JPH10236390A - Anode mounting structure of outboard engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anode mounting structure of an outboard engine, which can certainly keep the electric continuity of an anode with a cylinder head at all times and ensures the function of the anode for a long period of time. SOLUTION: An anode 31 is to be removably mounted on the cylinder head 18 of an outboard engine in such a way that its foremost part confronts a water jacket 32, and the mounting structure according to the present invention for this type of anode is configured so that the head flange (head part) 31b of the anode 31 is fitted by pressure in a circular hole (recess) 18a provided in the cylinder head 18. Because of this pressure fitting, the fit part has no risk of touching the seawater to result in corrosion, nor a risk of scale attachment thereto, and the electric continuity of the anode 31 to the cylinder head 18 is secured in the pressure fit part certainly at all times, so that the anode 31 can work with its design function for a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anode mounting structure detachably mounted on a cylinder head of an outboard engine.

[0002]

2. Description of the Related Art In an outboard motor equipped with a water-cooled engine as a driving source, seawater is used as a cooling medium for the engine, so that the water jacket portion of the engine is easily corroded by salt of seawater.

Therefore, as shown in FIG. 9, a rod-shaped anode 131 is attached to the cylinder head 118 so that its tip 131a faces the water jacket 132 (so as to come in contact with seawater as cooling water). To protect the other water jacket 132 from corrosion.

[0004]

By the way, in the conventional mounting structure shown in FIG. 9, the anode 131 has a front end 1 in a circular hole 118b formed in the cylinder head 118.
The cover 136 is attached to the cylinder head 118 by bolts 135 through the sealing grommet 134 with the head flange 131b abutting against the periphery of the circular hole 118b of the cylinder head 118. A structure that prevents the falling off is adopted.

However, in the above-mentioned conventional mounting structure, the contact portion between the head flange 131b of the anode 131 and the cylinder head 118 is not sufficiently sealed against seawater, so that the contact portion comes into contact with seawater. There is a problem in that the scale adheres to the contact portion due to the erosion of the anode 131 over time and the electrical conduction of the contact portion becomes incomplete, and the function of the anode 131 deteriorates over time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to ensure that the electrical conduction between the anode and the cylinder head is always maintained to ensure the function of the anode for a long period of time. To provide an anode mounting structure for an outboard motor engine.

[0007]

In order to achieve the above object, according to the present invention, there is provided an anode which is detachably attached to a cylinder head of an engine for an outboard motor so that a front end thereof faces a water jacket. Wherein the head of the anode is press-fitted into a recess of the cylinder head.

According to a second aspect of the present invention, there is provided an anode mounting structure detachably mounted on a cylinder head of an outboard engine so that a front end thereof faces a water jacket. And a part thereof is pressed against the cylinder head.

According to a third aspect of the present invention, in the second aspect of the present invention, the biasing means is constituted by a spring interposed between the head of the anode and a sealing grommet. I do.

According to a fourth aspect of the present invention, there is provided an anode mounting structure which is detachably mounted on a cylinder head of an outboard engine so that a front end thereof faces a water jacket. A sealing grommet is fitted into the cylinder head, and the anode is attached to the cylinder head outside the sealing grommet.

According to a fifth aspect of the present invention, in the fourth aspect of the invention, the anode is attached to the cylinder head via a conductive cover.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, a plurality of contact portions between the anode and the conductive cover are provided.

According to a seventh aspect of the present invention, in the fourth, fifth or sixth aspect, the anode is attached to a conductive cover via a bolt, and the conductive cover is attached to the cylinder head. And

Therefore, according to the first aspect of the present invention, since the head of the anode is press-fitted into the recess of the cylinder head, the press-fitted portion does not come into contact with seawater and is corroded. Electric conduction between the anode and the cylinder head is always ensured at the press-fit portion without the scale being attached, and the original function of the anode is ensured for a long time.

According to the second or third aspect of the present invention, the anode is urged by the urging means and a part thereof is pressed against the cylinder head. Corrosion due to seawater in the press-contact portion is prevented, so that scale does not adhere to the press-contact portion of the anode, and electrical conduction between the anode and the cylinder head is always ensured in the press-contact portion, and the anode is originally used. Can be performed over a long period of time.

According to the fourth aspect of the invention, since the anode and the cylinder head are electrically connected to each other outside the sealing grommet against seawater, the anode has its original function for a long time. Can be fulfilled.

According to the present invention, even when the cylinder head is corroded due to seawater entering from the seal portion, the anode is electrically connected to the cylinder head via the conductive cover or further bolts. To conduct electrically,
The anode can more reliably fulfill its original function.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

[First invention] An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a side view of an outboard motor having an anode mounting structure according to the present invention, FIG. 2 is a side view of an engine mounted on the outboard motor, and FIG. 3 is a bottom view of a cylinder head of the engine. 4 is an enlarged sectional view taken along line AA of FIG. 3, and FIG. 5 is a block diagram showing a flow of cooling water (seawater).

First, the overall configuration of the outboard motor 1 shown in FIG. 1 will be outlined.

An outboard motor 1 shown in FIG. 1 is attached to a stern plate of a hull (not shown) by a clamp bracket 2, and a swivel bracket 3 for elastically supporting the outboard motor body 1a is mounted on the clamp bracket 2 with a tilt shaft. 4 pivotally attachable to the upper and lower sides.

Thus, the outboard motor main body 1a is provided with the top cowl 5
And a housing composed of an upper case 6 and a lower case 7, and an engine 8 as a drive source is housed in the top cowl 5. A crankshaft 9 arranged above and below the engine 8 has a drive shaft 1 vertically installed in an upper case 6 and a lower case 7.
The drive shaft 10 is connected to a propeller shaft 12 via a forward / reverse switching mechanism 11.

The propeller shaft 12 is connected to the drive shaft 10.
The propeller 13 is attached to a rear end of the lower case 7 extending outside the lower case 7 at right angles to the front and rear directions (left and right directions in FIG. 1).

An intake port 14 for taking in seawater as cooling water is opened at the side of the lower case 7.
The seawater taken in from the water intake 14 is boosted in pressure by a cooling water pump 15 directly connected to the drive shaft 10 and sent to the engine 8 to be used for cooling various parts.

The engine 8 is a water-cooled, four-cycle, four-cylinder engine in which four cylinders are arranged vertically (up and down), and the crankshaft 9 common to each cylinder is It is arranged vertically. Note that, in the engine 8 shown in FIG.
Is a cylinder body, 18 is a cylinder head, 19 is a cylinder head cover, and a total of four pistons (not shown) are vertically slidably fitted in the cylinder body 17 in the horizontal direction. It is connected to the crankshaft 9 via a connecting rod (not shown).

As shown in FIG. 3, an intake passage 20 and an exhaust passage 21 are formed in the cylinder head 18 for each cylinder, and the intake passage 20 and the exhaust passage 21 are connected to the cylinder head 18. In the combustion chamber S formed for each cylinder, an intake port 20a and an exhaust port 21a are opened. Then, each intake port 20a is opened and closed at an appropriate timing by an intake valve 22 shown in FIG. 4, and an exhaust port 21a is respectively opened and closed by an exhaust valve (not shown) so that required gas exchange is performed in each cylinder.

Here, the drive mechanism (valve drive mechanism) of the intake valve 22 will be described with reference to FIG. 4. However, the drive mechanism of the exhaust valve is the same, so that illustration and description thereof will be omitted.

The intake valve 22 is slidably inserted into and held by a valve guide 23 press-fitted into the cylinder head 18, and includes a cylinder head 18 and a valve retainer 24.
And is constantly urged toward the closing side by the valve spring 25 contracted between them.

A space (cam chamber) covered by the cylinder head cover 19 above the cylinder head 18.
A rocker shaft 26 and a cam shaft 27 are arranged in a vertical direction (perpendicular to the plane of FIG. 4), and one end of a rocker arm 28 supported swingably on the rocker shaft 26 is formed integrally with the cam shaft 27. The other end of the rocker arm 28 is in contact with the top surface of the intake valve 22 via an adjustable pin 29.

When the engine 8 is driven and the rotation of the crankshaft 9 is transmitted to the camshaft 27 and the camshaft 27 is driven to rotate at a predetermined speed, the camshaft 27 is formed integrally with the camshaft 27. The rocker arm 28 slidingly contacting the cam 27a swings about the rocker shaft 26 according to the profile of the cam 27a, whereby the intake valve 22 is opened and closed at an appropriate timing.

As shown in FIG. 4, one ignition plug 30 for each cylinder is screwed obliquely to the cylinder head 18, and an anode 31 for corrosion prevention is formed parallel to the ignition plug 31. The rod-shaped tip 31a of each anode 31 is attached to the cylinder head 18
And faces the inside of the water jacket 32 formed.
The electrode portion 30a of the ignition plug 30 faces the combustion chamber S, and the ignition plug 30 is covered by a plug cap 33. In FIG. 4, reference numeral 38 denotes a sand vent hole at the time of casting, and a plug 39 is screwed into the sand vent hole 38.

The anodes 31 function to protect the water jacket 32 from corrosion by vigorously corroding the rod-shaped tip 31a of the cylinder head 18 that comes into contact with the seawater flowing in the water jacket 32. Which includes the cylinder head 1
Electricity is supplied through the switch 8.

Here, the anode 3 according to the gist of the present invention is described.
The mounting structure of the first cylinder head 18 will be described with reference to FIG.

The cylinder head 18 is formed with large and small diameter holes 18 a and 18 b which are open to the water jacket 32. The inside diameter of the large diameter hole 18 a is the anode 31.
The outer diameter of the small-diameter circular hole 18 b is set to be substantially equal to the outer diameter of the rod-shaped tip portion 31 a of the anode 31.

The anode 31 has a tip 31a.
Is passed through a small-diameter circular hole 18b formed in the cylinder head 18 and a large-diameter head flange 31 is formed.
b is pressed into the large-diameter circular hole 18a of the cylinder head 18 for attachment. A sealing grommet 34 made of an elastic material is fitted in the circular hole 18a of the cylinder head 18, and the circular hole 18a is closed by a cover 36 attached to the cylinder head 18 by bolts 35.

Next, the operation of the outboard motor 1 will be described.

When the engine 8 is driven, the rotation of the crankshaft 9 is controlled by the drive shaft 10 and the forward / reverse switching mechanism 1.
1 (see FIG. 1), the propeller shaft 12 is transmitted to the propeller shaft 12, and the propeller shaft 12 and the propeller 13 connected thereto are rotationally driven to generate a required propulsion force.

When the cooling water pump 15 is driven by the drive shaft 10, the seawater taken in from the water intake 14 is pressurized by the cooling water pump 15 and sent to the engine 8, as shown in FIG. As described above, after the exhaust gas flows around the exhaust passage of the cylinder body 17 to cool the exhaust gas, it branches into two systems, a part of which cools around the cylinder of the cylinder body 17, and the other cools the bottom of the cylinder head 18 shown in FIG. The cooling water is introduced into the cylinder head 18 from the opened cooling water inlet 32a, flows through the water jacket 32, and cools around the combustion chamber S. The seawater cooled around the combustion chamber S of the cylinder head 18 is supplied to the cylinder head 18 shown in FIG.
Flows from the cooling water outlet 32b opening to the bottom surface of the cylinder body 18 into the cylinder body 18 and joins the cooling water cooled around the cylinder of the cylinder body 18. Then, the merged seawater passes through the thermostat 40, flows around the exhaust passage of the cylinder body 17, cools the exhaust gas again, and is discharged to the upper case 6 (see FIG. 1). In FIG. 5, 3
1 is an anode.

Thus, in the cylinder head 18,
Corrosion is effectively prevented by the function of the anode 31 attached to each cylinder. In the present embodiment, the head flange 31b of the anode 31 is press-fitted into the circular hole 18a of the cylinder head 18. Therefore, the press-fitted portion does not corrode due to contact with seawater, so that scale does not adhere to the press-fitted portion, and electrical conduction between the anode 31 and the cylinder head 18 is always ensured at the press-fitted portion. In addition, the original corrosion preventing function of the anode 31 is ensured for a long period of time, and its durability is enhanced. [Second Invention] Next, an embodiment of the second invention will be described with reference to FIG. FIG. 6 is a partial cross-sectional view of the cylinder head showing the anode mounting structure according to the second invention. In this figure, the same elements as those shown in FIG. 4 are denoted by the same reference numerals. Is omitted.

In the present invention, a disc-shaped spring 37 is provided between the head flange 31b of the anode 31 and the sealing grommet 34 in the circular hole 18a formed in the cylinder head 18, and the spring 37 As a result, the anode 31 is urged toward the cylinder head 18 to press the head flange 31b against the cylinder head 18.

In this embodiment, as described above, since the head flange 31b of the anode 31 is pressed against the cylinder head 18 by the spring 37, the sealing performance of the pressed portion against seawater is improved. Thus, corrosion of the pressure-welded portion by seawater is prevented, and thus the anode 3
The scale does not adhere to the bottom surface of the head flange 31b, which is the press contact portion of No. 1, and electrical conduction between the anode 31 and the cylinder head 18 is always ensured at the press contact portions of both. The same effect as that of the first invention, in which the above function can be performed for a long time, is obtained. Third Embodiment Next, an embodiment of the third invention will be described with reference to FIGS. FIG. 7 is a partial sectional view of a cylinder head showing an anode mounting structure according to the third invention, and FIG.
7 is an enlarged cross-sectional view taken along the line BB of FIG. 7. In these figures, the same elements as those shown in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted below.

In the present invention, the cylinder head 18 is provided with a circular hole 1 having a large diameter and a small diameter, which is opened in the water jacket 32.
8a and 18b are formed. A ring-shaped sealing grommet 34 is fitted into the large-diameter circular hole 18a, and the anode 31 penetrates the sealing grommet 34. The tip 31a of the anode 31 is Small diameter circular hole 18b
Through the water jacket 32.

The outer periphery of the part of the anode 31 protruding outside the sealing grommet 34 is covered with a metal cover 36. The anode 31 is attached to the cover 36 by bolts 41. I have. The cover 36 is fixed to the cylinder head 1 by bolts 35.
8 attached.

The head of the bolt 41 is held down by a plate 42 made of sheet metal.
Has been tightened together. The plate 42 is for preventing the bolt 41 from falling off when the anode 31 has disappeared due to corrosion.

By the way, as shown in FIG.
Two rib-shaped projections 31c are integrally provided at opposing positions on the outer periphery of a portion protruding outside the sealing grommet 34, and protrude outside the sealing grommet 34 of the anode 31. The portion is fitted in a fitting groove 36a formed in the cover 36. Therefore, the anode 31 and the cover 36 come into contact at a plurality of locations.

As described above, in the present invention, the anode 31 is covered with the cover 3 at the portion sealed by the sealing grommet 34 (the outer portion of the sealing grommet 34).
Since the anode 31 is electrically connected to the cylinder head 18 via the bolt 6 and the bolt 41, the anode 31 can perform its original function for a long time.

Even if the cylinder head 18 is corroded due to the intrusion of seawater from the sealing portion sealed by the sealing grommet 34, the anode is connected to the cylinder head 18 via the cover 36 and the bolt 41. Because of the electrical conduction, the original function of the anode 31 is not impaired, and the anode 31 can perform its original function for a long time.

As described above, the ribs 3 are attached to the anode 31.
1c is formed to provide a plurality of contact portions between the anode 31 and the cover 36, so that electrical conduction between the anode 31 and the cover 36 is further ensured.

[0049]

As is apparent from the above description, claim 1
According to the described invention, since the head of the anode is press-fitted into the recess of the cylinder head, the press-fitted portion does not come into contact with seawater to corrode, and therefore, the scale does not adhere to the press-fitted portion, Electrical conduction between the anode and the cylinder head is always ensured at the press-fit portion, and an effect is obtained that the original function of the anode is secured for a long period of time.

According to the second or third aspect of the present invention, the anode is urged by the urging means and a part thereof is pressed against the cylinder head. Corrosion due to seawater is prevented,
Therefore, the scale does not adhere to the pressure contact portion of the anode, electrical conduction between the anode and the cylinder head is always ensured in the pressure contact portion, and the anode can perform its original function for a long time. The effect is obtained.

According to the fourth aspect of the present invention, the anode and the cylinder head are electrically connected to each other outside the sealing grommet which is sealed with respect to seawater, so that the anode has its original function for a long time. The effect that it can be achieved over the whole is obtained.

According to the fifth to seventh aspects of the present invention, even when the cylinder head is corroded due to seawater entering from the sealing portion, the anode is electrically connected to the cylinder head via the conductive cover or further bolts. To conduct electrically,
The effect is obtained that the anode can more reliably perform its original function.

[Brief description of the drawings]

FIG. 1 is a side view of an outboard motor having an anode mounting structure according to a first invention.

FIG. 2 is a side view of the outboard motor engine having the anode mounting structure according to the first invention.

FIG. 3 is a bottom view of the cylinder head of the outboard engine having the anode mounting structure according to the first invention.

FIG. 4 is an enlarged sectional view taken along line AA of FIG. 3;

FIG. 5 is a block diagram showing a flow of cooling water (seawater).

FIG. 6 is a partial sectional view of a cylinder head showing an anode mounting structure according to a second invention.

FIG. 7 is a partial sectional view of a cylinder head showing an anode mounting structure according to a third invention.

FIG. 8 is an enlarged sectional view taken along line BB of FIG. 7;

FIG. 9 is a partial sectional view of a cylinder head showing a conventional anode mounting structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outboard motor 8 Outboard engine 18 Cylinder head 18a Circular hole (recess) 31 Anode 31a Anode tip 31b Anode head flange (head) 32 Water jacket 34 Sealing grommet 36 Cover (conductive cover) 37 spring (biasing means) 41 bolt

Claims (7)

[Claims] 1. An anode mounting structure detachably mounted on a cylinder head of an outboard engine so that a front end thereof faces a water jacket, wherein the anode head is press-fitted into a recess of the cylinder head. An anode mounting structure for an outboard engine. 2. An anode mounting structure which is detachably mounted on a cylinder head of an outboard motor engine such that a front end thereof faces a water jacket. The anode mounting structure for an engine for an outboard motor, wherein the anode mounting structure is pressed against the cylinder head. 3. The anode for an outboard motor engine according to claim 2, wherein said biasing means comprises a spring interposed between a head of said anode and a grommet for sealing. Mounting structure. 4. An anode mounting structure detachably mounted on a cylinder head of an outboard engine so that a front end thereof faces a water jacket, wherein a sealing grommet is fitted into a hole formed in the cylinder head. An anode mounting structure for an outboard engine, wherein the anode is mounted on a cylinder head outside the sealing grommet. 5. The anode mounting structure for an outboard engine according to claim 4, wherein said anode is mounted on said cylinder head via a conductive cover. 6. The anode mounting structure for an outboard engine according to claim 5, wherein a plurality of contact portions between said anode and said conductive cover are provided. 7. The outboard motor engine anode according to claim 4, wherein said anode is attached to a conductive cover via bolts, and said conductive cover is attached to said cylinder head. Mounting structure.