the steering motor is arranged within a lateral dimension of the ring gear in a plan view.

4. The propulsion device for the water-surface movable body according to claim 1, wherein the output shaft of the steering motor and the turning axis are arranged on a same straight line extending in a front-and-rear direction.

5. The propulsion device for the water-surface movable body according to claim 1, further comprising a brake mechanism configured to restrict turning of the lower case, wherein a contour of the brake mechanism is arranged within a lateral dimension of the ring gear in a plan view.

6. The propulsion device for the water-surface movable body according to claim 1, further comprising a separator that partitions an internal space of the upper case into an oil chamber and a dry chamber, wherein the steering motor includes a motor body accommodated in the dry chamber, and the plurality of deceleration gears is accommodated in the oil chamber.

7. The propulsion device for the water-surface movable body according to claim 1, further comprising a planetary deceleration mechanism provided on a driving force transmission path from the propulsion motor to the propulsor and configured to decelerate rotation of the propulsion motor, wherein the lower case includes a turning portion having a cylindrical shape centered on the turning axis, the planetary deceleration mechanism is arranged on an inner circumference of the turning portion, and the plurality of deceleration gears is arranged at a same height as the turning portion.

8. The propulsion device for the water-surface movable body according to claim 1, wherein the plurality of deceleration gears includes a downstream end gear that engages with the ring gear, and the downstream end gear is arranged highest among the plurality of deceleration gears.

9. The propulsion device for the water-surface movable body according to claim 1, wherein the plurality of deceleration gears includes an upstream end gear that engages with the output shaft gear, and the upstream end gear is arranged lowest among the plurality of deceleration gears.

Description

BRIEF DESCRIPTION OF THE DRAWING(S)

[0025] FIG. 1 is a side view showing an outboard motor according to the first embodiment;

[0026] FIG. 2 is a cross-sectional view showing the outboard motor according to the first embodiment;

[0027] FIG. 3 is a cross-sectional view showing a steering deceleration mechanism and the vicinity thereof according to the first embodiment;

[0028] FIG. 4 is a cross-sectional view showing a turning portion and the vicinity thereof according to the first embodiment;

[0029] FIG. 5 is a cross-sectional view showing a gear case and the vicinity thereof according to the first embodiment;

[0030] FIG. 6 is a plan view showing the steering deceleration mechanism and the vicinity thereof according to the first embodiment;

[0031] FIG. 7 is a cross-sectional view showing a state where a manual rotation member is in the first position according to the first embodiment;

[0032] FIG. 8 is a cross-sectional view showing a state where the manual rotation member is in the second position according to the first embodiment;

[0033] FIG. 9 is a cross-sectional view showing a turning angle detection mechanism and the vicinity thereof according to the first embodiment;

[0034] FIG. 10 is a perspective view showing the turning angle detection mechanism and the vicinity thereof according to the first embodiment; and

[0035] FIG. 11 is a cross-sectional view showing a steering deceleration mechanism and the vicinity thereof according to the second embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The First Embodiment

[0036] Hereinafter, with reference to the drawings, an outboard motor 1 (an example of a propulsion device for a water-surface movable body) according to an embodiment of the present invention will be described. An arrow Fr in each drawing indicates the front of the outboard motor 1. Hereinafter, the term coupled or coupling refers to a state where plural members are engaged with each other such that these members cannot rotate relative to each other.

[0037] As shown in FIG. 1, the outboard motor 1 is arranged outside a hull 4 of a ship 3 (an example of a water-surface movable body) such as a boat. The outboard motor 1 is attached to the rear end of the hull 4 via an attachment device 5. The attachment device 5 includes a bracket 7 that supports the outboard motor 1 via a tilt shaft 6 that extends in the lateral direction, and a clamp device 8 that detachably fixes the bracket 7 to the rear end of the hull 4. The outboard motor 1 is configured to tilt around the tilt shaft 6 by a hydraulic or electric actuator 9.

[0038] With reference to FIGS. 1 and 2, the outboard motor 1 includes an upper case 11 supported by the hull 4 of the ship 3 via the attachment device 5, a propulsion motor 12 accommodated in the upper case 11, a lower case 13 supported by the upper case 11 so as to turn around a turning axis X1, a propulsor 14 supported by the lower case 13 and configured to rotated around a propulsion axis X2 by the driving force of the propulsion motor 12, a driving shaft 15 provided on a driving force transmission path R1 from the propulsion motor 12 to the propulsor 14 and extending along the turning axis X1, a bevel gear mechanism 16 accommodated in the lower case 13 and connecting the driving shaft 15 and the propulsor 14, a planetary deceleration mechanism 17 provided on the driving force transmission path R1 and configured to decelerate the rotation of the propulsion motor 12, an oil pump 18 (an example of a refrigerant supply mechanism) configured to supply cooling oil (an example of a refrigerant) to the planetary deceleration mechanism 17, a steering motor 19 accommodated in the upper case 11, a steering deceleration mechanism 20 provided on a steering force transmission path R2 from the steering motor 19 to the lower case 13 and configured to decelerate the rotation of the steering motor 19, a brake mechanism 21 configured to restrict turning of the lower case 13, and a turning angle detection mechanism 22 configured to detect a turning angle of the lower case 13 relative to the upper case 11. Hereinafter, components of the outboard motor 1 will be described based on a state where the turning axis X1 extends in the vertical direction and the propulsion axis X2 extends in the front-and-rear direction (see FIG. 2).

<The Upper Case 11>

[0039] With reference to FIG. 3, the upper case 11 includes an upper wall 25, a lower wall 26 arranged below the upper wall 25, and a separator 27 arranged between the upper wall 25 and the lower wall 26. A communication hole 31 through which the internal space of the upper case 11 and the external space thereof communicate with each other is provided in the front-and-rear central portion of the upper wall 25. The communication hole 31 is closed by a detachable plug 32. The separator 27 partitions the internal space of the upper case 11 into an oil chamber S1 and a dry chamber S2. The oil chamber S1 is arranged below the separator 27 and contains the cooling oil. The dry chamber S2 is arranged above the separator 27 and does not contain the cooling oil. A boss 33 that protrudes upward is provided in the front-and-rear central portion of the separator 27.

<The Propulsion Motor 12>

[0040] With reference to FIG. 2, the propulsion motor 12 is accommodated in the front upper portion of the upper case 11. The propulsion motor 12 is composed of an electric motor. The propulsion motor 12 includes a motor body 35 and a motor shaft 36 extending downward from the motor body 35.

<The Lower Case 13>

[0041] With reference to FIGS. 4 and 5, the lower case 13 includes a turning portion 38 and a case body 39 arranged below the turning portion 38.

[0042] With reference to FIG. 4, the turning portion 38 has a cylindrical shape centered on the turning axis X1. A portion of the turning portion 38 except for the lower end thereof is accommodated in the upper case 11. An annular protrusion 41 is provided on the inner circumferential surface of the lower portion of the turning portion 38. Hereinafter, a portion of the internal space of the turning portion 38 higher the annular protrusion 41 will be referred to as the turning space 42.

[0043] An upper bearing 44 is arranged on the outer circumference of the upper portion of the turning portion 38. The upper bearing 44 is attached to the separator 27 of the upper case 11. A lower bearing 45 is arranged on the outer circumference of the lower portion of the turning portion 38. The lower bearing 45 is attached to the lower wall 26 of the upper case 11. According to such a configuration, the lower case 13 is supported by the upper case 11 via the upper bearing 44 and the lower bearing 45 so as to turn around the turning axis X1. An annular enlarged diameter portion 46 is provided at the upper end of the turning portion 38. The enlarged diameter portion 46 is arranged above the upper bearing 44, and a diameter of the turning portion 38 is enlarged at the enlarged diameter portion 46.

[0044] With reference to FIG. 5, the case body 39 is provided with a first bearing recess 48 arranged below the turning portion 38. The first bearing recess 48 communicates with the turning space 42 via an axis passage 49 extending in the up-and-down direction along the turning axis X1. A first bearing 50 is fitted into the first bearing recess 48.

[0045] The case body 39 is provided with a first heat exchange chamber 52 arranged on a lower front side of the first bearing recess 48. The upper portion of the first heat exchange chamber 52 communicates with the first bearing recess 48 via a first communication passage 53 extending downward toward the front.

[0046] The case body 39 is provided with a second heat exchange chamber 55 arranged in front of and above the first heat exchange chamber 52. The second heat exchange chamber 55 and the first heat exchange chamber 52 compose a heat exchange portion 56 to exchange heat with the cooling oil. The lower portion of the second heat exchange chamber 55 communicates with the lower portion of the first heat exchange chamber 52 via a second communication passage 57 extending downward toward the front. The upper portion of the second heat exchange chamber 55 is partitioned from the upper portion of the first heat exchange chamber 52 by a partition member 58. An oil filter 59 (an example of a filter member) configured to filter the cooling oil is accommodated in the upper portion of the second heat exchange chamber 55. The oil filter 59 is supported by the partition member 58 from below. The upper portion of the second heat exchange chamber 55 communicates with the turning space 42 via a third communication passage 60 arranged in front of the axis passage 49 and extending in the up-and-down direction.

[0047] The turning space 42, the axis passage 49, the first bearing recess 48, the first communication passage 53, the first heat exchange chamber 52, the second communication passage 57, the second heat exchange chamber 55, and the third communication passage 60 compose a first passage P1 of the cooling oil. The upper portion of the first passage P1 is arranged at the same height as the lower portion of the upper case 11. The height of the liquid surface of the cooling oil contained in the first passage P1 is set lower than the planetary deceleration mechanism 17 (see FIG. 4 and the like) and higher than the oil pump 18, for example. Broken line arrows in FIG. 5 indicate the flow of the cooling oil in the first passage P1.

[0048] A bullet-shaped gear case 62 extending in the front-and-rear direction is provided in the lower portion of the case body 39. The front surface of the gear case 62 is provided with a first discharge port 63 for discharging the cooling oil from the first passage P1. The first discharge port 63 is opened forward. The first discharge port 63 communicates with the lower end of the second heat exchange chamber 55 via a first discharge passage 64 that slopes downward toward the front. The first discharge port 63 is closed by a detachable first cap (not shown).

[0049] The gear case 62 of the case body 39 is provided with a second bearing recess 66 arranged below the first bearing recess 48. A second bearing 67 is fitted into the second bearing recess 66. The second bearing 67 is arranged below the first bearing 50.

[0050] The gear case 62 of the case body 39 is provided with a bevel gear chamber 69 arranged below the second bearing recess 66. The bevel gear chamber 69 communicates directly with the second bearing recess 66. The bevel gear chamber 69 accommodates the bevel gear mechanism 16 (which will be described later). The bevel gear mechanism 16 is arranged below the second bearing 67.

[0051] The case body 39 is provided with a third heat exchange chamber 71 arranged on a rear upper side of the second bearing recess 66 and the bevel gear chamber 69. The third heat exchange chamber 71 communicates with the second bearing recess 66 via a fourth communication passage 72 that extends upward toward the rear. The third heat exchange chamber 71 communicates with the bevel gear chamber 69 via a fifth communication passage 73 that extends upward toward the rear.

[0052] The bevel gear chamber 69, the second bearing recess 66, the fourth communication passage 72, the third heat exchange chamber 71, and the fifth communication passage 73 compose a second passage P2 of the cooling oil. The second passage P2 is partitioned from the first passage P1 by a sealing member 74 arranged between the first bearing 50 and the second bearing 67. The entirety of the second passage P2 is arranged lower than the upper case 11. The height of the liquid surface of the cooling oil accommodated in the second passage P2 is set lower than the second bearing 67 and higher than the bevel gear mechanism 16, for example. The type of the cooling oil contained in the second passage P2 is different from the type of the cooling oil contained in the first passage P1. For example, the viscosity of the cooling oil contained in the second passage P2 is higher than the viscosity of the cooling oil contained in the first passage P1.

[0053] The front surface of the gear case 62 of the case body 39 is provided with a second discharge port 76 for discharging the cooling oil from the second passage P2. The second discharge port 76 is arranged lower than the first discharge port 63. The second discharge port 76 is opened forward. The second discharge port 76 communicates with the front end of the bevel gear chamber 69 via a second discharge passage 77 that slopes downward toward the front. The second discharge port 76 is closed by a detachable second cap (not shown).

<The Propulsor 14>

[0054] With reference to FIG. 2, the propulsor 14 is configured to turn integrally with the lower case 13 around the turning axis X1, and to rotate relative to the lower case 13 around the propulsion axis X2. The propulsor 14 includes a propeller shaft 91 extending along the propulsion axis X2 and a propeller 92 fixed to the rear portion of the propeller shaft 91. The front portion of the propeller shaft 91 is rotatably supported by the gear case 62 of the lower case 13.

<The Driving Shaft 15>

[0055] With reference to FIG. 2, the driving shaft 15 extends in the up-and-down direction. The driving shaft 15 includes an upper shaft 94 and a lower shaft 95 arranged below the upper shaft 94 and provided coaxially with the upper shaft 94.

[0056] The upper portion of the upper shaft 94 is rotatably supported by the upper wall 25 of the upper case 11. The upper end of the upper shaft 94 is fixed to the motor shaft 36 of the propulsion motor 12. This allows the upper shaft 94 to rotate integrally with the motor shaft 36 of the propulsion motor 12.

[0057] With reference to FIG. 4, the lower portion of the upper shaft 94 is inserted into the upper portion of the lower shaft 95 so as to rotate relatively thereto. The lower portion of the upper shaft 94 is provided with an upper axial passage 99 extending in the up-and-down direction (axial direction), and a plurality of upper radial passages 100 extending radially from the upper axial passage 99 to the outer circumferential surface of the upper shaft 94.

[0058] The upper portion of the lower shaft 95 is provided with a lower axial passage 102 extending in the up-and-down direction (axial direction), an annular groove 103 provided on the outer circumferential surface of the lower shaft 95, and a lower radial passage 104 extending radially from the lower axial passage 102 to the annular groove 103. The upper end of the lower axial passage 102 communicates with the lower end of the upper axial passage 99 of the upper shaft 94.

[0059] With reference to FIG. 5, the first bearing 50 is attached to the up-and-down central portion of the lower shaft 95. The second bearing 67 is attached to the lower portion of the lower shaft 95. According to such a configuration, the lower shaft 95 is rotatably supported by the lower case 13 via the first bearing 50 and the second bearing 67.

<The Bevel Gear Mechanism 16>

[0060] With reference to FIG. 5, the bevel gear mechanism 16 includes a first bevel gear 106 arranged coaxially with the turning axis X1, and a second bevel gear 107 arranged coaxially with the propulsion axis X2 and engaging with the first bevel gear 106. The first bevel gear 106 is fixed to the lower end of the lower shaft 95 of the driving shaft 15 and configured to rotate integrally with the lower shaft 95. The second bevel gear 107 is fixed to the front end of the propeller shaft 91 of the propulsor 14 and configured to rotate integrally with the propeller shaft 91.

<The Planetary Deceleration Mechanism 17>

[0061] With reference to FIG. 4, the planetary deceleration mechanism 17 is accommodated in the turning space 42 of the turning portion 38 of the lower case 13. The planetary deceleration mechanism 17 is arranged on the inner circumference of the enlarged diameter portion 46 of the turning portion 38. The planetary deceleration mechanism 17 is, for example, composed of a planetary gear mechanism of a planetary type. In another embodiment, the planetary deceleration mechanism 17 may be composed of a planetary gear mechanism of a type (for example, a solar type or a star type) other than the planetary type.

[0062] The planetary deceleration mechanism 17 includes a sun gear 109, a plurality of planet gears 110 that engage with the sun gear 109, a planet carrier 111 that rotatably supports the plurality of planet gears 110, and an inward gear 112 that engages with the plurality of planet gears 110. The sun gear 109 is coupled to the lower portion of the upper shaft 94 and configured to rotate integrally with the upper shaft 94. The planet carrier 111 is formed integrally with the upper end of the lower shaft 95 and configured to rotate integrally with the lower shaft 95.

<The Oil Pump 18>

[0063] With reference to FIG. 4, the oil pump 18 is accommodated in the turning space 42 of the turning portion 38 of the lower case 13. The oil pump 18 is arranged lower than the enlarged diameter portion 46 and provided on the inner circumference of the turning portion 38. The oil pump 18 is arranged lower than the planetary deceleration mechanism 17. The oil pump 18 is arranged on the outer circumference of the lower shaft 95 of the driving shaft 15, and is configured to operate in conjunction with the rotation of the lower shaft 95. The oil pump 18 is, for example, a trochoid pump. In another embodiment, the oil pump 18 may be composed of a mechanical pump (for example, a screw pump) other than the trochoid pump, or may be composed of an electric pump.

[0064] An oil suction port 114 (an example of a refrigerant suction port) for sucking the cooling oil into the oil pump 18 is provided in the lower portion of the oil pump 18. The oil suction port 114 is formed in the turning portion 38 of the lower case 13, and is configured to turn integrally with the turning portion 38. The oil suction port 114 is arranged forward of the turning axis X1. The oil suction port 114 is arranged lower than the planetary deceleration mechanism 17. The oil suction port 114 communicates with the upper end of the third communication passage 60.

[0065] An oil discharge port 115 (an example of a refrigerant discharge port) for discharging the cooling oil from the oil pump 18 is provided in the upper portion of the oil pump 18. The oil discharge port 115 is formed in the turning portion 38 of the lower case 13, and is configured to turn integrally with the turning portion 38. The oil discharge port 115 is arranged lower than the planetary deceleration mechanism 17. The oil discharge port 115 communicates with the annular groove 103 of the lower shaft 95.

<The Steering Motor 19>

[0066] With reference to FIGS. 3 and 6, the steering motor 19 is accommodated in the rear portion of the upper case 11. The steering motor 19 is composed of an electric motor. The contour of the steering motor 19 is arranged within a lateral dimension W1 of a ring gear 126 (which will be described later) of the steering deceleration mechanism 20 in a plan view. The contour of the steering motor 19 is arranged within a lateral dimension W2 of the turning portion 38 of the lower case 13 in a plan view.

[0067] The steering motor 19 includes a motor body 117 and an output shaft 118 extending downward from the motor body 117. The motor body 117 is accommodated in the dry chamber S2 of the upper case 11. The output shaft 118 extends in the up-and-down direction. The output shaft 118 penetrates through the separator 27 of the upper case 11, and extends to the oil chamber S1 of the upper case 11. The output shaft 118 and the turning axis X1 are arranged on the same straight line Y extending in the front-and-rear direction.

<The Steering Deceleration Mechanism 20>

[0068] In the following, the term the upstream side or the downstream side used for the description of the steering deceleration mechanism 20 refers to the upstream side or the downstream side on the steering force transmission path R2 from the steering motor 19 to the lower case 13.

[0069] With reference to FIG. 3, the steering deceleration mechanism 20 is accommodated in the upper case 11. The steering deceleration mechanism 20 is composed of a gear train with parallel shafts. The steering deceleration mechanism 20 includes a plurality of gear shafts 121 to 123 arranged in parallel with the output shaft 118 of the steering motor 19, a detent mechanism 124 that engages with one of the gear shafts 121 to 123 (more specifically, a third gear shaft 123 which will be described later), an output shaft gear 125 arranged coaxially with the output shaft 118 of the steering motor 19, a ring gear 126 arranged coaxially with the turning axis X1, and a plurality of deceleration gears 131 to 136 provided on the plurality of gear shafts 121 to 123 and interposed between the output shaft gear 125 and the ring gear 126 on the steering force transmission path R2. FIG. 3 is a cross-sectional view along a longitudinal section bent along the steering force transmission path R2. Accordingly, the driving shaft 15, the output shaft 118 of the steering motor 19, and the plurality of gear shafts 121 to 123, which are not arranged on the same plane in an actual space, are shown on the same plane in FIG. 3.

[0070] With reference to FIG. 6, all of the plurality of gear shafts 121 to 123 are arranged within the lateral dimension W1 of the ring gear 126 in a plan view. All of the plurality of gear shafts 121 to 123 are arranged within the lateral dimension W2 of the turning portion 38 of the lower case 13 in a plan view. The plurality of gear shafts 121 to 123 includes a first gear shaft 121, a second gear shaft 122, and a third gear shaft 123. The plurality of gear shafts 121 to 123 is arranged in the order of the first gear shaft 121, the second gear shaft 122, and the third gear shaft 123 from the upstream side to the downstream side.

[0071] With reference to FIG. 3, the first gear shaft 121 and the second gear shaft 122 extend in the up-and-down direction. The upper ends of the first gear shaft 121 and the second gear shaft 122 are rotatably supported by the separator 27 of the upper case 11. The lower ends of the first gear shaft 121 and the second gear shaft 122 are rotatably supported by the lower wall 26 of the upper case 11.

[0072] The third gear shaft 123 includes an upstream rotation member 138 to which the rotation of the output shaft 118 of the steering motor 19 is transmitted, a downstream rotation member 139 provided on the downstream side of the upstream rotation member 138, and a manual rotation member 140 interposed between the upstream rotation member 138 and the downstream rotation member 139 on the steering force transmission path R2. The upstream rotation member 138, the downstream rotation member 139, and the manual rotation member 140 are arranged coaxially.

[0073] With reference to FIGS. 7 and 8, the upstream rotation member 138 has a cylindrical shape extending in the up-and-down direction (axial direction). The upstream rotation member 138 is rotatably supported by the lower wall 26 of the upper case 11. An annular upstream coupling portion 142 is provided on the inner circumferential surface of the lower portion of the upstream rotation member 138. An annular fitting groove 143 is provided on the inner circumferential surface of the up-and-down central portion and the upper portion of the upstream rotation member 138. The dimension of the fitting groove 143 in the up-and-down direction is greater than the dimension of the upstream coupling portion 142 in the up-and-down direction.

[0074] The downstream rotation member 139 has a cylindrical shape extending in the up-and-down direction (axial direction). The upper end of the downstream rotation member 139 is rotatably supported by the separator 27 of the upper case 11. The lower portion of the downstream rotation member 139 fits into the fitting groove 143 of the upstream rotation member 138 with a spigot structure so as to rotate relative to the fitting groove 143. A downstream coupling portion 144 is provided on the inner circumferential surface of the lower portion of the downstream rotation member 139 and arranged above the upstream coupling portion 142 of the upstream rotation member 138.

[0075] The manual rotation member 140 has a cylindrical shape extending in the up-and-down direction (axial direction). The upper end of the manual rotation member 140 is provided with a tool engagement portion 146 with which a rotation tool T (see FIG. 8) is engaged. The upper portion of the manual rotation member 140 is rotatably supported by the upper wall 25 of the upper case 11. The upper portion of the manual rotation member 140 is inserted into the communication hole 31 of the upper wall 25. A manual rotation shaft portion 147 is provided at the lower end of the manual rotation member 140. The manual rotation shaft portion 147 is arranged on the inner circumference of the upstream rotation member 138 and the downstream rotation member 139. A manual coupling portion 148 is provided on the outer circumferential surface of the manual rotation shaft portion 147.

[0076] A first engagement recess 151 and a second engagement recess 152 are provided on the outer circumferential surface of the up-and-down central portion of the manual rotation member 140. The first engagement recess 151 and the second engagement recess 152 are curved in an arc. The second engagement recess 152 is arranged below the first engagement recess 151.

[0077] The manual rotation member 140 is configured to move in the up-and-down direction relative to the upstream rotation member 138 and the downstream rotation member 139. More specifically, the manual rotation member 140 is configured to move in the up-and-down direction between a first position (see FIG. 7) and a second position (see FIG. 8) that is shifted upward from the first position. In a state where the manual rotation member 140 is in the first position, the manual coupling portion 148 is coupled to the upstream coupling portion 142 and the downstream coupling portion 144 by a spline structure. Accordingly, the rotation of the upstream rotation member 138 and the downstream rotation member 139 relative to the manual rotation member 140 is restricted. In a state where the manual rotation member 140 is in the second position, the manual coupling portion 148 is decoupled from the upstream coupling portion 142 (that is, coupling of the manual coupling portion 148 and the upstream coupling portion 142 by a spline structure is released), and the manual coupling portion 148 is coupled to the downstream coupling portion 144 by a spline structure. Accordingly, the rotation of the manual rotation member 140 relative to the upstream rotation member 138 is allowed, and the rotation of the downstream rotation member 139 relative to the manual rotation member 140 is restricted.

[0078] With reference to FIG. 9, the detent mechanism 124 includes an engagement body 155 supported by a resolver holder 169 (which will be described later) of the turning angle detection mechanism 22, and a biasing body 156 interposed between the resolver holder 169 and the engagement body 155. The engagement body 155 is configured to move in a horizontal direction (a direction perpendicular to the up-and-down direction) between an engagement position (see a solid circle in FIG. 9) and a disengagement position (see a two-dot chain circle in FIG. 9). In the engagement position, the engagement body 155 engages with either the first engagement recess 151 or the second engagement recess 152 of the manual rotation member 140. In the disengagement position, the engagement body 155 disengages from the first engagement recess 151 and the second engagement recess 152. The biasing body 156 is composed of a compression coil spring. The biasing body 156 biases the engagement body 155 to the engagement position.

[0079] With reference to FIG. 7, in a state where the manual rotation member 140 is in the first position, the engagement body 155 is in the engagement position and engages with the first engagement recess 151 of the manual rotation member 140. Accordingly, the manual rotation member 140 is held in the first position, and an inadvertent movement of the manual rotation member 140 from the first position to the second position is restricted. With reference to FIG. 8, in a state where the manual rotation member 140 is in the second position, the engagement body 155 is in the engagement position and engages with the second engagement recess 152 of the manual rotation member 140. Accordingly, the manual rotation member 140 is held in the second position, and an inadvertent movement of the manual rotation member 140 from the second position to the first position is restricted.

[0080] With reference to FIG. 3, the output shaft gear 125 is accommodated in the oil chamber S1 of the upper case 11. The output shaft gear 125 is coupled to the output shaft 118 of the steering motor 19 and configured to rotate integrally with the output shaft 118 of the steering motor 19. The output shaft gear 125 is arranged right below the motor body 117 of the steering motor 19. The output shaft gear 125 may be formed integrally with the output shaft 118 of the steering motor 19.

[0081] The ring gear 126 is accommodated in the oil chamber S1 of the upper case 11. The ring gear 126 is coupled to the outer circumferential surface of the turning portion 38 of the lower case 13 between the upper bearing 44 and the lower bearing 45 and configured to rotate integrally with the turning portion 38. The ring gear 126 is arranged higher than the output shaft gear 125. The ring gear 126 is arranged at substantially the same height as the oil pump 18.

[0082] All of the plurality of deceleration gears 131 to 136 are accommodated in the oil chamber S1 of the upper case 11. All of the plurality of deceleration gears 131 to 136 are arranged at the same height as the turning portion 38 of the lower case 13. With reference to FIG. 6, all of the plurality of deceleration gears 131 to 136 are arranged within the lateral dimension W1 of the ring gear 126 in a plan view. Preferably, the outer diameters (contours) of the plurality of deceleration gears 131 to 136 are arranged within the lateral dimension W1 of the ring gear 126 in a plan view.

[0083] The plurality of deceleration gears 131 to 136 includes a first deceleration gear 131 (an example of an upstream end gear), a second deceleration gear 132, a third deceleration gear 133, a fourth deceleration gear 134, a fifth deceleration gear 135, and a sixth deceleration gear 136 (an example of a downstream end gear). The plurality of deceleration gears 131 to 136 is arranged in the order of the first deceleration gear 131, the second deceleration gear 132, the third deceleration gear 133, the fourth deceleration gear 134, the fifth deceleration gear 135, and the sixth deceleration gear 136 from the upstream side to the downstream side.

[0084] The first deceleration gear 131 is fixed to the outer circumferential surface of the first gear shaft 121 and configured to rotate integrally with the first gear shaft 121. The first deceleration gear 131 engages with the output shaft gear 125. The first deceleration gear 131 and the output shaft gear 125 compose a first deceleration gear unit. The first deceleration gear 131 is arranged at the same height as the output shaft gear 125.

[0085] The second deceleration gear 132 is formed integrally with the first gear shaft 121 and configured to rotate integrally with the first gear shaft 121. The second deceleration gear 132 is arranged coaxially with the first deceleration gear 131 and has a smaller diameter than the first deceleration gear 131. The second deceleration gear 132 is arranged lower than the output shaft gear 125.

[0086] The third deceleration gear 133 is fixed to the outer circumferential surface of the second gear shaft 122 and configured to rotate integrally with the second gear shaft 122. The third deceleration gear 133 engages with the second deceleration gear 132. The third deceleration gear 133 and the second deceleration gear 132 compose a second deceleration gear unit. The third deceleration gear 133 is arranged lower than the output shaft gear 125.

[0087] The fourth deceleration gear 134 is formed integrally with the second gear shaft 122 and configured to rotate integrally with the second gear shaft 122. The fourth deceleration gear 134 is arranged coaxially with the third deceleration gear 133 and has a smaller diameter than the third deceleration gear 133. The fourth deceleration gear 134 is arranged at the same height as the output shaft gear 125.

[0088] The fifth deceleration gear 135 is formed integrally with the upper portion of the upstream rotation member 138 of the third gear shaft 123 and configured to rotate integrally with the upstream rotation member 138. The fifth deceleration gear 135 engages with the fourth deceleration gear 134. The fifth deceleration gear 135 and the fourth deceleration gear 134 compose a third deceleration gear unit. The fifth deceleration gear 135 is arranged at the same height as the output shaft gear 125. A portion of the fifth deceleration gear 135 is arranged between the upper bearing 44 and the lower bearing 45.

[0089] The sixth deceleration gear 136 is formed integrally with the upper portion of the downstream rotation member 139 of the third gear shaft 123 and configured to rotate integrally with the downstream rotation member 139. The sixth deceleration gear 136 engages with the ring gear 126. The sixth deceleration gear 136 and the ring gear 126 compose a fourth deceleration gear unit. The sixth deceleration gear 136 is arranged coaxially with the fifth deceleration gear 135 and has a smaller diameter than the fifth deceleration gear 135. The sixth deceleration gear 136 is arranged higher than the output shaft gear 125. The sixth deceleration gear 136 is arranged highest among the plurality of deceleration gears 131 to 136.

<The Brake Mechanism 21>

[0090] With reference to FIGS. 3 and 6, the brake mechanism 21 is arranged coaxially with the output shaft 118 of the steering motor 19. The brake mechanism 21 is arranged right below the motor body 117 of the steering motor 19. The contour of the brake mechanism 21 is arranged within the lateral dimension W1 of the ring gear 126 in a plan view. The contour of the brake mechanism 21 is arranged within the lateral dimension W2 of the turning portion 38 of the lower case 13 in a plan view.

[0091] With reference to FIG. 3, the brake mechanism 21 includes a brake case 158, an electromagnet 159 accommodated in the brake case 158, a fixed plate 160 spaced apart from the electromagnet 159 in the up-and-down direction, a rotation plate 161 arranged between the electromagnet 159 and the fixed plate 160, configured to move in the up-and-down direction, and configured to rotate integrally with the output shaft 118 of the steering motor 19, a movable plate 162 arranged between the electromagnet 159 and the rotation plate 161 and configured to move in the up-and-down direction, and a plurality of compression coil springs 163 arranged between the brake case 158 and the movable plate 162.

[0092] When the outboard motor 1 is not used, the movable plate 162 presses the rotation plate 161 against the fixed plate 160 by the biasing force of the compression coil springs 163. Accordingly, the rotation of the rotation plate 161 and the output shaft 118 of the steering motor 19 is restricted. Further, turning of the lower case 13, which is connected to the output shaft 118 of the steering motor 19 via the steering deceleration mechanism 20, is restricted. In contrast, when the outboard motor 1 is used, the electromagnet 159 is energized and attracts the movable plate 162, and pressing of the rotation plate 161 against the fixed plate 160 by the movable plate 162 is released. Accordingly, the rotation of the rotation plate 161 and the output shaft 118 of the steering motor 19 is allowed. Further, turning of the lower case 13, which is connected to the output shaft 118 of the steering motor 19 via the steering deceleration mechanism 20, is allowed.

<The Turning Angle Detection Mechanism 22>

[0093] With reference to FIG. 7, the turning angle detection mechanism 22 is accommodated in the dry chamber S2 of the upper case 11. The turning angle detection mechanism 22 includes a detection shaft 165 provided separately from the gear shafts 121 to 123 of the plurality of deceleration gears 131 to 136, a connection gear unit 166 (an example of a connection unit) that connects the third gear shaft 123 (a gear shaft of the fifth deceleration gear 135 and the sixth deceleration gear 136) and the detection shaft 165, a collar 167 arranged coaxially with the detection shaft 165, a resolver 168 (an example of a detection unit) configured to detect the rotation angle of the detection shaft 165, a resolver holder 169 arranged on the outer circumference of the resolver 168, and a fastening nut 170 (an example of a rotation restricting member) that engages with the detection shaft 165.

[0094] With reference to FIGS. 9 and 10, the detection shaft 165 extends in the up-and-down direction. The lower portion of the detection shaft 165 is rotatably supported by the separator 27 of the upper case 11. An annular locking protrusion 172 is provided on the outer circumferential surface of the up-and-down central portion of the detection shaft 165.

[0095] The connection gear unit 166 includes a driving gear 174 arranged on the third gear shaft 123, and a driven gear 175 arranged on the detection shaft 165 and engaging with the driving gear 174. The driving gear 174 is formed integrally with the manual rotation member 140 of the third gear shaft 123 and configured to rotate integrally with the manual rotation member 140. The driving gear 174 has a smaller diameter than the sixth deceleration gear 136. The driven gear 175 abuts against the locking protrusion 172 of the detection shaft 165 from above. The inner circumferential surface of the driven gear 175 is not coupled to the outer circumferential surface of the detection shaft 165 by a spline structure, but fits to the outer circumferential surface of the detection shaft 165 so as to rotate relatively thereto. With reference to FIG. 3, the gear ratio between the driving gear 174 and the driven gear 175 is the same as the gear ratio between the sixth deceleration gear 136 and the ring gear 126. Accordingly, the rotation speed of the detection shaft 165 is the same as the turning speed of the lower case 13.

[0096] With reference to FIGS. 9 and 10, the collar 167 has a cylindrical shape extending in the up-and-down direction. The collar 167 is configured to rotate integrally with the detection shaft 165. The collar 167 is arranged above the driven gear 175. The lower end of the collar 167 abuts against the driven gear 175 from above. A pair of flat surfaces 177 (only one of the flat surfaces 177 is shown in FIG. 10) are provided on the outer circumferential surface of the lower portion of the collar 167. A coupling recess 178 is provided on the outer circumferential surface of the upper portion of the collar 167.

[0097] The resolver 168 includes a rotor 180 configured to rotate integrally with the detection shaft 165 and the collar 167, and a stator 181 arranged on the outer circumference of the rotor 180. The rotor 180 has an annular shape and is coupled to the coupling recess 178 of the collar 167. The stator 181 outputs a detection signal (an analog signal) corresponding to the rotational position of the rotor 180.

[0098] The resolver holder 169 includes an annular holder body 183 arranged on the outer circumference of the stator 181 of the resolver 168, and a protruding piece 184 that protrudes horizontally from the outer circumferential surface of the holder body 183. The stator 181 of the resolver 168 is fixed to the holder body 183. The holder body 183 is provided with a pin hole 185 formed in the horizontal direction. The tip of the protruding piece 184 is fixed to the boss 33 of the separator 27 of the upper case 11.

[0099] The fastening nut 170 has an annular shape and is arranged on the inner circumference of the stator 181 of the resolver 168. The outer diameter D1 of the lower end of the fastening nut 170 is larger than the inner diameter D2 of the rotor 180 of the resolver 168. The fastening nut 170 abuts against the rotor 180 from above, thereby preventing the rotor 180 from falling off the collar 167. The collar 167 and the driven gear 175 are sandwiched between the fastening nut 170 and the locking protrusion 172 of the detection shaft 165.

[0100] The fastening nut 170 is configured to move in the up-and-down direction between an allowing position (see a two-dot chain line in FIG. 9) and a restricting position (see a solid line in FIG. 9) that is shifted downward from the allowing position. When the fastening nut 170 is in the allowing position, the driven gear 175 is not pressed against the locking protrusion 172 of the detection shaft 165. Accordingly, the detection shaft 165 is allowed to rotate relative to the driven gear 175. In contrast, when the fastening nut 170 is in the restricting position, the driven gear 175 is pressed against the locking protrusion 172 of the detection shaft 165 by the fastening force of the fastening nut 170. Accordingly, the rotation of the detection shaft 165 relative to the driven gear 175 is restricted, and the driven gear 175 and the detection shaft 165 can rotate integrally.

<Propulsion and Turning of the Ship 3>

[0101] With reference to FIG. 2, when the motor shaft 36 of the propulsion motor 12 rotates in a normal direction, the rotation of the motor shaft 36 is transmitted to the planetary deceleration mechanism 17 via the upper shaft 94, and the rotation of the motor shaft 36 is decelerated by the planetary deceleration mechanism 17. The decelerated rotation of the motor shaft 36 is transmitted to the lower shaft 95, and the lower shaft 95 rotates accordingly. The rotation of the lower shaft 95 is transmitted to the propulsor 14 via the bevel gear mechanism 16, and the propulsor 14 rotates in one direction around the propulsion axis X2. This applies a forward propulsion force to the ship 3, and the ship 3 moves forward accordingly. Similarly, when the motor shaft 36 of the propulsion motor 12 rotates in a reverse direction opposite to the normal direction, the propulsor 14 rotates in the direction opposite to the one direction around the propulsion axis X2. This applies a rearward propulsion force to the ship 3, and the ship 3 moves rearward accordingly.

[0102] With reference to FIG. 3, when the output shaft 118 of the steering motor 19 rotates in a normal direction, the rotation of the output shaft 118 is transmitted to the steering deceleration mechanism 20, and the rotation of the output shaft 118 is decelerated by the steering deceleration mechanism 20. The decelerated rotation of the output shaft 118 is transmitted to the lower case 13, and the lower case 13 and the propulsor 14 turn in one direction around the turning axis X1. This applies the turning force toward one lateral side to the ship 3, and the ship 3 turns to the one lateral side accordingly. Similarly, when the output shaft 118 of the steering motor 19 rotates in a reverse direction opposite to the normal direction, the lower case 13 and the propulsor 14 turn around the turning axis X1 in the direction opposite to the one direction. This applies the turning force toward the other lateral side to the ship 3, and the ship 3 turns to the other lateral side accordingly.

<Effects>

[0103] In the first embodiment, the steering deceleration mechanism 20 is composed of a gear train with parallel shafts, and the sixth deceleration gear 136 is arranged higher than the output shaft gear 125. Accordingly, as compared with a case where the plurality of deceleration gears 131 to 136 are arranged downward from the output shaft gear 125 and the sixth deceleration gear 136 is arranged lower than the output shaft gear 125, the overall height of the outboard motor 1 (especially, the steering deceleration mechanism 20) is reduced, so that the top of the outboard motor 1 can be lowered.

[0104] Further, the output shaft gear 125 is arranged lower than the sixth deceleration gear 136 that engages with the ring gear 126. Accordingly, the position of the upper end of the steering deceleration mechanism 20 can be lowered, so that the top of the outboard motor 1 can be further lowered.

[0105] Further, the output shaft gear 125, the ring gear 126, and the plurality of deceleration gears 131 to 136 compose four deceleration gear units. Accordingly, large deceleration can be achieved without using a planetary gear mechanism.

The Second Embodiment

[0106] Next, an outboard motor 201 (an example of a propulsion device for a water-surface movable body) according to the second embodiment of the present invention will be described. Components other than a steering deceleration mechanism 203 are similar to those of the outboard motor 1 according to the first embodiment, and therefore the descriptions thereof will be omitted. Regarding the steering deceleration mechanism 203, the descriptions similar to those of the steering deceleration mechanism 20 according to the first embodiment will be omitted.

<The Steering Deceleration Mechanism 203>

[0107] With reference to FIG. 11, the steering deceleration mechanism 203 is composed of a gear train with parallel shafts. The steering deceleration mechanism 203 includes a plurality of gear shafts 211 to 214 arranged in parallel with the output shaft 118 of the steering motor 19, an output shaft gear 215 arranged coaxially with the output shaft 118 of the steering motor 19, a ring gear 216 arranged coaxially with the turning axis X1, and a plurality of deceleration gears 221 to 228 provided on the plurality of gear shafts 211 to 214 and interposed between the output shaft gear 215 and the ring gear 216 on a steering force transmission path R2.

[0108] The plurality of gear shafts 211 to 214 include a first gear shaft 211, a second gear shaft 212, a third gear shaft 213, and a fourth gear shaft 214. The plurality of gear shafts 211 to 214 are arranged in the order of the first gear shaft 211, the second gear shaft 212, the third gear shaft 213, and the fourth gear shaft 214 from the upstream side to the downstream side.

[0109] The plurality of deceleration gears 221 to 228 include a first deceleration gear 221 (an example of an upstream end gear), a second deceleration gear 222, a third deceleration gear 223, a fourth deceleration gear 224, a fifth deceleration gear 225, a sixth deceleration gear 226, a seventh deceleration gear 227, and an eighth deceleration gear 228 (an example of a downstream end gear). The plurality of deceleration gears 221 to 228 are arranged in the order of the first deceleration gear 221, the second deceleration gear 222, the third deceleration gear 223, the fourth deceleration gear 224, the fifth deceleration gear 225, the sixth deceleration gear 226, the seventh deceleration gear 227, and the eighth deceleration gear 228 from the upstream side to the downstream side.

[0110] The first deceleration gear 221 and the second deceleration gear 222 are configured to rotate integrally with the first gear shaft 211. The first deceleration gear 221 engages with the output shaft gear 215 and is arranged at the same height as the output shaft gear 215. The first deceleration gear 221 is arranged lowest among the plurality of deceleration gears 221 to 228. The second deceleration gear 222 is arranged higher than the output shaft gear 215.

[0111] The third deceleration gear 223 and the fourth deceleration gear 224 are configured to rotate integrally with the second gear shaft 212. The third deceleration gear 223 engages with the second deceleration gear 222. The third deceleration gear 223 and the fourth deceleration gear 224 are arranged higher than the output shaft gear 215.

[0112] The fifth deceleration gear 225 and the sixth deceleration gear 226 are configured to rotate integrally with the third gear shaft 213. The fifth deceleration gear 225 engages with the fourth deceleration gear 224. The fifth deceleration gear 225 and the sixth deceleration gear 226 are arranged higher than the output shaft gear 215.

[0113] The seventh deceleration gear 227 and the eighth deceleration gear 228 are configured to rotate integrally with the fourth gear shaft 214. The seventh deceleration gear 227 engages with the sixth deceleration gear 226. The eighth deceleration gear 228 engages with the ring gear 216. The seventh deceleration gear 227 and the eighth deceleration gear 228 are arranged higher than the output shaft gear 215.

<Effects>

[0114] In the present embodiment, the steering deceleration mechanism 203 is composed of a gear train with parallel shafts, and the second to eighth deceleration gears 222 to 228 (i.e., all of the deceleration gears except for the first deceleration gear 221) are arranged higher than the output shaft gear 215. Accordingly, as compared with a case where the plurality of deceleration gears 221 to 228 are arranged downward from the output shaft gear 215 and the second to eighth deceleration gears 222 to 228 are arranged lower than the output shaft gear 215, the overall height of the outboard motor 201 (especially, the steering deceleration mechanism 203) is reduced, so that the top of the outboard motor 201 can be lowered.

[0115] Further, the output shaft gear 215 is arranged lower than the eighth deceleration gear 228 that engages with the ring gear 216. Accordingly, the position of the upper end of the steering deceleration mechanism 203 can be lowered, so that the top of the outboard motor 201 can be further lowered.

<Modifications>

[0116] In the first and second embodiments, the steering deceleration mechanism 20, 203 includes a plurality of gear shafts. In another embodiment, the steering deceleration mechanism 20, 203 may include only one gear shaft.

[0117] In the first and second embodiments, the outboard motor 1 arranged outside the ship 3 is an example of the propulsion device for the water-surface movable body. In another embodiment, an inboard motor arranged inside the ship 3 may be an example of the propulsion device for the water-surface movable body.

[0118] Concrete embodiments of the present invention have been described in the foregoing, but the present invention should not be limited by the foregoing embodiments and various modifications and alterations are possible within the scope of the present invention.