JPS5872608A - Lubricating device of 2-cycle internal-combustion engine - Google Patents

Abstract

PURPOSE:To simplify construction of a device, by feeding lubricating oil, delivered from a pump, to crank chambers through a selector valve at a high load and leading the lubricating oil, in a tank, directly to the crank chambers at a low load. CONSTITUTION:A main tank 100, auxiliary tank 102, storing lubricating oil, main oil passages 104, 106, communicating crank chambers 48, 50, sub-oil passage 154, diaphragm pump 116, and a selector valve 134, equipping two flow outlets 142, 144 and supplying lubricating oil, are provided. At a low load, lubricating oil flows in through the main oil passages 104, 106 from the auxiliary tank 102 and is sucked to the crank chambers 48, 50, while delivered lubricating oil by the pump 116 is recirculated flowing through the selector valve 134 and recirculation passage 156 to the auxiliary tank 102. While at a high load, the lubricating oil is forcibly fed to the crank chambers 48, 50 from the sub- oil passage 154 through the selector valve 134. In this way, the necessity for using a plunger pump can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lubricating device applied to a separately lubricated two-stroke internal combustion engine.

Lubrication systems for two-stroke internal combustion engines are broadly classified into mixed lubrication systems and separate lubrication systems. In the mixed lubrication system, the mixing ratio of lubricating oil is always constant, so there is a disadvantage that more lubricating oil than necessary is consumed during low loads. The separate lubrication system uses a plunger pump, etc. whose discharge volume changes depending on the load and rotational speed, to supply the appropriate amount of lubricant depending on the operating situation, and not only has excellent lubrication performance but also reduces lubricant consumption. It has the advantage of being able to reduce the amount of water used.

However, conventional separate lubrication systems require expensive plunger pumps or other pumps whose discharge volume changes depending on operating conditions, and the structure is complicated.

The present invention has been made in view of these disadvantages, and provides a lubrication device for a two-stroke internal combustion engine using a separate lubrication system that is simple and inexpensive, eliminating the need to use a plunger pump that is complex and expensive. The purpose is to

In order to achieve this object, this invention has two main oil passages that communicate between a tank containing lubricating oil and the crank chamber, a diaphragm pump that discharges lubricating oil by being activated by the pulsation of pressure in the crank chamber, and a switching valve having an outlet and guiding lubricating oil discharged by the pump to one of the outlets according to the load; and a sub-oil passage communicating the one outlet and the main oil passage.

A return passage communicates the other outlet with the tank, and when the load is high, the lubricating oil discharged by the pump is routed through the switching valve, and when the load is low, the lubricating oil in the tank is routed directly to the crankshaft. It is designed to lead indoors. The present invention will be described in detail below based on the illustrated embodiments.

FIG. 1 is a diagram showing an embodiment in which the present invention is applied to a two-cylinder internal combustion engine for an outboard motor, and FIGS. 2 and 3 are cross-sectional views of a switching valve, and FIG. Figure 3 shows a high load situation. FIG. 4 is a diagram showing the average internal pressure P in the crank chamber with respect to the rotational speed N or throttle valve opening degree 0.

In FIG. 1, reference numeral 10 indicates a lower bearing 16 disposed approximately vertically between the cylinder body 12 and the crankcase 14.
, an intermediate bearing 18 and a lower bearing 2°. The large ends of connecting rods 26, 28 are attached to the crank pins 22, 24 of the upper and lower cylinders via needle bearings 30, 32.

e's: Fyo) '26. Piston 3 is on the small end of 28.
4.36 is installed. Above the upper bearing 16,
A retainer 38 is attached to hold down the seven outer races of the upper bearing 16, and the inner surface of the retainer 38 and the crankshaft 1
A sealing member 4o is interposed between the sealing member 4o and the sealing member 4o. A seal member 42 that forms a labyrinth seal between the intermediate bearing 18 and the crankshaft 10 is fixed below the intermediate bearing 18 . An annular member 44 is fixed below the lower bearing 2° between the cylinder body 12 and the crankcase 14, and a seal member 46 is interposed between the annular member 44 and the crankshaft 1o. As a result, the crank chamber 48 of each upper and lower cylinder
．． The airtightness of the 5th quarter will be maintained.

52 is a rotor fixed to the upper end of the crankshaft 1o; 54
is a permanent magnet fixed to the inner surface of this rotor 52, 56 is a disk held by the retainer 38, and this disk 56 has a coil (not shown) facing the permanent magnet 54.
are fixed, and these constitute a known flywheel magneto.

58 is a carburetor, and this carburetor 58 is fixed to the crankcase 14 via a connecting member 60. Two sets of reed valves (not shown) are installed within the connecting member 60, and the carburetor 58. An intake passage 62 formed in the connecting member 60 communicates with the crank chambers 48 and 50 of the upper and lower cylinders via these reed valves. 64 is a throttle valve provided in the carburetor 58, and 65 is a valve shaft that holds this throttle valve 64.

An annular saucer 66 located below the upper bearing 16 and an annular saucer 68 located below the seal member 42 are fixed to the crankshaft 10, and a portion of each saucer 66, 68 has a beak shape. The oil lubrication lower is 0°72. These lubrication lowers 0.72 are each crank pin 22.24
It extends into oil passages 74, 76 formed in the. Note that the lower portions of the oil passages 74 and 76 open into the bearings 30 and 32 at the small end. Further, the upper edge of the lower cylinder saucer 68 slightly protrudes from the upper surface of the crank web 78, and an inner annular oil passage 80 is formed by the inner peripheral side upper edge of the saucer 68 and the upper surface of the crank web 78. A detour oil passage 82 is formed in the crank web 78. The detour oil passage 82 detours from the inner annular oil passage 80 below the receiver m6g and opens on the outer circumferential surface of the crank web 78.

100 is a main tank, and 102 is an auxiliary tank.

Both tanks 100 and 102 contain lubricating oil. l 04 and '106 are main oil passages, one end of which opens into each crank chamber 48, 50 from above the upper bearing 16 and the saucer 68, respectively, and these main oil passages 10
The other end of 4.106 joins in the middle and extends into the auxiliary tank 102. These main oil passages 104, 106 each have two generators) 108, 110 and 112, 11.
4 is installed.

116 is a diaphragm type pump, and diaphragm 1
18 defines an air chamber 120 and an oil chamber 122, and the air chamber 120 communicates with the crank chamber 50. The suction port 124 and the discharge port 126 of this pump 116 communicate with the oil chamber 122 via one-way valves 128 and 130, respectively.
The todada inlet 124 is connected to the main tank 100 by an oil passage 132.
is connected to. Therefore, while the engine is operating, the diaphragm 118 vibrates as the internal pressure in the crank chamber 50 pulsates, sucking up the lubricating oil in the main tank 100 and discharging the lubricating oil from the discharge port 126.

Reference numeral 134 designates a switching valve, which, as shown in FIG. 2.3, includes a cylinder 136 and a spool 138, and the cylinder 136 has one inlet 140 and two outlets 142 and 144 formed therein. The inflow port 140 communicates with either one of the outflow ports 142 or 144 by movement of the subwoofer 138. One end of the sprue A/138 protrudes upward from the cylinder 136, and a coil spring '148 is installed between the tip 146 and the cylinder 138.
In FIG. 8, 150 is a lever fixed to the shaft end ζ of the valve shaft 65, and the rotating end of this lever 150 is in contact with the upper surface of the tip 146 of the spool 138. As a result, when the throttle valve 64 is in the idle link position, the spool 138 returns upward due to the spring force of the coil spring 148, and the inlet 140 and outlet 144 communicate with each other, as shown in FIG. Further, as the throttle valve 64 opens, the lever 150 also opens.
By rotating counterclockwise as shown, the spool 138 is pushed downward and the inlet 140 communicates with the outlet 142. The inlet 140 is connected to the discharge port 126 of the pump 116 by an oil passage 152, and the outlet 142 is connected by an auxiliary oil passage 154 between the jets of the main oil passages 104 and 108, that is, between the jets 108 and 110 and 1.
12 and 114, respectively. Further, another outlet 144 is connected to the auxiliary tank 102 by a recirculation passage 156.
is communicated with. In FIG. 1, reference numeral 158 designates a second circulation path for circulating lubricating oil overflowing from the auxiliary tank 102 to the main tank 100.

Further, the main tank 100 is shown in a position close to the auxiliary tank 102 etc. in FIG.
02. The pump 116, the switching valve 134, and the like are housed in a cowling (not shown) that covers the engine.

Next, the operation of this embodiment will be explained. A mixture of air and fuel generated in the carburetor 58 by the rotation of the crankshaft 10 is intermittently (=inhaled into the crank chamber 48, 50, pre-pressurized, and then sent to the combustion chamber through the scavenging passage. Therefore, the internal pressure in the crank chamber 48° 50 pulsates as the crankshaft 10 rotates.The average internal pressure P obtained by averaging these pulsations is
is the rotational speed N or the opening degree θ of the throttle valve 64 in FIG.
= changes as shown. In other words, during low/medium speed rotation or low/medium load, the average internal pressure P is below atmospheric pressure (po), and furthermore, up to point a in the figure, the negative pressure increases as the rotational speed N or opening degree θ increases. I will do it. In addition, when the rotational speed N or the opening degree θ increases above point a, the negative pressure of this average internal pressure P becomes smaller, and the negative pressure becomes atmospheric pressure (P=O) at point b, which is the post-feeding ζ2 positive pressure.

Point C in the figure indicates the maximum rotational speed or maximum opening degree.

The switching valve 134 has an inlet 140 and an outlet 144 communicating with each other as shown in FIG. 2 when the throttle valve 64 is at a low or medium opening, that is, when the opening is below point a in FIG. In other words, when the opening is above point a, the inlet 140 and the outlet 142 are set to communicate with each other, as shown in FIG.

In a marine engine, the rotational speed N changes in accordance with the opening degree θ of the throttle valve 64, so when the throttle valve 64 is at a low or medium opening degree, the rotational speed N also becomes low or medium speed. Therefore, below point a in FIG. 4, as the rotational speed N increases, the negative pressure of the average internal pressure P in the crank chamber 48.50 also increases. through which it is drawn into each crank chamber 48,50, the flow rate of which increases as the negative pressure increases. At this time, pump 11
The lubricating oil discharged from the switching valve 134 and the circulation path 156
The lubricating oil overflowing from the auxiliary tank 102 is further recycled to the main tank 100. The dotted arrows in FIG. 1 indicate the flow of lubricating oil at this time.

When the opening degree θ of the throttle valve 64 increases, the rotational speed N also increases,
When the temperature reaches point a in FIG. 4 or above, the lever 150 pushes the spool 138 downward as shown in FIG. 3, thereby communicating the inlet 140 of the switching valve 134 with the outlet 144. Therefore, the lubricating oil discharged by the pump 116 is supplied to the oil path 152. Inflow port 140
．． The main oil passage 104 passes through the outlet 144 and the auxiliary oil passage 154.
106. When the rotation speed reaches point a or higher, the fourth
As shown in the figure, the negative pressure in the crank chamber 48.50 decreases, and the amount of lubricating oil flowing directly into the crank chamber 48.50 from the auxiliary tank 102 through the main oil passage 104.106 decreases.
Above this point, it becomes zero, but at this time, the lubricating oil power is sent under pressure from the auxiliary oil passage 154 to each crank chamber 48° 50, so
The amount of lubricating oil flowing into the crank chamber 48,50 increases.

At this time, the amount of lubricating oil is controlled by jets 108, 112 and 110, 114 provided in the main oil passages 104, 106.

In the upper cylinder, the lubricating oil flows from the upper bearing 16 through the receiving plate 66 and the oil passage 74 to the bearing 30 at the large end, and further flows down to the intermediate bearing 18. In addition, in the lower cylinder, the main oil passage 10
6, the lubricating oil flows into the saucer 68, the oil passage 76, and the bearing 32.
and flows down to the lower bearing 20. Note that a portion of the lubricating oil in the upper cylinder is diluted with fuel and flows down to the lower cylinder through the seal member 42, but this diluted lubricating oil flows through the inner annular oil passage 8.
0, since it passes through the detour oil path 82, only the rich lubricating oil supplied from the main oil path 106 is supplied to the large end bearing 32, where the lubrication conditions are particularly severe, and the lubricity of the bearing 32 is improved.

In this embodiment, the invention is applied to an outboard motor, so an auxiliary tank 102 is provided in the cowling of the engine separately from the main tank 100. However, if the female tongue 7100 can be placed near the engine, this The desired effect can be obtained even without providing the auxiliary tank 102. Furthermore, although it is impossible at the current technological level to manufacture the diaphragm pump 116 so that it has an appropriate discharge amount corresponding to the rotational speed over the entire rotational range, it is possible to manufacture the diaphragm pump 116 in a narrow rotational range, that is, as shown in FIG. It is easy to make the discharge amount appropriate within the range between points a and c.

As described above, this invention is configured so that lubricating oil is supplied directly from the tank into the crank chamber during low and medium loads, and from the diaphragm pump into the crank chamber during high loads, so that all operating conditions can be met. An appropriate amount of lubricant can always be supplied underneath. Furthermore, since a diaphragm type pump is used instead of a complicated and expensive plunger type pump, the structure is simple and inexpensive.

4. Brief explanation of the drawings Figure 1 shows an embodiment of the present invention, Figures 2 and 3 are cross-sectional views of the switching valve at low/medium load and high load, Figure 4 i It is a diagram showing the average internal pressure P of the crank chamber with respect to the rotational speed N or the throttle valve opening θ. .

48.50...Crank chamber, 100, 4 tanks.

102... Auxiliary tank, 104.106... Main oil path.

116...Diaphragm pump, 134...Switching valve.

140... Inlet, 442, 144... Outlet.

154... Sub-oil passage, 156... Circulation passage.

Patent applicant: Sanshin Kogyo Co., Ltd.

Claims (1)

[Claims] In a separate lubrication type two-stroke internal combustion engine, there is a main oil passage that communicates the lubricating oil tank and the crank chamber, a diaphragm pump that discharges lubricating oil by operating due to the pulsation of the crank chamber pressure, and two outlet ports. a switching valve that guides the lubricating oil discharged by the pump to one of the outflow ports depending on the load; a sub-oil passage that communicates the one of the outflow ports with the main oil passage; and the other outlet. and a recirculation path communicating with the tank, and at high loads, the lubricating oil discharged by the pump is guided through the switching valve, and at low loads, the lubricating oil in the tank is guided directly into the crank chamber. A lubricating system for two-stroke internal combustion engines.