Ship propulsion systems and ships

Abstract

Reduce rattle noise from ship propulsion systems. [Solution] The ship propulsion system comprises an engine, a propeller shaft, a transmission mechanism, a rotating body, a non-rotating body, an elastic body, a housing, a contained body, and a pusher. The transmission mechanism has a drive gear that rotates by the driving force of the engine and a driven gear that meshes with the drive gear. The rotating body rotates in conjunction with the rotation of the propeller shaft. The rotation of the non-rotating body is restricted from rotating around the propeller shaft. The elastic body biases the rotating body and the non-rotating body to contact each other. The housing has a first surface that inclins outward from the radial center side of the propeller shaft toward the other axial side. The housing rotates in conjunction with the rotation of the propeller shaft. The contained body is in contact with the first surface and is radially movable. The pusher has a first part that contacts the contained body and a second part that contacts one of the rotating body and the non-rotating body located on the other axial side.

Description

Technical Field

[0006] ,

[0007] , ,

[0001] The technology disclosed in this specification relates to a ship propulsion machine and a ship.

Background Art

[0002] Known ship propulsion machines include an engine, an output shaft, an input pinion that rotates by the driving force of the engine, a forward gear and a reverse gear that mesh with the input pinion, and an actuator. The actuator reduces rattling noise by braking the forward gear or the reverse gear. The driving method of the actuator is electric, hydraulic or pneumatic (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There was room for improvement in reducing the rattling noise of the ship propulsion machine. ​​​​​​​​​​​​​(1) A ship propulsion system disclosed herein comprises an engine, a propeller shaft, a transmission mechanism, a rotating body, a non-rotating body, an elastic body, a housing, a casing, and a pusher. The transmission mechanism transmits the driving force of the engine to the propeller shaft. The transmission mechanism has a drive gear that rotates by the driving force of the engine and a driven gear that meshes with the drive gear. The rotating body is positioned around the propeller shaft. The rotating body is movable in the axial direction of the propeller shaft and rotates around the propeller shaft as the propeller shaft rotates. The non-rotating body is positioned around the propeller shaft and is adjacent to the rotating body in the axial direction. The non-rotating body is movable in the axial direction and its rotation around the propeller shaft is restricted. The elastic body pushes at least one of the rotating body and the non-rotating body to one side in the axial direction, biasing the rotating body and the non-rotating body to contact each other. The housing covers the outer circumference of the propeller shaft. The housing has a first surface facing the other side in the axial direction, which is inclined outward from the radial center of the propeller shaft toward the other side in the axial direction. The housing rotates around the propeller shaft as the propeller shaft rotates. The housing is in contact with the first surface and is movable in the radial direction. The pusher is movable in the axial direction. The pusher has a first portion that is in contact with the other end of the housing in the axial direction, and a second portion that is in contact with the one end of the rotating body and the non-rotating body located on the other side in the axial direction.

[0008] According to this ship propulsion system, rattle noise can be reduced by applying friction to the propeller shaft through the action of an elastic body, and the friction applied to the propeller shaft can be attenuated as the rotational speed of the propeller shaft increases.

[0009] (2) Other ship propulsion systems disclosed herein include an engine, a shaft, a transmission mechanism, a rotating body, a non-rotating body, an elastic body, a housing, a casing, and a pusher. The transmission mechanism transmits the driving force of the engine to the shaft. The transmission mechanism includes a drive gear that rotates by the driving force of the engine and a driven gear that meshes with the drive gear. The rotating body is positioned around the shaft. The rotating body is movable in the axial direction of the shaft and rotates around the shaft as the shaft rotates. The non-rotating body is positioned around the shaft and is adjacent to the rotating body in the axial direction. The non-rotating body is movable in the axial direction and its rotation around the shaft is restricted. The elastic body pushes at least one of the rotating body and the non-rotating body to one side in the axial direction, biasing the rotating body and the non-rotating body to contact each other. The housing covers the outer circumference of the shaft. The housing has a first surface facing the other side in the axial direction, which is inclined outward from the radial center of the shaft toward the other side in the axial direction. The housing rotates around the shaft as the shaft rotates. The housing is in contact with the first surface and is movable in the radial direction. The pusher is movable in the axial direction. The pusher has a first portion in contact with the other end of the housing in the axial direction, and a second portion in contact with the one end of the rotating body and the non-rotating body located on the other side in the axial direction.

[0010] According to this ship propulsion system, rattle noise can be reduced by applying friction to the shaft through the action of an elastic body, and the friction applied to the shaft can be dampened as the rotational speed of the shaft increases.

[0011] Furthermore, the technologies disclosed herein can be implemented in various forms, for example, in the form of an outboard motor, a ship equipped with an outboard motor and a hull, and so on. [Effects of the Invention]

[0012] According to this ship propulsion system, rattle noise can be reduced by applying friction to the shaft through the action of an elastic body, and the friction applied to the shaft can be dampened as the rotational speed of the shaft increases. [Brief explanation of the drawing]

[0013] [Figure 1] A perspective view illustrating the ship's configuration. [Figure 2] A schematic side view showing the configuration of the outboard motor. [Figure 3] Diagram illustrating the detailed configuration around the propeller shaft. [Figure 4] Figure 3 is an explanatory diagram showing a cross-section of the outboard motor at position IV-IV. [Figure 5] A diagram illustrating the detailed configuration around the propeller shaft when the engine's rotational speed is relatively low. [Figure 6] A diagram illustrating the detailed configuration around the propeller shaft when the engine body is rotating at a relatively high speed. [Figure 7] A conceptual diagram illustrating the forces acting on the roller. [Modes for carrying out the invention]

[0014] A. Embodiments: (Composition of ship 10) FIG. 1 is a perspective view schematically showing the configuration of the ship 10. In FIG. 1 and other drawings described later, arrows indicating respective directions based on the position of the ship 10 are shown. In each drawing, arrows indicating FRONT, REAR, LEFT, RIGHT, UPPER, and LOWER are shown. The front-rear direction, left-right direction, and up-down direction (vertical direction) are directions orthogonal to each other. Note that the axis or member extending in the front-rear direction in this specification does not necessarily have to be parallel to the front-rear direction. The axis or member extending in the front-rear direction includes an axis or member inclined within a range of ±45° with respect to the front-rear direction. Similarly, the axis or member extending in the up-down direction includes an axis or member inclined within a range of ±45° with respect to the up-down direction, and the axis or member extending in the left-right direction includes an axis or member inclined within a range of ±45° with respect to the left-right direction.

[0015] The ship 10 includes a hull 200 and an outboard motor 100. In this embodiment, the ship 10 includes one outboard motor 100, but the ship 10 may include a plurality of outboard motors 100.

[0016] (Configuration of the hull 200) The hull 200 is a part where the crew of the ship 10 boards. The hull 200 has a hull main body 202, a cockpit 240, and a steering device 250. A living space 204 is formed in the hull main body 202. The cockpit 240 is installed in the living space 204. The steering device 250 is installed near the cockpit 240. The steering device 250 is a device for ship operation. The steering device 250 has, for example, a steering wheel 252, a shift throttle lever 254, a monitor 256, and an input device 258. Further, the hull 200 has a partition wall 220 and a transom 210. The partition wall 220 partitions the rear end of the living space 204. The transom 210 is located at the rear end of the hull 200. In the front-rear direction, a space 206 exists between the transom 210 and the partition wall 220.

[0017] (Configuration of the outboard motor 100) FIG. 2 is a side view schematically showing the configuration of the outboard motor 100. Hereinafter, unless otherwise specified, the outboard motor 100 in the reference posture will be described. The reference posture is a posture in which the rotation axis Ac of the crankshaft 123 described later extends in the vertical direction and the rotation axis Ap of the propeller shaft 136 described later extends in the front-rear direction. Each of the front-rear direction, the left-right direction, and the vertical direction is defined based on the outboard motor 100 in the reference posture. The outboard motor 100 is an example of a marine propulsion unit.

[0018] The outboard motor 100 is a device that generates a thrust for propelling the ship 10. The outboard motor 100 is attached to the transom 210 at the rear part of the hull 200. The outboard motor 100 includes an outboard motor main body 110 and a suspension device 150.

[0019] (Configuration of the outboard motor main body 110) The outboard motor main body 110 includes an engine assembly 120, a cowl 112, a casing 116, a drive shaft 132, a propeller shaft 136, a propeller 111, a transmission mechanism 140, a silencing device 300, and a housing 350.

[0020] The engine assembly 120 is an aggregate of a plurality of components including an engine body 122. In addition to the engine body 122, the engine assembly 120 includes intake system components 126 (e.g., throttle body, supercharger, etc.) and electrical components 128 (e.g., fuse box, ECU, steering CU, etc.). The engine assembly 120 is disposed relatively above in the outboard motor 100.

[0021] The engine body 122 is a prime mover that generates power. The engine body 122 is, for example, an internal combustion engine. The engine body 122 has a crankshaft 123 that converts the reciprocating motion of a piston (not shown) into rotational motion. The crankshaft 123 is positioned such that its axis of rotation Ac extends in the vertical direction. The crankshaft 123 has journals 124 and splines 125. The journals 124 support the crankshaft 123 itself at the bearing portion of the crankcase (not shown). The splines 125 are locations where multiple longitudinal grooves are formed for connection with the drive shaft 132.

[0022] The cowl 112 is a housing located on top of the outboard motor body 110. The cowl 112 has an upper cowl 113 and a lower cowl 114. The upper cowl 113 constitutes the upper part of the cowl 112. The lower cowl 114 constitutes the lower part of the cowl 112. The upper cowl 113 is detachably attached to the lower cowl 114. The cowl 112 houses at least a portion of the engine assembly 120.

[0023] The casing 116 is a housing located at the bottom of the outboard motor body 110. The casing 116 is located below the cowl 112. The casing 116 has an upper case 117 and a lower case 118. The upper case 117 constitutes the upper part of the casing 116. The lower case 118 constitutes the lower part of the casing 116.

[0024] The drive shaft 132 is a rod-shaped member that extends vertically. The upper end of the drive shaft 132 is connected to a spline 125 in the engine body 122. The drive shaft 132 extends downward from the connection point with the spline 125. The drive shaft 132 rotates together with the crankshaft 123 due to the driving force of the engine body 122. At least a portion of the drive shaft 132 is housed in the casing 116.

[0025] The propeller shaft 136 is a rod-shaped member. The propeller shaft 136 is positioned relatively below the outboard motor body 110, with its rotation axis Ap extending in the longitudinal direction. That is, the axial direction of the propeller shaft 136 coincides with the longitudinal direction of the outboard motor 100. One axial end of the propeller shaft 136 is located on the rear side of the outboard motor 100, and the other axial end of the propeller shaft 136 is located on the front side of the outboard motor 100. The front end of the propeller shaft 136 is housed in the lower case 118. The rear end of the propeller shaft 136 protrudes rearward from the lower case 118. The propeller shaft 136 is an example of a shaft.

[0026] The propeller 111 is a rotating body having multiple blades. The propeller 111 is attached to the rear end of the propeller shaft 136. The propeller 111 rotates together with the propeller shaft 136. The propeller 111 generates thrust for the ship 10 by rotating.

[0027] The transmission mechanism 140 is a mechanism that transmits the driving force of the engine body 122 to the propeller shaft 136. The transmission mechanism 140 includes a first gear 141, a second gear 142, a third gear 143, and a dog clutch 145. The first gear 141 is an example of a drive gear. The second gear 142 and the third gear 143 are examples of driven gears.

[0028] The first gear 141 is connected to the lower end of the drive shaft 132. The first gear 141 rotates together with the drive shaft 132 due to the driving force of the engine body 122. The axis of rotation of the first gear 141 is parallel to the axis of rotation Ac of the crankshaft 123. In other words, the axis of rotation of the first gear 141 is parallel in the vertical direction.

[0029] The second gear 142 and the third gear 143 are tubular gears that surround the front end of the propeller shaft 136. The rotation axes of the second gear 142 and the third gear 143 are parallel to the rotation axis Ap of the propeller shaft 136. In other words, the rotation axes of the second gear 142 and the third gear 143 are parallel to the horizontal direction and perpendicular to the rotation axis of the first gear 141. Each of the second gear 142 and the third gear 143 meshes with the first gear 141. As a result, the driving force of the engine body 122 is transmitted to the second gear 142 and the third gear 143 via the first gear 141.

[0030] The dog clutch 145 is positioned between the second gear 142 and the third gear 143 in the longitudinal direction. The dog clutch 145 is tubular and surrounds the front end of the propeller shaft 136. The dog clutch 145 is connected to the propeller shaft 136, for example, by a spline. The dog clutch 145 rotates together with the propeller shaft 136.

[0031] The dog clutch 145 is movable in the forward and backward directions. More specifically, the dog clutch 145 is movable between a first engagement position in which it is connected to the second gear 142, a second engagement position in which it is connected to the third gear 143, and a disengagement position in which it is separated from the second gear 142 and the third gear 143. When the dog clutch 145 is in the first engagement position, the rotation of the second gear 142 is transmitted to the dog clutch 145, and the rotation of the dog clutch 145 is transmitted to the propeller shaft 136. This causes the propeller 111 to rotate in a direction that moves the vessel 10 forward. When the dog clutch 145 is in the second engagement position, the rotation of the third gear 143 is transmitted to the dog clutch 145, and the rotation of the dog clutch 145 is transmitted to the propeller shaft 136. This causes the propeller 111 to rotate in a direction that moves the vessel 10 backward. When the dog clutch 145 is in the disengaged position, the rotation of the first gear 141 and the second gear 142 is not transmitted to the dog clutch 145. As a result, the propeller 111 does not receive the driving force of the engine body 122. In other words, when the dog clutch 145 is in the disengaged position, the outboard motor 100 is in a neutral state.

[0032] The silencer 300 and housing 350 are located relatively low down on the outboard motor 100. The silencer 300 and housing 350 are housed in the lower case 118. Details of the silencer 300 and housing 350 will be described later.

[0033] (Configuration of suspension system 150) The suspension system 150 is a device for suspending the outboard motor body 110 from the hull 200. The suspension system 150 includes a pair of left and right clamp brackets 152, a tilt shaft 154, and a swivel bracket 156.

[0034] A pair of left and right clamp brackets 152 are positioned at the rear of the hull 200, spaced apart from each other in the left-right direction, and are fixed to the transom 210 of the hull 200, for example, by bolts. Each clamp bracket 152 has a cylindrical support portion 153 with a through hole extending in the left-right direction.

[0035] The tilt shaft 154 is a rod-shaped body and is rotatably supported within a through-hole in the support portion 153 of the clamp bracket 152. The tilt axis line At, which is the center line of the tilt shaft 154, constitutes the horizontal (left-right) axis in the tilt operation of the outboard motor 100.

[0036] The swivel bracket 156 is positioned between a pair of clamp brackets 152 and is supported by a support portion 153 of the clamp brackets 152 via a tilt axis 154 so as to be rotatable around the tilt axis At. The swivel bracket 156 is rotationally driven around the tilt axis At relative to the clamp brackets 152 by a tilt device (not shown) including an actuator such as a hydraulic cylinder.

[0037] When the swivel bracket 156 rotates around the tilt axis At relative to the clamp bracket 152, the outboard motor body 110 supported by the swivel bracket 156 also rotates around the tilt axis At. This enables a tilt operation that rotates the outboard motor body 110 vertically relative to the hull 200. The tilt operation of the outboard motor 100 allows the angle of the outboard motor body 110 around the tilt axis At to be changed within a range from a tilt-down state where the propeller 111 is submerged (the outboard motor 100 is in its standard position) to a tilt-up state where the propeller 111 is above the water surface. Furthermore, a trim operation can be performed to adjust the attitude of the vessel 10 while it is running by adjusting the angle of the outboard motor body 110 around the tilt axis At.

[0038] (Detailed configuration around propeller shaft 136) Figure 3 is an explanatory diagram showing the detailed configuration around the propeller shaft 136. Figure 4 is an explanatory diagram showing a cross-section of the outboard motor 100 at position IV-IV in Figure 3. Figure 5 is an explanatory diagram showing the detailed configuration around the propeller shaft 136 when the rotational speed of the engine body 122 is relatively low. Figures 3 and 5 show a cross-section of the outboard motor 100 perpendicular to the left-right direction. Figure 4 shows a cross-section of the outboard motor 100 perpendicular to the front-rear direction.

[0039] The silencing device 300 is an assembly of components arranged around the propeller shaft 136. As will be described later, the silencing device 300 reduces rattle noise generated between the first gear 141 and the second gear 142, and between the first gear 141 and the third gear 143, by applying friction to the propeller shaft 136. The housing 350 is a housing that accommodates the silencing device 300. In this embodiment, oil is stored inside the housing 350. The housing 350 is an example of a case.

[0040] The silencing device 300 comprises a key 310, a roller housing 312, a snap ring 314, a thrust bearing 316, a roller 318, a disc 322, a plate 324, a coil spring 326, a pressure plate 328, a spring seat 330, a snap ring 334, a thrust bearing 340, a snap ring 342, and a pusher 344.

[0041] The key 310 is a prismatic member extending in the longitudinal direction. The key 310 is connected to a portion of the radially facing surface of the propeller shaft 136. The key 310 rotates together with the propeller shaft 136. In this embodiment, the outboard motor 100 includes two keys 310 positioned at different locations relative to each other in the rotational direction of the propeller shaft 136. The two keys 310 are spaced equally apart from each other in the rotational direction of the propeller shaft 136.

[0042] The roller housing 312 is a component with a hole 312H formed in the center. The propeller shaft 136 and the key 310 are positioned in the hole 312H of the roller housing 312. The roller housing 312 covers the outer circumference of the propeller shaft 136 in the radial direction. The roller housing 312 also covers the outer circumference of the key 310 in the radial direction of the propeller shaft 136. A portion of the surface of the roller housing 312 facing the hole 312H is connected to the key 310. As the propeller shaft 136 rotates, the roller housing 312 rotates around the propeller shaft 136 together with the key 310.

[0043] The roller housing 312 has a housing space 313 formed therein, with the axial front side of the propeller shaft 136 open. The roller housing 312 has a first surface S1, a second surface S2, and a third surface S3, each facing the housing space 313. The first surface S1 faces the axial front side of the propeller shaft 136. The first surface S1 is inclined so as to move outward from the radial center side of the propeller shaft 136 toward the axial front side of the propeller shaft 136. The second surface S2 faces the radial outer side of the propeller shaft 136. The second surface S2 is the inner circumference side of the housing space 313. The second surface S2 faces the radial center side of the propeller shaft 136. The third surface S3 is the outer circumference side of the housing space 313. The roller housing 312 is an example of a housing.

[0044] The snap ring 314 is an annular component. The snap ring 314 is mounted on the roller housing 312 such that it protrudes from the third surface S3 of the roller housing 312 toward the radial center of the propeller shaft 136.

[0045] The thrust bearing 316 is positioned between the roller housing 312 and the housing 350 in the longitudinal direction. The roller housing 312 is connected to the housing 350 via the thrust bearing 316. Because the roller housing 312 is in contact with the thrust bearing 316, friction is reduced when it rotates in conjunction with the rotation of the propeller shaft 136. The thrust bearing 316 is an example of a second thrust bearing.

[0046] The roller 318 is housed in a housing space 313 of the roller housing 312. The roller 318 is in contact with a first surface S1 in the roller housing 312. The roller 318 is movable in the radial direction of the propeller shaft 136 by rolling in the radial direction of the propeller shaft 136. In this embodiment, the outboard motor 100 comprises eight rollers 318 arranged at different positions from one another in the rotational direction of the propeller shaft 136. The eight rollers 318 are arranged at equal intervals from one another in the rotational direction of the propeller shaft 136. The roller 318 is an example of a housing.

[0047] The disc 322 is positioned around the propeller shaft 136. The disc 322 is located forward of the roller housing 312 and roller 318 in the axial direction of the propeller shaft 136. The disc 322 is a plate-shaped member with a hole 322H formed in the center. The propeller shaft 136 is positioned in the hole 322H of the disc 322. The disc 322 covers the outer circumference of the propeller shaft 136. The disc 322 is movable in the axial direction of the propeller shaft 136. The disc 322 rotates around the propeller shaft 136 as the propeller shaft 136 rotates. In this embodiment, the outboard motor 100 includes two discs 322 that are parallel to each other in the axial direction of the propeller shaft 136. The disc 322 is an example of a rotating body.

[0048] The plate 324 is positioned around the propeller shaft 136. The plate 324 is located in front of the roller housing 312 and rollers 318 in the axial direction of the propeller shaft 136. The plate 324 is a plate-shaped member with a hole 324H formed in the center. The propeller shaft 136 is positioned in the hole 324H of the plate 324. The plate 324 covers the outer circumference of the propeller shaft 136. The size of the hole 324H in the plate 324 is larger than the size of the hole 322H in the disk 322. In other words, in the radial direction of the propeller shaft 136, the inner surface of the plate 324 is outside the inner surface of the disk 322. The plate 324 is adjacent to the disk 322 in the axial direction of the propeller shaft 136. The plate 324 is movable in the axial direction of the propeller shaft 136. The rotation of the plate 324 around the propeller shaft 136 is restricted. The plate 324 does not rotate around the propeller shaft 136. In this embodiment, the outboard motor 100 has two plates 324 that are parallel to each other in the axial direction of the propeller shaft 136. Also, each disk 322 and each plate 324 are arranged alternately in the axial direction of the propeller shaft 136. In this embodiment, from the front to the rear, they are arranged in the order of front disk 322, front plate 324, rear disk 322, and rear plate 324. The plate 324 is an example of a non-rotating body.

[0049] The coil spring 326 is positioned around the propeller shaft 136. The coil spring 326 is a compression coil spring that expands and contracts in the longitudinal direction. More specifically, the coil spring 326 is a multi-row coil spring in which two coil springs are arranged radially. The coil spring 326 pushes the front disc 322 toward the axial rearward side of the propeller shaft 136 by the elastic force of the coil spring 326. In other words, the coil spring 326 biases the disc 322 and plate 324, which are arranged in parallel in the axial direction of the propeller shaft 136, to come into contact with each other. The coil spring 326 is an example of an elastic body.

[0050] The pressure plate 328 is positioned around the propeller shaft 136. The pressure plate 328 is positioned between the coil spring 326 and the disc 322 and plate 324 in the axial direction of the propeller shaft 136. The pressure plate 328 is movable in the axial direction of the propeller shaft 136. The pressure plate 328 is in contact with the coil spring 326 and transmits the elastic force of the coil spring 326 to the disc 322 and plate 324.

[0051] The spring seat 330 is positioned around the propeller shaft 136. The spring seat 330 is positioned in front of the coil spring 326. The snap ring 334 is an annular member. The snap ring 334 is mounted on the housing 350 so as to protrude from the inner surface of the housing 350 toward the radial center of the propeller shaft 136. The snap ring 334 is positioned in front of the spring seat 330. The spring seat 330 is in contact with the snap ring 334, restricting the axial movement of the propeller shaft 136. Also, the front end of the coil spring 326 is in contact with the spring seat 330, restricting the axial movement of the propeller shaft 136.

[0052] The thrust bearing 340 is positioned around the propeller shaft 136. In the axial direction of the propeller shaft 136, the thrust bearing 340 is positioned between the pressure plate 328 and the discs 322 and plate 324. The thrust bearing 340 is in contact with the pressure plate 328 and transmits the elastic force of the coil spring 326, transmitted via the pressure plate 328, to the discs 322 and plate 324. The front disc 322 is connected to the pressure plate 328 via the thrust bearing 340. Because the front disc 322 is in contact with the thrust bearing 340, friction is reduced when it rotates with the rotation of the propeller shaft 136. The thrust bearing 340 is an example of a first thrust bearing.

[0053] The snap ring 342 is mounted on the housing 350 so as to protrude from the inner surface of the housing 350 toward the radial center of the propeller shaft 136. The snap ring 342 is positioned behind the disc 322 and plate 324 in the axial direction of the propeller shaft 136. At least one of the disc 322 and plate 324 overlaps with the snap ring 342 in the axial direction of the propeller shaft 136. The range of movement of the disc 322 and plate 324 in the axial direction of the propeller shaft 136 is defined by the snap ring 342.

[0054] The pusher 344 is positioned around the propeller shaft 136. The pusher 344 is movable in the axial direction of the propeller shaft 136. The pusher 344 has a return hub 345 and a snap ring 346.

[0055] The return hub 345 is a component with a hole 345H formed in the center. The propeller shaft 136 is positioned in the hole 345H of the return hub 345. The return hub 345 covers the outer circumference of the propeller shaft 136. The return hub 345 contacts the axially forward end of the propeller shaft 136 on the roller 318. More specifically, the return hub 345 has a surface 345S which is the surface facing the axially rear side of the propeller shaft 136. The surface 345S of the return hub 345 is in contact with the roller 318. The return hub 345 is an example of the first part.

[0056] The snap ring 346 is mounted on the return hub 345 so as to protrude radially outward from the surface of the return hub 345 that faces the propeller shaft 136 radially outward. The snap ring 346 contacts the axial rear end of the disc 322, which is located on the front side of the propeller shaft 136, of the disc 322 and plate 324. More specifically, the snap ring 346 is positioned behind the front disc 322 in the axial direction of the propeller shaft 136. The snap ring 346 has a surface 346S which is the surface facing the axial front side of the propeller shaft 136. The surface 346S of the snap ring 346 contacts the disc 322 as the pusher 344 moves axially forward of the propeller shaft 136. Furthermore, the outer circumferential surface of the snap ring 346 is located outside the inner circumferential surface of the disc 322 and inside the inner circumferential surface of the plate 324 in the radial direction of the propeller shaft 136. Therefore, the surface 346S of the snap ring 346 can contact the disc 322 but does not contact the plate 324. The snap ring 346 is an example of the second part.

[0057] (Operation of the silencer 300) Figure 6 is an explanatory diagram showing the detailed configuration around the propeller shaft 136 when the engine body 122 is rotating at a relatively high speed. Figure 7 is an explanatory diagram conceptually showing the force acting on the roller 318. The operation of the silencer 300 will be explained in detail using Figures 5 to 7.

[0058] First, using Figure 5, the operation of the silencer 300 when the rotational speed of the engine body 122 is relatively low will be explained. As described above, the coil spring 326 biases the disc 322 and the plate 324 to come into contact with each other. In detail, the coil spring 326 is a compression coil spring and is positioned in a compressed state between the spring seat 330 and the pressure plate 328. Therefore, an elastic force acts on the coil spring 326 in the direction that causes the coil spring 326 to extend axially along the propeller shaft 136. The pressure plate 328 receives the elastic force of the coil spring 326 and is pressed against the axial rear side of the propeller shaft 136. The thrust bearing 340 receives the elastic force of the coil spring 326 via the pressure plate 328 and is pressed against the axial rear side of the propeller shaft 136. The disc 322 and plate 324 are subjected to the elastic force of the coil spring 326 via the pressure plate 328 and thrust bearing 340, and are pressed against the axial rear side of the propeller shaft 136. In other words, the elastic force acting on the disc 322 and plate 324 is an axial rearward force on the propeller shaft 136. As a result, the disc 322 and plate 324 come into contact with each other.

[0059] As mentioned above, the disc 322 rotates around the propeller shaft 136 in conjunction with the rotation of the propeller shaft 136. On the other hand, the rotation of the plate 324 around the propeller shaft 136 is restricted. Therefore, when the disc 322 and the plate 324 are in contact with each other, a frictional force is generated between the disc 322 and the plate 324 when the disc 322 rotates around the propeller shaft 136 in conjunction with the rotation of the propeller shaft 136. As a result, for example, when the rotational speed of the engine body 122 is relatively low, when the engine body 122 is not rotating, or when the rotation of the engine body 122 is not transmitted to the propeller shaft 136 (i.e., in a neutral state), the rotation of the disc 322 around the propeller shaft 136 is restricted. In other words, the coil spring 326 applies friction to the propeller shaft 136 as it rotates with the disc 322 by pressing the disc 322 and plate 324 to the axial rear side of the propeller shaft 136.

[0060] The outboard motor 100 is prone to rattling noise when the rotational speed of the engine body 122 is relatively low. Specifically, for example, when the rotational speed of the first gear 141 fluctuates due to fluctuations in the rotational speed of the engine body 122, the rotational speeds of the second gear 142 and the third gear 143 cannot keep up with the rotational speed of the first gear 141. This causes contact between the tooth surfaces of the first gear 141 and the second gear 142, and between the first gear 141 and the third gear 143, resulting in rattling noise. In the outboard motor 100 of this embodiment, friction is applied to the propeller shaft 136 when the rotational speed of the engine body 122 is relatively low, making it easier for the rotational speeds of the second gear 142 and the third gear 143 to keep up with the rotational speed of the first gear 141. As a result, rattling noise generated between the first gear 141 and the second gear 142, and between the first gear 141 and the third gear 143 is reduced.

[0061] Next, the operation of the silencer 300 when the rotational speed of the engine body 122 is relatively high will be explained using Figures 6 and 7. Even when the rotational speed of the engine body 122 is relatively high, an elastic force acts on the coil spring 326 in the direction that causes the coil spring 326 to extend in the axial direction of the propeller shaft 136, similar to when the rotational speed of the engine body 122 is relatively low.

[0062] Furthermore, as described above, the roller housing 312 rotates around the propeller shaft 136 together with the key 310 as the propeller shaft 136 rotates. Therefore, the roller 318 housed in the roller housing 312 is subjected to the centrifugal force F1 generated as the propeller shaft 136 rotates (see Figure 7). Also, as described above, the roller 318 is movable in the radial direction of the propeller shaft 136. Therefore, the roller 318, subjected to the centrifugal force F1 caused by the rotation of the propeller shaft 136, attempts to move from the radial center side of the propeller shaft 136 outward within the housing space 313.

[0063] The roller 318 is in contact with the first surface S1 of the roller housing 312. In this state, when the roller 318 attempts to move outward from the radial center of the propeller shaft 136, the roller housing 312 receives a force from the roller 318. Specifically, the first surface S1 of the roller housing 312 is not parallel to the radial direction of the propeller shaft 136, but is inclined so as to move outward from the radial center of the propeller shaft 136 toward the axial front side of the propeller shaft 136. Therefore, when the roller 318 attempts to move outward from the radial center of the propeller shaft 136, the roller housing 312 receives a force F2 from the roller 318 in a direction perpendicular to the first surface S1. At this time, the roller 318 also receives a reaction force to the force F2. Specifically, the force F2 can be decomposed into an axial force F2A of the propeller shaft 136 and a radial force F2R of the propeller shaft 136. As a reaction to force F2A, roller 318 receives force F3 from the roller housing 312, which is an axial force on the propeller shaft 136. Force F3 is a forward axial force on the propeller shaft 136. Pusher 344 also receives force F3 via roller 318 because its return hub 345 is in contact with the forward axial end of the propeller shaft 136 on roller 318. Due to receiving force F3, pusher 344 attempts to move forward in the axial direction of the propeller shaft 136.

[0064] When the pusher 344 attempts to move forward in the axial direction of the propeller shaft 136, the snap ring 346 of the pusher 344 comes into contact with the rear end of the disc 322. As a result, the disc 322 is subjected to a force F3 transmitted through the pusher 344 and the elastic force of the coil spring 326. In other words, the disc 322 is subjected to a forward axial force from the propeller shaft 136 and a rearward axial force from the propeller shaft 136. The force F3 transmitted to the disc 322 through the pusher 344 is a reaction to the force F2 generated by the centrifugal force F1 associated with the rotation of the propeller shaft 136, and therefore increases with increasing rotational speed of the propeller shaft 136. As a result, when the rotational speed of the propeller shaft 136 exceeds a certain value, the force F3 transmitted to the disc 322 through the pusher 344 exceeds the elastic force transmitted to the disc 322 by the coil spring 326. As a result, the disc 322 located on the axially forward side of the propeller shaft 136 is pushed by the snap ring 346 of the pusher 344, causing the disc 322 and plate 324 to move away from each other against the elastic force of the coil spring 326. In other words, the pusher 344 reduces the frictional force between the disc 322 and plate 324 by pushing the disc 322 axially forward of the propeller shaft 136, thereby damping the friction applied to the propeller shaft 136.

[0065] The outboard motor 100 is less prone to rattling noise when the rotational speed of the engine body 122 is relatively high. In the outboard motor 100 of this embodiment, the friction applied to the propeller shaft 136 is reduced when the rotational speed of the propeller shaft 136 exceeds a certain value, thereby reducing the generation of rattling noise and attenuating the friction applied to the propeller shaft 136 as the rotational speed of the propeller shaft 136 increases.

[0066] The rotational speed of the engine body 122 when the disc 322 and plate 324 separate from each other can be set to any value by adjusting, for example, the spring constant of the coil spring 326, the mass of the roller 318, etc. In this embodiment, the disc 322 and plate 324 are in contact with each other when the rotational speed of the engine body 122 is less than or equal to the trolling rotational speed, and are separated from each other when the rotational speed of the engine body 122 is greater than the trolling rotational speed.

[0067] B. Variations: The technologies disclosed herein are not limited to the embodiments described above and can be modified in various forms without departing from their essence, for example, the following modifications are possible.

[0068] The configurations of the ship 10 and the outboard motor 100 in the above embodiment are merely examples and can be modified in various ways. For example, in the above embodiment, an outboard motor 100 was used as an example of a ship's propulsion system, but an inboard motor or a jet propulsion system could also be used.

[0069] In the above embodiment, the outboard motor 100 is equipped only with an engine body 122 as a drive source, but the ship's propulsion system may be a hybrid type equipped with a motor in addition to the engine.

[0070] In the above embodiment, the force F3 that the disc 322 receives via the pusher 344 is a forward force in the axial direction of the propeller shaft 136, and the elastic force that the disc 322 receives from the coil spring 326 is a rearward force in the axial direction of the propeller shaft 136, but it is not limited to this. In other words, the force that the rotating body receives via the pusher may be a rearward force in the axial direction of the propeller shaft, and the elastic force that the rotating body receives from the elastic body may be a forward force in the axial direction of the propeller shaft. Furthermore, the shaft of the ship's propulsion system does not necessarily have to extend in the longitudinal direction of the ship's propulsion system.

[0071] In the above embodiment, the outboard motor 100 is equipped with a coil spring 326 as an elastic body, but the ship's propulsion system may be equipped with an elastic body other than a coil spring.

[0072] In the above embodiment, the outboard motor 100 is equipped with eight rollers 318, but a ship propulsion system only needs to be equipped with at least one housing.

[0073] In the above embodiment, the outboard motor 100 is equipped with rollers 318 as a housing, but the ship's propulsion system may be equipped with housings other than rollers.

[0074] In the above embodiment, the outboard motor 100 is provided with a plurality of discs 322, but the ship's propulsion system only needs to have at least one rotating body. In the above embodiment, the outboard motor 100 is provided with a plurality of plates 324, but the ship's propulsion system only needs to have at least one non-rotating body.

[0075] In the above embodiment, the pusher 344 has a return hub 345 and a snap ring 346, but it is not necessarily limited to this configuration, and the pusher may be, for example, a member in which a first part and a second part are integrated.

[0076] In the above embodiment, the coil spring 326 presses against the disc 322 of the plate 324, but the elastic body may also press against the non-rotating body of the rotating body.

[0077] In the above embodiment, oil is stored inside the housing 350, but oil does not need to be stored inside the case.

[0078] In the above embodiment, a propeller shaft 136 was exemplified as the shaft, but other types of shafts may also be used. [Explanation of Symbols]

[0079] 10: Ship 100: Outboard motor 110: Outboard motor body 111: Propeller 112: Cowl 113: Upper cowl 114: Lower cowl 116: Casing 117: Upper case 118: Lower case 120: Engine assembly 122: Engine body 123: Crankshaft 124: Journal 125: Spline 126: Intake system components 128: Electrical components 132: Drive shaft 136: Propeller shaft 140: Transmission mechanism 141: First gear 142: Second gear 143: Third gear 145: Dog clutch 150: Suspension system 152: Clamp bracket 153: Support 154: Tilt axis 156: Swivel bracket 200: Hull 202: Hull body 204: Living space 206: Space 210: Transom 220: Partition wall 240: Cockpit 250: Controls 252: Steering wheel 254: Shift / throttle lever 256: Monitor 258: Input device 300: Silencer 310: Key 312: Roller housing S1: First surface S2: Second surface S3: Third surface 313: Enclosure 314: Snap ring 316: Thrust bearing 318: Roller 322: Disc 324: Plate 326: Coil spring 328: Pressure plate 330: Spring seat 334: Snap ring 340: Thrust bearing 342: Snap ring 344: Pusher 345: Return hub 346: Snap ring 350: Housing Ac: Rotation axis Ap: Rotation axis

Claims

1. A ship propulsion system, The engine and The propeller shaft and A transmission mechanism for transmitting the driving force of the engine to the propeller shaft, A drive gear that rotates by the driving force of the aforementioned engine, A transmission mechanism having a driven gear that meshes with the drive gear, A rotating body disposed around the propeller shaft, which is movable in the axial direction of the propeller shaft and rotates around the propeller shaft in conjunction with the rotation of the propeller shaft, A non-rotating body is arranged around the propeller shaft, adjacent to the rotating body in the axial direction, and is movable in the axial direction, and whose rotation around the propeller shaft is restricted. An elastic body that pushes at least one of the rotating body and the non-rotating body to one side in the axial direction, biasing the rotating body and the non-rotating body to come into contact with each other, A housing that covers the outer circumference of the propeller shaft, A first surface facing the other side in the axial direction, having a first surface that is inclined to approach the other side in the axial direction from the radial center side of the propeller shaft outward, A housing that rotates around the propeller shaft in conjunction with the rotation of the propeller shaft, A resident that is in contact with the first surface and is movable in the radial direction, A pusher that is movable in the axial direction, A first portion in the contained body that is in contact with the other end in the axial direction, A pusher having the rotating body and a second portion of the non-rotating body located on the other side in the axial direction, which contacts the end on the other side in the axial direction, A ship's propulsion system equipped with the following features.

2. A ship propulsion system according to claim 1, The contained object moves radially outward due to the centrifugal force generated as the propeller shaft rotates. The pusher is pushed by the housing to the other side in the axial direction, A ship propulsion system in which the rotating body and the non-rotating body located on the other side in the axial direction are pushed by the second portion of the pusher, thereby separating the rotating body and the non-rotating body from each other.

3. A ship propulsion system according to claim 2, A marine propulsion system in which the rotating body and the non-rotating body separate from each other when the rotational speed of the engine is greater than the trolling rotational speed.

4. A ship propulsion system according to claim 1, The propeller shaft extends in the longitudinal direction of the ship's propulsion system, The aforementioned axial side is the rear side in the ship's propulsion system. The other side in the axial direction is the forward side of the ship's propulsion system.

5. A ship propulsion system according to claim 1, The elastic body is a coil spring in a ship's propulsion system.

6. A ship propulsion system according to claim 1, The elastic body is a multi-row coil spring in which multiple coil springs are arranged in the radial direction, in a ship propulsion device.

7. A ship propulsion system according to claim 1, A ship propulsion system comprising multiple of the aforementioned housings.

8. A ship propulsion system according to claim 7, A ship propulsion system in which the plurality of housings are arranged at equal intervals in the direction of rotation of the propeller shaft.

9. A ship propulsion system according to claim 1, The contained object is a roller that rolls in the radial direction, in a ship propulsion system.

10. A ship propulsion system according to claim 1, further, A ship propulsion system comprising a pressure plate, which is arranged around the propeller shaft and positioned in the axial direction between the elastic body, the rotating body and the non-rotating body.

11. A ship propulsion system according to claim 10, further, A marine propulsion system comprising a first thrust bearing, which is arranged around the propeller shaft and positioned in the axial direction between the pressure plate, the rotating body and the non-rotating body.

12. A ship propulsion system according to claim 1, A ship propulsion system comprising a plurality of the aforementioned rotating bodies and a plurality of the aforementioned non-rotating bodies.

13. A ship propulsion system according to claim 12, A ship propulsion system in which each of the rotating bodies and each of the non-rotating bodies are arranged alternately in the axial direction.

14. A ship propulsion system according to claim 1, The first part of the pusher is a return hub, The second portion of the pusher is a snap ring attached to the return hub, in a marine propulsion system.

15. A ship propulsion system according to claim 1, A ship propulsion machine wherein the elastic body pushes the rotating body of the two rotating bodies to one side in the axial direction, biasing the rotating body and the non-rotating body to come into contact with each other.

16. A ship propulsion system according to claim 1, further, A case that houses the rotating body, the non-rotating body, the elastic body, the housing, the object to be housed, and the pusher, The second thrust bearing and Equipped with, A marine propulsion system in which the housing is connected to the case via the second thrust bearing.

17. A ship propulsion system according to claim 1, further, It is equipped with a drive shaft that rotates by the driving force of the aforementioned engine, The drive gear rotates together with the drive shaft, A marine propulsion system further comprising a dog clutch that is movable between a connection position where it connects to the driven gear and a disconnection position where it is separated from the driven gear, and which rotates together with the propeller shaft.

18. A ship propulsion system according to claim 1, further, The case comprises the rotating body, the non-rotating body, the elastic body, the housing, the contained object, and the pusher. Inside the aforementioned case is a ship's propulsion system, in which oil is stored.

19. The hull and, A ship propulsion system according to claim 1, attached to the rear of the hull, A ship equipped with these features.

20. A ship propulsion system, The engine and The shaft and A transmission mechanism for transmitting the driving force of the engine to the shaft, A drive gear that rotates by the driving force of the aforementioned engine, A transmission mechanism having a driven gear that meshes with the drive gear, A rotating body disposed around the shaft, which is movable in the axial direction of the shaft and rotates around the shaft as the shaft rotates, A non-rotating body arranged around the shaft and adjacent to the rotating body in the axial direction, which is movable in the axial direction and whose rotation around the shaft is restricted, An elastic body that pushes at least one of the rotating body and the non-rotating body to one side in the axial direction, biasing the rotating body and the non-rotating body to come into contact with each other, A housing that covers the outer circumference of the shaft, A first surface facing the other side in the axial direction, the first surface being inclined outward from the radial center side of the shaft toward the other side in the axial direction, A housing that rotates around the shaft in conjunction with the rotation of the shaft, A resident that is in contact with the first surface and is movable in the radial direction, A pusher that is movable in the axial direction, A first portion in the contained body that is in contact with the other end in the axial direction, A pusher having the rotating body and a second portion of the non-rotating body located on the other side in the axial direction, which contacts the end on the other side in the axial direction, A ship's propulsion system equipped with the following features.

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