US20120094559A1

US20120094559A1 - Marine vessel propulsion apparatus

Info

Publication number: US20120094559A1
Application number: US13/212,256
Authority: US
Inventors: Hiroaki Takase; Takashi Kimura
Original assignee: Yamaha Motor Co Ltd
Current assignee: Yamaha Motor Co Ltd
Priority date: 2010-10-13
Filing date: 2011-08-18
Publication date: 2012-04-19
Also published as: JP2012081900A

Abstract

A marine vessel propulsion apparatus includes a transom bracket, a steering shaft, an outboard motor, a steering mechanism, a first cylinder, and a second cylinder. The steering mechanism is arranged to turn the steering shaft and the outboard motor around the steering axis with respect to the transom bracket. The first cylinder is arranged to turn the outboard motor around the tilt axis between a first angle and a second angle larger than the first angle, and support the outboard motor between the first angle and the second angle. The second cylinder is arranged to turn the outboard motor around the tilt axis between the first angle and a third angle larger than the second angle, and support the outboard motor between the first angle and the third angle.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a marine vessel propulsion apparatus.
2. Description of the Related Art
A conventional marine vessel propulsion apparatus is described in, for example, Japanese Published Unexamined Patent Application No. 2006-143066. This marine vessel propulsion apparatus includes two clamp brackets, a swivel bracket, a tilt shaft, an outboard motor, a steering shaft, and a PTT mechanism (power trim & tilt mechanism).
Clamp brackets are attachable to the transom of the hull. Two clamp brackets are disposed at an interval in the right-left direction. The swivel bracket is joined to the clamp brackets via the tilt shaft extending horizontally. The outboard motor is joined to the swivel bracket via the steering shaft extending in the up-down direction. The swivel bracket and the outboard motor are turnable around a tilt axis (central axis of the tilt shaft) with respect to the clamp brackets. The outboard motor is turnable around a steering axis (central axis of the steering shaft) with respect to the clamp brackets and the swivel bracket. The steering shaft turns with respect to the clamp brackets according to turning of the outboard motor around the tilt axis. Therefore, the steering axis turns with respect to the clamp brackets according to turning of the outboard motor around the tilt axis.
The PTT mechanism turns the outboard motor around the tilt axis with respect to the clamp brackets by turning the swivel bracket around the tilt axis. The PTT mechanism supports the outboard motor in both of a trim range in which the tilting angle of the outboard motor is small and a tilt range in which the tilting angle of the outboard motor is larger than in the trim range. The PTT mechanism turns the outboard motor around the tilt axis in these ranges. The PTT mechanism includes a trim cylinder that supports the outboard motor in the trim range and turns the outboard motor in the trim range, and a tilt cylinder that supports the outboard motor in both of the trim range and the tilt range and turns the outboard motor in both ranges.
The trim cylinder and the tilt cylinder are disposed between the two clamp brackets. At the rear of these cylinders, a portion of the swivel bracket is disposed, and ahead of these cylinders, the transom is disposed. The cylinder main bodies of the cylinders are joined to the clamp brackets. The rod of the tilt cylinder is joined to the swivel bracket. In a state in which the outboard motor is positioned in the trim range, the rod of the trim cylinder is in contact with the swivel bracket. When the tilting angle of the outboard motor exceeds the trim range, the rod of the trim cylinder separates from the swivel bracket. Therefore, in the state in which the outboard motor is positioned in the trim range, the outboard motor is supported by the trim cylinder and the tilt cylinder, and when the tilting angle of the outboard motor exceeds the trim range, the outboard motor is supported only by the tilt cylinder.
Another conventional marine vessel propulsion apparatus is described in, for example, U.S. Pat. No. 6,146,220. This marine vessel propulsion apparatus includes a transom bracket, a steering shaft, an outboard motor, a tilt shaft, and a tilt mechanism.
The transom bracket is attachable to the transom of the hull. The steering shaft is joined to the transom bracket. The steering shaft extends in the up-down direction. The outboard motor is joined to the steering shaft via the tilt shaft extending horizontally. The outboard motor is turnable around the tilt axis (central axis of the tilt shaft) with respect to the steering shaft. The steering shaft and the outboard motor are turnable around the steering axis (central axis of the steering shaft) with respect to the transom bracket. When the outboard motor turns around the tilt axis, the steering shaft does not turn with respect to the transom bracket. Therefore, the steering axis does not turn with respect to the transom bracket according to turning of the outboard motor around the tilt axis.
The tilt mechanism turns the outboard motor around the tilt axis with respect to the steering shaft. The tilt mechanism includes two tilt cylinders that support the outboard motor and turn the outboard motor. The two tilt cylinders are disposed in parallel to each other at an interval. The steering shaft is disposed between two tilt cylinders. The outboard motor is disposed at the rear of the tilt cylinder, and the transom bracket is disposed ahead of the tilt cylinder. The side of each tilt cylinder is opened. The cylinder main body of each tilt cylinder is joined to the steering shaft. The rods of the tilt cylinders are joined to the outboard motor. The outboard motor is supported by the two tilt cylinders.

SUMMARY OF THE INVENTION

The inventors of preferred embodiments of the present invention described and claimed in the present application conducted an extensive study and research regarding a marine vessel propulsion apparatus, such as the ones described above, and in doing so, discovered and first recognized new unique challenges and previously unrecognized possibilities for improvements as described in greater detail below.
In detail, the trim range is a range to be used mainly so as to adjust the posture of the hull when the marine vessel runs forward, and the tilt range is a range to be used mainly when the marine vessel is moored or runs in shallow water. The tilt range is a range in which the tilting angle of the outboard motor is large, so that when the outboard motor is moved from the trim range to the tilt range, the propeller may come out of the water. If the propeller comes out of the water when the marine vessel runs forward, the propulsive force to be transmitted to the hull is reduced. Therefore, if the outboard motor moves to the tilt range when the marine vessel runs forward, the marine vessel may be decelerated.
As described above, when the trim cylinder and the tilt cylinder are provided, in the state in which the outboard motor is positioned in the trim range, the outboard motor is supported by the trim cylinder and the tilt cylinder. Further, in the state in which the outboard motor is positioned in the tilt range, the trim cylinder separates from the outboard motor, and the outboard motor is supported only by the tilt cylinder. When the outboard motor moves from the trim range to the tilt range, loads including the own weight of the outboard motor and the forward propulsive force that had been applied to the trim cylinder are applied to the tilt cylinder, so that the loads to be applied to the tilt cylinder increase. Therefore, when the outboard motor moves from the trim range to the tilt range, the internal pressure of the tilt cylinder increases.
For example, in a case where the forward propulsive force is great, when the outboard motor moves from the trim range to the tilt range, the internal pressure of the tilt cylinder increases. To the tilt cylinder, piping in which hydraulic oil circulates is connected, and to this piping, a relief valve is attached. When the internal pressure of the tilt cylinder increases, the relief valve opens and the hydraulic oil is discharged from the tilt cylinder. Accordingly, the projecting amount of the rod of the tilt cylinder is reduced, and the outboard motor returns from the tilt range to the trim range. Therefore, the propeller can be prevented from coming out of the water when the marine vessel runs forward.
On the other hand, when the forward propulsive force is small or the marine vessel stops, even if the outboard motor moves from the trim range to the tilt range, the internal pressure of the tilt cylinder rises only up to a pressure lower than in the case where the propulsive force is great, so that the relief valve does not open. Therefore, in these cases, the outboard motor can be positioned in the tilt range. Further, when the outboard motor moves from the trim range to the tilt range, the amount of hydraulic oil that had been supplied to the trim cylinder of the hydraulic oil fed from a hydraulic pump is supplied to the tilt cylinder, so that the supply flow rate of hydraulic oil to the tilt cylinder increases. Therefore, the movement speed of the rod of the tilt cylinder increases, and the outboard motor turns around the tilt axis at a speed higher than the movement speed in the trim range. Accordingly, the outboard motor can be quickly tilted up in the tilt range.
In recent years, outboard motors have tended to be increased in size and/or output. If an outboard motor is large in size, the weight of the outboard motor increases, so that the load to be applied to each cylinder increases. The propulsive force of the outboard motor is transmitted to each cylinder, so that if the outboard motor has a high output, the load to be applied to each cylinder increases. Therefore, if the outboard motor is increased in size and/or output, the problem of an increase in internal pressure of each cylinder occurs. For example, by increasing the size of each cylinder main body, the internal pressure increase can be reduced, and this problem can be solved. However, in the marine vessel propulsive apparatus described in Japanese Published Unexamined Patent Application No. 2006-143066, the PTT mechanism is surrounded by the clamp brackets, the swivel bracket, and the transom, so that if the trim cylinder and the tilt cylinder are increased in size, a new problem occurs in which these cylinders interfere with the clamp brackets, etc. Therefore, it is difficult to increase the size of each cylinder main body. In order to prevent the clamp brackets from interfering with the cylinders, it is possible that the distance between the right and left clamp brackets is increased by moving the clamp brackets outward. However, the attaching range of the clamp brackets to the hull is regulated according to the standards, so that the problem cannot be solved even by this method.
On the other hand, in the marine vessel propulsion apparatus described in U.S. Pat. No. 6,146,220, the outboard motor is supported by two tilt cylinders. The sides of the tilt cylinders are opened. Therefore, the cylinder main bodies can be increased in size. However, in this marine vessel propulsion apparatus, the trim cylinder is not provided, so that even when the outboard motor moves from the trim range to the tilt range while the forward propulsive force is great, the internal pressure of the tilt cylinder does not increase unlike the case where the trim cylinder is provided. Therefore, even if the above-described piping and relief valve are provided, the outboard motor cannot be moved from the tilt range to the trim range. Therefore, the propeller may come out of the water when the marine vessel runs forward. Further, in the marine vessel propulsion apparatus described in U.S. Pat. No. 6,146,220, the trim cylinder is not provided, so that the speed of turning of the outboard motor around the tilt axis cannot be easily changed between the trim range and the tilt range.
In the marine vessel propulsion apparatus described in U.S. Pat. No. 6,146,220, in order to prevent the propeller from coming out of the water during forward running of the marine vessel, it is possible that, for example, a sensor that detects the position of the outboard motor is provided, and based on a detection value of this sensor, the supply amount of the hydraulic oil to the tilt cylinder is controlled. However, in this case, the sensor and related devices are necessary, and the control becomes complicated. Further, in the marine vessel propulsion apparatus described in U.S. Pat. No. 6,146,220, in order to change the speed of turning of the outboard motor around the tilt axis between the trim range and the tilt range, it is possible that the supply flow rate of the hydraulic oil to the tilt cylinder is changed. However, in this case, for example, the rotational speed of an electric motor that drives the hydraulic pump must be changed, and the control becomes complicated.
In order to overcome the previously unrecognized and unsolved challenges described above, a preferred embodiment of the present invention provides a marine vessel propulsion apparatus including a transom bracket, a steering shaft, an outboard motor, a steering mechanism, a first cylinder, and a second cylinder. The transom bracket is arranged to be attachable to the transom of the hull. The steering shaft is joined to the transom bracket, and is arranged turnably around a steering axis extending in the up-down direction. The outboard motor is joined to the steering shaft. The outboard motor is arranged turnably around a tilt axis extending along a plane perpendicular or substantially perpendicular to the steering axis. Further, the outboard motor is arranged turnably around the steering axis together with the steering shaft. The steering mechanism is joined to the transom bracket and the steering shaft. The steering mechanism is arranged to turn the steering shaft and the outboard motor around the steering axis with respect to the transom bracket. The first cylinder is joined to the steering shaft and the outboardmotor. The first cylinder is arranged to turn the outboard motor around the tilt axis between a first angle and a second angle larger than the first angle, and support the outboard motor between the first angle and the second angle. The second cylinder is joined to the steering shaft and the outboard motor. The second cylinder is arranged to turn the outboard motor around the tilt axis between the first angle and a third angle larger than the second angle, and support the outboard motor between the first angle and the third angle.
With this arrangement of the present preferred embodiment of the present invention, the outboard motor is joined to the steering shaft. The outboard motor is turnable around the tilt axis extending along a plane perpendicular or substantially perpendicular to the steering axis with respect to the steering shaft. The first cylinder and the second cylinder are joined to the steering shaft and the outboard motor. The first cylinder turns the outboard motor around the tilt axis between the first angle and the second angle larger than the first angle, and supports the outboard motor between the first angle and the second angle. The second cylinder turns the outboard motor around the tilt axis between the first angle and the third angle larger than the second angle, and supports the outboard motor between the first angle and the third angle.
Thus, the first cylinder supports the outboard motor between the first angle and the second angle, and the second cylinder supports the outboard motor between the first angle and the third angle. Specifically, the range (first range) in which the first cylinder supports the outboard motor is smaller than the range (first and second ranges) in which the second cylinder supports the outboard motor. In the first range (range between the first angle and the second angle), the outboard motor is supported by the first cylinder and the second cylinder, and in the second range (range excluding the first range in the range between the first angle and the third angle), the outboard motor is supported by the second cylinder. Therefore, in the state in which the forward propulsive force is great, when the outboard motor moves from the first range to the second range, the internal pressure of the second cylinder increases. Therefore, by discharging a hydraulic fluid from the second cylinder by using, for example, a relief valve, the outboard motor can be returned to the first range. Accordingly, the outboard motor can be mechanically prevented from being positioned in the second range during a high thrust. Further, the first cylinder and the second cylinder are provided, so that the outboard motor can be mechanically quickly turned in the second range. Further, unlike the conventional marine vessel propulsion apparatus, the clamp brackets are not disposed on the lateral sides of the cylinders, so that the cylinders can be increased in size. Accordingly, when the outboard motor is large in size or the outboard motor has a high output, the increases in internal pressure of the cylinders can be minimized.
The steering shaft includes a tubular portion extending along the steering axis, and at least a portion of the second cylinder may be housed inside the tubular portion. In this case, the increase in size of the marine vessel propulsion apparatus can be minimized.
The first cylinder and the second cylinder may be arranged to turn around the steering axis together with the steering shaft.
The marine vessel propulsion apparatus may further include a pump that supplies hydraulic oil to the first cylinder and the second cylinder, an electric motor that drives the pump, and a piping in which hydraulic oil circulates, and the first cylinder, the second cylinder, the pump, the electric motor, and the piping may be arranged to turn around the steering axis together with the steering shaft.
It is possible that at least a portion of the pump is exposed, and at least a portion of the electric motor is exposed. In this case, a user of the marine vessel propulsion apparatus can easily access the pump and the electric motor. Therefore, the user can easily perform maintenance operations such as replacement of the hydraulic oil.
The marine vessel propulsion apparatus may further include a detachable protective cover covering at least one of the pump and the electric motor. In this case, at least one of the pump and the electric motor is protected by the protective cover, so that at least one of the pump and the electric motor can be prevented from being damaged. The protective cover is detachable, so that a user of the marine vessel propulsion apparatus can expose the pump and the electric motor by detaching the protective cover. Accordingly, the user can easily access the pump and the electric motor. Therefore, the user can easily perform maintenance operations such as replacement of the hydraulic oil.
At least a portion of the piping may be exposed. In this case, the piping can be easily accessed. Therefore, a user of the marine vessel propulsion apparatus can easily perform maintenance operations such as replacement of the piping, etc.
The outboard motor may include a tilt bracket joined to the steering shaft. The tilt bracket may be turnable around the tilt axis with respect to the steering shaft.
The second cylinder may be joined to the outboard motor via a first turning shaft turnably around the first turning shaft with respect to the outboard motor. Further, the second cylinder may be joined to the first cylinder via a second turning shaft turnably around the second turning shaft with respect to the first cylinder. In detail, it is also possible that the rod of the second cylinder is joined to the outboard motor via the first turning shaft, and the main body of the second cylinder is joined to the first cylinder via the second turning shaft. It is also possible that the main body of the second cylinder is joined to the outboard motor via the first turning shaft, and the rod of the second cylinder is joined to the first cylinder via the second turning shaft.
The first cylinder and the second cylinder may be disposed so as not to overlap as viewed in a direction orthogonal or substantially orthogonal to the tilt axis.
It is also possible that the marine vessel propulsion apparatus includes a pair of the first cylinders disposed at an interval in a direction parallel or substantially parallel to the tilt axis, and the second cylinder is disposed so that the second cylinder is positioned between the pair of first cylinders as viewed in a direction orthogonal or substantially orthogonal to the tilt axis. In detail, it is possible that the second cylinder is disposed so that at least a portion of the second cylinder is positioned between the pair of first cylinders, and the second cylinder is positioned between the pair of first cylinders as viewed in the direction orthogonal or substantially orthogonal to the tilt axis. It is also possible that the second cylinder is disposed so that the second cylinder is not positioned between the pair of first cylinders, and the second cylinder is positioned between the pair of first cylinders as viewed in the direction orthogonal or substantially orthogonal to the tilt axis.
The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a first marine vessel propulsion apparatus according to a first preferred embodiment of the present invention.

FIG. 2 is a side view of the first marine vessel propulsion apparatus according to the first preferred embodiment of the present invention.

FIG. 3 is a plan view of the first marine vessel propulsion apparatus according to the first preferred embodiment of the present invention.

FIG. 4A is a perspective view of a portion of the first marine vessel propulsion apparatus according to the first preferred embodiment of the present invention.

FIG. 4B is an exploded perspective view of a portion of the first marine vessel propulsion apparatus according to the first preferred embodiment of the present invention.

FIG. 4C is an exploded view of a portion of the first marine vessel propulsion apparatus according to the first preferred embodiment of the present invention.

FIG. 5 is a back view of a tilt mechanism according to the first preferred embodiment of the present invention.

FIG. 6 is a partial sectional view of a portion of the first marine vessel propulsion apparatus including the tilt mechanism according to the first preferred embodiment of the present invention.

FIG. 7 is a side view of a portion of the first marine vessel propulsion apparatus including the tilt mechanism according to the first preferred embodiment of the present invention.

FIG. 8 is a side view of a portion of the first marine vessel propulsion apparatus including the tilt mechanism according to the first preferred embodiment of the present invention.

FIG. 9 is a partial sectional view of a portion of the first marine vessel propulsion apparatus including a steering mechanism according to the first preferred embodiment of the present invention.

FIG. 10 is a schematic plan view of a portion of the first marine vessel propulsion apparatus including the steering mechanism according to the first preferred embodiment of the present invention.

FIG. 11 is a schematic plan view of a portion of the first marine vessel propulsion apparatus including the steering mechanism according to the first preferred embodiment of the present invention.

FIG. 12 is a side view of a second marine vessel propulsion apparatus according to a second preferred embodiment of the present invention.

FIG. 13A is a perspective view of a portion of the second marine vessel propulsion apparatus according to the second preferred embodiment of the present invention.

FIG. 13B is an exploded perspective view of a portion of the second marine vessel propulsion apparatus according to the second preferred embodiment of the present invention.

FIG. 13C is an exploded view of a portion of the second marine vessel propulsion apparatus according to the second preferred embodiment of the present invention.

FIG. 14 is a partial sectional view of a portion of the second marine vessel propulsion apparatus according to the second preferred embodiment of the present invention.

FIG. 15 is a side view of the second marine vessel propulsion apparatus according to the second preferred embodiment of the present invention.

FIG. 16 is a plan view of the second marine vessel propulsion apparatus according to the second preferred embodiment of the present invention.

FIG. 17 is an exploded view of a portion of the second marine vessel propulsion apparatus according to the second preferred embodiment of the present invention.

FIG. 18 is a partial sectional view of a portion of the second marine vessel propulsion apparatus including a steering mechanism according to the second preferred embodiment of the present invention.

FIG. 19 is a schematic plan view of a portion of the second marine vessel propulsion apparatus including the steering mechanism according to the second preferred embodiment of the present invention.

FIG. 20 is a schematic plan view of a portion of the second marine vessel propulsion apparatus including the steering mechanism according to the second preferred embodiment of the present invention.

FIG. 21 is a back view of a portion of the second marine vessel propulsion apparatus according to a third preferred embodiment of the present invention.

FIG. 22 is a plan view of a portion of the second marine vessel propulsion apparatus according to the third preferred embodiment of the present invention.

FIG. 23 is a side view of a portion of the second marine vessel propulsion apparatus according to the third preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a first marine vessel propulsion apparatus including an electric motor fixed to the transom bracket and a second marine vessel propulsion apparatus including an electric motor fixed to the steering shaft will be described. The description given below is based on a state in which the outboard motor is in a reference posture. The reference posture is a posture of the outboard motor when the tilting angle of the outboard motor is zero and the steering angle of the outboard motor is zero. The tilting angle of the outboard motor is an angle of the rotational axis (crank axis L1) of the crankshaft with respect to a vertical plane. The tilting angle of the outboard motor 2 when the crank axis L1 extends vertically is zero. The steering angle of the outboard motor is an angle of the rotational axis (rotational axis L2) of the propeller with respect to the center line of the hull. The steering angle of the outboard motor when the rotational axis L2 of the propeller extends in the front-rear direction is zero. A direction toward one side of the front-rear direction (forward direction) is a direction approaching the transom, and the other direction of the front-rear direction (rearward direction) is a direction extending away from the transom.

First Marine Vessel Propulsion Apparatus

First Preferred Embodiment

FIG. 1 and FIG. 2 are side views of a first marine vessel propulsion apparatus 1 according to a first preferred embodiment of the present invention. FIG. 3 is a plan view of the first marine vessel propulsion apparatus 1 according to the first preferred embodiment of the present invention. FIG. 4A is a perspective view of a portion of the first marine vessel propulsion apparatus 1 according to the first preferred embodiment of the present invention. FIG. 4B is an exploded perspective view of a portion of the first marine vessel propulsion apparatus 1 according to the first preferred embodiment of the present invention. FIG. 4C is an exploded view of a portion of the first marine vessel propulsion apparatus 1 according to the first preferred embodiment of the present invention.
The first marine vessel propulsion apparatus 1 includes an outboard motor 2. The outboard motor 2 is attached to a transom T1 provided on the rear portion of the hull H1. The outboard motor 2 includes an engine 3, an engine cover 4, and a casing 5. The engine 3 is housed inside the engine cover 4. The engine 3 includes a crankshaft 6. The crankshaft 6 is rotatable around a crank axis L1. The crankshaft 6 is joined to a drive shaft (not shown). The drive shaft is joined to a propeller shaft (not shown). The drive shaft and the propeller shaft are housed in the casing 5. The casing 5 includes an upper case 7 and a lower case 8 disposed below the engine cover 4. The lower case 8 supports the propeller 9 rotatably around a rotational axis L2. Rotation of the crankshaft 6 is transmitted to the propeller 9 via the drive shaft and the propeller shaft. The propeller 9 is rotatable in a forward propelling direction and a backward propelling direction opposite to the forward propelling direction. The propeller 9 is driven to rotate in the forward propelling direction and the backward propelling direction by the engine 3.
The first marine vessel propulsion apparatus 1 includes a transom bracket 10, a steering shaft 11, and a tilt shaft 12. The outboard motor 2 includes a tilt bracket 13. The transom bracket 10 is attachable to the transom T1. The transom bracket 10 includes a plate-shaped attaching portion 14 to be attached to the transom T1 and a tubular housing portion 15 disposed at the rear of the attaching portion 14. The steering shaft 11 is joined to the transom bracket 10. The tilt bracket 13 is joined to the steering shaft 11 via the tilt shaft 12. The steering shaft 11 and the outboard motor 2 are turnable around a steering axis L3 extending in the up-down direction with respect to the transom bracket 10. The outboard motor 2 is turnable around a tilt axis L4 extending in the horizontal direction with respect to the transom bracket 10 and the steering shaft 11. The tilt axis L4 is a central axis of the tilt shaft 12.
As shown in FIG. 4B and FIG. 4C, the steering shaft 11 includes a tubular portion 16, a joint portion 17, and an intermediate portion 18. The steering axis L3 is the central axis of the tubular portion 16. The joint portion 17 is joined to the upper end portion of the tubular portion 16 via the intermediate portion 18. The tubular portion 16, the joint portion 17, and the intermediate portion 18 may be separate members as in this preferred embodiment, or may constitute an integral member. Specifically, the steering shaft 11 may be a member including a plurality of divided bodies, or may be an integral member. The tilt bracket 13 is joined to the joint portion 17 via the tilt shaft 12. The steering shaft 11 is inserted in the housing portion 15 of the transom bracket 10. The tubular portion 16 is housed in the housing portion 15. The housing portion 15 extends along the steering axis L3. The steering shaft 11 is turnable around the steering axis L3 with respect to the transom bracket 10.
The first marine vessel propulsion apparatus 1 includes a tilt mechanism 19. The tilt mechanism 19 is joined to the steering shaft 11 and the outboard motor 2. The tilt mechanism 19 turns the outboard motor 2 around the tilt axis L4 with respect to the transom bracket 10 and the steering shaft 11. The outboard motor 2 turns around the tilt axis L4 with respect to the steering shaft 11, so that even if the tilting angle of the outboard motor 2 changes, the steering axis L3 does not move. Specifically, the steering axis L3 is an axis that does not move with respect to the transom bracket 10. A direction in which the outboard motor 2 tilts around the tilt axis L4 so that the upper end of the crank axis L1 is positioned forward relative to the lower end of the crank axis L1 is defined as a positive direction. A range in which the tilting angle of the outboard motor 2 is small is a trim range, and a range in which the tilting angle of the outboard motor 2 is larger than the upper limit of the trim range is a tilt range.
In FIG. 2, a state in which the tilting angle of the outboard motor 2 is the lower limit (full trim-in angle) of the trim range is shown by the alternate long and short dashed lines, and a state in which the tilting angle of the outboard motor 2 is the upper limit (full trim-out angle) of the trim range is shown by the alternate long and two short dashed lines. In FIG. 2, a state in which the tilting angle of the outboard motor 2 is the upper limit (full tilt-up angle) of the tilt range is shown by the solid line. The full trim-in angle is an example of the first angle according to the first preferred embodiment of the present invention, and the full trim-out angle is an example of the second angle according to the first preferred embodiment of the present invention. The full tilt-up angle is an example of a third angle according to the first preferred embodiment of the present invention. The full trim-in angle is, for example, −5 degrees, and the full trim-out angle is, for example, 15 degrees. The full tilt-up angle is, for example, 65 degrees. The tilt mechanism 19 can hold the outboard motor 2 at an arbitrary position including the trim range and the tilt range. The trim range is a range to be used mainly when adjusting the posture of the hull H1 when the marine vessel is propelled forward, and the tilt range is a range to be used mainly when the marine vessel is moored or runs in shallow water.
The first marine vessel propulsion apparatus 1 includes a steering mechanism 20. The steering mechanism 20 is joined to the transom bracket 10 and the steering shaft 11. The steering mechanism 20 turns the steering shaft 11 and the tilt shaft 12 around the steering axis L3 with respect to the transom bracket 10. The outboard motor 2 and the tilt mechanism 19 turn around the steering axis L3 together with the steering shaft 11 and the tilt shaft 12 according to turning of the steering shaft 11. The tilt shaft 12 turns around the steering axis L3 together with the outboard motor 2, so that the tilt axis L4 that is the central axis of the tilt shaft 12 turns around the steering axis L3 with respect to the transom bracket 10 according to turning of the outboard motor 2 around the steering axis L3. The position of the outboard motor 2 when the steering angle of the outboard motor 2 is zero is defined as a steering origin. As shown in FIG. 3, the outboard motor 2 is turnable to the right and left around the steering origin (the position shown by the solid line). The steering mechanism 20 turns the outboard motor 2 around the steering axis L3 between a maximum rightward steering position (the position shown by the alternate long and short dashed lines) and a maximum leftward steering position (the position shown by the alternate long and two short dashed lines). The steering mechanism 20 can hold the outboard motor 2 at an arbitrary position between the maximum rightward steering position and the maximum leftward steering position.
FIG. 5 is a back view of the tilt mechanism 19 according to the first preferred embodiment of the present invention. Hereinafter, the tilt mechanism 19 will be described with reference to FIG. 4B, FIG. 4C, and FIG. 5.
The tilt mechanism 19 includes two trim cylinders 21, a tilt cylinder 22, and a frame 23. Two trim cylinders 21 are disposed in parallel or substantially parallel to each other at an interval in the right-left direction, that is, a direction parallel or substantially parallel to the tilt axis L4. Each trim cylinder 21 is disposed obliquely along the front-rear direction so that the upper end of the trim cylinder 21 is positioned rearward relative to the lower end of the trim cylinder 21. The tilt cylinder 22 extends in the up-down direction. The upper end of the tilt cylinder 22 (upper end portion of a tilt rod 27) is positioned higher than the trim cylinders 21. The tilt cylinder 22 is disposed so that the tilt cylinder 22 is positioned between the two trim cylinders 21 as viewed in the front-rear direction, that is, a direction orthogonal or substantially orthogonal to the tilt axis L4.
Each trim cylinder 21 includes a cylinder main body 24 and a trim rod 25 extending along the central axis of the trim cylinder 21. Each trim rod 25 projects upward from the upper end of the cylinder main body 24. Each cylinder main body 24 is fixed to the frame 23. On the other hand, the tilt cylinder 22 includes a cylinder main body 26 and a tilt rod 27 extending along the central axis of the tilt cylinder 22. The tilt rod 27 projects upward from the upper end of the cylinder main body 26. The lower end portion of the cylinder main body 26 is joined to the frame 23 via a lower pin 28 extending in the right-left direction. The tilt cylinder 22 is joined to the frame 23 and the trim cylinders 21 via the lower pin 28. The tilt cylinder 22 is turnable around the lower pin 28 with respect to the frame 23 and the trim cylinders 21. The lower pin 28 is an example of the second turning shaft according to the first preferred embodiment of the present invention.
The cylinders 21 and 22 preferably are, for example, hydraulic cylinders. The tilt mechanism 19 includes a pump 30 that supplies hydraulic oil, a tank 31 storing the hydraulic oil, an electric motor 32 that drives the pump 30, and a plurality of pipes 33 connected to the pump 30 and the tank 31. The pump 30, the tank 31, the electric motor 32, and the pipes 33 are held by the frame 23. The pump 30 and the tank 31 are disposed at an interval in the right-left direction. The electric motor 32 is disposed above the pump 30. The pump 30 and the electric motor 32 are disposed above one trim cylinder 21, and the tank 31 is disposed above the other trim cylinder 21. The tilt cylinder 22 is disposed so that the tilt cylinder 22 is positioned between the pump 30 and electric motor 32 and the tank 31 as viewed in the front-rear direction.
The frame 23 includes a seat portion 23 a disposed along a horizontal plane, a pair of projections 23 b projecting downward from the seat portion 23 a, and a support portion 23 c disposed along a horizontal plane above the seat portion 23 a. The pair of projections 23 b are disposed at an interval in the right-left direction below the seat portion 23 a. The cylinder main body 24 of the trim cylinder 21 is fixed to the frame 23. In the first preferred embodiment, for example, the cylinder main body 24 of the trim cylinder 21 and the frame 23 preferably are an integral casting. The cylinder main body 26 of the tilt cylinder 22 is inserted in a through-hole 23 d (refer to FIG. 6) penetrating through the seat portion 23 a in the up-down direction. The lower end portion of the cylinder main body 26 of the tilt cylinder 22 is disposed between the pair of projections 23 b. The lower end portion of the cylinder main body 26 of the tilt cylinder 22 is joined to the pair of projections 23 b via the lower pin 28. The pump 30, the tank 31, and the electric motor 32 are supported by the support portion 23 c.
The pump 30, the tank 31, and the electric motor 32 are disposed rearward relative to the tilt cylinder 22. The lateral side of the pump 30, the tank 31, and the electric motor 32 is opened (for example, refer to FIG. 1). Therefore, the pump 30, the tank 31, and the electric motor 32 are exposed. The pipes 33 project downward from the frame 23. The pipes 33 are exposed from the frame 23. The cylinder main bodies 24 and 26 are connected to the pump 30 and the tank 31 via the plurality of pipes 33. The pipes 33 lead the hydraulic oil to the cylinders 21 and 22 and the tank 31. When the pump 30 is driven by the electric motor 32, the hydraulic oil is supplied to the cylinders 21 and 22 from the pump 30. When the hydraulic oil is supplied to the cylinder main bodies 24 of the trim cylinders 21 from the pump 30, the projecting amounts of the trim rods 25 change. Similarly, when the hydraulic oil is supplied from the pump 30 to the cylinder main body 26 of the tilt cylinder 22, the projecting amount of the tilt rod 27 changes. The cylinder main body 26 of the tilt cylinder 22 has an upper oil chamber and a lower oil chamber partitioned by a piston although they are not shown. When a load in a direction in which the projecting amount of the tilt rod 27 decreases of the loads to be applied to the tilt cylinder 22 increases, the pressure of the lower oil chamber increases. When the pressure of the lower oil chamber reaches a predetermined value, the relief valve (not shown) opens and the hydraulic oil is accordingly discharged from the lower oil chamber. Accordingly, the pressure of the lower oil chamber decreases, and the projecting amount of the tilt rod 27 decreases.
FIG. 6 is a partial sectional view of a portion of the first marine vessel propulsion apparatus 1 including the tilt mechanism 19 according to the first preferred embodiment of the present invention. FIG. 7 and FIG. 8 are side views of a portion of the first marine vessel propulsion apparatus 1 including the tilt mechanism 19 according to the first preferred embodiment of the present invention. FIG. 7 shows a position of the tilt bracket 13 when the outboard motor 2 is in a reference posture, and FIG. 8 shows a position of the tilt bracket 13 when the outboard motor 2 is fully tilted up (when the tilting angle of the outboard motor 2 is a full tilt-up angle).
As shown in FIG. 6, the intermediate portion 18 of the steering shaft 11 is tubular. The joint portion 17 of the steering shaft 11 has a through-hole 34 penetrating through the joint portion 17 in the up-down direction. The inside of the tubular portion 16 of the steering shaft 11 is connected to the through-hole 34 of the joint portion 17 via the inside of the intermediate portion 18. The tilt cylinder 22 is inserted in the steering shaft 11. The cylinder main body 26 is disposed inside the tubular portion 16. The lower end portion of the tubular portion 16 is joined to the frame 23. The frame 23 turns around the steering axis L3 together with the steering shaft 11. As described above, the cylinders 21 and 22, the pump 30, the tank 31, the electric motor 32, and the pipes 33 are held by the frame 23. Therefore, the cylinders 21 and 22, the pump 30, the tank 31, the electric motor 32, and the pipes 33 turn around the steering axis L3 together with the steering shaft 11.
The upper end portion of the tilt rod 27 projects upward from the through-hole 34 of the joint portion 17. The upper end portion of the tilt rod 27 is joined to the tilt bracket 13 via an upper pin 35 extending in the right-left direction. Therefore, the outboard motor 2 is supported by the tilt cylinder 22. The tilt rod 27 is turnable around the upper pin 35 with respect to the tilt bracket 13. The upper pin 35 is an example of a first turning shaft according to the first preferred embodiment of the present invention. On the other hand, as shown in FIG. 7, in a state in which the outboard motor 2 is positioned in the trim range, the tip ends of the trim rods 25 are in contact with contact portions 36 provided on the tilt bracket 13. Therefore, in the state in which the outboard motor 2 is positioned in the trim range, the outboard motor 2 is supported by the tilt cylinder 22 and the two trim cylinders 21. The contact portions 36 project laterally.
When the projecting amount of the tilt rod 27 increases, the tilt bracket 13 is pushed up by the tilt rod 27 and the outboard motor 2 turns up around the tilt axis L4. When the projecting amounts of the trim rods 25 increase in the state in which the outboard motor 2 is positioned in the trim range, the tilt bracket 13 is pushed up by the trim rods 25 and the outboard motor 2 turns up around the tilt axis L4. The tilt cylinder 22 can hold the outboard motor 2 at an arbitrary position between a full trim-in angle (see the outboard motor 2 shown by the alternate long and short dashed lines in FIG. 2) and a full tilt-up angle (see the outboard motor 2 shown by the solid line in FIG. 2). On the other hand, the trim cylinders 21 can hold the outboard motor 2 at an arbitrary position between the full trim-in angle and a full trim-out angle (see the outboard motor 2 shown by the alternate long and two short dashed lines in FIG. 2). Specifically, as shown in FIG. 8, when the tilting angle of the outboard motor 2 becomes larger than the full trim-out angle, the tip ends of the trim rods 25 separate from the contact portions 36 of the tilt bracket 13. Therefore, in the tilt range, the outboard motor 2 is supported by the tilt cylinder 22. Further, when the outboard motor 2 moves from the trim range to the tilt range, the amount of hydraulic oil that had been supplied to the trim cylinder 21 of the hydraulic oil fed from the pump 30 (refer to FIG. 5) is supplied to the tilt cylinder 22, and the supply flow rate of the hydraulic oil to the tilt cylinder 22 increases.
FIG. 9 is a partial sectional view of a portion of the first marine vessel propulsion apparatus 1 including a steering mechanism 20 according to the first preferred embodiment of the present invention. FIG. 10 and FIG. 11 are schematic plan views of a portion of the first marine vessel propulsion apparatus 1 including the steering mechanism 20 according to the first preferred embodiment of the present invention.
The steering mechanism 20 includes an electric motor 37, a power conversion mechanism 38, a reduction gear mechanism 39, and a steering case 40. The reduction gear mechanism 39 decelerates the rotation of the electric motor 37 and transmits the decelerated rotation to the power conversion mechanism 38. The power conversion mechanism 38 converts the power of the electric motor 37 transmitted by the reduction gear mechanism 39 into turning of the steering shaft 11 around the steering axis L3. The outboard motor 2 turns around the steering axis L3 with respect to the transom bracket 10 according to turning of the steering shaft 11 around the steering axis L3. The power conversion mechanism 38 includes a first conversion mechanism 41 that converts the rotation of the electric motor 37 into linear motion, and a second conversion mechanism 42 that converts the linear motion into turning of the steering shaft 11 around the steering axis L3 with respect to the transom bracket 10.
The electric motor 37 includes a motor main body 43 and a rotary shaft 44. The rotary shaft 44 is rotatable in the forward direction and the reverse direction opposite to the forward direction. The rotation of the rotary shaft 44 is transmitted to the first conversion mechanism 41 of the power conversion mechanism 38 via the reduction gear mechanism 39. The electric motor 37 is housed in a steering case 40. The electric motor 37 is disposed so that, for example, the rotary shaft 44 extends in the right-left direction. The motor main body 43 is fixed to the steering case 40. The steering case 40 is fixed to the transom bracket 10. Therefore, the electric motor 37 is fixed to the transom bracket 10 via the steering case 40. The electric motor 37 may be fixed to the transom bracket 10 via an intermediate member such as the steering case 40, or may be directly fixed to the transom bracket 10.
The first conversion mechanism 41 includes a first ball screw 45, and a tubular first ball nut 46 attached to the first ball screw 45 via a plurality of balls. The second conversion mechanism 42 includes a first rack 47 joined to the first ball nut 46, and a first pinion 48 engaged with the first rack 47. The first ball screw 45, the first ball nut 46, and the first rack 47 are housed in the steering case 40, and are held by the steering case 40. On the other hand, most of the first pinion 48 is disposed outside the steering case 40. The first pinion 48 is joined to the intermediate portion 18. Therefore, the first pinion 48 is joined to the tubular portion 16 and the joint portion 17 via the intermediate portion 18. The first pinion 48 turns around the steering axis L3 together with the steering shaft 11.
The first ball screw 45 extends in the right-left direction inside the steering case 40. The rotational axis of the first ball screw 45 and the rotational axis of the electric motor 37 are parallel or substantially parallel to each other. The first ball screw 45 is disposed rearward relative to the electric motor 37. Both end portions of the first ball screw 45 are supported on the steering case 40 via bearings 49. The first ball screw 45 is joined to the transom bracket 10 via the steering case 40, and joined to the electric motor 37 via the reduction gear mechanism 39. The rotation of the electric motor 37 is transmitted to the first ball screw 45 via the reduction gear mechanism 39. Accordingly, the first ball screw 45 is driven to rotate by the electric motor 37. When the first ball screw 45 rotates around the central axis of the first ball screw 45, the first ball nut 46 moves along the first ball screw 45, and the rotation of the first ball screw 45 is converted into linear motion of the first ball nut 46 with respect to the first ball screw 45.
The first rack 47 is provided on the outer peripheral portion of the first ball nut 46. The first rack 47 is, for example, integral with the first ball nut 46. The first rack 47 and the first ball nut 46 may constitute an integral member, or may constitute a member including a plurality of divided bodies joined integrally. The first rack 47 includes a plurality of teeth aligned in the axial direction of the first ball screw 45. The first rack 47 is opposed to the steering opening 50 provided in the steering case 40. The inside of the steering case 40 is connected to the inside of the housing portion 15 via a transom opening 51 provided in the housing portion 15 of the transom bracket 10. When the first ball screw 45 rotates, the first rack 47 moves along the first ball screw 45 together with the first ball nut 46.
The first pinion 48 projects from the outer peripheral portion of the intermediate portion 18. The first pinion 48 has, for example, a fan shape having a central axis positioned on the steering axis L3. The first pinion 48 is, for example, integral with the intermediate portion 18. The first pinion 48 and the intermediate portion 18 may constitute an integral member, or may constitute a member including a plurality of divided bodies joined integrally. The first pinion 48 enters the inside of the steering case 40 through the steering opening 50 and the transom opening 51. When the first rack 47 moves in the axial direction of the first ball screw 45, the position of engagement between the first rack 47 and the first pinion 48 moves and the first pinion 48 turns around the steering axis L3. Accordingly, the linear motion of the first ball nut 46 is converted into turning of the steering shaft 11 around the steering axis L3.
The reduction gear mechanism 39 includes a plurality of reduction gears (a first reduction gear 52, a second reduction gear 53, a third reduction gear 54, and a fourth reduction gear 55). The reduction gears 52 to 55 are, for example, external gears. The first reduction gear 52 is joined to the rotary shaft 44 of the electric motor 37. The first reduction gear 52 and the rotary shaft 44 are disposed coaxially with each other. The first reduction gear 52 rotates together with the rotary shaft 44. The first reduction gear 52 engages with the second reduction gear 53, and the second reduction gear 53 engages with the third reduction gear 54. The third reduction gear 54 engages with the fourth reduction gear 55. The second reduction gear 53 and the third reduction gear 54 are held rotatably by the steering case 40. The fourth reduction gear 55 is joined to the first ball screw 45. The fourth reduction gear 55 and the first ball screw 45 are disposed coaxially with each other. The first ball screw 45 rotates together with the fourth reduction gear 55.
The rotation of the electric motor 37 is transmitted to the first ball screw 45 by the reduction gear mechanism 39. The power of the electric motor 37 is amplified by deceleration of the rotation of the electric motor 37 by the reduction gear mechanism 39. The rotation of the first ball screw 45 is converted into linear motion of the first ball nut 46 with respect to the first ball screw 45 by the first ball screw 45 and the first ball nut 46. Then, the linear motion of the first ball nut 46 is converted into turning of the steering shaft 11 around the steering axis L3 by the first rack 47 and the first pinion 48. Accordingly, as shown in FIG. 11, the outboard motor 2 turns around the steering axis L3 with respect to the transom bracket 10. When the rotary shaft 44 of the electric motor 37 is driven to rotate in the forward direction, the outboard motor 2 turns in one rotating direction around the steering axis L3, and when the rotary shaft 44 of the electric motor 37 is driven to rotate in the reverse direction, the outboard motor 2 turns in the other rotating direction around the steering axis L3.
As described above, the electric motor 37 is fixed to the transom bracket 10 via the steering case 40. Therefore, when the outboard motor 2 turns around the steering axis L3 with respect to the transom bracket 10, the electric motor 37 does not turn around the steering axis L3 with respect to the transom bracket 10 together with the outboard motor 2 (refer to FIG. 11). Specifically, when the outboard motor 2 turns around the steering axis L3 with respect to the transom bracket 10, the position of the electric motor 37 with respect to the outboard motor 2 changes. On the other hand, the electric motor 37 is fixed to the transom bracket 10, so that when the outboard motor 2 turns around the tilt axis L4 with respect to the transom bracket 10, the electric motor 37 does not turn around the tilt axis L4 with respect to the transom bracket 10 together with the outboard motor 2 (refer to FIG. 2). Specifically, when the outboard motor 2 turns around the tilt axis L4 with respect to the transom bracket 10, the position of the electric motor 37 with respect to the outboard motor 2 changes.
As described above, in the first preferred embodiment, the tilt mechanism 19 that turns the outboard motor 2 around the tilt axis L4 preferably includes two trim cylinders 21 and a tilt cylinder 22. The trim cylinders 21 turn the outboard motor 2 around the tilt axis L4 between a full trim-in angle and a full trim-out angle larger than the full trim-in angle, and support the outboard motor 2 between the full trim-in angle and the full trim-out angle. The tilt cylinder 22 turns the outboard motor 2 around the tilt axis L4 between the full trim-in angle and a full tilt-up angle larger than the full trim-out angle, and supports the outboard motor 2 between the full trim-in angle and the full tilt-up angle.
Thus, the tilt mechanism 19 includes two trim cylinders 21 that turn the outboard motor 2 around the tilt axis L4 in the trim range. A range (a trim range) in which the trim cylinders 21 support the outboard motor 2 is smaller than a range (a trim range and a tilt range) in which the tilt cylinder 22 supports the outboard motor 2. Specifically, in the trim range, the outboard motor 2 is supported by the trim cylinder 21 and the tilt cylinder 22, and in the tilt range, the outboard motor 2 is supported only by the tilt cylinder 22. Therefore, when the outboard motor 2 moves from the trim range to the tilt range in a state in which the forward propulsive force is great, the internal pressure of the tilt cylinder 22 increases. Therefore, by discharging the hydraulic oil from the tilt cylinder 22 by using a relief valve, the outboard motor 2 can be returned to the tilt range. Accordingly, when the tilting angle of the outboard motor 2 is adjusted in the trim range while propelling the marine vessel forward in a state in which the forward propulsive force is great, the propeller 9 can be prevented from coming out of the water and reducing the propulsive force to be transmitted to the hull H1.
When the outboard motor 2 moves from the trim range to the tilt range, the amount of hydraulic oil that had been supplied to the trim cylinder 21 of the hydraulic oil fed from the pump 30 is supplied to the tilt cylinder 22, so that the supply flow rate of the hydraulic oil to the tilt cylinder 22 increases. Therefore, the movement speed of the tilt rod 27 of the tilt cylinder 22 increases, and the outboard motor 2 turns around the tilt axis L4 at a speed higher than the movement speed in the trim range. Accordingly, the outboard motor 2 can be quickly tilted up in the tilt range. Further, unlike the conventional marine vessel propulsion apparatus, the clamp brackets are not disposed on the lateral sides of the cylinders 21 and 22, so that the cylinders 21 and 22 can be increased in size. Accordingly, when the outboard motor 2 is large in size or the outboard motor 2 has a high output, the increases in internal pressure of the cylinders 21 and 22 can be minimized.
In the first preferred embodiment, the pump 30, the tank 31, the electric motor 32, and the pipings 33 are exposed. Therefore, a user of the first marine vessel propulsion apparatus 1 can easily access the pump 30, the tank 31, the electric motor 32, and the pipings 33. Therefore, a user of the first marine vessel propulsion apparatus 1 can easily perform maintenance operations such as replacement of the hydraulic oil and the pipings 33.

Second Marine Vessel Propulsion Apparatus

Next, a second marine vessel propulsion apparatus including an electric motor fixed to the steering shaft will be described. In the description given below, components equivalent to those shown in FIG. 1 to FIG. 11 are provided with the same reference numerals as in FIG. 1, etc., and description thereof will be omitted.

Second Preferred Embodiment

FIG. 12 is a side view of a second marine vessel propulsion apparatus 201 according to a second preferred embodiment of the present invention. FIG. 13A is a perspective view of a portion of the second marine vessel propulsion apparatus 201 according to the second preferred embodiment of the present invention. FIG. 13B is an exploded perspective view of a portion of the second marine vessel propulsion apparatus 201 according to the second preferred embodiment of the present invention. FIG. 13C is an exploded view of a portion of the second marine vessel propulsion apparatus 201 according to the second preferred embodiment of the present invention. FIG. 14 is a partial side view of a portion of the second marine vessel propulsion apparatus 201 according to the second preferred embodiment of the present invention. FIG. 14 is a partial side view of a portion of the second marine vessel propulsion apparatus 201 according to the second preferred embodiment of the present invention.
The second marine vessel propulsion apparatus 201 includes the outboard motor 2, the transom bracket 10, a steering shaft 211, and the tilt shaft 211. The second marine vessel propulsion apparatus 201 further includes the tilt mechanism 19 and a steering mechanism 220. The steering shaft 211 includes the tubular portion 16 and the joint portion 17. The joint portion 17 is joined to the upper end portion of the tubular portion 16. The joint portion 17 is, for example, integral with the tubular portion 16. The tubular portion 16 and the joint portion 17 may constitute an integral member, or may constitute a member including a plurality of divided bodies joined integrally. Specifically, the steering shaft 211 may be a member including a plurality of divided bodies, or may be an integral member. The inside of the tubular portion 16 is connected to the through-hole 34 of the joint portion 17. The cylinder main body 26 of the tilt cylinder 22 is dispersed inside the tubular portion 16. The lower end portion of the tubular portion 16 is joined to the frame 23. The upper end portion of the tilt rod 27 projects upward from the through-hole 34 of the joint portion 17. The upper end portion of the tilt rod 27 is joined to the tilt bracket 13 via the upper pin 35.
FIG. 15 is a side view of the second marine vessel propulsion apparatus 201 according to the second preferred embodiment of the present invention. FIG. 16 is a plan view of the second marine vessel propulsion apparatus 201 according to the second preferred embodiment of the present invention. FIG. 16 shows a state in which the outboard motor 2 is positioned at a maximum rightward steering position by the solid line. FIG. 16 shows a state in which the outboard motor 2 is positioned at the steering origin by alternate long and short dashed lines, and shows a state in which the outboard motor 2 is positioned at a maximum leftward steering position by the alternate long and two short dashed lines.
The steering shaft 211 further includes a fixing portion 267 provided on the joint portion 17. The steering case 40 is fixed to the fixing portion 267. Therefore, the electric motor 37 is fixed to the steering shaft 211 via the steering case 40. The outboard motor 2 turns around the tilt axis L4 with respect to the steering shaft 211. Therefore, as shown in FIG. 15, when the outboard motor 2 turns around the tilt axis L4 with respect to the transom bracket 10, the electric motor 37 does not turn around the tilt axis L4 with respect to the transom bracket 10. Specifically, when the outboard motor 2 turns around the tilt axis L4 with respect to the transom bracket 10, the position of the electric motor 37 with respect to the outboard motor 2 changes.
On the other hand, the electric motor 37 is fixed to the steering shaft 211, so that when the steering shaft 211 turns around the steering axis L3, the electric motor 37 turns around the steering axis L3 together with the steering shaft 211 and the outboard motor 2. Therefore, as shown in FIG. 16, when the outboard motor 2 turns around the steering axis L3 with respect to the transom bracket 10, the electric motor 37 turns around the steering axis L3 with respect to the transom bracket 10 together with the outboard motor 2. Specifically, even when the outboard motor 2 turns around the steering axis L3 with respect to the transom bracket 10, the position of the electric motor 37 with respect to the outboard motor 2 does not change.
FIG. 17 is an exploded view of a portion of the second marine vessel propulsion apparatus 20 according to the second preferred embodiment of the present invention. FIG. 18 is a partial sectional view of a portion of the second marine vessel propulsion apparatus 201 including a steering mechanism 220 according to the second preferred embodiment of the present invention. FIG. 19 and FIG. 20 are schematic plan views of a portion of the second marine vessel propulsion apparatus 201 including the steering mechanism 220 according to the second preferred embodiment of the present invention.
The steering mechanism 220 includes the electric motor 37, a power conversion mechanism 238, the reduction gear mechanism 39, and the steering case 40. As shown in FIG. 17, the steering mechanism 220 further includes a gear case 268 and a stay 269. The power conversion mechanism 238 includes a first conversion mechanism 241 and a second conversion mechanism 242. As shown in FIG. 18, the steering case 40 is fixed to a fixing portion 267 of the steering shaft 211, and the gear case 268 is fixed to the steering case 40. Therefore, the gear case 268 is fixed to the steering shaft 211 via the steering case 40. The steering shaft 211 is turnable around the steering axis L3 with respect to the transom bracket 10. Therefore, the gear case 268 is turnable around the steering axis L3 with respect to the transom bracket 10. As shown in FIG. 18, the gear case 268 has a gear opening 270 opposed to the steering opening 50. The inside of the steering case 40 is connected to the inside of the gear case 268 via the gear opening 270.
As shown in FIG. 19, the first conversion mechanism 241 includes a second ball screw 245, and a tubular second ball nut 246 attached to the second ball screw 245 via a plurality of balls. The second conversion mechanism 242 includes a second rack 247 joined to the second ball nut 246, and a second pinion 248 engaged with the second rack 247. The second ball screw 245, the second ball nut 246, and the second rack 247 are housed in the steering case 40, and held by the steering case 40. On the other hand, most of the second pinion 248 is housed in the gear case 268. The second pinion 248 is joined to the transom bracket 10. The steering shaft 211 is turnable around the steering axis L3 with respect to the transom bracket 10, so that the steering shaft 211 is turnable around the steering axis L3 with respect to the second pinion 248.
As shown in FIG. 19, the second ball screw 245 extends in the right-left direction inside the steering case 40. The rotational axis of the second ball screw 245 and the rotational axis of the electric motor 37 are parallel or substantially parallel to each other. The second ball screw 245 is disposed rearward relative to the electric motor 37. Both end portions of the second ball screw 245 are supported on the steering case 40 via bearings 49. The second ball screw 245 is joined to the transom bracket 10 via the steering case 40, and joined to the electric motor 37 via the reduction gear mechanism 39. The rotation of the electric motor 37 is transmitted to the second ball screw 245 via the reduction gear mechanism 39. Accordingly, the second ball screw 245 is driven to rotate by the electric motor 37. When the second ball screw 245 rotates around the central axis of the second ball screw 245, the second ball nut 246 moves along the second ball screw 245, and the rotation of the second ball screw 245 is converted into linear motion of the second ball nut 246, with respect to the second ball screw 245.
As shown in FIG. 19, the second rack 247 is provided on the outer peripheral portion of the second ball nut 246. The second rack 247 is, for example, integral with the second ball nut 246. The second rack 247 and the second ball nut 246 may constitute an integral member, or may constitute a member including a plurality of divided bodies joined integrally. The second rack 247 includes a plurality of teeth aligned in the axial direction of the second ball screw 245. The second rack 247 is opposed to the steering opening 50 provided in the steering case 40. When the second ball screw 245 rotates, the second rack 247 moves along the second ball screw 245 together with the second ball nut 246.
As shown in FIG. 19, the second pinion 248 includes a cylindrical portion 271 and a gear portion 272. As shown in FIG. 18, the cylindrical portion 271 of the second pinion 248 is fixed to the stay 269. The stay 269 is fixed to the transom bracket 10. Therefore, the second pinion 248 is fixed to the transom bracket 10 via the stay 269. The stay 269 is tubular. The stay 269 and the cylindrical portion 271 are disposed coaxially with each other. The inside of the stay 269 is connected to the inside of the cylindrical portion 271. As shown in FIG. 18, the housing portion 15 of the transom bracket 10 is inserted into the cylindrical portion 271 and the stay 269. The housing portion 15 penetrates through the cylindrical portion 271 and the stay 269 in the up-down direction. Therefore, the cylindrical portion 271 and the stay 269 surround the housing portion 15 around the steering axis L3.
As shown in FIG. 18 and FIG. 19, the second pinion 248 is covered by the gear case 268. The gear case 268 is disposed around the second pinion 248. The gear portion 272 of the second pinion 248 projects from the outer peripheral portion of the cylindrical portion 271. The gear portion 272 has, for example, a fan shape having a central axis positioned on the steering axis L3. The gear portion 272 enters the inside of the steering case 40 through the steering opening 50 and the gear opening 270. The gear portion 272 engages with the second rack 247 inside the steering case 40. The rotation of the electric motor 37 is converted into turning of the steering shaft 211 around the steering axis L3 by the second ball screw 245, the second ball nut 246, the second rack 247, and the second pinion 248.
In detail, the rotation of the electric motor 37 is transmitted to the second ball screw 245 by the reduction gear mechanism 39. When the second ball screw 245 rotates, a force of relative movement in the axial direction of the second ball screw 245 is applied to the second ball screw 245 and the second ball nut 246. According to movement of the position of engagement between the second rack 247 and the second pinion 248, the force is converted into a force that turns the second ball screw 245 and the second ball nut 246 around the steering axis L3. Accordingly, as shown in FIG. 20, the second ball screw 245 and the second ball nut 246 turn around the steering axis L3 while the second ball screw 245 moves in the axial direction of the second ball screw 245 with respect to the second ball nut 246.
The second ball screw 245 is joined to the steering shaft 211 via the steering case 40. Therefore, the second ball screw 245 turns around the steering axis L3, and accordingly, the steering shaft 211 turns around the steering axis L3 with respect to the transom bracket 10. Specifically, the rotation of the electric motor 37 is converted into linear motion of the second ball nut 246 with respect to the second ball screw 245 by the second ball screw 245 and the second ball nut 246. Concurrently, the linear motion of the second ball nut 246 is converted into turning of the steering shaft 211 around the steering axis L3 by the second rack 247 and the second pinion 248. Accordingly, as shown in FIG. 20, the outboard motor 2 turns around the steering axis L3 with respect to the transom bracket 10.

Third Preferred Embodiment

FIG. 21 is a back view of a portion of a second marine vessel propulsion apparatus 301 according to a third preferred embodiment of the present invention. FIG. 22 is a plan view of a portion of the second marine vessel propulsion apparatus 301 according to the third preferred embodiment of the present invention. FIG. 23 is a side view of a portion of the second marine vessel propulsion apparatus 301 according to the third preferred embodiment of the present invention. In these FIG. 21 to FIG. 23, the constituent portions equivalent to the portions shown in FIG. 1 to FIG. 20 are provided with the same reference numerals as in FIG. 1, etc., and descriptions thereof will be omitted.
A main difference between the third preferred embodiment and the second preferred embodiment described above is that the second marine vessel propulsion apparatus 301 preferably includes two protective covers 356 that protect the tilt mechanism 19.
In detail, the two protective covers 356 are disposed at an interval in the right-left direction. Each protective cover 356 includes an upper wall portion 357 disposed above the tank 31 or above the electric motor 32, and a side wall portion 358 disposed on the lateral side of the pump 30, the electric motor 32, and the trim cylinder 21 or the lateral side of the tank 31 and the trim cylinder 21. The pump 30, the tank 31, the electric motor 32, and the trim cylinders 21 are disposed between the two side wall portions 358. One protective cover 356 (left protective cover 356) covers the pump 30, the electric motor 32, and the trim cylinder 21, and the other protective cover 356 (right protective cover 356) covers the tank 31 and the trim cylinder 21. The pump 30, the tank 31, the electric motor 32, and the trim cylinders 21 are protected by the two protective covers 356. Accordingly, the pump 30, etc., are prevented from being damaged.
Each protective cover 356 is attached to, for example, the tilt bracket 13. Without limiting to the tilt bracket 13, each protective cover 356 may be attached to any of the transom bracket 10, the steering shaft 611, the tilt shaft 12, the pump 30, the electric motor 32, and the frame 23, or may be attached to a plurality of members including any of the above-described members. Each protective cover 356 is attached to the tilt bracket 13 by, for example, a plurality of bolts 359. Each protective cover 356 is detachable from the tilt bracket 13. When each protective cover 356 is detached, the pump 30, the tank 31, the electric motor 32, and each trim cylinder 21 are exposed. Therefore, a user of the second marine vessel propulsion apparatus 130 can easily access the pump 30, the tank 31, the electric motor 32, and each trim cylinder 21 by detaching each protective cover 356. Therefore, a user of the second marine vessel propulsion apparatus 130 can easily perform maintenance operations such as replacement of hydraulic oil.

Other Preferred Embodiments

Although preferred embodiments of the present invention are described above, the present invention is not limited to the contents of the above-described first to third preferred embodiments, and can be variously changed within the scope described in the claims.
For example, the first to third preferred embodiments describe a case where the steering mechanism preferably is an electric steering mechanism including an electric motor. However, the steering mechanism is not limited to an electric steering mechanism but may be a hydraulic steering mechanism including a hydraulic pump.
The first to third embodiments described above describe a case where a portion of the tilt cylinder (cylinder main body) is preferably housed inside the tubular portion of the steering shaft. However, the entire tilt cylinder may be housed inside the tubular portion of the steering shaft.
The third preferred embodiment described above describes a case where the second marine vessel propulsion apparatus preferably includes two protective covers that protect the tilt mechanism. However, it is also possible that the first marine vessel propulsion apparatus includes two protective covers that protect the tilt mechanism.
The first to third preferred embodiments describe a case where one tilt cylinder and two trim cylinders are preferably provided. However, it is also possible that one tilt cylinder and one trim cylinder are provided.
A non-limiting example of the correspondence between the components mentioned in the “SUMMARY OF THE INVENTION” and the components of the above-described preferred embodiments are as follows.

Hull: Hull H1

Transom: Transom T1

Transom bracket: Transom bracket 10
Steering axis: Steering axis L3,
Steering shaft: Steering shaft 11, 211
Tilt axis: Tilt axis L4
Outboard motor: Outboard motor 2
Steering mechanism: Steering mechanism 20, 220
First angle: Full trim-in angle
Second angle: Full trim-out angle
First cylinder: Trim cylinder 21
Third angle: Full tilt-up angle
Second cylinder: Tilt cylinder 22
Marine vessel propulsion apparatus: First marine vessel propulsion apparatus 1, second marine vessel propulsion apparatus 201, 301
Tubular portion: Tubular portion 16

Pump: Pump 30

Electric motor: Electric motor 32

Piping: Piping 33

Protective cover: Protective cover 356
Tilt bracket: Tilt bracket 13
First turning shaft: Upper pin 35
Second turning shaft: Lower pin 28
The present application corresponds to Japanese Patent Application No. 2010-230852 filed in the Japan Patent Office on Oct. 13, 2010, and the entire disclosure of this application is incorporated herein by reference.
While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.

Claims

1. A marine vessel propulsion apparatus comprising:

a transom bracket attachable to a transom of a hull;

a steering shaft joined to the transom bracket, the steering shaft being turnable around a steering axis extending in an up-down direction;

an outboard motor joined to the steering shaft, the outboard motor being turnable around a tilt axis extending along a plane that is perpendicular or substantially perpendicular to the steering axis, the outboard motor being turnable around the steering axis together with the steering shaft;

a steering mechanism joined to the transom bracket and the steering shaft, the steering mechanism arranged to turn the steering shaft and the outboard motor around the steering axis with respect to the transom bracket;

a first cylinder joined to the steering shaft and the outboard motor, the first cylinder being arranged to turn the outboard motor around the tilt axis between a first angle and a second angle larger than the first angle, the first cylinder being arranged to support the outboard motor between the first angle and the second angle; and

a second cylinder joined to the steering shaft and the outboard motor, the second cylinder being arranged to turn the outboard motor around the tilt axis between the first angle and a third angle larger than the second angle, the second cylinder being arranged to support the outboard motor between the first angle and the third angle.

2. The marine vessel propulsion apparatus according to claim 1, wherein

the steering shaft includes a tubular portion extending along the steering axis, and

at least a portion of the second cylinder is housed inside the tubular portion.

3. The marine vessel propulsion apparatus according to claim 1, wherein the first cylinder and the second cylinder are arranged to turn around the steering axis together with the steering shaft.

4. The marine vessel propulsion apparatus according to claim 1, further comprising:

a pump arranged to supply hydraulic oil to the first cylinder and the second cylinder;

an electric motor arranged to drive the pump; and

a piping in which hydraulic oil circulates; wherein

the first cylinder, the second cylinder, the pump, the electric motor, and the piping are arranged to turn around the steering axis together with the steering shaft.

5. The marine vessel propulsion apparatus according to claim 4, wherein at least a portion of the pump is exposed, and at least a portion of the electric motor is exposed.

6. The marine vessel propulsion apparatus according to claim 4, further comprising a detachable protective cover covering at least one of the pump and the electric motor.

7. The marine vessel propulsion apparatus according to claim 4, wherein at least a portion of the piping is exposed.

8. The marine vessel propulsion apparatus according to claim 1, wherein the outboard motor includes a tilt bracket joined to the steering shaft, the tilt bracket being turnable around the tilt axis with respect to the steering shaft.

9. The marine vessel propulsion apparatus according to claim 1, wherein the second cylinder is joined to the outboard motor via a turning shaft, the second cylinder being turnable around the turning shaft with respect to the outboard motor.

10. The marine vessel propulsion apparatus according to claim 1, wherein the second cylinder is joined to the first cylinder via a turning shaft, the second cylinder being turnable around the turning shaft with respect to the first cylinder.

11. The marine vessel propulsion apparatus according to claim 1, wherein the first cylinder and the second cylinder are disposed so as not to overlap each other as viewed in a direction orthogonal or substantially orthogonal to the tilt axis.

12. The marine vessel propulsion apparatus according to claim 1, wherein

the marine vessel propulsion apparatus includes a pair of the first cylinders disposed at an interval in a direction parallel or substantially parallel to the tilt axis, and

the second cylinder is disposed such that the second cylinder is positioned between the pair of first cylinders as viewed in a direction orthogonal or substantially orthogonal to the tilt axis.