JPH09291808A - Structure of oil pan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce foaming of oil for lubricating an automobile engine. SOLUTION: Oil passages 12 whose upper ends face oil returning holes 13 of a cylinder block 1 are provided along the inner wall surface of an oil pan 2. In each oil passage 12, the sectional area of the lower part 12a is made smaller than that of the upper part 12b so that flow velocity of oil passing it may be increased. Each oil passage is bent at the intermediate part in the constant direction, and swirls are produced in the flow of oil in the oil pan 2. Since bubbles are concentrated to the central part of the coil pan 2 by the swirls, oil is sucked from the outer side in which there is few bubbles, and recirculated to lubricating parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a type in which lubricating oil stored in an oil pan is pumped up, supplied to a lubrication point, lubricated, and then dropped into an oil pan and returned.
The present invention relates to the structure of an oil pan applied to a so-called wet sump type engine.

[0002]

2. Description of the Related Art In an engine of the above type, the oil returning to the oil pan after lubrication contains air bubbles, and when the oil directly drops into the oil pan or moves after falling. Also bubbles are generated. When the bubbles are pumped up again by the oil pump and supplied to the lubrication site, the amount of oil is reduced by the amount of the bubbles, so that a sufficient lubrication effect cannot be obtained.

Therefore, in order to suppress the generation of air bubbles, a baffle plate is erected inside the oil pan to regulate the movement of the oil, or a baffle plate is horizontally installed inside the oil pan to receive the oil. The generation of gas and liquid is suppressed, or the air bubbles are separated and then returned to the oil pan.

FIG. 5 shows an example in which a baffle plate is horizontally provided inside an oil pan. In this figure, reference numeral 1 denotes a cylinder block, which is a lower portion also called a crankcase. A mounting portion 2a on the outer periphery of an oil pan 2 having a U-shaped cross section contacts the lower end of the cylinder block 1 through a sealing material, and is integrally coupled with a bolt provided at a portion not shown. A baffle plate 3 is horizontally attached to the oil pan 2 by welding an outer peripheral portion inside the oil pan 2. 4 is an oil strainer and 5 is a pipe.

The baffle plate 3 is provided with a hole 6 for passing the pipe 5. The upper end of the pipe 5
Cylinder block 1 with flange 8 by bolt 8
Is attached to the underside of. An oil passage 9 is provided on the cylinder block 1 side and communicates with a lubrication point. Reference numeral 10 is a stay, the lower end of which is connected to a part of the pipe 5 and the upper end of which is connected to the cylinder block 1 by a bolt 11. The stay 10 also passes through the hole 6 of the baffle plate 3.

[0006]

In the case of such a structure, oil may be accumulated on the upper surface of the baffle plate although it is not related to the original function of lubrication, and if oil is accumulated there, the crank web and connecting It will be scraped up with a rod. Therefore, it is conceivable to provide an oil drop hole in the baffle plate to prevent the oil from accumulating, but if the hole is made large, the original function of the baffle plate will not work for the oil passing through the hole.

The present invention has been made in view of this point, and it is an object of the present invention to provide an oil pan structure which does not complicate the structure and which can effectively suppress the generation of bubbles. is there.

As prior art relating to the oil pan, there are those disclosed in Japanese Utility Model Laid-Open No. 4-17112, Japanese Utility Model Laid-Open No. 7-14106, Japanese Utility Model Laid-Open No. 3-43513, and the like. In all of these techniques, a part of the bottom of the oil pan is made deeper than the other part, or in addition thereto, a rib for guiding the oil flow from the bottom is provided upright. The present invention intends to provide a structure in which the generation of bubbles is effectively suppressed by means different from these techniques, and the oil strainer does not suck bubbles.

[0009]

As a means for solving the above-mentioned problems, the present invention is, in the invention described in claim 1, in which oil after being sucked from an oil pan through an oil strainer and lubricated is oiled. An oil passage for returning to the pan is formed on the inner wall surface of the oil pan at a position facing the oil return hole of the cylinder block, and the oil passing through the oil passage is configured to generate a swirl in the oil in the oil pan. Characterize.

According to the invention described in claim 2, in the invention described in claim 1, the cross-sectional area from a part of the oil passage to the lower part is made smaller than that of the upper part, and the opening at the lower end is formed. It is characterized by being bent in a certain direction.

According to the invention described in claim 3, in the invention described in claim 2, the suction port of the oil strainer opening toward the bottom of the oil pan is provided in a direction opposite to the bending direction of the oil passage. Characterized by tilting.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
And FIG. 2 showing the side portion thereof will be described. In these figures, the oil strainer and the pipe are not shown. In both figures, 12 is an oil passage, which is formed at a position in contact with the inner wall surface 2b of the oil pan 2 so that its upper end faces the oil return hole 13 of the cylinder block 1. The oil return hole 13 guides the oil after lubrication to the oil pan side, like the oil passage 9 shown in FIG.

As shown in the figure, the lower portion of the oil passage 12 is narrowed from a part thereof, and the cross-sectional area of the lower portion 12a is
It is smaller than the cross-sectional area of the upper portion 12b. The opening 12c at the lower end is bent so as to face a certain direction (leftward in FIG. 1). Since the oil passage 12 has such a shape and cross-sectional area, the oil flowing from the oil return hole 13 through the oil passage 12 into the oil pan 2 has a high flow velocity and enters the oil pan 2.
A vortex will be generated in the oil in the oil pan 2.

The opening 12c at the lower end of the oil passage 12 is oriented in the direction in which the Coriolis force acts. The orientations shown in FIGS. 1 and 2 are for the northern hemisphere, and in the northern hemisphere, eddy currents are well generated as described later. As a matter of course, in the case of an automobile used in the Southern Hemisphere, the direction of the opening 12c is reversed.

3 and 4 show the oil strainer 4 provided in FIG. As shown in FIG. 3, the oil strainer 4 is arranged at a position along the inner wall surface 2b of the oil pan 2. As shown in FIG. 4, the suction port 4 a of the oil strainer 4 opening toward the bottom of the oil pan 2 is connected to the opening 1 of the oil passage 12.
It is almost directed to the flow of oil from 2c. Although illustration is omitted, the structure for reinforcing the pipe 5 with the stay is the same as the conventional structure.

With such a structure, the efficiency of collecting the oil entering the oil passage 12 from the oil return hole 13 of the cylinder block 1 is increased, and the collected oil has a small cross-sectional area at the intermediate portion of the oil passage 12. As a result, the flow velocity is high, and the curved flow causes a vortex flow in a fixed direction along the inner wall surface 2b of the oil pan 2 (see arrows in FIGS. 3 and 4). Then, the oil hits the bent portion to remove bubbles. When the vortex is generated, the bubbles 14 gather in the center of the oil pan 2 due to the principle of the centrifugal separator.

The mass difference between the air bubbles and the oil is large, and since the oil having a large weight naturally has a large inertial force, it moves along the inner wall surface 2b of the oil pan 2. The bubbles 14 are relatively concentrated in the center. From this theory, although not shown, it is preferable that the central portion of the oil pan 2 has a shallow bottom and the outside (a portion along the inner wall surface 2b) has a deep bottom. By doing so, the fluid resistance becomes small in the outer peripheral portion along the inner wall, so that the vortex flow becomes good.

[0018]

The present invention has the structure of the oil pan configured as described above, and the oil passage is provided at a position along the inner wall surface of the oil pan. Air bubbles can be prevented from being sucked in through the suction port of the oil strainer. Further, since the suction port of the oil strainer is inclined in the direction opposite to the bending direction of the oil passage, the oil can be smoothly sucked. Therefore, the oil pump can be downsized, and the mechanical loss of the engine can be reduced. By providing the oil passage between the lower portion of the cylinder block and the oil pan, it is not necessary to provide a large opening in the baffle plate, so that fluctuation of oil can be suppressed. Since the oil accumulated on the upper surface of the baffle plate and the oil falling from the cylinder block or the lower case are not scraped up by the crankshaft or the connecting rod, it is possible to reduce the mechanical loss due to the increase of air bubbles and the circulation.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of one embodiment of the present invention.

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

3 is a cross-sectional view taken along line BB of FIG. 1, showing the oil strainer provided in FIG.

FIG. 4 is a cross-sectional view taken along the line CC of FIG.

FIG. 5 is a sectional view of a conventional device.

[Explanation of symbols]

 1 Cylinder Block 2 Oil Pan 2b Inner Wall of Oil Pan 4 Oil Strainer 4a Suction Port 12 Oil Passage 12a Lower Oil Passage 12b Oil Passage Upper 12c Oil Passage Opening 13 Cylinder Block Oil Return Hole 14 Bubbles

Claims (3)

[Claims] 1. An oil passage for returning oil, which has been sucked from an oil pan and lubricated through an oil strainer, to the oil pan, is formed at a portion of an inner wall surface of the oil pan facing the oil return hole of the cylinder block. An oil pan structure characterized in that a vortex is generated in the oil in the oil pan by the oil passing through the passage. 2. A cross-sectional area from a part of the oil passage to a lower portion,
The structure of the oil pan according to claim 1, wherein the oil pan is smaller than the upper part and the opening at the lower end is bent in a fixed direction. 3. The structure of the oil pan according to claim 2, wherein the suction port of the oil strainer that opens toward the bottom of the oil pan is inclined in a direction opposite to the bending direction of the oil passage.