JPH037565Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to an improvement of an oil pan for a multi-cylinder (two or more cylinders) engine.

[Conventional technology]

Conventional oil pans generally consist of a box-shaped body 5 with an open top end, as shown in FIG. 6, and are attached to the bottom end of the open crankcase skirt 2a with bolts 7. Therefore, during engine operation, the skirt 2a is intermittently deformed in the longitudinal direction due to the load force of the piston.
This deformation causes surface vibrations of the crankcase 2, which in turn causes vibrations of the oil pan, and these vibrations contribute to engine noise.

Therefore, in conventional oil pans, the crankcase has been reinforced as a measure to prevent the above-mentioned vibrations, but this has the disadvantage that the weight of the crankcase increases.

In addition, in order to prevent the vibration of the oil pan itself and the accompanying noise, the oil pan is made of reinforced plastic material or a damper is installed in the oil pan attachment part, but in these cases, The disadvantage is that production costs increase.

Furthermore, in the invention described in Japanese Utility Model Application Publication No. 56-136150, the lower main bearing holder of the crankshaft was integrated with the oil pan, and the rigidity of this main bearing holder was strengthened, especially for shaft devices of marine internal combustion engines. Some ideas have been proposed. The original purpose of this invention was to strengthen the rigidity of the main bearing holder, and also to divide the inside of the oil pan in a marine internal combustion engine into small sections, which would allow for better lubrication during the rolling, pitching, and other movements of the ship's hull. The purpose is to prevent large fluctuations in the oil level and to prevent oil build-up. To achieve this objective, in the present invention, the bottom surface of the oil pan is formed into a normal flat shape, and a reinforcing support wall is provided over almost the entire surface between the bottom surface or side wall of the oil pan and the lower bearing. The inside of the oil pan is partitioned and oil passages are established where necessary.

[The problem that the idea attempts to solve]

In the device described in the above-mentioned Japanese Utility Model Application Publication No. 56-136150,
It is true that the bearing rigidity has been sufficiently strengthened, but on the other hand, in this configuration, the entire support wall also forms part of the lower bearing holder, so the entire lower bearing holder becomes extremely large. This results in a significant increase in weight. Moreover, it is undeniable that the structure will also become more complex. Since this conventional design is intended for marine internal combustion engines, such an increase in weight is allowed, but such a configuration is generally not applicable to other types of internal combustion engines.

The purpose of this invention was to improve the structure of the oil pan without increasing its weight, thereby reducing vibrations in the oil pan and crankcase, thereby reducing engine noise. be.

[Means to solve the problem]

In order to achieve this purpose, the oil pan of this invention has a part of the oil pan recessed toward the shaft side corresponding to the intermediate bearing position of the crankshaft supported by the upper and lower bearings, and the recessed end is recessed. The gist is that the upper and lower bearings are fixed to the bearing position by fixing the bearing at the position, and a bolt is attached to the recessed end to join and fix the upper and lower bearings. This is a summary of what was done.

[Effect]

In the above configuration, each bearing of the crankshaft is integrally connected in the longitudinal direction via the oil pan without increasing the weight of the crankcase or oil pan, improving strength and reducing the piston load force. deformation of the lower part of the engine is prevented, thereby reducing vibrations in the lower part of the engine.

Furthermore, since the mounting bolt is attached to the recessed end, its length can be shortened, and variations in tightening torque due to deflection of the bolt during tightening can be prevented.

〔Example〕

An embodiment of this invention will be described below with reference to FIGS. 1 and 2.

Figure 1 is a sectional view taken along the - line in Figure 2, Figure 2 is a bottom view of the oil pan, where 1 is the cylinder of a 4-cylinder engine, 2 is the crankcase below cylinder 1,
2a is the skirt at the bottom of case 2, 3 is a hanging type crankshaft, and this shaft 3 is attached to case 2.
It is rotatably supported by a bearing 4 inside.

5 is an oil pan body with an open top end, and this body 5
A flange 5a is provided on the periphery of the upper end, a bolt 7 mounting hole 5b is bored in the flange 5a, and the bottom surface of the main body 5 is recessed with an inverted U-shaped cross section corresponding to the intermediate bearing 4. Bolt 8 on the end face of entry part 6
An insertion hole 6a is bored. Then, the oil pan body 5 is attached to the lower end of the skirt 2a and the lower surface of the bearing 4 using bolts 7 and 8, and the upper and lower bearings 4 are joined and fixed.

With this configuration, the lower bearings remain as they are conventionally, each bearing 4 is integrally connected in the longitudinal direction via the oil pan 5, and the crankcase skirt 2a portion is connected to the oil pan flange 5.
Since it is attached to a, the strength is greatly improved. Further, since the crankcase 2 has a monoblock structure including the bearing 4 and the oil pan body 5, there is no need to particularly reinforce the crankcase 2 for vibration isolation. Note that the oil pan of this embodiment is usually press-formed from a steel plate.

Next, a second embodiment of this invention will be described based on FIGS. 3 to 5.

3 is a sectional view taken along the line -- in FIG. 4, FIG. 4 is a front view of the oil pan mounted on the cylinder and crankcase, and FIG. 5 is a view taken along the - line in FIG. 4. The difference from the above embodiment is that the cylinder 1 and crankcase 2 are for a three-cylinder engine, and the crankcase 2 is divided into two vertically with the crankshaft 3 at the center, and the oil pan body 5 The lower bearing 4a of the crankshaft 3 is integrally provided on the end face of the recess 6, and the upper part of the oil pan main body 5 is formed into a lower crankcase 2'. In this embodiment as well, the lower bearing 4a is the same as the conventional one, so there is no increase in weight.

Therefore, the oil pan of this embodiment is usually formed by aluminum die casting.

[Effects of the invention] In the oil pan of the invention described above, a part of the oil pan is recessed toward the crankshaft side, so that the following effects can be obtained. That is, (a) it is possible to reinforce the space between each bearing without making the lower bearing excessively large as in the conventional case, keeping the conventional size, that is, without causing an increase in weight; During engine operation, deformation of the crankshaft bearing and crankcase skirt due to piston load force is less likely to occur, and vibrations in the lower part of the engine are significantly reduced, resulting in a reduction in overall engine noise.

(b) Since the crankcase does not need to be particularly reinforced to prevent vibration, it can also be made smaller and lighter.

(c) Since the mounting bolt is attached to the recessed end, its length can be shortened, and variations in tightening torque due to deflection of the bolt during tightening can be prevented.

[Brief explanation of drawings]

Fig. 1 is a sectional view taken along the line - - of Fig. 2 showing the oil pan of the first embodiment of this invention, Fig. 2 is a bottom view of the same oil pan, and Fig. 3 is a sectional view showing the oil pan of the second embodiment. 4 is a sectional view taken along the - line in Fig. 4, Fig. 4 is a front view of the oil pan attached to the cylinder and crankcase, Fig. 5 is a view taken along the - line in Fig. 4, and Fig. 6 is a conventional oil pan. FIG. 2 is a sectional view of the same aspect as FIG. 1 shown in FIG. 1...Cylinder, 2...Crankcase, 2a
...Skirt, 2'...Lower crankcase, 3
... Crankshaft, 4 ... Bearing, 4a ... Lower bearing, 5 ... Oil pan body, 5a ... Flange, 5b ... Bolt mounting hole, 6 ... Recessed part, 6a
...Bolt insertion hole, 7, 8...Bolt.

Claims (1)

[Claims for Utility Model Registration] (1) Corresponding to the intermediate bearing position of the crankshaft supported by the upper and lower bearings, a part of the oil pan is recessed toward the shaft side, and the recessed end is connected to the bearing. An oil pan for a multi-cylinder engine, characterized in that the oil pan is fixed in position, and a bolt is attached to the recessed end to join and fix the upper and lower bearings. (2) The oil pan for a multi-cylinder engine according to claim (1), wherein the recessed end portion is formed as a bearing.