JPS6332330Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides an exhaust system for an outboard motor, in particular, a hollow extension case that accommodates a drive shaft that is driven by the engine and drives a propeller shaft, is connected to the engine body of the engine, and the An exhaust inflow hole is formed in the side wall of the extension case to communicate the exhaust pipe of the engine with the hollow part of the extension case, and an exhaust guide plate is disposed between the exhaust inflow hole and the drive shaft. This invention relates to a device in which the exhaust gas is discharged underwater through an extension case.

The exhaust guide plate receives high-temperature exhaust gas discharged into the extension case from the exhaust inflow hole, cools it and guides it in a predetermined direction, thereby sealing the drive shaft and its rotating parts by the high-temperature exhaust gas. It plays a role in preventing deterioration of components.

By the way, in conventional outboard motors, this exhaust guide plate was integrally formed with the extension case when it was cast, so the guide length of the exhaust guide plate could not be made sufficiently long due to mold cutting. There is a drawback that the induction and cooling effect on exhaust gas cannot be fully satisfied.

Therefore, it is conceivable to manufacture an exhaust guide plate with a long guide part separately from the extension case and fix it to the inner wall of the extension case with bolts, etc., but if this is done, the mounting structure of the exhaust guide plate will be This is undesirable because it becomes complicated and requires troublesome installation work to the inner wall of the extension case.

The present invention was proposed in order to eliminate these drawbacks, and it is designed to allow the exhaust guide plate, which is manufactured separately from the extension case, to be attached to the extension case extremely easily without using special fixing members. The purpose of the present invention is to provide a simple and effective exhaust device, the features of which include a guide portion that makes the exhaust guide plate face the exhaust inflow hole;
It consists of a mounting part bent toward one side from one end of the guiding part, and the mounting part is sandwiched between the engine main body and the extension case.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. In Fig. 1, an outboard motor engine E is arranged so that the crankshaft 1 is vertical when in use, and the rotational torque of the crankshaft 1 is vertically arranged. The power is transmitted to a horizontally arranged propeller shaft 4 through a drive shaft 2 and a bevel gear transmission 3, and rotationally drives a propeller 5.

An oil pan 7 is bonded to the lower surface of the crankcase 6 that supports the crankshaft 1, and these constitute an engine body Ea. An extension case 8 accommodating the drive shaft 2 is fixed to the bottom surface of the oil pan 7 with bolts 10, which are overlapped with each other through a gasket 9. Furthermore, a bevel gear transmission 3 is mounted on the bottom surface of the extension case 8 in an oil-tight manner. A gear case 11 housed in is fastened with bolts 12. The extension case 8 is rotatably supported by a swivel case 14 via a bearing 13, and the swivel case 14 is connected via a horizontal pivot 16 to a stern bracket 15 which is clamped and attached to the hull S.

Exhaust inflow holes 17 and exhaust outflow holes 18 that open into the case 8 are formed in the rear walls of the upper and lower ends of the extension case 8, respectively.
An exhaust pipe 19 of the engine E is connected to the exhaust inflow hole 17 .

Inside the extension case 8, an exhaust guide plate 20 is disposed between the exhaust inflow hole 17 and the drive shaft 2. As clearly shown in FIG. 7, this exhaust guide plate 20 consists of a vertical guide part 20a and a mounting part 20b bent to one side from the top of the guide part 20a. It has positioning pieces 21, 21, 22 bent downward, respectively.
Further, the guiding portion 20a includes the left and right positioning pieces 21,
It is formed into a groove shape with a pair of side walls 23, 23 connected to each other, and the groove portion faces the exhaust gas inflow hole 17, as clearly shown in FIG.

The mounting portion 20b of the exhaust guide plate 20 is held between the extension case 8 and the oil pan 7 when the extension case 8 is polymerized and bonded to the oil pan 7. In order to position the attachment part 20b, the upper end surface of the extension case 8 has a pair of ribs 24, 24 that engage with the outer surfaces of the left and right positioning pieces 21, 21 of the attachment part 20b, and a pair of ribs 24, 24 on the rear end. A rib 25 that engages with the inner surface of the positioning piece 21 is provided in a protruding manner.

Further, on the upper end surface of the extension case 8, there is a partition wall 26 which is curved in a U-shape so as to surround the drive shaft 2 and connect between the pair of ribs 24, 24.
are provided protrudingly, and these ribs 24, 25 and partition wall 26
A water jacket 27 for cooling the oil pan 7 is recessed on the outside of the rib 25, and cooling grooves 40, 41 communicating with the water jacket 27 are provided before and after the rib 25.
is recessed. In addition, a shallow notch 28 and a deep notch 29 are provided at one end and the other end of the curved partition wall 26, which face each other, to communicate the inside and outside of each. The ribs 24, 25, the partition wall 26, the water jacket 27, and the notches 28, 29 are formed when the extension case 8 is cast, and the partition wall 26 becomes the inner wall of the water jacket 27.

The extension case 8 is inserted into the shallow notch 28.
An elastic grommet 31 attached to the upper end of the water pipe 30 running vertically inside is fitted into the deep notch 29.
An elastic stopper 33 is fitted leaving a drain port 32 at the bottom thereof, and these grommet 31 and stopper 33 are pressed by the lower surface of the oil pan 7 and are connected to each notch 28, 29.
be prevented from leaving.

The lower end of the water pipe 30 is connected to a discharge port of a water pump 34 installed in the gear case 11 and driven by the drive shaft 2, and the water pump 34 sucks external water from a water intake hole 35 bored in the gear case 11. The water is then pumped to the water pipe 30.

An inlet of a water test hole 36 passing through the wall of the extension case 8 is opened at the bottom of the water jacket 27, and an outlet thereof is opened at the outer surface of the extension case 8 above the water line.

In the figure, numeral 37 is a water seal for the upper rotating portion of the drive shaft 2, numeral 38 is a steering handle connected to the oil pan 7, and numeral 39 is an engine cover that covers the engine E.

Next, the operation of this embodiment will be explained.

While engine E is running, its exhaust gas flows into exhaust pipe 19.
When the exhaust gas is discharged into the extension case 8 through the exhaust inflow hole 17, the exhaust gas hits the thin guide portion 20a of the exhaust guide plate 20, and is guided downward while being cooled by the groove. Therefore, the drive shaft 2 and the water seal 37 are prevented from being directly exposed to the high temperature exhaust gas flowing in from the exhaust gas inlet 17. The exhaust gas diverted downward by the exhaust guide plate 20 is discharged into the water from the exhaust outlet 18.

On the other hand, the water sucked in from the water suction hole 35 by the operation of the water pump 34 and sent under pressure to the water pipe 30 is
As shown by the arrow in the figure, water is introduced into the water jacket 27 from the center of the grommet 31, and most of the water flows into the water jacket 27 along the curved partition wall 26.
7 and drain port 32 below plug body 33.
Water is drained from the water into the extension case 8.
During this time, the lubricating oil stored inside the oil pan 7 is cooled.

The water discharged into the extension case 8 scatters on the exhaust guide plate 20, the drive shaft 2, the inner surface of the extension case 8, etc., cools these and falls, and is discharged to the outside from the exhaust outlet hole 18 together with the exhaust gas. be done.

Further, a part of the water introduced into the water jacket 27 flows into the cooling grooves 40 and 41 and also cools the mounting portion 20b of the exhaust guide plate 20. The other part flows into the water inspection hole 36 and is discharged to the outside from the outlet of the water inspection hole 36, which opens above the water line. You can check the status.

As described above, according to the present invention, the exhaust guide plate is composed of a guide part facing the exhaust inflow hole and a mounting part bent to one side from one end of the guide part, and this mounting part is connected to the engine body. Since it is sandwiched between the extension cases, the exhaust guide plate can be attached to the extension case by simply inserting its mounting part between the engine body and the extension case when they are connected. Since no special fixing members such as bolts are required, the installation work is extremely easy. In addition, the single exhaust guide plate can have a sufficiently long guide section regardless of the molding of the extension case.
This makes it possible to improve the guidance and cooling effect on exhaust gas.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a vertical sectional side view of the entire outboard motor, Fig. 2 is an enlarged view of its main parts, Fig. 3 is a sectional view taken along the line - - in Fig. 2, Fourth
5 and 5 are cross-sectional views taken along lines - and - of FIG. 3, and FIG. 6 is an exploded perspective view of the area around the water jacket.
FIG. 7 is a perspective view of the exhaust guide plate. E...Engine, Ea...Engine body, 2...
...Drive shaft, 4...Propeller shaft, 8...Extension case, 17...Exhaust inflow hole, 18...Exhaust outlet hole, 20...Exhaust guide plate, 20a...Guiding part, 20b...Mounting part, 21, 22... positioning piece, 24, 25... rib.

Claims (1)

[Claims for Utility Model Registration] (1) An extension case that accommodates a drive shaft driven by an engine to drive a propeller shaft is connected to an engine body, and an exhaust pipe of the engine is attached to a side wall of the extension case. An exhaust system for an outboard motor, comprising: an exhaust inlet hole communicating with the extension case; and an exhaust guide plate disposed between the exhaust inlet hole and the drive shaft. The engine is characterized by comprising a guide part facing the exhaust inflow hole and a mounting part bent to one side from one end of the guide part, and the mounting part is sandwiched between the engine body and the extension case. , outboard motor exhaust system. (2) In the utility model registration claim described in claim (1), the attachment portion engages with a rib protruding from the joint surface of the extension case with the engine body. An outboard motor exhaust system that has a positioning piece that defines the mounting position of the outboard motor.