CN108343487B

CN108343487B - Oil pan

Info

Publication number: CN108343487B
Application number: CN201810053140.3A
Authority: CN
Inventors: 林义裕; 伊藤泰隆
Original assignee: Suzuki Motor Corp
Current assignee: Suzuki Motor Corp
Priority date: 2017-01-24
Filing date: 2018-01-19
Publication date: 2020-09-01
Anticipated expiration: 2038-01-19
Also published as: DE102018200901A1; FR3062160A1; FR3062160B1; JP6809252B2; JP2018119425A; CN108343487A

Abstract

Provided is an oil pan which can be increased in rigidity and suppressed in deformation. A1 st oil strainer portion (34) is formed in a 1 st oil bottom case portion (31) having a shallow depth, and the 1 st oil strainer portion (34) extends from a front wall (31B) of the 1 st oil bottom case portion (31) along a bottom wall (31A) of the 1 st oil bottom case portion (31) in a direction of a rotation center axis (3A) of a crankshaft (3A) and is formed integrally with the 1 st oil bottom case portion (31). A2 nd oil strainer section (35) extending from the rear end of the 1 st oil strainer section (34) toward the bottom wall (32A) of the 2 nd oil bottom case section (32) is provided in the 2 nd oil bottom case section (32) having a large depth. A boss part (31E) into which the front end part of the 2 nd oil strainer part (35) is fitted is formed at the rear end part of the 1 st oil strainer part (34), and the boss part (31E) is formed at a position where the bottom wall (31A) of the 1 st oil bottom shell part (31) and the bent part (33) are connected.

Description

Oil pan

Technical Field

The present invention relates to an oil pan mounted on a vehicle.

Background

An oil pan for storing oil for lubricating an internal combustion engine mounted on a vehicle is provided below the internal combustion engine, and an oil strainer for removing foreign matter from the oil sucked up by an oil pump is provided in the oil pan. As a conventional oil pan having an oil strainer, for example, an oil pan described in patent document 1 is known.

The oil pan has two-stage bottom surfaces of different heights with a plate material interposed therebetween, and a bottom surface on a high-level side of a shallow depth and a bottom surface on a low-level side of a deep depth are connected by a bent portion. The oil strainer is formed integrally with the bottom surface of the lower side.

Documents of the prior art

Patent document

Patent document 1: showa 62-24730 publication

Disclosure of Invention

Problems to be solved by the invention

The internal combustion engine provided with such an oil pan is connected to a transmission, and the transmission vibrates in the vertical and horizontal directions due to vibration of the internal combustion engine, vibration of the vehicle, and the like. Thus, the vibration of the transmission is transmitted to the oil pan.

The bottom surface on the high-position side and the bottom surface on the low-position side of the conventional oil pan are connected by a bent portion, and the rigidity of the portion of the oil pan having the bottom surface on the low-position side (hereinafter referred to as the low-position side oil pan section) is lower than that of the portion of the oil pan having the bottom surface on the high-position side (hereinafter referred to as the high-position side oil pan section).

Therefore, when the transmission is connected to the high-position-side oil bottom case portion, the low-position-side oil bottom case portion is likely to be deformed starting from the bent portion due to vibration of the transmission. Since the oil strainer is integrally provided in the lower oil bottom casing, the oil stored in the lower oil bottom casing may be shaken vigorously when the lower oil bottom casing is deformed. Therefore, there is a concern that the oil strainer sucks in air and the oil pump sucks in the air.

The present invention has been made in view of the above-described problems, and an object thereof is to provide an oil pan that can improve rigidity and suppress deformation.

Means for solving the problems

An oil pan according to the present invention is an oil pan provided in an internal combustion engine provided in a vehicle, the internal combustion engine including a cylinder block, a rotation center axis of a crankshaft being oriented in a front-rear direction of the vehicle, the oil pan being connected to a lower portion of the cylinder block and a transmission provided behind the internal combustion engine, the oil pan including: 1 st oil sump portion; a 2 nd oil bottom casing portion which is located rearward of the 1 st oil bottom casing portion, is connected to the transmission, and has a bottom wall located below the bottom wall of the 1 st oil bottom casing portion, and has a depth greater than that of the 1 st oil bottom casing portion; and a bending portion which is bent from a bottom wall of the 1 st oil bottom case portion toward a bottom wall of the 2 nd oil bottom case portion, wherein the 1 st oil bottom case portion is formed with a 1 st oil strainer portion, the 1 st oil strainer portion extends from a front wall of the 1 st oil bottom case portion along the bottom wall of the 1 st oil bottom case portion in a direction of a rotation center axis of the crankshaft, and is formed integrally with the 1 st oil bottom case portion, the 2 nd oil bottom case portion is provided with a 2 nd oil strainer portion, the 2 nd oil strainer portion extends from a rear end portion of the 1 st oil strainer portion toward the bottom wall of the 2 nd oil bottom case portion, a boss portion into which a front end portion of the 2 nd oil strainer is fitted is formed at a rear end portion of the 1 st oil strainer portion, and the boss portion is formed at least at a position where the bottom wall of the 1 st oil bottom case portion and the bending portion are connected.

Effects of the invention

Thus, according to the present invention described above, the rigidity of the oil pan is improved, and deformation of the oil pan is suppressed.

Drawings

Fig. 1 is a plan view of a vehicle equipped with an oil pan according to an embodiment of the present invention.

Fig. 2 is a bottom view of a vehicle equipped with an oil pan according to an embodiment of the present invention.

Fig. 3 is a side view of the power unit as viewed from the direction of arrow III of fig. 1.

Fig. 4 is a front view of an engine provided with an oil pan according to an embodiment of the present invention.

Fig. 5 is a plan view of an oil pan according to an embodiment of the present invention.

Fig. 6 is a sectional view taken along direction VI-VI of fig. 5.

Fig. 7 is a view in section in the direction VII-VII of fig. 5.

Fig. 8 is a diagram showing an oil pan according to an embodiment of the present invention, and is a plan view of an oil pan provided with a 2 nd oil strainer portion having another shape.

Fig. 9 is a view in section from direction IX-IX of fig. 8.

Description of the reference numerals

1: a vehicle; 2: an engine (internal combustion engine); 3: a cylinder block; 3A: a crankshaft; 3 a: rotating the central shaft; 5: an oil pan; 6: a transmission; 7: 1 st front propeller shaft (1 st propeller shaft); 8: a transfer device; 9: 2 nd front propeller shaft (front propeller shaft); 11: a front side differential device (differential device); 31: 1 st oil sump portion; 31A, 32A: a bottom wall; 31B: a front wall; 31: a side wall; 31E: a boss portion (1 st boss portion); 31F: a bulging portion; 31 e: a thread groove (fastening portion); 32: 2 nd oil sump portion; 33: a bending section; 33A: a boss portion (2 nd boss portion); 34: 1 st oil strainer section; 35: 2 nd oil strainer portion.

Detailed Description

An oil pan according to an embodiment of the present invention is provided in an internal combustion engine provided in a vehicle, the internal combustion engine including a cylinder block, a rotation center axis of a crankshaft being oriented in a front-rear direction of the vehicle, the oil pan being connected to a lower portion of the cylinder block and a transmission provided behind the internal combustion engine, and the internal combustion engine including: 1 st oil sump portion; a 2 nd oil bottom casing portion which is located rearward of the 1 st oil bottom casing portion, is connected to the transmission, and has a bottom wall located below the bottom wall of the 1 st oil bottom casing portion, and has a depth greater than that of the 1 st oil bottom casing portion; and a bending portion bent from a bottom wall of the 1 st oil sump portion toward a bottom wall of the 2 nd oil sump portion, wherein the 1 st oil sump portion is formed with a 1 st oil strainer portion, the 1 st oil strainer portion extends from a front wall of the 1 st oil sump portion along the bottom wall of the 1 st oil sump portion in a rotational center axis direction of the crankshaft, and is formed integrally with the 1 st oil sump portion, the 2 nd oil sump portion is provided with a 2 nd oil strainer portion, the 2 nd oil strainer portion extends from a rear end portion of the 1 st oil strainer portion toward the bottom wall of the 2 nd oil sump portion, a boss portion into which a front end portion of the 2 nd oil strainer is fitted is formed at a rear end portion of the 1 st oil strainer portion, and the boss portion is formed at least at a position connecting the bottom wall of the 1 st oil sump portion and the bending portion.

This improves the rigidity of the oil pan, and suppresses deformation of the oil pan.

[ examples ]

Hereinafter, an oil pan according to an embodiment of the present invention will be described with reference to the drawings.

Fig. 1 to 9 are views showing an oil pan according to an embodiment of the present invention. In fig. 1 to 9, the upper, lower, front, rear, left, and right are directions as viewed from a driver mounted on the vehicle.

First, the configuration is explained.

In fig. 1 and 2, a vehicle 1 includes an engine 2 as an internal combustion engine. In fig. 3 and 4, the engine 2 includes: a cylinder block 3; a cylinder head 4 coupled to an upper portion of the cylinder block 3; and an oil pan 5 joined to a lower portion of the cylinder block 3.

A cylinder, not shown, is formed in the cylinder block 3, and a piston, not shown, is provided in the cylinder to be capable of reciprocating. The cylinder block 3 is provided with a crankshaft 3A (see fig. 4) that is rotatable, and the reciprocating motion of the piston is converted into the rotational motion of the crankshaft 3A. Fig. 3 shows a rotation center axis 3A of the crankshaft 3A.

The cylinder head 4 is provided with an intake/exhaust camshaft, not shown, and an intake/exhaust valve, not shown, for opening and closing an intake/exhaust port, not shown, and the cylinder head 4 introduces intake air into the cylinder through the intake port and discharges exhaust gas from the cylinder through the exhaust port. The oil pan 5 stores oil for lubricating a lubricating portion such as a crankshaft and a piston.

The engine 2 is provided such that a rotation center axis 3A of the crankshaft 3A is oriented in the front-rear direction of the vehicle 1 (see fig. 3), and the vehicle 1 of the present embodiment has a vertical engine.

In fig. 1 and 2, the engine 2 is connected to a transmission 6, and the transmission 6 changes the rotational speed of the crankshaft 3A and outputs the changed rotational speed. The transmission 6 is provided behind the engine 2, and the oil pan 5 is coupled to a lower portion of the cylinder block 3 and the transmission 6 (see fig. 3).

The transmission 6 is coupled to a front end portion of a 1 st front propeller shaft 7, and the 1 st front propeller shaft 7 extends rearward in the front-rear direction of the vehicle 1 from the transmission 6. A transfer device 8 is provided behind the transmission 6, and a rear end portion of the 1 st front side transmission shaft 7 is coupled to the transfer device 8. Thereby, the power of the transmission 6 is transmitted to the transfer device 8 through the 1 st front side propeller shaft 7.

The transfer device 8 is connected to a rear end portion of the 2 nd front propeller shaft 9 and a front end portion of the rear propeller shaft 10. The 2 nd front side transmission shaft 9 extends forward in the front-rear direction of the vehicle 1 from the transfer device 8 toward the vehicle width direction side of the engine 2.

The front end of the 2 nd front propeller shaft 9 is coupled to a front differential 11. The front differential device 11 transmits power of the 2 nd front transmission shaft 9 to the

front wheels

13L, 13R through the front left and

right drive shafts

12L, 12R, and allows differential rotation of the

front wheels

13L, 13R.

The rear end portion of the rear propeller shaft 10 is coupled to a rear differential device, not shown. The rear differential device transmits power of the rear transmission shaft 10 to a rear wheel, not shown, via a rear left and right drive shaft, not shown, and allows differential rotation of the rear wheel.

The transfer device 8 switches the transmission path so as to transmit the power transmitted from the 1 st front side transmission shaft 7 to one or both of the 2 nd front side transmission shaft 9 and the rear side transmission shaft 10.

Thus, the vehicle 1 performs switching to two-wheel drive or four-wheel drive with time division four-wheel drive (part-time 4 WD). The transfer device 8 may be driven so that the vehicle 1 is always a power transmission path such as four-wheel drive, that is, the full-time 4 WD.

The 1 st front propeller shaft 7 of the present embodiment constitutes a 1 st propeller shaft of the present invention, and the 2 nd front propeller shaft 9 constitutes a 2 nd propeller shaft of the present invention. The front differential device 11 constitutes a differential device of the present invention.

In fig. 5 and 6, the oil pan 5 includes a 1 st oil pan section 31 and a 2 nd oil pan section 32 having

bottom walls

31A and 32A of different heights, and the 2 nd oil pan section 32 is located rearward of the 1 st oil pan section 31 and is coupled to the transmission 6. The 1 st oil bottom shell portion 31 includes a bottom wall 31A, a front wall 31B, and

side walls

31C, 31D.

The 2 nd oil sump portion 32 includes a sump 32A, a rear wall 32B, and

side walls

32C, 32D. The bottom wall 32A is located below the bottom wall 31A, and the 2 nd oil bottom shell portion 32 is formed to have a depth deeper than the 1 st oil bottom shell portion 31. The rear wall 32B is joined to the transmission 6 by a bolt 38 (see fig. 3).

The

side walls

31C, 31D are provided integrally with the

side walls

32C, 32D, and the

side walls

31C, 31D, 32D constitute side walls of the oil pan 5. The oil pan 5 stores oil in a space surrounded by the

bottom walls

31A, 32A, the front wall 31B, the rear wall 32B, and the

side walls

31C, 31D, 32D.

The oil pan 5 has a bent portion 33. The bent portion 33 is bent from the bottom wall 31A of the 1 st oil bottom shell portion 31 toward the bottom wall 32A of the 2 nd oil bottom shell portion 32. Here, the bent portion 33 may extend from the bottom wall 31A of the 1 st oil bottom shell portion 31 to the bottom wall 32A of the 2 nd oil bottom shell portion 32.

In the oil pan 5 of the present embodiment, the bent portion 33 need only be formed between the bottom wall 31A of the 1 st oil bottom shell portion 31 and the bottom wall 32A of the 2 nd oil bottom shell portion 32. Fig. 5 shows a range where the 1 st oil bottom shell portion 31, the 2 nd oil bottom shell portion 32, and the bent portion 33 are formed.

A 1 st oil strainer (oil strainer) portion 34 is formed in the 1 st oil bottom shell portion 31. The 1 st oil strainer portion 34 extends from the front wall 31B of the 1 st oil bottom case portion 31 along the bottom wall 31A in the direction of the rotational center axis 3a of the crankshaft, and is formed integrally with the 1 st oil bottom case portion 31. An oil passage 34a through which oil flows is formed inside the 1 st oil strainer portion 34.

The 2 nd oil bottom casing portion 32 is provided with a 2 nd oil strainer portion 35. The 2 nd oil strainer portion 35 extends from the rear end portion of the 1 st oil strainer portion 34 toward the bottom wall 32A of the 2 nd oil bottom case portion 32 along the bent portion 33. An oil passage 35a through which oil flows is formed inside the 2 nd oil strainer portion 35, and the oil passage 35a communicates with the oil passage 34 a.

A foreign matter trap, not shown, is provided at a rear end portion of the 2 nd oil strainer portion 35 opposite to the bottom wall 32A of the 2 nd oil bottom case portion 32. The tip of the 1 st oil strainer portion 34 is connected to an oil filter 41 (see fig. 4), and the oil filter 41 is connected to an oil pump 42 (see fig. 4) via an oil pipe (not shown).

The oil pump 42 is driven to rotate by the crankshaft 3A. When the oil pump 42 is driven to rotate, the oil in the oil pan 5 is sucked up from the rear end portion of the 2 nd oil strainer portion 35.

The oil sucked up by the 2 nd oil strainer portion 35 is removed from the oil by the foreign matter trap portion, flows through the oil passage 35a, and then flows through the oil passage 34a of the 1 st oil strainer portion 34.

The oil flowing through the oil passage 35a is introduced into the oil filter 41, is purified by the oil filter 41, and is then supplied from the oil pump 42 to a lubrication site of the engine 2. Thereby, the lubricated part is lubricated by the purified oil.

A boss (boss) portion 31E is formed at the rear end portion of the 1 st oil strainer portion 34, and the boss portion 31E is fitted to the front end portion of the 2 nd oil strainer portion 35. The boss portion 31E is formed at a position connecting the bottom wall 31A of the 1 st oil bottom shell portion 31 and the bent portion 33.

In fig. 5, a flange 35A is formed at the front end of the 1 st oil strainer portion 34. A screw groove 31E to which the bolt 38 is fastened is formed in the boss portion 31E, and the flange 35A is fixed to the boss portion 31E by the bolt 38. Thereby, the front end portion of the 2 nd oil strainer portion 35 is fixed to the boss portion 31E. The screw groove 31e of the present embodiment constitutes a fastening portion of the present invention.

The boss portion 31E is formed in a shape in which a dimension L2 in a direction orthogonal to the axial direction of the 1 st oil strainer portion 34 is larger than a dimension L1 in the axial direction (the same direction as the rotation center axis 3a) of the 1 st oil strainer portion 34.

A bulge 31F is formed in the bottom wall 31A of the 1 st oil bottom shell portion 31. The bulging portion 31F bulges upward from the bottom wall 31A (see fig. 7). The bulging portion 31F bulges upward from a bottom wall 31A located on the side where the front differential device 11 is provided with respect to the 1 st oil strainer portion 34.

The bulging portion 31F connects the side wall 31C of the 1 st oil bottom case portion 31, the 1 st oil strainer portion 34, the boss portion 31E, and the bent portion 33, which are opposed to the front differential device 11.

The engine 2, the transmission 6, the 1 st front propeller shaft 7, the transfer device 8, the 2 nd front propeller shaft 9, the rear propeller shaft 10, the front differential 11, and the

drive shafts

12L, 12R of the embodiment constitute a power train (power train) that transmits power generated by the engine 2 to the

front wheels

13L, 13R. In addition, the engine 2 and the transmission 6 of the embodiment constitute a power unit that generates power.

Next, the operation will be described.

During operation of the engine 2, the transmission 6 vibrates in the vertical direction X and the lateral direction Y due to vibration of the engine 2, vibration of the vehicle 1, and the like (see fig. 4). The oil pan 5 has the 2 nd oil bottom shell portion 32 that is deeper than the 1 st oil bottom shell portion 31, and therefore the rigidity of the 2 nd oil bottom shell portion 32 is lower than the 1 st oil bottom shell portion 31. The 2 nd oil pan portion 32 of the oil pan 5 is coupled to the transmission 6.

Thus, when the vibration of the transmission 6 is transmitted to the oil pan 5, the oil pan 5 tries to deform in the front-rear direction R (see fig. 3) of the vehicle 1 with the bent portion 33 as a starting point.

The oil pan 5 of the present embodiment has: 1 st oil sump portion 31; a 2 nd oil bottom case portion 32 which is located rearward of the 1 st oil bottom case portion 31, is connected to the transmission 6, has a bottom wall 32A located below the bottom wall 31A of the 1 st oil bottom case portion 31, and has a depth greater than that of the 1 st oil bottom case portion 31; and a bent portion 33 bent from the bottom wall 31A of the 1 st oil bottom shell portion 31 toward the bottom wall 32A of the 2 nd oil bottom shell portion 32.

A 1 st oil strainer portion 34 is formed in the 1 st oil bottom case portion 31, and the 1 st oil strainer portion 34 extends from the front wall 31B of the 1 st oil bottom case portion 31 along the bottom wall 31A of the 1 st oil bottom case portion 31 in the direction of the rotation center axis 3A of the crankshaft 3A, and is formed integrally with the 1 st oil bottom case portion 31.

A 2 nd oil strainer portion 35 is provided in the 2 nd oil bottom case portion 32, and the 2 nd oil strainer portion 35 extends from a rear end portion of the 1 st oil strainer portion 34 toward the bottom wall 32A of the 2 nd oil bottom case portion 32.

A boss portion 31E into which the front end portion of the 2 nd oil strainer portion 35 is fitted is formed at the rear end portion of the 1 st oil strainer portion 34, and the boss portion 31E is formed at a position connecting the bottom wall 31A of the 1 st oil bottom case portion 31 and the bent portion 33.

This can increase the rigidity of the 1 st oil bottom shell portion 31 by the 1 st oil strainer portion 34, and increase the rigidity of the bent portion 33 by the boss portion 31E. Therefore, the 2 nd oil bottom case portion 32 can be suppressed from being deformed from the bent portion 33 due to vibration of the transmission 6.

Thus, since the 2 nd oil bottom shell portion 32 having a large depth can be suppressed from being deformed, the oil can be prevented from vigorously sloshing in the 2 nd oil bottom shell portion 32 storing more oil than the 1 st oil bottom shell portion 31.

Therefore, the 2 nd oil strainer portion 35 can be prevented from sucking air in the 2 nd oil bottom case portion 32, and air suction of the oil pump 42 can be prevented from occurring.

Further, the 2 nd oil bottom shell portion 32 is located rearward of the 1 st oil bottom shell portion 31, so when the traveling wind B collides with the oil pan 5 from the front of the vehicle 1, the traveling wind B collides with the bent portion 33 along the bottom wall 31A of the 1 st oil bottom shell portion 31, and then flows rearward from the bent portion 33 along the bottom wall 32A (see fig. 3).

This allows the oil stored in the oil pan 5 to be cooled by the traveling wind, and the oil to be maintained at an appropriate temperature. Therefore, the viscosity of the oil can be appropriately maintained, the lubricity of the lubrication portion of the engine 2 can be improved, and the engine component can be prevented from being prematurely deteriorated.

In addition, according to the oil pan 5 of the present embodiment, the boss portion 31E is formed in a shape in which the dimension L2 in the direction orthogonal to the axial direction of the 1 st oil strainer portion 34 is larger than the dimension L1 in the axial direction of the 1 st oil strainer portion 34.

Also, the boss portion 31E has a screw groove 31E, and the leading end portion of the 2 nd oil strainer portion 35 is fixed to the screw groove 31E by a bolt 38.

This can increase the installation area of the boss portion 31E with respect to the curved portion 33, and can increase the thickness of the boss portion 31E in the direction of the thread groove 31E by the depth of the thread groove 31E. Therefore, the rigidity of the bent portion 33 can be more effectively increased, and the 2 nd oil bottom case portion 32 can be more effectively suppressed from being deformed starting from the bent portion 33 due to vibration of the transmission 6.

On the other hand, the power train of the present embodiment includes: a transfer device 8 provided behind the transmission 6 and coupled to the transmission 6 via a 1 st front transmission shaft 7; and a 2 nd front side transmission shaft 9 extending in the front-rear direction of the vehicle 1 from the transfer device 8 toward the side of the engine 2.

The power train includes a front differential device 11, and the front differential device 11 is provided at a front end portion of the 2 nd front propeller shaft 9, and transmits power of the 2 nd front propeller shaft 9 to the

front wheels

13L and 13R to enable differential rotation of the

front wheels

13L and 13R.

Thus, when the transmission 6 vibrates in the up-down, left-right direction, the 1 st front propeller shaft 7 vibrates in the front-rear direction of the vehicle 1, and this vibration is transmitted to the front differential 11 through the transfer device 8 and the 2 nd front propeller shaft 9.

The 2 nd front propeller shaft 9 and the front differential 11 are provided offset laterally with respect to the oil pan 5, so the oil pan 5 is easily deformed toward the side (the X1 direction in fig. 1) where the 2 nd front propeller shaft 9 and the front differential 11 are provided.

According to the oil pan 5 of the present embodiment, the bulging portion 31F is formed at the bottom wall 31A of the 1 st oil bottom shell portion 31. The bulging portion 31F bulges upward from a bottom wall 31A located on the side where the front differential device 11 is provided with respect to the 1 st oil strainer portion 34.

This can increase the rigidity of the 1 st oil pan section 31, and can easily suppress deformation of the oil pan 5 toward the front differential device 11. Therefore, the 2 nd oil bottom case portion 32 can be more effectively suppressed from being deformed from the bent portion 33 due to vibration of the transmission 6.

In the oil pan 5 of the present embodiment, as shown in fig. 8 and 9, a rib 35B may be provided in the 2 nd oil strainer portion 35, a boss portion 33A forming a screw groove may be provided in the bent portion 33, and the rib 35B may be fastened to the boss portion 33A by a bolt 43. The boss portion 31E of the present embodiment constitutes a 1 st boss portion of the present invention, and the boss portion 33A constitutes a 2 nd boss portion of the present invention.

Thus, the bending portion 33 and the 2 nd oil strainer portion 35 can be connected, and the rigidity of the bending portion 33 can be more effectively improved. Therefore, the 2 nd oil bottom case portion 32 can be more effectively suppressed from being deformed from the bent portion 33 due to vibration of the transmission 6.

Although embodiments of the present invention have been disclosed, it will be apparent to those skilled in the art that changes may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the claims.

Claims

1. An oil pan provided in an internal combustion engine provided in a vehicle and having a cylinder block with a rotation center axis of a crankshaft oriented in a front-rear direction of the vehicle, the oil pan being connected to a lower portion of the cylinder block and a transmission provided behind the internal combustion engine,

the oil pan includes: 1 st oil sump portion; a 2 nd oil bottom casing portion which is located rearward of the 1 st oil bottom casing portion, is connected to the transmission, and has a bottom wall located below the bottom wall of the 1 st oil bottom casing portion, and has a depth greater than that of the 1 st oil bottom casing portion; and a bending portion that is bent from the bottom wall of the 1 st oil sump portion toward the bottom wall of the 2 nd oil sump portion,

the oil pan described above is characterized in that,

a 1 st oil strainer portion is formed in the 1 st oil bottom case portion, the 1 st oil strainer portion extending in a direction of a rotation center axis of the crankshaft from a front wall of the 1 st oil bottom case portion along a bottom wall of the 1 st oil bottom case portion and being formed integrally with the 1 st oil bottom case portion,

a 2 nd oil strainer portion is provided in the 2 nd oil bottom case portion, the 2 nd oil strainer portion extending from a rear end portion of the 1 st oil strainer portion toward a bottom wall of the 2 nd oil bottom case portion,

a boss portion into which the front end portion of the 2 nd oil strainer is fitted is formed at the rear end portion of the 1 st oil strainer portion,

the boss portion is formed at least at a position connecting the bottom wall of the 1 st oil pan portion and the bent portion.

2. An oil pan according to claim 1,

the boss portion is formed in a shape in which a dimension in a direction orthogonal to the axial direction of the 1 st oil strainer portion is larger than a dimension in the axial direction of the 1 st oil strainer portion,

the boss portion has a fastening portion to which a front end portion of the 2 nd oil strainer portion is fixed.

3. An oil pan according to claim 1 or claim 2,

the vehicle includes:

a transfer device which is arranged at the rear of the speed changer and is connected with the speed changer through a 1 st transmission shaft;

a 2 nd propeller shaft extending in a vehicle front-rear direction from the transfer case toward a side of the internal combustion engine; and

a differential device provided at a front end portion of the 2 nd propeller shaft, for transmitting power of the 2 nd propeller shaft to the left and right front wheels to enable differential rotation of the left and right front wheels,

the oil pan has a bulging portion that bulges upward from at least a bottom wall located on a side where the 2 nd propeller shaft or the differential device is provided with respect to the 1 st oil strainer portion,

the bulging portion connects a side wall of the oil pan, the 1 st oil strainer portion, the boss portion, and the bent portion, which face the 2 nd propeller shaft or the differential device.

4. An oil pan according to claim 1 or claim 2,

the 2 nd oil strainer portion extends along the bent portion,

in a case where the boss part is set to the 1 st boss part, a 2 nd boss part is formed at the bent part, and the 2 nd oil strainer part is fixed to the 2 nd boss part.

5. An oil pan according to claim 3,

the 2 nd oil strainer portion extends along the bent portion,