Patent Application
20240359783
This application claims the benefit of priority to Japanese Patent Application No. 2023-072160 filed on Apr. 26, 2023. The entire contents of this application are hereby incorporated herein by reference.
The technologies disclosed herein relate to an outboard motor and a boat.
A boat is provided with a hull and an outboard motor mounted to a rear portion of the hull. The outboard motor is a device that generates thrust to propel the boat. The outboard motor has a drive source, a propeller, and a transmission mechanism that has a propeller shaft and transmits the drive power of the drive source to the propeller.
There has been disclosed an outboard motor including an electric motor including an output shaft extending along an upper-lower direction, a gear mechanism connected to the output shaft of the electric motor, and a case including a housing chamber accommodating the gear mechanism and oil. The gear mechanism has a gear that rotates around a rotation shaft along the upper-lower direction (hereinafter referred to as “a vertical shaft rotation gear”) (see e.g., JP 2016-37256 A).
In the outboard motor of the above conventional technology, in which the vertical shaft rotation gear and oil are accommodated in the housing chamber of the case, a level of the oil in the housing chamber of the case is comparatively low, and there is a risk that the lubricating effect of the oil may not be sufficient for the rotation of the vertical shaft rotation gear.
These issues are not limited to gear mechanisms but are common to outboard motors in which a transmission mechanism transmitting power from a drive source (not limited to an electric motor but may be an engine, among others) and including a rotor rotating around a rotation shaft along an upper-lower direction and oil are accommodated in a housing chamber of a case.
The present specification discloses technologies that are able to solve one or more of the above-mentioned problems.
The technologies disclosed herein can be implemented in the following aspects.
An outboard motor according to a preferred embodiment of the present invention includes an electric motor including an output shaft extending in an upper-lower direction, a gearing connected to the output shaft of the electric motor and including a plurality of gears to rotate around a plurality of rotation shafts extending in the upper-lower direction, and a housing chamber to accommodate the gearing and oil, wherein the housing chamber includes a peripheral wall extending along one gear of the plurality of gears, and includes a sloped portion between the one gear and the peripheral wall that is inclined upward along a rotating direction of the one gear. In the outboard motor, the peripheral wall extends along the one gear and the sloped portion is between the one gear and the peripheral wall. The sloped portion is inclined upward along the rotating direction of the one gear. This causes the oil to flow toward and along one side of the one gear as the gear rotates, and the momentum of the flow lifts some of the oil upward along the sloped portion. The lifted oil is applied to an upper side of the gear to improve the lubricating effect of the oil, e.g., improve the rotation of the one gear.
In the above outboard motor, an inner peripheral surface of the peripheral wall may be arc-shaped along the rotating direction of the one gear when viewed in the upper-lower direction. Accordingly, compared to a configuration in which the inner peripheral surface of the peripheral wall extends in a direction different from the rotating direction of the one gear, the momentum of the oil flow with the rotation of the one gear is higher so that the oil can be effectively lifted upward.
In the above outboard motor, the sloped portion may be spaced apart from the one gear in a radial direction of the one gear. The outboard motor is thus able to lift the oil upward without affecting the rotation of the one gear, compared to a configuration in which the sloped portion is adjacent to the one gear.
In the above outboard motor, the sloped portion may extend along and in contact with the inner peripheral surface of the peripheral wall. Thus, the outboard motor is able to lift the oil upward more effectively, compared to a configuration in which the sloped portion is slightly separated from the peripheral wall or the sloped portion does not extend along the inner peripheral surface of the peripheral wall.
In the above outboard motor, the sloped portion may have an inclination angle of about 45 degrees or less with respect to a horizontal direction. Thus, the outboard motor is able to effectively lift the oil upward by utilizing the momentum of the oil flow, compared to a configuration in which the sloped portion inclination angle with respect to the horizontal direction is greater than about 45 degrees.
In the above outboard motor, a lower end of the sloped portion may face a bottom surface of the housing chamber. Accordingly, oil flows smoothly into the sloped portion so that the oil is lifted upward more effectively, compared to a configuration in which a step exists between the lower end of the sloped portion and the bottom surface of the housing chamber.
In the above outboard motor, the gearing may include another gear to mesh with the one gear, and the sloped portion may be on an opposite side of the one gear to the other gear. Thus, the outboard motor is able to lift the oil above the gear more securely, compared to a configuration in which an upper end of the sloped portion is located below an upper surface of the one gear.
In the above outboard motor, the housing chamber may further include a reverse direction sloped portion between the one gear and the peripheral wall and inclined upward along the rotating direction of the one gear. Thus, the outboard motor is able to lift the oil upward regardless of whether the one gear is rotating in the forward or reverse direction.
In the above outboard motor, the sloped portion and the reverse direction sloped portion may be located at different positions on a virtual circle centered around the one gear. Thus, the outboard motor is able to reduce or prevent an increase in the size of the housing chamber, compared to a configuration in which the sloped portion and the reverse direction sloped portion are aligned in the radial direction of the gear.
In the above outboard motor, a highest end of the sloped portion and a highest end of the reverse direction sloped portion may be adjacent to each other. Thus, the outboard motor is able to reduce or prevent a reduction in the momentum of the oil flow due to the presence of the sloped portion and the reverse direction sloped portion, compared to a configuration in which the sloped portion and the reverse direction sloped portion are arranged in the rotating direction at a distance from each other, for example.
The above outboard motor may further include a bearing to support an the upper end of the rotation shaft connected to the one gear, and a guide to guide the oil lifted by the sloped portion to the bearing. Thus, the outboard motor can effectively supply the oil to the bearing supporting the upper end of the rotation shaft of the one gear.
In the above outboard motor, the gearing may include a reduction gearing connected to the output shaft of the electric motor and including an input gear to mesh with the gear. Thus, the outboard motor can lift the oil above the one gear of the reduction gearing.
The above outboard motor may further include a bearing to support the upper end of the rotation shaft connecting to the one gear, and a guide to guide the oil lifted by the sloped portion to the bearing, wherein a position at which the one gear meshes with the input gear is located on an outer circumference side of the bearing when viewed in the upper-lower direction. Thus, the outboard motor can effectively supply the oil to the bearing supporting the upper end of the rotation shaft of the gear.
An outboard motor according to another preferred embodiment of the present invention includes a drive source, a transmission to transmit power from the drive source and including a rotor to rotating around a rotation shaft extending in an upper-lower direction, and a case including a housing chamber to accommodate the transmission and oil, wherein the housing chamber includes a peripheral wall extending along the rotor and a sloped portion between the rotor and the peripheral wall and inclined upward along the rotating direction of the rotor. Thus, the outboard motor can effectively lift the oil upward.
The technologies disclosed herein may be implemented in various aspects, including, e.g., outboard motors, boats provided with outboard motors and hulls, among other configurations and apparatuses.
The outboard motors disclosed herein effectively lift the oil upward in the housing chamber of the case.
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.
The boat 10 includes a hull 200 and an outboard motor 100. In this preferred embodiment, the boat 10 includes only one outboard motor 100, but the boat 10 may include a plurality of outboard motors 100.
The hull 200 is a portion of the boat 10 for occupants to ride. The hull 200 includes a hull main body 202 including a living space 204, a pilot seat 240 installed in the living space 204, and an operating device 250 installed near the pilot seat 240. The operating device 250 steers the boat and includes, e.g., a steering wheel 252, a shift/throttle lever 254, a joystick 255, a monitor 256, and an input device 258. The hull 200 includes a partition wall 220 to partition the rear end of the living space 204 and a transom 210 positioned at the rear end of the hull 200. In the front-rear direction, a space 206 is provided between the transom 210 and the partition wall 220.
The outboard motor 100 generates thrust to propel the boat 10. The outboard motor 100 is attached to the transom 210 at a rear portion of the hull 200. The outboard motor 100 includes an outboard motor main body 110 and a suspension device 150.
The outboard motor main body 110 includes a motor assembly 120, a transmission mechanism 130, a propeller 112, a cowl 114, a casing 116, a water pump 140, and a pump shaft 134.
The cowl 114 is a housing located on top of the outboard motor main body 110. The cowl 114 includes an upper cowl 114a defining an upper portion of the cowl 114 and a lower cowl 114b defining a lower portion of the cowl 114. The upper cowl 114a is detachably attached to the lower cowl 114b.
The casing 116 is a housing located below the cowl 114 and provided in the lower portion of the outboard motor main body 110. The casing 116 includes a lower case 116b and an upper case 116a. The lower case 116b accommodates at least a portion of the drive shaft 133 and the propeller shaft 137 described below. The lower case 116b is connected to the upper case 116a so as to be pivotable around the drive shaft 133. The upper case 116a is located above the lower case 116b and accommodates a gearbox assembly 300 described below.
A motor assembly 120 is accommodated within the cowl 114. The motor assembly 120 includes an electric motor 122. The electric motor 122 is an example of a drive source. The electric motor 122 includes an output shaft 123 that outputs the drive power generated by the electric motor 122.
The transmission mechanism 130 transmits the driving force of the electric motor 122 to the propeller 112. At least a portion of the transmission mechanism 130 is accommodated in the casing 116. The transmission mechanism 130 includes a gearbox assembly 300, a drive shaft 133, and a propeller shaft 137.
The propeller shaft 137 is a rod-shaped member and extends in a forward and backward orientation below the outboard motor main body 110. The propeller shaft 137 rotates with the propeller 112. The front end of the propeller shaft 137 is accommodated in the lower case 116b, and the rear end of the propeller shaft 137 protrudes rearward from the lower case 116b. The front end of the propeller shaft 137 includes a gear 138.
The gearbox assembly 300 is connected to the output shaft 123 of the electric motor 122 and the drive shaft 133. The gearbox assembly 300 reduces the driving force of the electric motor 122 and transmits the reduced driving force to the propeller shaft 137. This allows the electric motor 122 to rotate at a desired torque. The configuration of the gearbox assembly 300 will be described in detail below.
The propeller 112 is a rotor including a plurality of blades and is attached to the rear end of the propeller shaft 137. The propeller 112 rotates along with the rotation of the propeller shaft 137 around the rotation axis Ap. The propeller 112 generates thrust by rotating. As mentioned above, since the lower case 116b is pivotable, the propeller 112 pivots about the drive shaft 133 along with the lower case 116b. Therefore, the boat 10 is steered by pivoting the lower case 116b.
The water pump 140 pumps water from outside the outboard motor 100, e.g., to cool the electric motor 122. The pump shaft 134 extends in an upper-lower direction. The pump shaft 134 is driven by the drive power of the electric motor 122 and transmits power to the water pump 140. The water pump 140 is driven by the driving force of the electric motor 122 transmitted by the pump shaft 134.
The suspension device 150 connects the outboard motor main body 110 to the hull 200. The suspension device 150 includes a pair of left and right clamp brackets 152, a tilt shaft 160, and a swivel bracket 156.
The pair of left and right clamp brackets 152 are disposed behind the hull 200 in a state separated from each other in the left-right direction and are fixed to the transom 210 of the hull 200 by using, e.g., bolts. Each clamp bracket 152 includes a cylindrical supporting portion 152a provided with a through-hole extending in the left-right direction.
The tilt shaft 160 is a rod-shaped member and is rotatably supported within the through-hole in the supporting portion 152a of the clamp bracket 152. The tilt axis At, which is the centerline of the tilt shaft 160, defines a horizontal (left-right) axis during the tilting operation of the outboard motor 100.
The swivel bracket 156 is sandwiched between the pair of clamp brackets 152 and is supported by the supporting portion 152a of the clamp brackets 152 via the tilt shaft 160 so as to be rotatable around the tilt axis At. The swivel bracket 156 is driven to rotate about the tilt axis At with respect to the clamp bracket 152 by a tilt device (not shown) that includes an actuator, such as a hydraulic cylinder, for example.
When the swivel bracket 156 rotates about the tilt axis At with respect to the clamp bracket 152, the outboard motor main body 110 supported by the swivel bracket 156 also rotates about the tilt axis At. This achieves the tilting operation of rotating the outboard motor main body 110 in the upper-lower direction with respect to the hull 200. By this tilting operation, the outboard motor 100 can change the angle of the outboard motor main body 110 around the tilt axis At in the range from the tilt-down state in which the propeller 112 is located under the water (the state in which the outboard motor 100 is in the reference attitude) to the tilt-up state in which the propeller 112 is located above the water surface. Trimming operation to adjust the attitude of the boat 10 during travel can also be performed by adjusting the angle around the tilt axis At of the outboard motor main body 110.
The motor assembly 120 includes the electric motor 122 as described above and a motor case 121 that supports the electric motor 122. The electric motor 122 is placed vertically in the motor case 121. Vertical placement means that the output shaft 123 (rotation axis Ac) of the electric motor 122 is arranged in an attitude in which it extends in the upper-lower direction. The upper and lower ends of the output shaft 123 are rotatably supported by a motor bearing 125 fixed to the motor case 121, respectively.
The gearbox assembly 300 includes a primary reduction gear mechanism 310 and a gear case 302. The gear case 302 is an example of a case, and the primary reduction gear mechanism 310 is an example of a gearing.
The gear case 302 includes a housing chamber R1 that accommodates the primary reduction gear mechanism 310 and oil S. The gear case 302 includes an upper gear case 302a and a lower gear case 302b combined in the upper-lower direction to define the housing chamber R1. The housing chamber R1 includes an input side region R11 and an output side region R12. The input side region R11 is the region of the housing chamber R1 that is located directly below the electric motor 122. The output side region R12 is a region of the housing chamber R1 that is located forward of the input side region R11. The gear case 302 is provided with an input through-hole H1 opening upward from the input side region R11, a through-hole H2 opening downward from the input side region R11, and an output through-hole H3 opening downward from the output side region R12.
The primary reduction gear mechanism 310 includes an input gear 320, an upper input bearing 326, a lower input bearing 350, an output gear 330, an upper output bearing 336, and a lower output bearing 337. The input gear 320, the upper input bearing 326, and the lower input bearing 350 are accommodated in the input side region R11 of the gear case 302. The output gear 330, the upper output bearing 336, and the lower output bearing 337 are accommodated in the output side region R12 of the gear case 302.
The input gear 320 includes an input gear shaft 324 extending in the upper-lower direction, and the upper end of the input gear shaft 324 is connected to the output shaft 123 of the electric motor 122. In this preferred embodiment, the input gear 320 is a helical gear. Specifically, the input gear 320 includes an input gear shaft 324 and an input gear body 322 fixed to the input gear shaft 324. The input gear body 322 and the input gear shaft 324 may be separated from each other or may be integral. The input gear shaft 324 is arranged in an attitude in which it extends in the upper-lower direction. An insertion hole 325 is provided in the upper end of the input gear shaft 324. The output shaft 123 of the electric motor 122 protrudes into the input side region R11 through the above-mentioned input through-hole H1 of the gear case 302 and is inserted into and fixed to the insertion hole 325 of the input gear shaft 324. Thus, the input gear 320 rotates integrally with the output shaft 123 around the rotation axis Ac.
The upper input bearing 326 is located on the upper side of the input gear body 322, is fixed to the gear case 302 (upper gear case 302a), and rotatably supports the upper end of the input gear shaft 324. The lower input bearing 350 is located on the lower side of the input gear body 322, is fixed to the gear case 302 (lower gear case 302b), and rotatably supports the lower end of the input gear shaft 324. The through-hole H2 of the gear case 302 is sealed by a cap 303.
The output gear 330 includes an output gear shaft 334 extending in the upper-lower direction and meshes with the input gear 320. In this preferred embodiment, the output gear 330 is a helical gear. Specifically, the output gear 330 includes an output gear shaft 334 and an output gear body 332 fixed to the output gear shaft 334. The output gear body 332 and the output gear shaft 334 may be separated from each other or may be integral. The output gear shaft 334 is arranged in an attitude in which it extends along the upper-lower direction. An insertion hole 345 is provided in the lower end of the output gear shaft 334. The drive shaft 133 protrudes into the output side region R12 through the above-mentioned output through-hole H3 of the gear case 302 and is inserted into and fixed to the insertion hole 345 of the output gear shaft 334. Thus, the output gear 330 rotates integrally with the drive shaft 133.
The upper output bearing 336 is located on the upper side of the output gear body 332, is fixed to the gear case 302 (upper gear case 302a), and rotatably supports the upper end of the output gear shaft 334. The lower output bearing 337 is located on the lower side of the output gear body 332, is fixed to the gear case 302 (lower gear case 302b), and rotatably supports the lower end of the output gear shaft 334.
With the above configuration, the input gear 320 rotates by receiving a driving force from the output shaft 123 of the electric motor 122. The output gear 330 rotates in conjunction with the input gear 320, and the drive shaft 133 rotates as the output gear 330 rotates. In this preferred embodiment, the number of teeth of the input gear 320 is greater than that of the output gear 330. Therefore, the drive shaft 133 rotates at a reduced speed relative to the rotational speed of the output shaft 123 by the ratio of the number of teeth of the input gear 320 to the number of teeth of the output gear 330 (reduction ratio). Thus, the primary reduction gear mechanism 310 transmits the driving force of the electric motor 122 to the drive shaft 133 while reducing the rotational speed of the electric motor 122.
As described above, the primary reduction gear mechanism 310 accommodated in the housing chamber R1 includes gears (the input gear 320 and the output gear 330, hereinafter collectively referred to as “vertical shaft rotation gears”) that rotate around rotation shafts extending in the upper-lower direction. In a configuration in which a gear mechanism with such a vertical shaft rotation gear is accommodated in the housing chamber R1 together with the oil S, there is a risk that the lubricating effect of the oil may not be sufficient for the rotation of the vertical shaft rotation gear.
For example, in the configuration shown in
On the other hand, the upper output bearing 336 is not located directly above the tooth meshing position of the input gear 320 and output gear 330. In other words, the tooth meshing position of the input gear 320 and the output gear 330 is located in a position outer than the upper output bearing 336. Therefore, even if the input gear 320 and output gear 330 rotate, sufficient oil S may not be supplied to the upper output bearing 336. Therefore, in this preferred embodiment, the outboard motor 100 is provided with a lifting mechanism to lift the oil S. The upper output bearing 336 is an example of a bearing.
The lifting mechanism to lift the oil S lifts the oil S in the housing chamber R1 upward by using the rotational force of the vertical shaft rotation gear (output gear 330). Specifically, the lifting mechanism to lift the oil S includes sloped portions 306a and 306b (in
The sloped portions 306a, 306b are disposed between the output gear 330 (output gear body 332) and the peripheral wall 304 and are inclined upward so as to become higher along the rotating direction of the output gear 330. Specifically, the sloped portion 306a is inclined upward along one of the rotating directions of the output gear 330 (in the direction of the white arrow in
The sloped portions 306a, 306b are positioned in the radial direction of the output gear 330 at a distance from the output gear 330. Therefore, compared to a configuration in which the sloped portions 306a, 306b are adjacent to the output gear 330, the oil S can be lifted upward without affecting the rotation of the output gear 330. In addition, the sloped portions 306a, 306b extend along the inner peripheral surface 305 while in contact with the inner peripheral surface 305 of the peripheral wall 304. Therefore, compared to a configuration in which the sloped portions 306a, 306b are slightly separated from the peripheral wall 304 or the sloped portions 306a, 306b do not extend along the inner peripheral surface 305 of the peripheral wall 304, the oil S can be lifted upward more effectively.
The inclination angle θ (see
The lower ends N of the sloped portions 306a and 306b face the bottom surface 308 of the housing chamber R1 (see also
The two sloped portions 306a, 306b are located at different positions from each other on a virtual circle centered around the output gear 330. This can reduce or prevent an increase in the size of the housing chamber R1, compared to a configuration in which the two sloped portions 306a, 306b are aligned in the radial direction of the output gear 330. The highest end of the sloped portion 306a and the highest end of the sloped portion 306b are at the same height and are adjacent or flush with each other. Therefore, it is possible to reduce or prevent a reduction in the momentum of the flow of the oil S to the other sloped portion 306b due to the presence of the one sloped portion 306a, compared to a configuration in which the two sloped portions 306a, 306b are arranged in the rotating direction separated from each other, for example.
When the output gear 330 rotates in one rotating direction (in the direction of the white arrow in
When the output gear 330 rotates in the other rotating direction (opposite to the direction of the white arrow in
The outboard motor 100 further includes a guiding mechanism 340. The guiding mechanism 340 guides the oil S lifted upward by the lifting mechanism (sloped portions 306a, 306b) described above to the upper output bearing 336. Specifically, the guiding mechanism 340 includes two first introduction tubes 342a, 342b and two second introduction tubes 344.
As shown in
In one first introduction tube 342a, the end surface 343a at which the lower opening 341a is provided is inclined downward along the rotating direction of the output gear 330 (toward the left side of the paper of
One end of each second introduction tube 344 is communicatively connected to the upper end of each of the first introduction tubes 342a, 342b, and the other end of each second introduction tube 344 is communicatively connected to the space R2 above the upper output bearing 336. Each second introduction tube 344 is inclined such that one end of the second introduction tube 344 is lower than the other end. Therefore, the oil S introduced into the second introduction tube 344 from each of the first introduction tubes 342a, 342b flows into the space R2 by its own weight. This guiding mechanism 340 can effectively supply the oil S to the upper output bearing 336 that supports the upper end of the output gear shaft 334 of the output gear 330.
It should be noted that, in this specification, axes, members, and the like extending in the front-rear direction need not necessarily be parallel to the front-rear direction. Axes and members extending in the front-rear direction include axes and members that are inclined in the range of ±45° to the front-rear direction. Similarly, axes and members extending in the upper-lower direction include axes and members inclined within a range of ±45° to the upper-lower direction, and axes and members extending in the left-right direction include axes and members inclined within a range of ±45° to the left-right direction.
The techniques disclosed herein are not limited to the above-described preferred embodiments and may be modified in various forms without departing from the gist of the present invention, including the following modifications.
The configuration of the boat 10 and outboard motor 100 of the preferred embodiments is only an example and may be variously changed. For example, in the above preferred embodiments, the drive shaft 133 is positioned in front of the output shaft 123, but the drive shaft 133 may be positioned behind the output shaft 123. In the above preferred embodiments, an electric motor 122 with the output shaft 123 disposed along the upper-lower direction is shown as the drive source, but the drive source may be an electric motor with the output shaft 123 disposed along a direction other than the upper-lower direction (e.g., horizontal direction) or an engine such as internal combustion engine.
In the above preferred embodiments, a primary reduction gear mechanism 310 is illustrated as the transmission mechanism, but the transmission mechanism is not limited to this but may be a multiple reduction gear, another gear mechanism (such as a speed change mechanism), a winding transmission mechanism (such as a belt mechanism or chain mechanism) with a rotor (such as a pulley or sprocket) rotating around a rotation shaft along an upper-lower direction, or a transmission shaft such as a drive shaft. The gear mechanism or the transmission mechanism need only have at least one gear or rotor that rotates around a rotation shaft along the upper-lower direction. The input gear 320 and output gear 330 are not limited to the helical gears but may be sprue gears or bevel gears.
In the above preferred embodiments, the lifting mechanism to lift the oil S includes two sloped portions 306a, 306b, but it may have only one or more than three sloped portions. Furthermore, in the above preferred embodiments, the lifting mechanism to lifting the oil S may include:
The above preferred embodiments may be configured such that the guiding mechanism 340 is not provided and the oil S lifted by the sloped portions 306a, 306b is directly supplied to the output gear 330 and the upper output bearing 336. In the above preferred embodiments, the guiding mechanism 340 is configured to have two first introduction tubes and two second introduction tubes, but at least one of the first and second introduction tubes may be only one or three or more.
In the casing 116 of the above preferred embodiments, the lower case 116b is connected to the upper case 116a so that the lower case 116b is rotatable, but the lower case 116b does not necessarily have to be rotatable. The casing 116 need not have the upper case 116a and the lower case 116b but may be composed of a single member.
In the above preferred embodiments, the outboard motor 100 is provided with the water pump 140 as a driven device, but it may not be provided with the water pump 140 or may be provided with another driven device instead of the water pump 140.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-072160 | Apr 2023 | JP | national |
