outboard motor

Abstract

To improve cooling effect of a power source, etc. while suppressing enlarging of an outboard engine.SOLUTION: An outboard engine includes: an intake channel 51 provided inside a lower case 5 for taking in water from outside the outboard engine; a primary pump 71 driven by rotation of a drive shaft 20 for supplying the water taken in from the intake channel 51 as coolant to an engine, etc.; and a secondary pump 81 driven by rotation of the drive shaft 20 for supplying the water taken in from the intake channel 51 as coolant to the engine, etc., wherein the primary pump 71 and the secondary pump 81 are dispersedly arranged inside the outboard engine.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an outboard motor equipped with a cooling mechanism for cooling a power source and the like. [Background technology]

[0002] Conventional outboard motors are equipped with cooling mechanisms that take in seawater, lake water, or other water and use the water as cooling water to cool the power source and other components. Conventional outboard motor cooling mechanisms include a water intake port located in a submerged portion of the outboard motor case, such as a lower case; a water supply passage for supplying the water flowing into the outboard motor through the water intake port to the power source and other components; a cooling passage, such as a water jacket, located in the power source and cooling the power source and other components by circulating the cooling water supplied through the water supply passage; a drainage passage for transferring the cooling water after flowing through the cooling passage to a drainage port; a drainage port located, for example, in the lower rear portion of the lower case, for discharging the cooling water transferred through the drainage passage to outside the outboard motor; and a pump that sequentially circulates the water that flows into the outboard motor from the water intake port through the water supply passage, the cooling passage, and the drainage passage, and then discharges it outside the outboard motor through the drainage port. Conventional outboard motor cooling mechanisms also include a single pump driven by rotational output from the power source.

[0003] Patent Document 1 listed below describes an outboard motor equipped with such a cooling mechanism. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-127499 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, if the output of the power source of an outboard motor is increased to strengthen the propulsive power of a boat, the amount of heat generated by the power source, etc. increases, so it is necessary to improve the cooling effect of the outboard motor's cooling mechanism.

[0006] Increasing the pump's discharge rate and increasing the flow rate of cooling water circulating through cooling passages such as the water jacket can improve the cooling effect of the cooling mechanism. However, increasing the pump's discharge rate requires increasing the diameter and height (width) of the pump's impeller, which results in a larger pump volume. Therefore, to accommodate the increased pump volume, the volume of the outboard motor's case (e.g., lower case or upper case) that houses the pump must be increased, resulting in a larger outboard motor. However, increasing the size of an outboard motor has disadvantages, such as increased water resistance during sailing.

[0007] The present invention has been made in consideration of the problems described above, and an object of the present invention is to provide an outboard motor that can improve the cooling effect of the power source and other components while preventing the outboard motor from becoming larger. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides an outboard motor for propelling a marine vessel, comprising: a power source provided on an upper portion of the outboard motor; a drive shaft extending vertically from the power source toward a lower portion of the outboard motor and rotated by the rotational output of the power source; a propeller shaft provided on a lower portion of the outboard motor and rotated by the rotation of the drive shaft; a propeller attached to the propeller shaft; a case covering the power source, the drive shaft, and the propeller shaft; and a housing for housing the case. At the bottom and a water supply pipe is provided in the case so that water flows from the outside of the outboard motor into the case. Intake for inflow and, a first pump and a second pump that are provided above the water intake in the case and are separately driven by rotation of the drive shaft, and that supply water that has flowed into the case from the water intake to the power source as cooling water; and a common passage that transfers the water that has flowed into the case from the water intake to the first pump and the second pump. Equipped with The common passage extends vertically within the case, a lower portion of the common passage is connected to the water intake, and the first pump and the second pump are connected in parallel to each other at an upper portion of the common passage, and water flowing into the case from the water intake flows through the common passage and is supplied to the first pump and the second pump, respectively. It is characterized by: [Effects of the Invention]

[0009] According to the present invention, the cooling effect of the power source and the like can be improved while suppressing an increase in the size of the outboard motor. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is an overall view showing an outboard motor according to an embodiment of the present invention; [Figure 2] FIG. 2 is a perspective view showing a lower part of the outboard motor in FIG. [Figure 3] FIG. 3 is a plan view showing the lower part of the outboard motor in FIG. 2. [Figure 4] 4 is a cross-sectional view showing the lower part of the outboard motor taken along the line IV-IV in FIG. 3. [Figure 5] 5 is a cross-sectional view showing mechanisms arranged in and around an upper accommodation chamber in the lower part of the outboard motor in FIG. 4. [Figure 6] 6 is a cross-sectional view showing the lower part of the outboard motor taken along the line VI-VI in FIG. 5. [Figure 7] 7 is a cross-sectional view showing the lower part of the outboard motor taken along the line VII-VII in FIG. 3. [Figure 8] 6 is a cross-sectional view showing a state in which the secondary pump unit is separated from the lower case at the bottom of the outboard motor in FIG. 5. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] An outboard motor according to an embodiment of the present invention comprises a power source provided on an upper portion of the outboard motor, a drive shaft extending vertically from the power source towards the lower portion of the outboard motor and rotated by the rotational output of the power source, a propeller shaft provided on the lower portion of the outboard motor and rotated by rotation of the drive shaft, a propeller attached to the propeller shaft, a case covering the power source, drive shaft and propeller shaft, a water intake channel provided in the case for taking in water from outside the outboard motor into the case, a first pump driven by rotation of the drive shaft for supplying the water taken in from the water intake channel to the power source as cooling water, and a second pump driven by rotation of the drive shaft for supplying the water taken in from the water intake channel to the power source as cooling water, the first pump and second pumps being arranged separately within the outboard motor.

[0012] The outboard motor of this embodiment is equipped with a first pump and a second pump, and even if the first pump and the second pump are each small, by simultaneously driving these two pumps to supply cooling water to the power source (for example, a cooling passage such as a water jacket provided in the power source), the amount of cooling water supplied to the power source can be increased, thereby improving the cooling effect of the power source. Furthermore, by distributing two small pumps, the two pumps can be installed inside the outboard motor by utilizing small open spaces that are distributed throughout the outboard motor, thereby preventing the outboard motor from becoming larger. [Example]

[0013] An embodiment of an outboard motor of the present invention will be described. In the embodiment, directions such as up (Ud), down (Dd), front (Fd), rear (Bd), left (Ld), and right (Rd) are indicated by arrows drawn at the bottom right of Figures 1 to 8.

[0014] (Outboard motor) Fig. 1 shows an outboard motor 1 according to an embodiment of the present invention. Fig. 2 shows the lower part of the outboard motor 1 as viewed from above and rear left. Fig. 3 shows the lower part of the outboard motor 1 as viewed from above. Fig. 4 shows a cross section of the lower part of the outboard motor 1 taken along section line IV-IV in Fig. 3 as viewed from the left (bottom in Fig. 3).

[0015] An outboard motor 1 is a device for propelling a boat, and the outboard motor 1 of this embodiment is a contra-rotating propeller outboard motor as shown in Figure 1. The outboard motor 1 includes an engine 15 as a power source, an outer propeller shaft 16, a front propeller 17 attached to the outer propeller shaft 16, an inner propeller shaft 18 provided inside the outer propeller shaft 16, a rear propeller 19 attached to the inner propeller shaft 18, a drive shaft 20 that rotates due to the rotational output of the engine 15, a gear mechanism 45 that transmits the rotation of the drive shaft 20 to each of the propeller shafts 16, 18, and a rotation direction switching mechanism 31 that switches the rotation direction of each of the propeller shafts 16, 18.

[0016] The engine 15 is disposed at the top of the outboard motor 1, and the propeller shafts 16, 18 are disposed at the bottom of the outboard motor 1. The drive shaft 20 extends vertically from the engine 15 toward the bottom of the outboard motor 1. The drive shaft 20 is divided into an upper shaft portion 21, an intermediate shaft portion 22, and a lower shaft portion 23. The upper end of the upper shaft portion 21 is connected to the engine 15. The intermediate shaft portion 22 and the lower shaft portion 23 are connected by a connecting member 24. The rotation direction switching mechanism 31 is provided between the upper shaft portion 21 and the intermediate shaft portion 22, and switches the rotation direction of the propeller shafts 16, 18 by switching the rotation direction of the intermediate shaft portion 22 relative to the upper shaft portion 21. The gear mechanism 45 is disposed at the bottom of the outboard motor 1, and connects the lower end of the lower shaft portion 23 to the front end of each propeller shaft 16, 18.

[0017] The engine 15 is covered by the bottom cowl 2 and the top cowl 3. The upper shaft portion 21 is covered by the upper case 4. The rotation direction switching mechanism 31, the intermediate shaft portion 22, the connecting member 24, the lower shaft portion 23, the gear mechanism 45, and the front portions of the propeller shafts 16, 18 are covered by the lower case 5.

[0018] As shown in FIGS. 2 to 4, the lower case 5 includes a lower case main body 6 formed in a generally box-like shape with an open top, and a cover member 7 that covers the top of the lower case main body 6. As shown in FIG. 4, a drive shaft insertion hole 8 is formed in the cover member 7. An upper housing chamber 9 is provided in the front upper part of the lower case 5. The drive shaft insertion hole 8 is connected to the upper housing chamber 9. A lower housing chamber 10 is provided in the front lower part of the lower case 5. A connection hole 11 is formed between the upper housing chamber 9 and the lower housing chamber 10 in the lower case 5, connecting the two chambers. A propeller shaft arrangement hole 12 is formed in the lower case 5 behind the lower housing chamber 10. As shown in FIG. 2, an anti-cavitation plate 13 that suppresses air intake into the propellers 17, 19 is provided in the rear upper part of the lower case main body 6.

[0019] The outer propeller shaft 16 and the inner propeller shaft 18 are each a specific example of a "propeller shaft," and the front propeller 17 and the rear propeller 19 are each a specific example of a "propeller." The upper shaft portion 21 is a specific example of a "first shaft portion," and the intermediate shaft portion 22, the lower shaft portion 23, and the connecting member 24 are each a specific example of a "second shaft portion." The bottom cowl 2, the top cowl 3, the upper case 4, and the lower case 5 are each a specific example of a "case," and the bottom cowl 2 and the top cowl 3 are each a specific example of a "cowl."

[0020] (Mechanism for generating thrust) Fig. 5 shows an enlarged view of the mechanisms arranged in and around the upper storage compartment 9 of the lower case 5 in Fig. 4. Fig. 6 shows a cross section of the lower part of the outboard motor 1 taken along section line VI-VI in Fig. 5, as viewed from above.

[0021] The upper end of the upper shaft portion 21 of the drive shaft 20 is connected to the engine 15, and the lower end is inserted into the drive shaft insertion hole 8 and connected to the rotation direction switching mechanism 31, as shown in FIG. 5. The upper shaft portion 21 rotates in one direction due to the rotation output of the engine 15. Hereinafter, the rotation direction of the upper shaft portion 21 is referred to as the forward direction.

[0022] The rotation direction switching mechanism 31 is disposed in the upper accommodation chamber 9 of the lower case 5. The rotation direction switching mechanism 31 includes a reverse drive gear 32, a reverse intermediate gear 34, an intermediate gear shaft 35, a reverse output gear 36, and a clutch 39.

[0023] The reverse drive gear 32 is a bevel gear that is disposed in the upper part of the upper accommodation chamber 9 with its toothed portion facing downward, and is rotatably supported by the cover member 7 via a bearing. The reverse drive gear 32 is spline-coupled (fitted) to the lower end of the upper shaft portion 21, for example, and rotates integrally with the upper shaft portion 21 in the forward direction.

[0024] The reverse intermediate gear 34 is a bevel gear and is disposed in the front of the upper housing chamber 9 with its teeth facing rearward. The intermediate gear shaft 35 is a shaft that supports the reverse intermediate gear 34 on the lower case main body 6 and is disposed in the front of the upper housing chamber 9. The reverse intermediate gear 34 and the intermediate gear shaft 35 are disposed in front of the drive shaft 20 (intermediate shaft portion 22) in the lower case 5. The intermediate gear shaft 35 extends in the front-rear direction and has an axis that is perpendicular to the axis A of the drive shaft 20. The reverse intermediate gear 34 is connected and fixed to the rear end of the intermediate gear shaft 35. In this embodiment, the intermediate gear shaft 35 and the reverse intermediate gear 34 are integrally formed. The intermediate gear shaft 35 is rotatably supported by the lower case main body 6 via a bearing. The intermediate gear shaft 35 and the reverse intermediate gear 34 rotate integrally.

[0025] The reverse output gear 36 is a bevel gear that is disposed in the lower part of the upper housing chamber 9 with its toothed portion facing upward, and is rotatably supported by the lower case body 6 via a bearing. The reverse output gear 36 is disposed coaxially with the reverse drive gear 32. A through hole 38 is formed in the center of the reverse output gear 36. The upper end portion of the intermediate shaft portion 22 is inserted into the through hole 38, but the through hole 38 and the upper end portion of the intermediate shaft portion 22 are spaced apart from each other.

[0026] The reverse drive gear 32 meshes with a reverse intermediate gear 34, and the reverse intermediate gear 34 meshes with a reverse output gear 36. When the reverse drive gear 32 rotates in the forward direction, the rotation is transmitted to the reverse output gear 36 via the reverse intermediate gear 34, causing the reverse output gear 36 to rotate in the reverse direction.

[0027] The clutch 39 is a member that has the function of selecting whether to transmit the forward rotation of the upper shaft portion 21 or the reverse drive gear 32 to the intermediate shaft portion 22, or to transmit the reverse rotation of the reverse output gear 36 to the intermediate shaft portion 22. The clutch 39 is a dog clutch that is formed in a cylindrical shape, with clutch pawls 40 formed on each of the upper and lower end surfaces. In addition, a groove 41 is formed around the entire outer periphery of the clutch 39. The clutch 39 is disposed between the reverse drive gear 32 and the reverse output gear 36.

[0028] Furthermore, the upper end portion of the intermediate shaft portion 22 passes through a through hole 38 of the reverse output gear 36 and is inserted between the reverse drive gear 32 and the reverse output gear 36. The clutch 39 is connected to the upper end portion of the intermediate shaft portion 22 so as to be immovable in the circumferential direction relative to the intermediate shaft portion 22 but movable in the axial direction. As a result, the clutch 39 and the intermediate shaft portion 22 rotate integrally, but the clutch 39 can move up and down relative to the intermediate shaft portion 22.

[0029] Additionally, a shift fork 42 is provided in the lower case 5 at the rear of the upper housing chamber 9, and a clutch control unit 43 is provided at the rear of the upper housing chamber 9. The shift fork 42 and clutch control unit 43 are disposed in the lower case 5 behind the drive shaft 20 (intermediate shaft portion 22). Additionally, as shown in FIG. 6 , the clutch control unit 43 is disposed on one side in the left-right direction (for example, the right side) in the lower case 5. The shift fork 42 extends in the front-rear direction while inclining in the left-right direction. A front end of the shift fork 42 is formed in a fork shape, and is inserted into a groove 41 of the clutch 39 so that the clutch 39 is rotatable relative to the shift fork 42. Additionally, a rear end of the shift fork 42 is connected to an actuator (not shown) provided in the clutch control unit 43.

[0030] By operating the actuator of the clutch control unit 43, the shift fork 42 can be moved up and down, thereby moving the clutch 39 up and down. When the clutch 39 moves up, the clutch pawl 40 formed on the upper end surface of the clutch 39 engages with the clutch pawl 33 formed on the lower end surface of the reverse drive gear 32. This directly transmits the forward rotation of the reverse drive gear 32 to the intermediate shaft portion 22, causing the intermediate shaft portion 22 to rotate in the forward direction. On the other hand, when the clutch 39 moves down, the clutch pawl 40 formed on the lower end surface of the clutch 39 engages with the clutch pawl 37 formed on the upper end surface of the reverse output gear 36. This transmits the reverse rotation of the reverse output gear 36 to the intermediate shaft portion 22, causing the intermediate shaft portion 22 to rotate in the reverse direction. Furthermore, when the clutch 39 is in the neutral position, the clutch pawl 40 formed on the upper end surface of the clutch 39 is not engaged with the clutch pawl 33 of the reverse drive gear 32, and the clutch pawl 40 formed on the lower end surface of the clutch 39 is not engaged with the clutch pawl 37 of the reverse output gear 36, neither the rotation of the reverse drive gear 32 nor the rotation of the reverse output gear 36 is transmitted to the intermediate shaft portion 22. In this case, the intermediate shaft portion 22 does not rotate.

[0031] As shown in FIG. 4 , the intermediate shaft portion 22 and the lower shaft portion 23 extend in the vertical direction within the connecting hole 11. The intermediate shaft portion 22 is located below the upper shaft portion 21 and is arranged coaxially with the upper shaft portion 21. The upper end portion of the intermediate shaft portion 22 is coupled to the clutch 39 as described above. The lower end portion of the intermediate shaft portion 22 is connected to the lower shaft portion 23 via the connecting member 24. The lower shaft portion 23 is located below the intermediate shaft portion 22 and is arranged coaxially with the intermediate shaft portion 22. The connecting member 24 is formed in a cylindrical shape, and the lower end portion of the intermediate shaft portion 22 is inserted into the upper portion of the connecting member 24, and the upper end portion of the lower shaft portion 23 is inserted into the lower portion of the connecting member 24. Splines are formed on the inner peripheral surface of the connecting member 24, the outer peripheral surface of the lower end of the intermediate shaft portion 22, and the outer peripheral surface of the upper end of the lower shaft portion 23, and the lower end of the intermediate shaft portion 22 and the upper end of the lower shaft portion 23 are spline-connected to the connecting member 24. The connecting member 24 is rotatably supported on the lower case main body 6 via bearings. The lower shaft portion 23 is rotatably supported in the connecting hole 11 via bearings. The intermediate shaft portion 22, the lower shaft portion 23, and the connecting member 24 rotate together.

[0032] The gear mechanism 45 is a mechanism that transmits the rotation of the lower shaft portion 23 to each of the propeller shafts 16, 18. The gear mechanism 45 is disposed in the lower housing chamber 10. The gear mechanism 45 includes a main drive gear 46, a front driven gear 47, and a rear driven gear 48.

[0033] The main drive gear 46 is a bevel gear and is disposed in the upper part of the lower housing chamber 10 with its teeth facing downward. The main drive gear 46 is coupled to and fixed to the lower end of the lower shaft portion 23. In this embodiment, the main drive gear 46 and the lower shaft portion 23 are integrally formed. The main drive gear 46 rotates integrally with the lower shaft portion 23.

[0034] The front driven gear 47 is a bevel gear and is disposed in the front part of the lower housing chamber 10 with the toothed portion facing rearward. The front driven gear 47 is rotatably supported by the lower case body 6 via a bearing. The front driven gear 47 is disposed in front of the main drive gear 46 and is in mesh with the main drive gear 46.

[0035] The rear driven gear 48 is a bevel gear and is disposed at the rear of the lower housing chamber 10 with its toothed portion facing forward. The rear driven gear 48 is rotatably supported by the lower case body 6 via a bearing. The rear driven gear 48 is disposed behind the main drive gear 46 and is in mesh with the main drive gear 46.

[0036] As shown in Figure 4, the outer propeller shaft 16 is formed in a cylindrical shape and extends in the front-to-rear direction. The front end portion of the outer propeller shaft 16 is disposed in the propeller shaft disposing hole 12 and is rotatably supported by the lower case main body 6 via a bearing. A rear driven gear 48 is spline-connected to the front end portion of the outer propeller shaft 16. This allows the rear driven gear 48 and the outer propeller shaft 16 to rotate integrally. A front propeller 17 is attached to the rear end portion of the outer propeller shaft 16.

[0037] The inner propeller shaft 18 extends in the fore-and-aft direction, and its front portion is disposed within the outer propeller shaft 16. The inner propeller shaft 18 is disposed coaxially with the outer propeller shaft 16. The inner propeller shaft 18 is supported by the outer propeller shaft 16 and the rear driven gear 48 via bearings so as to be rotatable relative to the outer propeller shaft 16 and the rear driven gear 48. A front driven gear 47 is spline-connected to the front end of the inner propeller shaft 18. This allows the front driven gear 47 and the inner propeller shaft 18 to rotate integrally. A rear propeller 19 is attached to the rear end of the inner propeller shaft 18.

[0038] When the main drive gear 46 rotates integrally with the lower shaft portion 23, the rotation is transmitted to the rear driven gear 48 and the front driven gear 47, respectively. As a result, the outer propeller shaft 16 and the inner propeller shaft 18 each rotate. At this time, the outer propeller shaft 16 and the inner propeller shaft 18 rotate in opposite directions. As the outer propeller shaft 16 and the inner propeller shaft 18 rotate, the front propeller 17 and the rear propeller 19 each rotate.

[0039] Furthermore, when the clutch 39 transmits the rotation of the upper shaft portion 21 in the forward direction to the outer propeller shaft 16 and the inner propeller shaft 18 via the intermediate shaft portion 22, the lower shaft portion 23, the gear mechanism 45, etc., a thrust force that moves the vessel forward is generated by the front propeller 17 and the rear propeller 19. Furthermore, when the clutch 39 transmits the rotation of the reverse output gear 36 in the reverse direction to the outer propeller shaft 16 and the inner propeller shaft 18 via the intermediate shaft portion 22, the lower shaft portion 23, the gear mechanism 45, etc., a thrust force that moves the vessel backward is generated by the front propeller 17 and the rear propeller 19.

[0040] (Engine cooling mechanisms) As shown in FIG. 4, the outboard motor 1 is equipped with a water intake passage 51 that takes in water such as seawater or lake water from outside the outboard motor 1 into the outboard motor 1, and two pumps (a primary pump 71 and a secondary pump 81) that supply the water taken in from the water intake passage 51 to the engine 15, etc. as cooling water.

[0041] The intake channel 51 has two main intakes 52, a common passage 54, a first dedicated passage 55, a first intake port 56, a second intake port 57, two sub-intakes 58, and a second dedicated passage 60.

[0042] The two main water intakes 52 are holes that allow water to flow into the lower case 5 from outside the outboard motor 1. Each main water intake 52 penetrates a portion of the wall of the lower case body 6. Each main water intake 52 is located below the water surface. The two main water intakes 52 are each provided at the lower part of the front end of the lower case body 6, with one main water intake 52 opening to the left of the lower case body 6 and the other main water intake 52 opening to the right of the lower case body 6. In addition, to prevent sand, debris, etc. from entering the lower case 5 through the main water intakes 52, a cover 53 with many small holes is attached to each main water intake 52, as shown in FIG. 2 . Each main water intake 52 is a specific example of a "water intake."

[0043] The common passage 54 is a passage that transfers water that flows in from each main water intake port 52 toward the primary pump 71 and the secondary pump 81. Both water transferred to the primary pump 71 and water transferred to the secondary pump 81 flow through the common passage 54. The common passage 54 is formed by a passage portion 61 provided at the front end portion inside the lower case body 6 and a lower portion of a passage portion 62 provided in a secondary pump unit 91 (described below) that is attached to the upper front end portion of the lower case 5. The common passage 54 extends in the vertical direction, and the lower end portion of the common passage 54 is connected to each main water intake port 52.

[0044] The first dedicated passage 55 is a passage that transfers the water transferred via the common passage 54 to the primary pump 71. The first dedicated passage 55 is formed by an upper portion of a passage portion 62 provided in the secondary pump unit 91 and a passage portion 63 provided in the front portion of the cover member 7. One end of the first dedicated passage 55 is connected to an upper portion of the common passage 54.

[0045] The first water intake port 56 is a hole that allows the water transferred via the first dedicated passage 55 to flow into the pump case 75 of the primary pump 71. The first water intake port 56 is provided in the bottom plate 72 of the primary pump 71. The other end of the first dedicated passage 55 is connected to the first water intake port 56.

[0046] The second water intake port 57 is a hole that allows water transferred via the common passage 54 to flow into the pump case 85 of the secondary pump 81. The second water intake port 57 is provided in a secondary pump unit 91 that is attached to the upper part of the front end of the lower case 5, and is disposed between the passage portion 62 and the pump case 85 in the secondary pump unit 91. The second water intake port 57 communicates between the passage portion 62 and the pump case 85. As a result, the upper part of the common passage 54 is connected to the inside of the pump case 85 via the second water intake port 57.

[0047] In this way, the common passage 54 branches at the upper part of the front end of the lower case 5 into a passage (first dedicated passage 55 and first water intake port 56) connected to the primary pump 71 and a passage (second water intake port 57) connected to the secondary pump 81. Note that the common passage 54 is a specific example of a "main passage," and the first dedicated passage 55, the first water intake port 56, and the second water intake port 57 are specific examples of a "branch passage."

[0048] The two sub-water intakes 58 are ports through which water flows into the lower case 5 from outside the outboard motor 1. Each sub-water intake 58 is a hole that penetrates part of the wall of the lower case main body 6 and is located below the water surface. One sub-water intake 58 is provided on the left side of the lower case main body 6, and the other sub-water intake 58 is provided on the right side of the lower case main body 6. Similar to the main water intake 52, each sub-water intake 58 is also fitted with a cover 59 having a number of small holes formed therein.

[0049] The second dedicated passage 60 is a passage that transfers water that has flowed in from each sub-water intake port 58 toward the primary pump 71. The second dedicated passage 60 is formed by a passage section 64 provided in the middle of the front-rear direction in the lower case body 6, and a passage section 65 provided in the middle of the front-rear direction in the cover member 7. The lower end of the second dedicated passage 60 is connected to each sub-water intake port 58, and the upper end of the second dedicated passage 60 is connected to the first water intake port 56.

[0050] The primary pump 71 is a positive displacement pump such as a vane pump. The primary pump 71 is driven by rotation of the drive shaft 20, specifically, by rotation of the upper shaft portion 21 of the drive shaft 20. As shown in FIG. 5 , the primary pump 71 is attached to the upper surface of the lower case 5. The primary pump 71 is disposed at a position intersecting the axis A of the drive shaft 20 and is provided on the outer circumferential side of the upper shaft portion 21 so as to surround the upper shaft portion 21. When the lower case 5 is attached to the upper case 4, the primary pump 71 is covered by the upper case 4. The primary pump 71 is a specific example of a "first pump."

[0051] The primary pump 71 has a bottom plate 72, an impeller 74, and a pump case 75. The bottom plate 72 is attached to the periphery of an opening 66 formed in the cover member 7 of the lower case 5 at a position through which the axis A of the drive shaft 20 passes, so as to close the opening 66. A drive shaft insertion hole 73 is formed in the bottom plate 72. The upper shaft portion 21 is inserted into the drive shaft insertion hole 73. The diameter of the drive shaft insertion hole 73 is larger than the diameter of the upper shaft portion 21, so that the upper shaft portion 21 can rotate relative to the drive shaft insertion hole 73. In addition, a first water intake port 56 is formed in a part of the outer circumferential portion of the bottom plate 72 around the drive shaft insertion hole 73.

[0052] The impeller 74 has an axis that is coaxial with the axis A of the drive shaft 20. The boss of the impeller 74 is coupled to and fixed to the upper shaft portion 21. Therefore, the impeller 74 rotates integrally with the upper shaft portion 21.

[0053] The pump case 75 is formed in a generally cylindrical shape with an axis generally coaxial with the axis A of the drive shaft 20 and covers the impeller 74. The pump case 75 is fixed on the bottom plate 72. The impeller 74 is disposed in a space defined by the pump case 75 and the bottom plate 72. The pump case 75 is provided with a drive shaft insertion hole 76, through which the upper shaft portion 21 is inserted. Because the diameter of the drive shaft insertion hole 76 is larger than the diameter of the upper shaft portion 21, the upper shaft portion 21 can rotate relative to the drive shaft insertion hole 76. The gap between the drive shaft insertion hole 76 and the upper shaft portion 21 is sealed. The pump case 75 is also provided with a discharge port 77 that discharges water sucked in through the first water intake port 56 as cooling water.

[0054] The secondary pump 81 is a non-positive displacement pump such as a centrifugal pump or a turbine pump. The secondary pump 81 is driven by rotation of the drive shaft 20, specifically, by rotation of the intermediate gear shaft 35, which is rotated by the rotation of the drive shaft 20 transmitted via the reverse drive gear 32 and the reverse intermediate gear 34. The secondary pump 81 is disposed forward of the drive shaft 20 and spaced apart from the drive shaft 20. Specifically, the secondary pump 81 is disposed in the upper front portion of the lower case 5. In this manner, the primary pump 71 and the secondary pump 81 are disposed separately within the outboard motor 1. As shown in FIG. 4 , the secondary pump 81 is disposed below the waterline when the boat is stopped and higher than the anti-cavitation plate 13. The secondary pump 81 is a specific example of a "second pump."

[0055] 5, the secondary pump 81 has a pump shaft 82, an impeller 83, a shaft support 84, and a pump case 85. The pump shaft 82 extends in the front-rear direction and is disposed coaxially with the intermediate gear shaft 35. The rear end of the pump shaft 82 is spline-connected to the front end of the intermediate gear shaft 35, for example, and rotates integrally with the intermediate gear shaft 35.

[0056] The impeller 83 has an axis that is coaxial with the axis of the intermediate gear shaft 35. The boss of the impeller 83 is coupled to and fixed to the front end of the pump shaft 82. The impeller 83 rotates integrally with the pump shaft 82.

[0057] The shaft support part 84 is formed in a cylindrical shape with an axis coaxial with the axis of the intermediate gear shaft 35. The pump shaft 82 is rotatably supported within the shaft support part 84 via a bearing. The gap between the shaft support part 84 and the pump shaft 82 is sealed.

[0058] The pump case 85 is formed in a generally cylindrical shape with a lid and has an axis generally coaxial with the axis of the intermediate gear shaft 35, and covers the impeller 83. The pump case 85 is disposed forward of and fixed to the shaft support portion 84. The impeller 83 is disposed in a space defined by the pump case 85 and the shaft support portion 84. A second water intake port 57 is provided at the front of the pump case 85. FIG. 7 shows a cross section of the lower portion of the outboard motor 1 taken along section line VII-VII in FIG. 3, viewed from the front (left side in FIG. 3). As shown in FIG. 7, the pump case 85 is provided with a discharge port 86 that discharges water drawn in through the second water intake port 57 as cooling water. A connecting pipe 88 is connected to the discharge port 86 via an L-shaped joint 87. The connecting pipe 88 extends rearward above the lower case 5, as shown in FIG. 3.

[0059] The secondary pump 81 and the passage 62 form a secondary pump unit 91. As shown in FIG. 8, the secondary pump unit 91 can be attached to and detached from the lower case 5. As shown in FIG. 3, the secondary pump unit 91 is attached to the lower case 5 with bolts 92. When the secondary pump unit 91 is attached to the lower case 5, as shown in FIG. 8, the rear portion of the shaft support portion 84 is inserted into a mounting hole 67 provided in the front upper part of the lower case main body 6. When the rear portion of the shaft support portion 84 is inserted into the mounting hole 67, the rear end of the pump shaft 82 is spline-connected to the front end of the intermediate gear shaft 35. The secondary pump unit 91 can be separated from the lower case 5 by removing the bolts 92 and moving the secondary pump unit 91 forward relative to the lower case 5.

[0060] Although not shown, the outboard motor 1 also includes a first water supply passage that transfers cooling water discharged from the discharge port 77 of the primary pump 71 to the engine 15 and other components; a second water supply passage that further transfers cooling water transferred through a connecting pipe 88 connected to the discharge port 86 of the secondary pump 81 to the engine 15 and other components; a cooling passage that cools the engine 15 and other components by circulating the cooling water transferred to the engine 15 and other components via the first water supply passage and the second water supply passage around or inside the engine 15 and other components; and a drain passage and a drain outlet that discharge the cooling water that has flowed through the cooling passage to the outside of the outboard motor 1. The first water supply passage and the second water supply passage are each formed, for example, by a water supply pipe or the like, and these water supply pipes are arranged inside the upper case 4 and the bottom cowl 2 and other components. The cooling passage is, for example, a water jacket provided on the engine 15 and other components. The drain passage is formed, for example, by a drain pipe or the like, and the drain pipe is arranged inside the bottom cowl 2, the upper case 4, the lower case 5 and other components. The drain port is provided, for example, at the rear of the lower case 5.

[0061] When the engine 15 is running and the upper shaft portion 21 and the intermediate gear shaft 35 are rotating, the impeller 74 of the primary pump 71 rotates, driving the primary pump 71. At the same time, the impeller 83 of the secondary pump 81 rotates, driving the secondary pump 81. As a result, water taken in from each main water intake 52 flows upward through the common passage 54 and is divided into the first dedicated passage 55 and the second water intake 57 at the upper part of the common passage 54. Water that flows into the first dedicated passage 55 from the upper part of the common passage 54 flows through the first dedicated passage 55 and flows into the pump case 75 of the primary pump 71 via the first water intake 56. Water that flows into the second water intake 57 from the upper part of the common passage 54 flows into the pump case 85 of the secondary pump 81. Meanwhile, when the primary pump 71 is driven, water taken in from each sub-intake port 58 flows through the second dedicated passage 60 and flows into the pump case 75 of the primary pump 71 via the first suction port 56.

[0062] The water that flows into the pump case 75 of the primary pump 71 is discharged as cooling water from the discharge port 77 of the primary pump 71. The water that flows into the pump case 85 of the secondary pump 81 is discharged as cooling water from the discharge port 86 of the secondary pump 81, and then flows through the connecting pipe 88.

[0063] The cooling water discharged from the discharge port 77 of the primary pump 71 and the cooling water discharged from the discharge port 86 of the secondary pump 81 and circulating through the connecting pipe 88 flow in parallel through the first water supply passage and the second water supply passage, and then flows through the cooling passage to cool the engine 15, etc. The cooling water then flows through the drain passage and is discharged to the outside of the outboard motor 1 from the drain port.

[0064] As described above, the outboard motor 1 according to the embodiment of the present invention is equipped with the primary pump 71 and the secondary pump 81, which are disposed in a dispersed manner within the outboard motor 1. According to the outboard motor 1 of this embodiment, even if the primary pump 71 and the secondary pump 81 are small pumps, by simultaneously driving these two pumps 71, 81 to supply cooling water to the cooling passages of the water jacket or the like, the flow rate of cooling water flowing through the cooling passages can be increased, thereby improving the cooling effect of the engine 15 and the like. Furthermore, by distributing the two small pumps 71, 81 in a dispersed manner, the two pumps 71, 81 can be installed within the outboard motor 1 by utilizing small open spaces or the like dispersed within the outboard motor 1, thereby preventing the outboard motor 1 from becoming larger.

[0065] Furthermore, since the outboard motor 1 of this embodiment is equipped with two pumps 71, 81, even if one of the pumps fails to operate normally due to a malfunction or the like, the other pump can continue to operate to supply cooling water to the cooling passage, thereby preventing the engine 15 from overheating.

[0066] Furthermore, in the outboard motor 1 of this embodiment, the primary pump 71 is disposed on the outer periphery of the drive shaft 20 so that its impeller 74 is coaxial with the drive shaft 20, and the secondary pump 81 is disposed in front of the drive shaft 20 at a distance from the drive shaft 20. With this configuration, the primary pump 71 can rotate the impeller 74 by directly utilizing the rotation of the drive shaft 20, thereby simplifying the configuration for transmitting rotation from the drive shaft 20 to the impeller 74. Furthermore, since there is a larger open area in front of the drive shaft 20 within the outboard motor 1 compared to other areas, it is relatively easy to ensure an area in front of the drive shaft 20 for installing the secondary pump 81, and therefore the secondary pump 81 can be installed within the outboard motor 1 without increasing the size of the outboard motor 1.

[0067] In the outboard motor 1 of this embodiment, the secondary pump 81 is disposed in the front part of the lower case 5, below the water surface when the boat is stopped and higher than the anti-cavitation plate 13. With this configuration, the secondary pump 81 is positioned below the water surface when the boat is stopped or traveling at a slow speed, and is positioned slightly above the water surface (higher than the water surface but close to the water surface) when the boat is planing. This prevents the secondary pump 81 from drawing in air, which could cause air to be mixed into the cooling water discharged from the secondary pump 81 and result in a decrease in the amount of cooling water discharged. In other words, when the boat is stopped or traveling at a slow speed, the secondary pump 81 is positioned below the water surface, and the intake path of the secondary pump 81 (the passage from the main intake port 52 to the second intake port 57) is also positioned below the water surface. Therefore, even when the impeller 83 of the secondary pump 81 is stopped when the vessel is stopped, or when the rotation speed of the impeller 83 of the secondary pump 81 is low when the vessel is traveling at a low speed, the water intake path of the secondary pump 81 is filled with water, thereby preventing the secondary pump 81 from taking in air. On the other hand, when the vessel is planing, the position of the secondary pump 81 is slightly higher than the water surface, but at this time the rotation speed of the drive shaft 20 is high, and therefore the rotation speed of the intermediate gear shaft 35 is also high, and therefore the rotation speed of the impeller 83 of the secondary pump 81 is also high, resulting in a large suction force generated by the impeller 83. Therefore, the water intake path of the secondary pump 81 is filled with water due to the suction force generated by the impeller 83, preventing the secondary pump 81 from taking in air.

[0068] Furthermore, because the secondary pump 81 is positioned above the water surface when the boat is planing, an increase in water resistance when the boat is planing can be suppressed. That is, even if the installation of secondary pump 81 increases the dimension of the part of lower case 5 above anti-cavitation plate 13 in the left-right direction, this part is above the water surface when the boat is planing, so an increase in water resistance can be suppressed.

[0069] In the outboard motor 1 of this embodiment, the primary pump 71 is mounted on the upper surface of the lower case 5. This allows the primary pump 71 to be easily removed from the lower case 5, facilitating maintenance such as replacement of the impeller 74.

[0070] In the outboard motor 1 of this embodiment, the water intake passage 51 includes a main water intake 52 provided at the bottom of the front portion of the lower case 5, a common passage 54 connected to the main water intake 52 and extending upward inside the front portion of the lower case 5, a first dedicated passage 55 and a first water intake 56 connecting an upper portion of the common passage 54 to the inside of a pump case 75 of the primary pump 71, and a second water intake 57 connecting an upper portion of the common passage 54 to the inside of a pump case 85 of the secondary pump 81. This configuration allows a portion of the water intake path connecting the primary pump 71, located on the top surface of the lower case 5, and the secondary pump 81, located at the front upper portion of the lower case 5, to be shared, and the shared water intake path can be shortened. This allows for smooth water intake in each pump 71, 81 and simplifies the structure of the water intake path.

[0071] In the outboard motor 1 of this embodiment, the secondary pump 81 is driven by rotation of the intermediate gear shaft 35 in the rotational direction switching mechanism 31. With this configuration, a part of the rotational direction switching mechanism 31 can be used to provide a means for transmitting the rotational output of the engine 15 to the impeller 83 of the secondary pump 81, which is located away from the axis A of the drive shaft 20. This eliminates the need for a separate means for transmitting the rotational output of the engine 15 to the impeller 83 of the secondary pump 81, which is located away from the axis A of the drive shaft 20. This prevents the structure of the outboard motor 1 from becoming too complicated and reduces the number of parts in the outboard motor 1. In addition, in the rotational direction switching mechanism 31, the diameter of the reverse intermediate gear 34 is smaller than the diameter of the reverse drive gear 32, so the intermediate gear shaft 35 rotates at a higher speed than the drive shaft 20. This makes it easy to increase the rotational speed of the impeller 83 of the secondary pump 81, thereby increasing the amount of coolant discharged by the secondary pump 81. Therefore, even when the rotation speed of the drive shaft 20 is low, the supply of cooling water to the cooling passage by the secondary pump 81 can be stabilized.

[0072] In the rotational direction switching mechanism 31 of the outboard motor 1 of this embodiment, the reverse intermediate gear 34 and the intermediate gear shaft 35 are disposed in front of the drive shaft 20, and the shift fork 42 and clutch control unit 43 are disposed behind the drive shaft 20. The secondary pump 81 is disposed in front of the drive shaft 20, and the rear end of the pump shaft 82 of the secondary pump 81 is connected to the front end of the intermediate gear shaft 35. With this configuration, it is possible to easily dispose the secondary pump 81 above the front of the lower case 5 and transmit the rotational output of the engine 15 to the secondary pump 81 without increasing the size of the outboard motor 1.

[0073] Furthermore, in the outboard motor 1 of this embodiment, the secondary pump 81 is disposed in the upper front portion of the lower case 5, so that the secondary pump 81 (secondary pump unit 91) can be easily attached to and detached from the lower case 5. This facilitates maintenance of the secondary pump 81, such as replacement of the impeller 83.

[0074] In the above embodiment, the two main water intakes 52 and the common passage 54 form a common water intake path for the primary pump 71 and the secondary pump 81. However, the water intake path for the primary pump 71 and the water intake path for the secondary pump 81 may be completely independent of each other. For example, a passage L connecting the left main water intake 52 and the first water intake 56 and a passage R connecting the right main water intake 52 and the second water intake 57 may be provided separately. In this way, even if one of the two left and right main water intakes 52 becomes clogged, water can be taken in from the other main water intake 52 to cool the engine 15, etc.

[0075] Furthermore, a communication passage may be provided that connects the passage L connecting the left main water intake 52 and the first water inlet 56 with the passage R connecting the right main water intake 52 and the second water inlet 57, and a valve may be provided to open and close the communication passage. When both pumps 71, 81 are operating normally, the valve may be closed to supply water to each of the two pumps via passage L and passage R. On the other hand, when one of the two pumps 71, 81 begins to operate abnormally, the valve may be opened to supply water to the other pump via passage R, passage L, and the communication passage. This prevents a significant decrease in the cooling effect of the engine 15, etc., when one of the two pumps 71, 81 begins to operate abnormally.

[0076] Furthermore, in the above embodiment, the primary pump 71 is disposed on the upper surface of the lower case 5, but the primary pump 71 may be disposed at another position (for example, a lower position) on the outer circumferential side of the drive shaft 20.

[0077] In addition, in the above embodiment, the reverse intermediate gear 34 and the intermediate gear shaft 35 are arranged in front of the drive shaft 20, the shift fork 42 and the clutch control unit 43 are arranged in rear of the drive shaft 20, the secondary pump 81 is arranged in front of the drive shaft 20, and the pump shaft 82 of the secondary pump 81 is connected to the intermediate gear shaft 35. However, if a location for installing the secondary pump 81 can be secured behind the drive shaft 20, the reverse intermediate gear 34 and the intermediate gear shaft 35 may be arranged behind the drive shaft 20, the shift fork 42 and the clutch control unit 43 may be arranged in front of the drive shaft 20, the secondary pump 81 may be arranged in rear of the drive shaft 20, and the pump shaft 82 of the secondary pump 81 may be connected to the intermediate gear shaft 35.

[0078] Furthermore, in the above embodiment, a positive displacement pump is used as the primary pump 71 and a non-positive displacement pump is used as the secondary pump 81, but the pump type or type of either the primary pump 71 or the secondary pump 81 is not limited.

[0079] In addition, in the above embodiment, the pump that directly transmits the rotation of the drive shaft 20 to rotate the impeller is referred to as the primary pump, and the pump that transmits the rotation of the intermediate shaft to rotate the impeller is referred to as the secondary pump, but the division of roles between the two pumps as primary (main) and secondary (sub) can be changed as appropriate, and the two pumps may also be given equal roles.

[0080] Furthermore, there are no limitations on the objects cooled by the cooling water discharged from the primary pump 71 and the cooling water discharged from the secondary pump 81. For example, the engine 15 may be cooled by the cooling water discharged from the primary pump 71 and the cooling water discharged from the secondary pump 81, or the engine 15 may be cooled by the cooling water discharged from the primary pump 71 and the cooling water discharged from the secondary pump 81 may cool an oil cooler.

[0081] Furthermore, the present invention may be modified as appropriate within the scope of the claims and the spirit or concept of the invention as can be read from the entire specification, and outboard motors incorporating such modifications are also included within the technical concept of the present invention. [Explanation of symbols]

[0082] 1 outboard motor 2 Bottom cowl (case, cowl) 3 Top cowl (case, cowl) 4 Upper case (case) 5 Lower case (case) 13 Anti-cavitation plate 15 Engine (power source) 16 Outer propeller shaft (propeller shaft) 17 Front propeller (propeller) 18 Inner propeller shaft (propeller shaft) 19 Rear propeller (propeller) 20 Drive shaft 21 upper shaft portion (first shaft portion) 22 intermediate shaft portion (second shaft portion) 23 Lower shaft portion (second shaft portion) 24 Connecting member (second shaft portion) 31 Rotation direction switching mechanism 32 Reverse drive gear 34 Reverse intermediate gear 35 Intermediate gear shaft 36 Reverse output gear 39 Clutch 51 Intake Channel 52 Main intake (intake) 54 Common aisle (main aisle) 55 First dedicated passage (branch passage) 56 First water intake (branch passage) 57 Second intake (branch passage) 71 Primary pump (first pump) 74 impeller 81 Secondary pump (second pump) 83 Impeller

Claims

1. An outboard motor for propelling a boat, a power source provided on an upper portion of the outboard motor; a drive shaft extending vertically from the power source toward a lower portion of the outboard motor and rotated by the rotational output of the power source; a propeller shaft provided at a lower portion of the outboard motor and rotated by rotation of the drive shaft; a propeller attached to the propeller shaft; a case that covers the power source, the drive shaft, and the propeller shaft; a water intake provided at a lower portion of the case for allowing water to flow into the case from outside the outboard motor; a first pump and a second pump that are provided above the water intake in the case and are separated from each other, are driven by rotation of the drive shaft, and supply water that flows into the case from the water intake to the power source as cooling water; a common passage for transferring water that has flowed into the case from the water intake to the first pump and the second pump, the common passage extends vertically within the case, a lower portion of the common passage connected to the water intake; the first pump and the second pump are connected in parallel to each other at an upper portion of the common passage; the water flowing into the case from the water intake duct flows through the common passage and is supplied to the first pump and the second pump.

2. An outboard motor as described in Claim 1, characterized in that the intake port of the first pump and the intake port of the second pump are connected in parallel to each other at the upper part of the common passage.

3. An upper portion of the common passage branches into two branch passages, one of which is connected to the first pump and the other of which is connected to the second pump; 2. The outboard motor according to claim 1, wherein water flowing into the case from the water intake duct flows through the common passage, then branches off to flow into the one branch passage and the other branch passage, the water flowing into the one branch passage being supplied to the first pump, and the water flowing into the other branch passage being supplied to the second pump.

4. 4. An outboard motor according to claim 1, wherein the first pump is disposed on the outer circumferential side of the drive shaft so that an impeller of the first pump is coaxial with the drive shaft, and the second pump is disposed in front of the drive shaft and at a distance from the drive shaft.

5. the case has a lower case that covers a lower portion of the drive shaft and a front portion of the propeller shaft, The lower case is provided with an anti-cavitation plate, 5. The outboard motor according to claim 4, wherein the second pump is disposed in a front portion of the lower case at a position that is below the water surface when the boat is stationary and that is higher than the anti-cavitation plate.

6. The second pump is disposed at the front upper part of the lower case, 6. The outboard motor according to claim 5, wherein the upper front portion of the lower case and the second pump form a pump unit that is detachable from the portion of the lower case excluding the upper front portion.

7. 6. An outboard motor according to claim 5, wherein said first pump is mounted on an upper surface of said lower case.

8. the drive shaft is divided into a first shaft portion that forms an upper portion of the drive shaft, has an upper end side connected to the power source, and rotates in one direction by rotational output of the power source, and a second shaft portion that forms a lower portion of the drive shaft, has a lower end side connected to the propeller shaft, a rotation direction switching mechanism that switches the rotation direction of the propeller shaft is provided between the first shaft portion and the second shaft portion, The rotation direction switching mechanism is a reverse drive gear which is a bevel gear fixed to a lower end side of the first shaft portion and rotates in the one direction; a reverse intermediate gear which is a bevel gear meshed with the reverse drive gear; an intermediate gear shaft having an axis perpendicular to the axis of the drive shaft and to which the reverse intermediate gear is fixed; a reverse output gear that is a bevel gear that is arranged coaxially with the reverse drive gear and meshes with the reverse intermediate gear, and that rotates in a direction opposite to the one direction; a clutch that selects whether to transmit the rotation of the first shaft portion or the reverse drive gear in the one direction to the second shaft portion or to transmit the rotation of the reverse output gear in the opposite direction to the second shaft portion, 8. An outboard motor according to claim 1, wherein the second pump is driven by rotation of the intermediate gear shaft.

Images