Outboard motor

Abstract

To provide an outboard engine capable of preventing insufficient cooling due to the breakage and coming-off of cooling pipes.SOLUTION: An outboard engine 10 comprises an outboard engine body 20, a stern bracket 40, and a cooler 60 placed in the water and in a supported state by a left bracket 50A and right bracket 50B, where the stern bracket has the left bracket 50A and the right bracket 50B fixed to a hull S, and has a swivel case 41 fixed to the outboard engine body 20 and pivotably connected to the left bracket 50A and to the right bracket 50B. A shaft part 42 is provided in the swivel case 41. A bearing part 52 to rotatably support the shaft part 42 is provided in the left bracket 50A and the right bracket 50B. A cooling passage passing through the shaft part 42 and the bearing part 52 is provided between the outboard engine body 20 and the cooler 60.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an outboard motor. [Background technology]

[0002] In general, when in a standard position during use, an outboard motor transmits the rotational output of a drive source, such as an engine or an electric motor, to a drive shaft that is arranged facing vertically, and the rotation of the drive shaft is converted to rotation about a horizontal axis by a bevel gear and transmitted to a propeller shaft. As the propeller shaft rotates, a propeller attached to the propeller shaft rotates about the horizontal axis to propel the hull.

[0003] The drive source generates heat during operation and therefore requires an appropriate cooling structure. A known cooling structure of this type is an air-cooled structure using a radiator, but this has low heat exchange efficiency and is large in size. Moreover, it needs to be installed in a place on the hull where it is exposed to the wind, which creates a problem of poor appearance. In contrast to such air-cooled structures, water-cooled structures, which take in water from outside the hull and perform cooling inside the hull, have many advantages, such as high heat exchange efficiency, small size, and no loss of appearance. An example of a conventional outboard motor (inboard-outboard motor) equipped with this type of water-cooled structure is shown in Patent Document 1 below. In the configuration disclosed in Patent Document 1, water from outside the hull is taken into the hull via a water supply hose and cooling pipes, etc., to cool the engine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 1-175592 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when a boat is moored or anchored in shallow waters, the outboard motor is tilted up and pulled above the water surface. The inboard-outboard motor of Patent Document 1 is similar, and the propulsion unit is supported swingably on a bracket (gimbal housing) fixed to the boat body. However, when the propulsion unit swings up and down, the cooling hose is bent and twisted as a result of this swing. If the water supply hose becomes dislodged or damaged due to this bending or twisting, there is a concern that sufficient cooling will not be achieved, causing engine malfunction.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide an outboard motor that can prevent insufficient cooling caused by detachment or damage to cooling pipes. [Means for solving the problem]

[0007] In order to solve the above problems, an outboard motor according to one aspect of the present invention employs the following configuration. (1) An outboard motor (e.g., the outboard motor 10 of the embodiments) that is mounted on a hull (e.g., the hull S of the embodiments) and propels the hull, the outboard motor comprising: an outboard motor main body (e.g., the outboard motor main body 20 of the embodiments); brackets fixed to the hull (e.g., the left bracket 50A and the right bracket 50B of the embodiments); and a swing mechanism (e.g., the stern bracket 40 of the embodiments) that is fixed to the outboard motor main body and connected to the brackets so as to be freely swingable relative to the brackets; and a cooler (e.g., cooler 60 in the embodiment) that is placed underwater while being supported by at least one of the bracket and the hull, a shaft body (e.g., shaft portion 42 in the embodiment) is provided on one of the bracket and the swivel case, and a bearing (e.g., bearing portion 52 in the embodiment) that supports the shaft body so that it can rotate freely is provided on the other, and a cooling passage (e.g., intra-shaft passage 42a and internal passage 53a in the embodiment) that passes through the shaft body and the bearing is provided between the outboard motor main body and the cooler.

[0008] According to this configuration, cooling liquid heated in the outboard motor body is made to flow to the cooler via the swivel case and the bracket. At that time, the heated liquid flows to the cooler via a cooling passage that passes through the shaft and the bearing. As the heated liquid passes through the cooler, it is cooled by the water surrounding the cooler. The liquid cooled in the cooler is returned to the outboard motor body via the bracket and the swivel case. At this time, the cooled liquid flows to the outboard motor body via the cooling passage that passes through the shaft and the bearing. By circulating liquid between the outboard motor body and the cooler in this way, the equipment inside the outboard motor body can be cooled with high cooling efficiency. Moreover, because the shaft and bearing are used as part of the cooling flow path, cooling piping as in conventional structures is not required. Therefore, even if the outboard motor body is tilted up together with the swivel case, problems associated with the cooling piping becoming dislodged or damaged do not occur, and insufficient cooling of the equipment inside the outboard motor body can be reliably prevented.

[0009] (2) The outboard motor described in (1) above may be configured as follows: the rocking mechanism includes a pair of connecting parts (e.g., connecting part J in the embodiment) each having the shaft body and the bearing and spaced apart from each other, and the cooling flow passage has an outward path that passes through one of the pair of connecting parts and a return path that passes through the other of the pair of connecting parts.

[0010] According to this configuration, the cooling liquid cooled in the cooler is supplied to the outboard motor body through the forward passage of the cooling flow passage, while the cooling liquid heated in the outboard motor body is returned to the cooler through the return passage of the cooling flow passage. In this manner, when the cooling liquid circulates between the outboard motor body and the cooler, the pair of connecting parts are spaced apart from each other, which more reliably prevents the cooling liquid cooled in the cooler from being heated by cooling liquid on its way to the cooler.

[0011] (3) The outboard motor described in (1) or (2) above may be configured as follows: the shaft body has an in-shaft passage (e.g., the in-shaft passage 42a in the embodiment) formed inside the shaft body, the connecting portion has an in-bearing passage (e.g., the gap C2 in the embodiment) formed between the inner surface of the bearing and the outer surface of the shaft body and communicating with the in-shaft passage, and the in-shaft passage and the in-bearing passage are included in the cooling passage.

[0012] According to this configuration, the cooling liquid that has flowed into the shaft passes through the in-shaft passage and then flows into the in-bearing passage of the bearing. Conversely, the cooling liquid that has flowed into the in-bearing passage passes through the in-bearing passage and then flows into the in-shaft passage of the shaft. In this way, the cooling liquid can flow smoothly through the bearing and the shaft body, so there is no shortage of flow rate, and the cooling capacity of the cooler can be fully utilized.

[0013] (4) In the outboard motor described in (3) above, the shaft passage may branch into a plurality of radial passages (e.g., radial passage 42a2 in the embodiment) extending radially of the shaft body and each of which is connected to the bearing passage.

[0014] According to this configuration, the cooling liquid that has flowed into the shaft is separated into a plurality of radial flows that flow through the radial flow passages. All of the liquid flowing through the radial flow passages is guided to the same in-bearing flow passage and then flows to the cooler. In this way, by providing a radial flow path that branches into a plurality of paths, the flow path area can be increased, and therefore the pressure loss when the liquid passes through the pair of connecting portions can be reduced.

[0015] (5) The outboard motor described in any one of (1) to (4) above may be configured as follows: the swivel case has a first connection port (for example, the large diameter portion 43b2 in the embodiment) through which the cooling passage passes and which is connected to the outboard motor main body, the outboard motor main body has a second connection port (for example, the large diameter portion 21g1 in the embodiment) to which the first connection port is coaxially connected, the swing mechanism has a pipe (for example, the pipe 45 in the embodiment) which is coaxially inserted into both the first connection port and the second connection port, and a seal member which seals between the pipe and both the first connection port and the second connection port, and center lines passing through the first connection port, the pipe, and the second connection port are parallel to the assembly direction of the swivel case to the outboard motor main body.

[0016] According to this configuration, after the sealing member is positioned, the swivel case can be assembled to the outboard motor body while aligning the center lines passing through the first connection port, the pipe material, and the second connection port, thereby forming a cooling flow path at the same time as assembly. Therefore, the cooling flow passage can be formed through a simple assembly procedure, thereby reducing manufacturing costs. Effect of the Invention

[0017] According to the above-described aspects of the present invention, the cooling liquid can be circulated and supplied to the drive source without using the conventional cooling piping. Therefore, the cooling piping that elastically deforms when the outboard motor is tilted up is no longer necessary, and insufficient cooling due to the cooling piping becoming dislodged or damaged can be reliably prevented. [Brief description of the drawings]

[0018] [Figure 1] 1 is a side view of an outboard motor according to a preferred embodiment of the present invention. FIG. [Diagram 2] FIG. [Diagram 3] FIG. 2 is an exploded perspective view illustrating the arrangement of equipment in the outboard motor and a circulation route of cooling oil. [Figure 4] FIG. 3 is a cross-sectional view taken along line AA in FIG. 2, showing a main portion of the outboard motor. [Diagram 5] FIG. 5 is a cross-sectional view taken along line BB in FIG. 4, showing a main portion of the outboard motor. [Figure 6] FIG. 5 is a diagram showing a main portion of the outboard motor, and is an enlarged view of part C in FIG. 4. [Figure 7] FIG. 6 is an enlarged view of a portion D in FIG. 5, showing a main portion of the outboard motor. [Figure 8] FIG. 8 is a view showing a main portion of the outboard motor, and is a cross-sectional view taken along line E-E of FIG. 7. [Figure 9] FIG. 9 is a diagram showing a main part of the outboard motor, and is an enlarged view of part F in FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] An embodiment of an outboard motor according to the present invention will now be described with reference to the drawings. In the drawings, the symbol FW indicates the front in the direction of travel, and the symbol RW indicates the rear in the direction of travel. Hereinafter, "forward in the direction of travel" may simply be referred to as "forward," and "rearward in the direction of travel" may simply be referred to as "rear." In addition, both the "forward direction in the direction of travel" and the "rearward direction in the direction of travel" may be collectively referred to simply as the "front-to-rear direction." In addition, the left in the direction of travel may be referred to as the "left direction," and the right in the direction of travel may be referred to as the "right direction." In addition, both the "left direction" and the "right direction" may be collectively referred to simply as the "left-to-right direction."

[0020] As shown in FIGS. 1 and 2, an outboard motor 10 of this embodiment is a propulsion device provided at the stern St of a hull S to propel the hull S. The outboard motor 10 includes an outboard motor body 20 , a stern bracket (swing mechanism) 40 , and a cooler 60 . The outboard motor body 20 includes a case 21, an oil pan 22, a drive shaft case 23, a gear case 24, a power unit 25, a steering mechanism 26, a drive shaft 27, a bevel gear unit 28, a propeller shaft 29, a propeller holder 30, and a propeller 31.

[0021] The case 21 is fixed to the upper part of the oil pan 22. A power unit 25 and a steering mechanism 26 are housed inside the case 21. The case 21 is attached to the stern St of the hull S via a stern bracket 40. More specifically, by attaching the case 21 to the stern bracket 40, the case 21 is supported so as to be able to swing up and down along the arrow T about the tilt axis Tc. The connection structure between the case 21 and the stern bracket 40 and the like will be described later. The oil pan 22 stores oil (cooling liquid; hereinafter, "cooling oil") that cools and lubricates, for example, the electric motor and reduction unit (neither of which are shown) of the power unit 25, the steering mechanism 26, and the like.

[0022] The power unit 25 includes the electric motor and the reduction gear unit. The electric motor is a drive source that rotates the propeller 31. Although not shown in the figure, the drive motor has a configuration in which its rotating shaft is arranged facing vertically and a rotor is rotatably supported inside a stator. The rotor is supported by the rotating shaft. The reduction gear unit is connected to the rotating shaft. The reduction gear unit reduces the rotation speed of the electric motor and transmits it to the drive shaft 27.

[0023] The drive shaft 27 is connected to the electric motor via the reduction gear unit, and is disposed generally along the vertical direction. Drive shaft 27 is housed in drive shaft case 23 and rotatably supported within drive shaft case 23 via bearings (not shown). Drive shaft case 23 is rotatably supported around a vertical axis, for example, via another bearing (not shown) disposed within case 21. The bevel gear unit 28 is housed in the gear case 24. The gear case 24 is fixed integrally to the drive shaft case 23.

[0024] The propeller shaft 29 extends rearward from the bevel gear unit 28 in a direction intersecting with the drive shaft 27. That is, the propeller shaft 29 is connected to the drive shaft 27 via the bevel gear unit 28 so as to intersect with the drive shaft 27. The base end of the propeller shaft 29, which is fixed to the bevel gear unit 28, is housed in the gear case 24.

[0025] The propeller shaft 29 protrudes rearward from the position of the bevel gear unit 28 via a propeller holder 30. The propeller holder 30 is fixed to the gear case 24. The propeller shaft 29 is rotatably supported in the propeller holder 30 via, for example, a bearing (not shown). A propeller 31 for propulsion is fixed to a portion of the propeller shaft 29 protruding rearward from the propeller holder 30. The propeller 31 has a plurality of blades 31a that rotate together with the propeller shaft 29 about a horizontal axis. The drive shaft case 23, the gear case 24, and the propeller holder 30 are fixed together and arranged to form a substantial L shape in a side view.

[0026] By driving the electric motor of the power unit 25, the rotation of the rotary shaft is transmitted to the propeller 31 via the reduction gear unit, the drive shaft 27, the bevel gear unit 28, and the propeller shaft 29. The rotation of the propeller 31 propels the hull S. The outboard motor 10 is steered by rotating the propeller 31 about the drive shaft 27 using the steering mechanism 26.

[0027] 3, the cooler 60 is supported by the stern bracket 40 at a position below the stern bracket 40. The cooler 60 is of a water-cooled type, and is placed underwater during normal operation of the outboard motor 10. The cooler 60 has a cooler main body 61, an outward piping 62, and a return piping 63.

[0028] A meandering flow passage 61a is formed inside the cooler body 61. By making the cross-sectional shape of the cooler 61 streamlined, the heat transfer area of ​​the flow passage 61a is increased to improve the heat exchange efficiency, without causing large fluid resistance when the hull S is propelled.

[0029] One end of the flow path 61a of the cooler body 61 is located near the left end of the cooler body 61 in the left-right direction, and communicates with the return pipe 63 fixedly disposed immediately above this position. The other end of the flow path 61a is located near the right end of the cooler body 61 in the left-right direction, and communicates with the outward pipe 62 fixedly disposed immediately above this position. The lower end of the outward piping 62 is connected vertically and integrally to the upper surface of the cooler body 61, while the upper end faces vertically upward. The lower end of the return piping 63 is also connected vertically and integrally to the upper surface of the cooler body 61, while the upper end faces vertically upward. The outward piping 62 and the return piping 63 are both straight pipes and are arranged parallel to each other. The outward piping 62 and the return piping 63 are a pair of metal pipes that do not elastically deform. Therefore, the relative position of the cooler body 61 with respect to the stern bracket 40 is always fixed.

[0030] 3, the outward piping 62 and the return piping 63 are fixed to the lower part of the bracket 50 of the stern bracket 40. However, the location of the cooler body 61 is not limited to this position, and it may be fixed to either the stern bracket 40 or the hull S. That is, for example, the cooler body 61 may be disposed at the position indicated by reference symbol 60A shown by an imaginary line in Fig. 1. In this case, the cooler body 61 can be fixed along the surface of the stern St. Then, it is considered that the cooler body 61 and the stern bracket 40 communicate with each other through an outward piping 62 and a return piping 63. Even when the cooler body 61 is disposed at the position indicated by reference symbol 60A in this way, the relative position between the stern bracket 40 and the cooler body 61 can be fixed regardless of the swinging of the outboard motor body 20. Furthermore, the cooler body 61 may be fixed to both the stern bracket 40 and the stern S. In this case, the cooler body 61 can be supported more firmly.

[0031] Next, the stern bracket 40 that supports the outboard engine body 20 and the cooler 60 having the above-mentioned configuration will be described. Before that, however, the case 21 to which the stern bracket 40 is attached will be described in detail. 4 and 5, the case 21 has a substantially cylindrical side wall portion 21a and an upper wall portion 21b that closes the upper portion of the side wall portion 21a. For the sake of explanation, the devices inside the case 21 are not shown in Figs. 4 and 5. The lower portion of the side wall portion 21a is open and communicates with the internal space of the oil pan 22.

[0032] A part of the outer peripheral surface of the side wall portion 21a serves as a mounting surface 21c for fixing the stern bracket 40 with, for example, four bolts 40a. The mounting surface 21c is a flat surface forming an approximately rectangular shape, and projections 21e with female threaded holes are formed at the four corners. The center lines of the female threaded holes of the four projections 21e are parallel to each other and open toward the stern bracket 40. In this embodiment, the number of bolts 40a and projections 21e is four, but is not limited to four, and may be one, two, or five or more. Fixing may be performed using a fastener other than a bolt.

[0033] A pair of protrusions 21f are formed on the outer circumferential surface of the side wall portion 21a above the mounting surface 21c. These protrusions 21f are parallel to each other and have through holes (21g in FIG. 6) that open toward the stern bracket 40. The through holes 21g are located at the same height. As shown in FIG. 6, each of the pair of through holes 21g has a large diameter portion 21g1 that opens toward the stern bracket 40 and a small diameter portion 21g2 that is smaller in diameter than the large diameter portion 21g1.

[0034] The large diameter portion 21g1 is a cylindrical space having a constant inner diameter, into which a pipe 45 with an O-ring 46 is fitted. The open end of the large diameter portion 21g1 widens toward the stern bracket 40. Since the large diameter portion 21g1 and the small diameter portion 21g2 have different inner diameters, a step is formed between them. The small diameter section 21g2 is a cylindrical space having a constant inner diameter smaller than that of the large diameter section 21g1, and its inner side is bent vertically downward in an L-shape. The small diameter section 21g2 is connected to a lubrication circuit (not shown) that communicates with the oil pan 22. This lubrication circuit has an outward path and a return path. The outward path sucks up the cooling oil that has been heated by lubricating and cooling the devices in the outboard motor body 20, and then sends it out toward the stern bracket 40 through one of the pair of through holes 21g, as shown in FIG. 6. On the other hand, the return path takes the cooling liquid that has been cooled by the cooler 60 and returned via the stern bracket 40 into the outboard motor body 20 through the other of the pair of through holes 21g.

[0035] The stern bracket 40 fixed to the case 21 includes a swivel case 41 and a bracket 50, as shown in FIGS.

[0036] The swivel case 41 has a shaft portion (shaft body) 42, a horizontal portion 43, an attachment portion 44, a pipe (tube material) 45, and an O-ring (sealing member) 46. As shown in FIG. 5, the shaft portion 42 has a substantially cylindrical shape and is rotatable about a central axis CL extending along the left-right direction. A pair of in-shaft flow passages 42a extending coaxially with the central axis CL is formed inside the shaft portion 42. As shown in FIG. 7, each of the in-shaft flow passages 42a has an axial flow passage 42a1 formed coaxially with the shaft portion 42 and a radial flow passage 42a2 branching from the axial flow passage 42a1 toward the radial direction of the shaft portion 42. Each of the axial flow passages 42a1 is formed from a position near the center in the longitudinal direction of the shaft portion 42 toward an end position. Each of the axial flow passages 42a1 opens at an end position of the shaft portion 42. On the other hand, the two axial flow passages 42a1 are separated from each other at the center position in the longitudinal direction of the shaft portion 42 in a planar cross section as shown in FIG. 5. On the other hand, the adjacent ends of the two axial flow passages 42a1 are bent in an L-shape toward the mounting surface 21c of the case 21.

[0037] As shown in Fig. 7 to Fig. 9, each of the radial flow passages 42a2 is formed of two flow passages that are perpendicular to the axial flow passages 42a1 and open on the outer circumferential surface of the shaft portion 42. Therefore, at each end of the shaft portion 42, the in-shaft flow passages 42a are divided into a total of three passages including one flow passage along the central axis CL and two flow passages perpendicular to the central axis CL. Note that, although the number of radial flow passages 42a2 is two in this embodiment, it is not limited to two, and may be one or three or more.

[0038] As shown in Fig. 7, a pair of O-ring grooves are formed at each end of the shaft portion 42. The radial flow passages 42a2 are disposed between the O-ring grooves. In other words, as viewed along the central axis CL, O-ring grooves are formed on both sides of each of the radial flow passages 42a2. An O-ring 42b is fitted into each of the O-ring grooves. The portion of the shaft portion 42 where the radial flow passages 42a2 are formed has a smaller diameter than the adjacent portions on both sides. That is, when the shaft portion 42 is viewed from the outer end position toward the center position along the central axis CL, the portion on the outermost side of the shaft portion 42 where the O-ring 42b is arranged is a large diameter portion having a relatively large outer diameter. The portion adjacent to this large diameter portion where the radial flow passages 42a2 are arranged is a small diameter portion having a smaller outer diameter than the large diameter portion. Furthermore, the portion adjacent to this small diameter portion where the O-ring 42b is arranged is a large diameter portion having a larger outer diameter than the small diameter portion. The pair of large diameter portions sandwiching the small diameter portion have the same outer diameter dimension.

[0039] As shown in FIG. 5, the horizontal portion 43 has a left support wall portion 43a, a central piping portion 43b, and a right support wall portion 43c. The central pipe section 43b is formed integrally with the shaft section 42 at the center in the left-right direction and extends rearward from the shaft section 42. A pair of connecting passages 43b1 are formed in the central pipe section 43b with a gap between them. The front ends of the connecting passages 43b1 are connected to the ends of the axial passages 42a1 at the center in the longitudinal direction of the shaft section 42. That is, the front end of the connecting passage 43b1 on the left side is connected to the axial passage 42a1 on the left side. The front end of the connecting passage 43b1 on the right side is connected to the axial passage 42a1 on the right side. 5, a space S is provided between the pair of connecting flow paths 43b1. This space S blocks heat transfer between the cooling oil flowing in the connecting flow path 43b1 of the outward path and the cooling oil flowing in the connecting flow path 43b1 of the return path. This prevents the cooled cooling oil flowing in the outward path from being heated and raised in temperature by the heated cooling oil flowing in the return path.

[0040] As shown in Fig. 6, a large diameter portion 43b2 is formed at each rear end of the pair of connecting flow paths 43b1. Since the large diameter portion 43b2 is a portion where the diameter is partially enlarged, there is a step between the other portions. These large diameter portions 43b2 have the same inner diameter dimension as the large diameter portion 21g1. A pipe 45 with an O-ring 46 fitted therein is fitted into these large diameter portions 43b2.

[0041] As shown in FIG. 6, when the stern bracket 40 is assembled to the case 21, the large diameter portion 21g1 and the large diameter portion 43b2 are arranged coaxially with each other, and the pipe 45 is fitted between them. A deep O-ring groove is formed on the outer circumferential surface of the pipe 45 at a position corresponding to the O-ring groove in the large diameter portion 21g1. Furthermore, a deep O-ring groove is also formed on the outer circumferential surface of the pipe 45 at a position corresponding to the O-ring groove in the large diameter portion 43b2. Therefore, the outer circumferential surface of the pipe 45 and the inner circumferential surface of the large diameter portion 21g1 are liquid-tightly sealed by the O-ring 46 arranged therebetween. Similarly, the outer circumferential surface of the pipe 45 and the inner circumferential surface of the large diameter portion 43b2 are liquid-tightly sealed by the O-ring 46 arranged therebetween. Therefore, the cooling oil flows only inside the pipe 45 without leaking out from between the large diameter portion 21g1 and the large diameter portion 43b2.

[0042] Moreover, even if pipe 45 is about to deviate from its specified installation position due to the flow of cooling oil, the step formed in connecting flow path 43b1 will stop it. Similarly, even if pipe 45 is about to deviate from its installation position in the opposite direction, this time it will be stopped by the step between large diameter portion 21g1 and small diameter portion 21g2. Therefore, although the configuration is simple, it is possible to prevent pipe 45 from deviating from its specified installation position and prevent leakage of cooling oil.

[0043] When assembling the stern bracket 40 to the case 21, first, O-rings 46 are fitted into the two O-ring grooves formed around the pipe 45. Then, the pipe 45 is inserted into the large diameter portion 43b2. At this time, the pipe 45 is pushed in until the O-ring 46 enters the O-ring groove in the large diameter portion 43b2 and the O-ring 46 is felt by the fingertips. Next, the stern bracket 40 with the pipe 45 inserted is assembled to the case 21. At this time, the pipe 45 is inserted into the large diameter portion 21g1, which can be easily inserted because the open end of the large diameter portion 21g1 is expanded in diameter. Next, the position of the stern bracket 40 relative to the case 21 is fixed with four bolts 40a, thereby forming a liquid-tight connection between the large diameter portion 21g1 and the large diameter portion 43b2. In this manner, simply by assembling the stern bracket 40 to the case 21, it is possible to simultaneously seal the gap between the large diameter portion 21g1 and the large diameter portion 43b2 and form a cooling passage that communicates between the two.

[0044] 5, the left support wall portion 43a and the right support wall portion 43c are disposed with the central pipe portion 43b therebetween. Specifically, the left support wall portion 43a extends rearward from a position near the left end of the shaft portion 42. Similarly, the right support wall portion 43c extends rearward from a position near the right end of the shaft portion 42.

[0045] 3, the mounting portion 44 is a generally plate-shaped portion disposed along the vertical direction, and the above-mentioned left support wall portion 43a, central piping portion 43b, and right support wall portion 43c are integrally connected to the upper portion of the mounting portion 44. The mounting portion 44 has four through holes 44a formed at positions corresponding to the four protrusions 21e formed on the mounting surface 21c of the case 21. The stern bracket 40 is fixed to the mounting surface 21c of the case 21 by four bolts 40a at each mounting portion 44 of the swivel case 41. This makes it possible to simultaneously mount the stern bracket 40 to the outboard motor body 20 and connect the cooling passages therebetween.

[0046] 3, the bracket 50 has a left bracket 50A and a right bracket 50B. The left bracket 50A and the right bracket 50B have the same configuration except that they are asymmetrical. Therefore, the following will describe the detailed structure of the left bracket 50A, and will omit a description of the right bracket 50B, which is similar. 8, the left bracket 50A is substantially L-shaped in vertical cross section. That is, the left bracket 50A has a bearing portion 52 that rotatably supports the shaft portion 42, a bracket upper portion 53 extending rearward from the bearing portion 52, a bracket middle portion 54 extending vertically downward from the rear end of the bracket upper portion 53, and a bracket lower portion 55 extending vertically downward from the lower end of the bracket middle portion 54.

[0047] As shown in Figs. 7 and 9, a recess 52a, which is a substantially cylindrical space, is formed inside the bearing portion 52. The shaft portion 42 is coaxially fitted into the recess 52a. That is, the recess 52a and the shaft portion 42 share the central axis CL, and the shaft portion 42 is rotatable about the central axis CL with respect to the recess 52a. A set of connecting portions J is formed by the bearing portion 52 and the shaft portion 42 journaled within the bearing portion 52. As shown in Fig. 5, the stern bracket 40 of this embodiment has two sets (a pair) of connecting portions J. These connecting portions J are arranged at a distance from each other along the left-right direction. The pair of connecting portions J journally support the swivel case 41 with respect to the bracket 50 so as to be swingable in the up-down direction.

[0048] 7, a gap C1 is formed between the end face of the shaft portion 42 and the inner surface of the recess 52a. In addition, an annular gap C2 is formed between the outer circumferential surface of the small diameter portion of the shaft portion 42 and the inner circumferential surface of the recess 52a. By providing the gap C1, the outer end surface of the shaft portion 42 can be kept out of contact with the inner surface of the recess 52a. In addition, a portion of the cooling oil can be stored in the gap C1. Therefore, when the swivel case 41 is swung relative to the bracket 50, the movement of the swivel case 41 can be made smooth.

[0049] The gap C2 is connected to an internal flow passage 53a, which will be described later. Therefore, in the left bracket 50A, through which the return path of the cooling oil passes, the cooling oil that has flowed from each radial flow passage 42a2 into the gap C2 can be further guided to the internal flow passage 53a. Conversely, in the right bracket 50B, through which the outward path of the cooling oil passes, the cooling oil that has flowed from the internal flow passage 53a into the gap C2 can be further guided to each radial flow passage 42a2. Because the gap C2 is annular, the in-shaft flow passage 42a and the internal flow passage 53a are always in communication with each other, regardless of the pivot position of the swivel case 41 relative to the stern bracket 40, and the flow of cooling oil between them is always maintained. In addition, because the gap C2 is sealed by a pair of O-rings 42b, leakage of cooling oil at the connection part J can always be prevented, regardless of the pivot position of the swivel case 41 relative to the bracket 50.

[0050] 8 and 9, the bracket upper part 53 is a plate that is long along the front-rear direction, and its front end is integrally connected to the shaft part 42. Inside the bracket upper part 53, an internal flow passage 53a is formed that communicates with the gap C2 and extends straight diagonally downward toward the rear. In the case of the left bracket 50A, through which the return path of the cooling oil passes, the internal flow passage 53a causes the cooling oil that has flowed in from the gap C2 to flow toward the rear. On the other hand, in the case of the right bracket 50B, through which the outward path of the cooling oil passes, the internal flow passage 53a causes the cooling oil to flow forward and send it to the gap C2.

[0051] As shown in Fig. 8, the bracket middle part 54 is a long plate extending vertically, and its upper end is integrally connected to the rear end of the bracket upper part 53. Inside the bracket middle part 54, an internal flow passage 54a is formed which is connected to the internal flow passage 53a and extends straight vertically downward. In the case of the left bracket 50A through which the return path of the cooling oil passes, the internal flow passage 54a causes the cooling oil flowing from the internal flow passage 53a to flow vertically downward. On the other hand, in the case of the right bracket 50B through which the outward path of the cooling oil passes, the internal flow passage 54a causes the cooling oil to flow vertically upward and send it to the internal flow passage 53a.

[0052] As shown in Fig. 8, the bracket lower part 55 is a long cylindrical body along the vertical direction, and its upper end is integrally connected to the lower end of the bracket middle part 54. Inside the bracket lower part 55, an internal flow passage 55a is formed which is connected to the internal flow passage 54a and extends straight vertically downward. In the case of the left bracket 50A through which the return path of the cooling oil passes, the internal flow passage 55a causes the cooling oil flowing from the internal flow passage 54a to flow vertically downward. On the other hand, in the case of the right bracket 50B through which the outward path of the cooling oil passes, the internal flow passage 55a causes the cooling oil to flow vertically upward and send it to the internal flow passage 54a.

[0053] The lower end of bracket lower portion 55 is configured to form a cooling passage between itself and a connecting partner via pipe 56, similar to the configuration described in FIG. That is, as shown in Fig. 8, the inner diameter of the lower end of the internal flow path 55a is partially increased. Similarly, the inner diameter of the upper end of the return pipe 63 is also partially increased. The lower end of the internal flow path 55a and the upper end of the return pipe 63 are in contact with each other coaxially, and the pipe 56 is coaxially arranged inside them. An O-ring provides a liquid-tight seal between the outer circumferential surface of the pipe 56 and the inner circumferential surface of the lower end of the internal flow path 55a. Similarly, an O-ring provides a liquid-tight seal between the outer circumferential surface of the pipe 56 and the inner circumferential surface of the upper end of the return pipe 63.

[0054] Also, a step is formed on the inner peripheral surface of the lower end of the internal flow path 55a. Similarly, a step is formed on the inner peripheral surface of the upper end of the return pipe 63. By disposing the pipe 56 between these two steps, it is possible to prevent the pipe 45 from receiving the flow of the cooling liquid and moving out of its specified position. Therefore, even though the configuration is simple, the pipe 56 does not move out of its specified position and cause a leakage of cooling oil.

[0055] The bracket lower part 55 is fixed to the cooler body 61 via bolts (not shown). The bolts are fastened in the vertical direction, which is the same as the assembly direction of the bracket lower part 55 to the return piping 63. Therefore, assembly can be performed simply by inserting the lower end of the pipe 56, which has two O-rings fitted in advance, into the upper end of the return piping 63, then inserting the upper end of the pipe 56 into the lower end of the bracket lower part 55, and finally fixing the bracket lower part 55 to the cooler body 61 with bolts. Therefore, complicated piping work is not required. The outward piping 62 has the same connection configuration as the return piping 63 described above.

[0056] The outboard motor 10 of this embodiment has the equipment configuration described above. As a result, cooling oil is circulated through the cooling passages shown in FIG. That is, in the return path of the cooling passage, the cooling oil that has been heated by lubricating and cooling each device in the outboard motor body 20 is sent to the cooler 60. Specifically, the cooling oil sent out from the lubrication circuit of the outboard motor body 20 first flows into the connecting passage 43b1. Then, the cooling oil that has flowed through the connecting passage 43b1 flows into the in-shaft passage 42a of the shaft portion 42. In the in-shaft passage 42a, the cooling oil that has been separated into two flows that pass through the pair of radial passages 42a2 each flows into the gap C2 in the bearing portion 52 and is combined again into one flow. The cooling oil that flows out from the gap C2 flows in the internal passage 53a, the internal passage 54a, and the internal passage 55a in this order in the left bracket 50A. The cooling oil that flows out from the internal passage 55a flows through the return path piping 63 and the passage 61a in the cooler body 61. At this time, the heat of the cooling oil is dissipated to the surrounding water through the wall of the cooler body 61. As a result, the cooling oil is cooled and its temperature drops. The cooled cooling oil flows through the forward path of the cooling passage toward the outboard motor body 20.

[0057] That is, the cooling oil that flows from the flow passage 61a of the cooler body 61 to the forward pipe 62 flows into the right bracket 50B. In the right bracket 50B, the cooling oil flows through the internal flow passage 55a, the internal flow passage 54a, and the internal flow passage 53a in this order. The cooling oil that flows out of the internal flow passage 53a flows into the gap C2 in the bearing part 52. The cooling oil in the gap C2 is separated into two flows that pass through the pair of radial flow passages 42a2. Then, the cooling oil is combined again into one flow by flowing through the axial flow passage 42a1. The cooling oil that flows through the axial flow passage 42a1 flows into the connecting flow passage 43b1. The cooling oil that flows through the connecting flow passage 43b1 finally flows into the lubrication circuit of the outboard motor body 20. While circulating through this lubrication circuit, the cooling oil cools and lubricates each device in the outboard motor body 20. The cooling oil that has been heated again as a result of this flows again toward the cooler body 61 through the return path.

[0058] The essential features of the outboard motor 10 having the above-described configuration will be summarized below. (1) The outboard motor 10 of this embodiment is mounted on a hull S to propel the hull S. The outboard motor 10 includes an outboard motor main body 20, a left bracket (bracket) 50A and a right bracket (bracket) 50B fixed to the hull S, a stern bracket (swing mechanism) 40 having a swivel case 41 fixed to the outboard motor main body 20 and connected to the left bracket (bracket) 50A and the right bracket (bracket) 50B so as to be freely swingable, and a cooler 60 supported by the left bracket (bracket) 50A and the right bracket (bracket) 50B and disposed underwater. A shaft portion (shaft body) 42 is provided on the swivel case 41, and a bearing portion (bearing) 52 that rotatably supports the shaft portion (shaft body) 42 is provided on the left bracket (bracket) 50A and the right bracket (bracket) 50B. In addition, as cooling passages passing through the shaft portion (shaft body) 42 and the bearing portion (bearing) 52, an in-shaft passage 42a and an internal passage 53a are provided between the outboard engine body 20 and the cooler 60.

[0059] According to this configuration, the cooling oil (liquid for cooling) heated in the outboard motor body 20 is made to flow to the cooler 60 via the swivel case 41 and the left bracket (bracket) 50A. At that time, the heated cooling oil flows to the cooler 60 via the in-shaft flow passage 42a and the internal flow passage 53a, which are cooling flow passages passing through the shaft portion (shaft body) 42 and the bearing portion (bearing) 52. The heated cooling liquid is cooled by the water around the cooler 60 while passing through the cooler 60. The cooling oil (liquid) cooled by the cooler 60 is returned to the outboard motor body 20 via the right bracket (bracket) 50B and the swivel case 41. At this time, the cooled cooling oil (liquid) flows to the outboard motor body 20 via the in-shaft flow passage 42a and the internal flow passage 53a, which are cooling flow passages passing through the shaft portion (shaft body) 42 and the bearing portion (bearing) 52. By circulating cooling oil (liquid) between the outboard motor body 20 and the cooler 60 in this manner, the equipment inside the outboard motor body 20 can be cooled with high cooling efficiency. Moreover, because the shaft portion (shaft body) 42 and the bearing portion (bearing) 52 are used as part of the cooling flow path, cooling piping as in conventional structures is not required. Therefore, even if the outboard motor body 20 is tilted up together with the swivel case 41, problems associated with disconnection or damage to the cooling piping do not occur, and insufficient cooling of the equipment inside the outboard motor body 20 can be reliably prevented.

[0060] In the above embodiment, the left bracket (bracket) 50A and the right bracket (bracket) 50B are provided with the bearing portion (bearing) 52, and the swivel case 41 is provided with the shaft portion (shaft body) 42, but the present invention is not limited to this configuration. Conversely, the left bracket (bracket) 50A and the right bracket (bracket) 50B may be provided with the shaft portion (shaft body) 42, and the swivel case 41 may be provided with the bearing portion (bearing) 52. In addition, the cooler 60 is configured to be supported in water by the left bracket (bracket) 50A and the right bracket (bracket) 50B, but is not limited to this configuration. As described above, the cooler 60 may be fixed to the hull S and supported in water.

[0061] (2) The outboard motor described in (1) above may be configured as follows: The stern bracket (swing mechanism) 40 is provided with a pair of connecting parts J that are spaced apart from each other and each have a shaft part (shaft body) 42 and a bearing part (bearing) 52, and the cooling flow passage has an outward path that passes through one of the pair of connecting parts J and a return path that passes through the other one.

[0062] According to this configuration, the cooling oil (cooling liquid) cooled by the cooler 60 passes through the forward path of the cooling flow passage and is supplied to the outboard motor body 20. On the other hand, the cooling oil (cooling liquid) heated in the outboard motor body 20 is returned to the cooler 60 through the return path of the cooling flow passage. In this manner, when the cooling oil (cooling liquid) circulates between the outboard motor main body 20 and the cooler 60, the pair of connecting parts J are spaced apart from each other, which more reliably prevents the cooling oil (cooling liquid) cooled in the cooler 60 from being heated by cooling oil (cooling liquid) on its way to the cooler 60.

[0063] (3) The outboard motor described in (1) or (2) above may be configured as follows: The shaft portion (shaft body) 42 has an in-shaft passage 42a formed inside the shaft portion (shaft body) 42, the connecting portion J has a gap (in-bearing passage) C2 formed between the inner surface of the bearing portion (bearing) 52 and the outer surface of the shaft portion (shaft body) 42 and communicating with the in-shaft passage 42a, and the in-shaft passage 42a and the gap (in-bearing passage) C2 are included in the cooling passage.

[0064] According to this configuration, the cooling oil (cooling liquid) that has flowed into the shaft portion (shaft body) 42 passes through the intra-shaft flow passage 42a, and then flows into the gap (intra-bearing flow passage) C2 of the bearing portion (bearing) 52. Conversely, the cooling oil (cooling liquid) that has flowed into the gap (intra-bearing flow passage) C2 passes through the gap (intra-bearing flow passage) C2, and then flows into the intra-shaft flow passage 42a of the shaft portion (shaft body) 42. In this way, the cooling oil (cooling liquid) can flow smoothly through the shaft portion (shaft body) 42 and the bearing portion (bearing) 52, so there is no shortage of flow rate. Therefore, the cooling capacity of the cooler 60 can be fully exerted.

[0065] (4) In the outboard motor described in (3) above, the in-shaft passage 42a may branch into two radial passages 42a2 that extend radially around the shaft portion (shaft body) 42 and each communicate with the gap (in-bearing passage) C2.

[0066] According to this configuration, the cooling oil (liquid for cooling) flowing into the shaft portion (shaft body) 42 is separated into two radial flows passing through each radial flow passage 42a2. Both of the cooling oils (liquid) flowing through each radial flow passage 42a2 are guided to the same gap (intra-bearing flow passage) C2 and then directed to the cooler 60. In this way, by providing the radial flow passage 42a2 branching into two, the flow passage area can be increased, so that the pressure loss when the cooling oil (liquid) passes through the pair of connecting portions J can be reduced. The number of radial flow passages 42a2 is not limited to two, but may be one or three or more.

[0067] (5) The outboard motor described in any one of (1) to (4) above may be configured as follows: the swivel case 41 has a large diameter portion (first connection port) 43b2 through which the cooling passage passes and which is connected to the outboard motor body 20, the outboard motor body 20 has a large diameter portion (second connection port) 21g1 to which the large diameter portion (first connection port) 43b2 is coaxially connected, and the stern bracket (swing mechanism) 40 is coaxially inserted into both the large diameter portion (first connection port) 43b2 and the large diameter portion (second connection port) 21g1. The swivel case 41 has a pipe (tube material) 45 that is connected to the large diameter portion (first connection port) 43b2 and an O-ring (sealing member) 46 that seals between the pipe (tube material) 45 and both the large diameter portion (first connection port) 43b2 and the large diameter portion (second connection port) 21g1, and a center line passing through each of the large diameter portion (first connection port) 43b2, the pipe (tube material) 45, and the large diameter portion (second connection port) 21g1 is parallel to the assembly direction of the swivel case 41 to the outboard motor main body 20.

[0068] According to this configuration, after the O-ring (sealing member) 46 is positioned, the swivel case 41 is assembled to the outboard motor main body 20 while aligning the center lines passing through the large diameter portion (first connection port) 43b2, the pipe (tube material) 45, and the large diameter portion (second connection port) 21g1, thereby forming a cooling flow path at the same time as assembly. Therefore, the cooling flow passage can be formed through a simple assembly procedure, thereby reducing manufacturing costs.

[0069] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. In addition, within the scope of the invention, the components in the above-described embodiments may be replaced with well-known components, and the above-described modified examples may be combined as appropriate. [Explanation of symbols]

[0070] 10 Outboard motor 20 Outboard motor body 21g1 Large diameter part (second connection port) 40 Stern bracket (swing mechanism) 41 Swivel Case 42 Shaft (shaft body) 42a In-shaft flow path 42a2 Radial flow passage 43b2 Large diameter section (first connection port) 45 Pipes (piping materials) 46 O-ring (sealing material) 50A Left bracket (bracket) 50B Right bracket (bracket) 52 Bearing section (bearing) 60 Cooler C2 Gap (flow passage inside bearing) J connection part S Hull

Claims

1. An outboard motor provided on a boat hull for propelling the boat hull, The outboard motor body, a swing mechanism including a bracket fixed to the hull and a swivel case fixed to the outboard motor body and connected to the bracket so as to be swingable relative to the bracket; a cooler that is supported by at least one of the bracket and the hull and that is placed underwater; Equipped with a shaft body is provided on one of the bracket and the swivel case, and a bearing that rotatably supports the shaft body is provided on the other of the bracket and the swivel case; a cooling passage passing through the shaft body and the bearing is provided between the outboard motor body and the cooler, the rocking mechanism includes a pair of connecting portions each having the shaft body and the bearing and spaced apart from each other, The cooling flow path has an outward path passing through one of the pair of connecting portions and a return path passing through the other of the pair of connecting portions. An outboard motor characterized by:

2. The shaft body has an in-shaft flow passage formed inside the shaft body, the connecting portion has an in-bearing passage formed between an inner surface of the bearing and an outer surface of the shaft body and communicating with the in-shaft passage, The shaft passage and the bearing passage are included in the cooling passage.

2. An outboard motor according to claim 1 .

3. The shaft passage extends in the radial direction of the shaft body and branches into a plurality of radial passages each of which communicates with the bearing passage.

3. An outboard motor according to claim 2.

4. the swivel case has a first connection port through which the cooling passage passes and which is connected to the outboard motor main body, the outboard engine body has a second connection port to which the first connection port is coaxially connected, the swing mechanism includes a pipe that is coaxially inserted into both the first connection port and the second connection port, and a seal member that seals between the pipe and both the first connection port and the second connection port, A center line passing through each of the first connection port, the pipe material, and the second connection port is parallel to a direction in which the swivel case is assembled to the outboard motor body.

4. An outboard motor according to claim 1, wherein the outboard motor is a water-repellent type.

5. The cooler has a meandering flow path formed therein.

5. An outboard motor according to claim 1, wherein the outboard motor is a water-repellent type.

6. The cross-sectional shape of the cooler is streamlined.

6. An outboard motor according to claim 1, wherein the outboard motor is a water-repellent type.

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