JPH078677B2 - Exhaust structure of ship propulsion - Google Patents

Description

The present invention relates to an exhaust structure for a ship propulsion device.

[Prior Art] Conventionally, an exhaust structure of a ship propulsion device as described in JP-A-60-64096 has been proposed. This exhaust structure is
An exhaust expansion chamber is formed inside a tubular body held in the center of the propulsion casing, and an exhaust pipe communicating with the exhaust passage of the engine is arranged in the exhaust expansion chamber to muffle the exhaust.
In addition, this exhaust structure forms a water jacket between the propulsion casing and the cylindrical body to prevent overheating due to exhaust heat of the propulsion casing, and to prevent corrosion due to salt on the propulsion casing and peeling of paint. .

Further, in this exhaust structure, a water channel forming body is arranged around the upper part of the exhaust pipe, and the water channel forming body forms a drainage channel whose lower end is narrowed around the exhaust pipe.

[Problems to be Solved by the Invention] However, the above-mentioned conventional techniques have the following problems.

Since both the cylinder and the exhaust pipe are arranged in the propulsion casing, the structure becomes complicated.

Since the water jacket has an exhaust expansion chamber between it and the exhaust pipe, the cooling effect on the exhaust pipe is low, and it is difficult to sufficiently prevent overheating due to exhaust heat of the propulsion casing.

The drainage channel formed around the exhaust pipe is open at the lower end, and does not form a water jacket that serves as a reliable water reservoir around the exhaust pipe, and the exhaust pipe should be cooled stably. Have difficulty.

Since the lower end of the exhaust pipe hangs without being supported, it vibrates due to the exhaust gas from the engine during operation, which causes vibration of the propulsion casing.

An object of the present invention is to simplify the structure of an exhaust structure of a ship propulsion device, to reliably cool the exhaust pipe, and to sufficiently isolate the exhaust pipe.

[Means for Solving the Problem] The present invention provides a marine propulsion device in which an exhaust pipe communicating with an exhaust passage of an engine is arranged in a propulsion casing, and an exhaust expansion chamber communicating with the exhaust pipe is formed in the propulsion casing. In the exhaust structure of 1, the exhaust pipe is formed around the exhaust pipe in the vicinity of the exhaust pipe so as to form a part of the propulsion casing, and the exhaust pipe is provided between the inner circumference of the surrounding wall and the outer circumference of the exhaust pipe. A water jacket extending along the water jacket is formed, and a seal member that seals between the inner circumference of the surrounding wall and the outer circumference of the exhaust pipe is attached to the opening at the lower end of the water jacket. An exhaust expansion chamber is formed outside the wall, and the exhaust expansion chamber is communicated with the exhaust pipe.

[Operation] According to the present invention, there are the following operations.

"The surrounding wall that is a part of the propulsion casing is formed around the exhaust pipe,""The exhaust pipe and the surrounding wall are configured as separate members, and between the inner circumference of the surrounding wall and the outer circumference of the exhaust pipe. Since the water jacket has been formed ”, the water jacket can be easily formed in comparison with the case where the water jacket whose lower portion is closed is integrally formed with the exhaust pipe, and the water jacket can be easily formed in manufacturing.

Since the "water jacket extends along the exhaust pipe on the outer circumference of the exhaust pipe," the water jacket is formed in a state of being in direct contact with the periphery of the exhaust pipe to enhance the cooling effect on the exhaust pipe.
By sufficiently lowering the temperature of the exhaust pipe and the temperature of the exhaust gas flowing out from the exhaust pipe, it is possible to sufficiently prevent overheating due to the exhaust heat of the propulsion casing.

"Since a seal member is attached to the opening at the lower end of the water jacket, a water jacket that serves as a reliable water reservoir can be formed around the exhaust pipe, and the exhaust pipe can be cooled stably.

Since "a seal member was installed between the exhaust pipe and the surrounding wall formed by a part of the propulsion casing," even if the exhaust pipe vibrates due to exhaust gas from the engine during operation, the exhaust pipe does not pass through the seal member. Since it is supported by the surrounding wall that is rigidly formed, the exhaust pipe can be sufficiently vibration-isolated.

[Embodiment] FIG. 1 is a partially cutaway side view showing an outboard motor according to an embodiment of the present invention, and FIG. 2 is an end view taken along line II-II of FIG.
3 is a sectional view taken along the line III-III in FIG. 1, FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1, and FIG. 5 is a side view showing the entire outboard motor. The drawing is a sectional view taken along the line VI-VI of FIG.

As shown in FIGS. 1 and 5, the outboard motor 10 has a clamp bracket 11 attached to a hull 12 and is provided with a clamp bracket.
The swivel bracket 14 is tiltably supported by the tilt shaft 13 and the steering shaft 15 is supported by the swivel bracket 14.
Is rotatably supported.

The outboard motor 10 has a steering handlebar 16 fixed to an upper end portion of a steering shaft 15, supports an upper portion of a propulsion casing 18 via an upper mount portion 17 connected to the steering handlebar 16, and also supports a lower end portion of the steering shaft 15. The lower part of the propulsion casing 18 is supported by the lower mount part 19 on the above-mentioned part. The propulsion casing 18 has an engine 20 mounted on the upper part,
It has a propeller 21 driven by an engine 20. 22 is a drive shaft.

As shown in FIGS. 1 and 2, the upper mount portion 17 is attached to the lower mount housing 23 and the lower mount housing 23 that closes the opening 18A of the propulsion casing 18 through which the drive shaft 22 penetrates. And a mount housing 24. 23A is an insertion hole for the drive shaft 22 provided in the lower mount housing 23. . Both mount housings 23, 24 are internally held in a state of sandwiching a pair of left and right mount rubbers 25, and are fixed to the propulsion casing 18 by bolts 26. A connecting pipe 27 connected to the steering handle 16 is joined to the center of each mount rubber 25. An annular seal member 28 is mounted between the propulsion casing 18 and the lower mount housing 23. The seal member 28 is configured to reliably seal the opening 18A.

As shown in FIGS. 1 and 3, the lower mount portion 19 includes an upper mount housing 30A and a lower mount housing 30B which are vertically divided. Both mount housings 30A,
30B is fastened vertically by bolts 30C, and holds left and right mount rubbers 31 located on both sides of the propulsion casing 18 and a mount rubber 32 located on the front side of the propulsion casing 18. 33 is the mount rubber mounting part of the propulsion casing 18, and the width of the mounting part 33 is 30
It is set smaller than the inner width of the left and right mount rubbers 31 placed in A and 30B. Reference numeral 34 is a rear positioning portion for the mount rubber 31 formed on the propulsion casing 18, and 35 is a front positioning member for the mount rubber 31 fixed to the propulsion casing 18.

In the outboard motor 10, an exhaust pipe 37 that directly communicates with the exhaust passage 36 of the engine 20 is arranged inside the propulsion casing 18.
Further, the outboard motor 10 includes a water pump 38 driven by the drive shaft 22 inside the propulsion casing 18, and the water pump 38
The outside water to be sucked and pumped by is supplied to the water jacket of the engine 20 to cool the engine 20 with water. A drain passage 40 communicating with a drain passage 39 of the engine 20 is formed at the upper end of the exhaust pipe 37.

The propulsion casing 18 includes a partition wall 41 in front of the exhaust pipe 37.

The outboard motor 10 is an enclosing wall formed by a part of the propulsion casing 18, and is provided on the exhaust pipe 37 between the inner periphery of the partition wall 41 and the rear outer peripheral wall 42A on the rear side and the outer periphery of the exhaust pipe 37. A water jacket 43 is formed that extends along and surrounds the entire circumference. Reference numeral 44 is a seal member that seals between the propulsion casing 18 and the exhaust pipe 37 located at the bottom (lower end opening) of the water jacket 43. Reference numeral 45 is a drain passage provided in the exhaust pipe 37 for draining overflow water of the water jacket 43. The outlet portion of the drainage passage 45 is arranged below the outlet portion of the exhaust passage 37A of the exhaust pipe 37 by a predetermined length, and can prevent water from entering the inside of the engine 20 due to exhaust pulsation.

The outboard motor 10 includes, on the outside of the partition wall 41 of the propulsion casing 18, the partition wall 41 and another partition wall arranged in front of the partition wall 41.
41B forms an exhaust expansion chamber 46 that is located in front of the location where the exhaust pipe 37 is disposed and communicates with the exhaust pipe 37. A part of the partition wall 41B surrounds the drive shaft 22 with the outer peripheral wall 42B to form a drive shaft 22 insertion chamber 46B. The drive shaft 22 is inserted into the insertion chamber 46B of the propulsion casing 18 through the opening 23A provided in the lower mount housing 23. A seal member 29 is arranged at the upper end of the partition wall 41B, and the exhaust gas of the expansion chamber 46 passes through the gap between the lower mount housing 23 and the upper end of the partition wall 41B to the insertion chamber 46B, and further through the opening 23A to the upper mount portion. Leakage to 17 is prevented. The exhaust expansion chamber 46 communicates with the outside through an exhaust passage 47 formed in a lower portion of the propulsion casing 18 and an exhaust passage formed in a boss portion of the propeller 21. Incidentally, the propulsion casing 18 has an exhaust passage 48 opened at an upper portion of the partition wall 41. This allows the exhaust expansion chamber 46
Communicates with the upper space of the water jacket 43 through the exhaust communication passage 48, and further communicates with the outside through an idle port 49 provided in the outer peripheral wall 42A on the rear side of the propulsion casing 18. That is, in the low-speed low-load operating range of the engine 20, the exhaust pressure reaching the exhaust expansion chamber 46 is lower than the head pressure of the external water acting on the exhaust passage 46, so the exhaust gas is exhausted from the exhaust expansion chamber 46 and the exhaust communication passage. 48, through the space above the water jacket 43 and discharged from the idle port 49. On the other hand, the engine
In the high-speed, high-load operation region of 20, the exhaust pressure reaching the exhaust expansion chamber 46 becomes higher than the head pressure of the external water acting on the exhaust passage 46, and the exhaust gas passes through the exhaust expansion chamber 46 and the exhaust passage 47 to the propeller 21. It is discharged from the boss.

The outboard motor 10 opens the idle port 49 at the rear portion of the left side surface or the rear portion of the right side surface (in the present embodiment, rear portion of the right side surface) of the propulsion casing 18. As a result, the idle port 49 is arranged on the port side of the hull 12 opposite to the driver's seat,
The presence of the propulsion casing 18 can block the exhaust sound emitted from the idle port 49 from reaching the driver's seat.

Further, the outboard motor 10 is provided with drainage holes 50 communicating with the bottom portion of the water jacket 43 at portions on both side surfaces of the propulsion casing 18 which are close to the rear positioning portion 34 for the mount rubber 31. The water drain hole 50 forms a flow of water from the upper side to the lower side inside the water jacket 43 by draining water when the engine 20 is operating, and suppresses an increase in the water temperature inside the water jacket 43, and After stopping, all accumulated water can be discharged. The water drain hole 50 is a water jacket
Since it opens to the front bottom of 43, the propulsion casing 18
Can completely drain water even when tilted up. Further, the water drained from the water drain hole 50 cools the mount rubbers 31 on both sides of the lower mount portion 19.

Therefore, according to this embodiment, there are the following effects.

"A surrounding wall (partition wall 41 and outer peripheral wall 42A) that is a part of the propulsion casing 18 is formed around the exhaust pipe 37."
7 and its surrounding wall (partition wall 41 and outer peripheral wall 42A) are formed by separate members, and a water jacket 43 is formed between the inner circumference of the surrounding wall (partition wall 41 and outer peripheral wall 42A) and the outer circumference of the exhaust pipe 37. Therefore, as compared with the case where the water jacket 43 having the closed bottom is integrally formed with the exhaust pipe 37, the die cutting is easier and the water jacket 43 can be formed easily in manufacturing.

Since the water jacket 43 extends along the exhaust pipe 37 on the outer circumference of the exhaust pipe 37, the water jacket 43 is formed so as to be in direct contact with the periphery of the exhaust pipe 37, and the cooling effect on the exhaust pipe 37 is improved. By raising the temperature of the exhaust pipe 37 and the temperature of the exhaust gas flowing out from the exhaust pipe 37, the overheat due to the exhaust heat of the propulsion casing 18 can be sufficiently prevented.

"A seal member 44 is provided at the opening at the lower end of the water jacket 43.
Since the water jacket 43 is attached, it is possible to form the water jacket 43 around the exhaust pipe 37, which serves as a reliable pool of water, and to stably cool the exhaust pipe 37.

“A seal member 44 is provided between the exhaust pipe 37 and a surrounding wall (partition wall 41 and outer peripheral wall 42A) formed by a part of the propulsion casing 18.
Since the exhaust pipe 37 vibrates due to exhaust gas from the engine 20 during operation, the exhaust pipe 37 is firmly surrounded by the surrounding wall (the partition wall 41 and the outer peripheral wall 42) through the seal member 44.
Since it is supported by A), the exhaust pipe 37 can be sufficiently vibration-proofed.

[Advantages of the Invention] As described above, according to the present invention, in the exhaust structure of a ship propulsion device, the structure can be simplified, the exhaust pipe can be reliably cooled, and the exhaust pipe can be sufficiently vibration-isolated. .

[Brief description of drawings]

FIG. 1 is a side view showing an outboard motor according to an embodiment of the present invention partially broken away, and FIG. 2 is an end view taken along line II-II of FIG.
3 is a sectional view taken along the line III-III in FIG. 1, FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1, and FIG. 5 is a side view showing the entire outboard motor. The drawing is a sectional view taken along the line VI-VI of FIG. 10 ... Outboard motor, 18 ... Propulsion casing, 20 ... Engine, 36 ... Exhaust passage, 37 ... Exhaust pipe, 41, 42A ... Wall (enclosing wall), 43 ... Water jacket, 44 ... Sealing member,
46 ... Exhaust expansion chamber.

Claims (1)

[Claims] 1. An exhaust structure of a marine propulsion apparatus, wherein an exhaust pipe communicating with an exhaust passage of an engine is arranged in a propulsion casing, and an exhaust expansion chamber communicating with the exhaust pipe is formed in the propulsion casing. A water jacket which is formed in the vicinity of the surrounding wall and is formed in the vicinity of the surrounding wall by a part of the propulsion casing, and extends along the exhaust pipe between the inner circumference of the surrounding wall and the outer circumference of the exhaust pipe. A seal member for sealing between the inner circumference of the surrounding wall and the outer circumference of the exhaust pipe is attached to the opening at the lower end of the water jacket, and the exhaust expansion chamber is provided outside the surrounding wall. And an exhaust expansion chamber that communicates with the exhaust pipe.