JPH08158847A - Crankcase structure for engine - Google Patents

Abstract

PURPOSE: To obtain satisfactory output characteristics and lubricancy in a crankcase structure for an engine, at high speed operation where stirring loss is increased by a crankshaft, etc., by decreasing lubricating oil and blowby gas scattered due to partition wall of a crankcase and a unidirectional valve, and reducing output loss and suppressing temperature rise of the lubricating oil which may be caused by stirring of the crankshaft. CONSTITUTION: A crankcase is divided into a rotation part 10a where a crankshaft and a connecting rod 7 are rotated and an oil reservoir 10b by means of a partition wall 3. A unidirectional valve 5 is provided on the partition wall 3 for allowing the flow from the rotation part to the oil reservoir only.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine crankcase structure, and more particularly, to a crankshaft and a connecting rod, etc. in the crankcase during high-speed operation of the engine, which is capable of reducing agitation of lubricating oil and blow-by gas. Regarding improvement of room structure.

[0002]

2. Description of the Related Art In a crank chamber of an engine, the volume of the lower side of the piston changes due to the vertical movement of the piston, and the piston receives back pressure to reduce the output. Conventionally, in order to relieve the back pressure, it is known that the air under the piston is exchanged between the cylinders having different phases through the crank chamber space. In addition, it is known that a counterweight can be provided on the crankshaft to stabilize the balance of the crankshaft and the relative balance of the crankshaft with the piston and the connecting rod.

[0003]

However, as described above, in the structure for reducing the back pressure, the air in the crank chamber is swirled by the replacement of air between the cylinders and the rotation of the counterweight or the like during the high speed operation of the engine. There is a problem that the lubricating oil scatters in the crank chamber along with the flow, and the output loss of the engine and the temperature of the lubricating oil increase due to being stirred by the counter weight or the like. The present invention has been made to solve the above-mentioned conventional problems, and reduces the scattering of lubricating oil in the crank chamber during high-speed operation and reduces the gas density to increase the engine output loss and the lubricating oil temperature. It is an object of the present invention to provide an engine crankcase structure that prevents the above.

[0004]

According to the present invention, in a crank chamber structure of an engine for forcibly lubricating a crank pin, a crank journal and the like, there are provided a rotating portion and an oil sump portion in which a crank shaft, a connecting rod and the like rotate in the crank chamber. The chamber is provided with a separating wall, and the separating wall is provided with a one-way valve capable of flowing only from the rotating portion to the oil sump portion.

[0005]

According to the crank chamber structure of the present invention, a wall for separating the crank chamber into two chambers, that is, a rotating portion for rotating the crankshaft and the connecting rod and an oil sump portion, is provided.
Since a one-way valve that can flow only from the rotating portion to the oil sump portion is provided on the separation wall, the pressure fluctuation of the crank chamber rotating portion due to the vertical movement of the piston and the swirling flow of gas due to the rotation of the counterweight and the like become large. In addition, the one-way valve prevents the lubricating oil discharged from the rotating part of the crank chamber from returning to the rotating part of the crank chamber, and the density of blow-by gas is reduced, and the lubricating oil is scraped by the counter weight. The output loss of the engine and the rise of the lubricating oil temperature due to the above are improved.

Incidentally, in the case of the conventional structure, the crank chamber is provided with a baffle plate between the rotating portion and the oil sump portion. Due to the swirling flow in the crank chamber, the lubricating oil in the oil sump portion is scattered again on the rotating portion and is stirred by the counter weight or the like, which causes an output loss and an increase in the lubricating oil temperature.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to 7 are views for explaining a crank chamber structure of a four-cycle engine according to an embodiment of the present invention, and FIGS. 1 and 2 and 3 are cross-sectional views showing a wet sump type crank chamber structure. 5 and 6 and 7 are dry
FIG. 4 is a sectional view showing a sump type crank chamber structure, and FIG. 4 is a sectional view showing a one-way valve installation portion. 2 and 3 are AA of FIG.
Line sectional view, BB line sectional view, FIGS. 6 and 7 are CC of FIG.
It is a line sectional view and a DD sectional view.

In the figure, reference numeral 1 is a water-cooled 4-cycle in-line 4-cylinder engine in which the present embodiment is adopted. The cylinder block 2 has a crank chamber separating wall 3 and an oil pan 4 mounted on the lower surface thereof, and an upper surface thereof. Cylinder head 1
It has a wet sump type crankcase structure in which No. 4 is fastened. 5 to 7 show the cylinder block 2
Is a dry sump type crank chamber structure in which a crank case 13 in which a crank chamber separating wall is integrated is attached to the lower surface of the.

A total of four cylinders (cylinder bores) are formed in series in the crankshaft direction in the cylinder block 2, and a piston 8 inserted in each cylinder is connected to a crankshaft 6 by a connecting rod 7. . Crankshaft 6
6a is a crank journal, 6b is a crank pin,
6c is a counter weight.

The crankshaft 6 has four crankpins 6b and five crank journals 6a, and a connecting rod 7 is connected to each crankpin 6b. The crank journal 6a includes a journal receiving portion on the cylinder block 2 side and a crankshaft bearing cap 9
It is supported by and. The seal rubber 2b is inserted in the gap between the crankshaft bearing cap 9 and the cylinder block 2 so as not to come off.

A crank chamber separating wall 3 is laminated and fastened together with an oil pan 4 below the crank shaft 6 and the cylinder block 2. Further, the crank chamber separating wall 3 has a crankshaft bearing cap 9 and a seal rubber 2
crank chamber rotating part 1 together with b
The dividing wall 3a that divides 0a into each cylinder is integrally configured, and the one-way valve 5 that can flow only from the crank chamber rotating portion 10a to the oil sump portion 10b is fastened.

In the cylinder block 2, a lubricating oil sump portion 10b in which a cam shaft in the cylinder head 14 and valve operating system parts are lubricated and a crank chamber oil sump portion 10b are provided in an oil return passage 1
It is connected via 7. Also, the cylinder block 2
An oil feed pump 16 is attached to the front part of the above, and is connected to the lubricating oil 18 accumulated in the crank chamber oil sump portion 10b in the oil pan via an oil strainer 12. Further, the lubricating oil outlet of the oil feed pump 16 and the oil main gallery 2a are connected via an oil passage (not shown).

FIGS. 5 to 7 show a dry sump type crank chamber structure, in which a crank case 1 in which a crank chamber separating wall and an oil pan are integrally formed on the lower surface of a cylinder block 2.
3 has been concluded. The dry sump type crank chamber oil sump portion 10b also has the function of an oil recovery rail, and is connected to the suction port of an oil return pump 15 attached to the side wall of the crankcase 13, and the discharge port of the return pump 15 is oil. It is connected to a tank (not shown) by a return hose (not shown). The suction port of the oil feed pump 16 is connected to an oil tank (not shown) with a feed hose (not shown).

Next, the function and effect of this embodiment will be described. When the engine 1 equipped with the device of the present embodiment is operated at high speed, the lubricating oil 18 in the crank chamber oil sump portion 10b is transferred to each lubricating portion of the engine through the oil main gallery 2a as the oil feed pump 16 rotates. Supplied. After that, the lubricating oil 18 that has lubricated the camshaft and valve operating system components in the cylinder head 14 returns to the crank chamber 10 through the oil return passage 17. Lubricating oil 18 that lubricates the crank pin 6b, the crank journal 6a, the piston 8 and the like is scattered in the crank chamber 10 and then collects in the lower dent.

In this case, in the conventional crank chamber 10 (shown in FIGS. 8 to 10), although the baffle plate 11 is installed, the air is exchanged between the cylinders by the vertical movement of the piston 8 and the counter weight 6c is used. As the speed of the swirling flow in the crank chamber is increased, the lubricating oil 18 in the crank chamber oil sump portion 10b is returned to the crank chamber rotating portion 1 again.
The lubricating oil 18 scattered to 0a was swirled by the counterweight 6c and the like, and the output loss of the engine and the temperature of the lubricating oil 18 increased.

However, the crank chamber is replaced by the crankshaft 6
Also, the rotating portion 10a in which the connecting rod 7 and the like rotate, the crank chamber separating wall 3 that separates into two chambers of the oil sump portion 10b, and the one-way valve 5 that can flow only from the rotating portion 10a to the oil sump portion 10b in the separating wall. With the provision, the amount of lubricating oil scattered in the crank chamber rotating portion 10a is reduced, and as a result, the amount of lubricating oil swirled by the counterweight 6c and the like is also reduced, and the density of the probe-by gas is reduced, resulting in engine output loss. , The increase in lubricating oil temperature is reduced.

[0017]

As described above, according to the crank chamber structure for an engine of the present invention, a wall for separating the crank chamber into two chambers of a crankshaft, a connecting rod and the like and an oil sump are provided. Since a one-way valve that can flow only from the rotating portion to the oil sump portion is provided on the separation wall, pressure fluctuations in the crank chamber rotating portion due to vertical movement of the piston during high-speed operation, etc. Even if the swirling flow becomes large, the lubricating oil discharged from the rotating part of the crank chamber to the oil sump will not return to the rotating part of the crank chamber again, and the density of blow-by gas will also decrease, and the counterweight etc. It has the effect of suppressing the output loss of the engine and the rise in the lubricating oil temperature due to being scratched. Further, in the crank chamber oil sump portion, the influence of the air flow is reduced, so that the air mixing ratio of the lubricating oil is reduced, and the lubricity is improved accordingly.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a crankcase structure of a 4-cycle engine.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a sectional view taken along line AA of FIG. 1;

FIG. 5 is a vertical cross-sectional view showing an example of a crankcase structure of a 4-cycle engine.

6 is a cross-sectional view taken along the line CC of FIG.

FIG. 7 is a sectional view taken along line DD of FIG. 5;

FIG. 8 is a vertical sectional view showing a conventional method.

FIG. 9 is a sectional view taken along line EE of FIG. 8;

10 is a sectional view taken along line FF in FIG.

[Explanation of symbols]

 1 ... 4-cycle engine 2 ... Shirin block 2a ... Oil main gallery 2b ... Seal / rubber 3 ... Crank chamber separating wall 3a ... Dividing wall 4 ... Oil pan 5 ... One-way valve 6 ... Crank shaft 6a ... Crank journal 6b ... Crank pin 6c ... Counter weight 7 ... Con rod 8 ... Piston 9 ...・ Crankshaft bearing cap 10 ・ ・ ・ Crank chamber 10a ・ ・ Crank chamber rotating part 10b ・ ・ Crank chamber oil reservoir 11 ・ ・ ・ Baffle plate 12 ・ ・ ・ Oil strainer 13 ・ ・ ・ Crank case 14 ・ ・ ・Cylinder head 15 ... Oil return pump 16 ... Oil feed pump 17 ... Oil return passage 18 ... Lubricating oil

Claims (2)

[Claims] 1. In a crank chamber structure of an engine forcibly lubricating a crank pin, a crank journal and the like, a wall that separates the crank chamber into two chambers, that is, a rotating part for rotating a crank shaft, a connecting rod and the like, and an oil sump part is provided. A crankcase structure for an engine, characterized in that a one-way valve, which is provided and is capable of flowing only from the rotating part to the oil sump part, is provided on the separating wall. 2. The crank chamber structure according to claim 1, wherein a rotating portion of the crank chamber for rotating a crank shaft, a connecting rod and the like is divided by a crank journal wall portion.