JP3163865B2 - Oil pan vibration control structure of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration control structure for an oil pan mounted on a lower surface of a cylinder block of an internal combustion engine.

[0002]

2. Description of the Related Art Many internal combustion engines represented by internal combustion engines for automobiles are provided with a relatively deep oil pan on the lower surface of a cylinder block, in which lubricating oil is stored and sucked up by an oil pump to be pumped to various parts. It has a configuration. Here, the oil pan generally has a thin-walled structure formed by press-molding a metal plate. Therefore, there is a problem that the film vibrates due to the vibration input of the engine, and a relatively large radiated sound is generated.

For this reason, conventionally, Japanese Utility Model Laid-Open Publication No.
As disclosed in Japanese Patent Application Laid-Open No. 41 and JP-A-3-294611, the oil pan has a double structure of an outer plate and an inner plate, and the gap between the two is filled with lubricating oil to flow the oil layer. There has been proposed a low-noise oil pan in which vibration is suppressed by an energy damping effect of the oil pan.

[0004] Oil pans for internal combustion engines are generally
A part has a deep bottom for storing lubricating oil, and the rest is a shallow bottom.During engine operation, the oil level drops below the shallow bottom, so the lubricating oil is stored. Radiated sound at the shallow bottom occupies a larger proportion than at the deep bottom. Because of that, the actual opening 58-84309
The publication discloses an oil pan in which a ridge is formed at a boundary between a shallow portion and a deep portion so that lubricating oil is retained in the shallow portion.

[0005]

However, if the oil pan has a double structure over the entire oil pan, that is, over both the shallow bottom and the deep bottom as described in the former, as described above, the radiated sound is large. It is not possible to focus on the shallow bottom. Moreover, in the above-described conventional configuration, the inner plate is fixed to the inside of the outer plate while keeping a small gap, so that not only the oil layer between the inner plate and the outer plate cannot be made so thin. However, the effect of pressing the oil pan on the oil layer due to the weight of the inner pan cannot be utilized, so that a large energy damping effect due to the flow of the lubricating oil in the oil layer cannot be obtained.
Therefore, there is a problem that the noise reduction effect is lower than the increase in weight due to the addition of the inner plate.

Further, in the configuration in which the lubricating oil is held at the shallow bottom like the latter, radiated sound can be reduced to some extent as compared with a conventional oil pan in which the shallow bottom is exposed inside the crankcase. However, there is a limit to the vibration damping effect only by retaining the lubricating oil, and a sufficient radiation sound reduction effect cannot be obtained.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an oil pan mounted on the lower surface of a cylinder block of an internal combustion engine and having a deep bottom part for storing lubricating oil and a shallow bottom part in the remainder. In the above, the inner pan having a bottom wall shaped along the bottom wall surface of the shallow bottom is accommodated in the shallow bottom without being fixed to the oil pan, and a stopper for preventing the inner pan from moving to the deep bottom side is provided. It is characterized by being provided on the oil pan side.

According to the second aspect of the present invention, an oil holding wall for holding lubricating oil is formed in the shallow bottom along a boundary between the deep bottom and the shallow bottom of the oil pan. Used as a stopper. In claim 3, a communication hole is formed in the lower part of the oil holding wall.

Further, in the invention of claim 4, the lubricating oil outlet at the tip of the relief passage of the oil pump is arranged so as to supply the lubricating oil into the shallow bottom part partitioned by the oil holding wall.

[0010]

The lubricating oil flowing down the inner wall surface of the crankcase and the oil droplets scattered in the crankcase are always supplied to the shallow portion. Then, the inner pan tends to press against the bottom surface of the oil pan by its own weight. Therefore, the bottom surface of the oil pan and the outer surface of the bottom surface of the inner pan are close to each other via the thin oil layer. If the oil pan shallowly vibrates in this state, the lubricating oil tends to flow along the wall surface in the thin oil layer with a minute change in the distance between the two, and an energy damping effect is obtained. As a result, vibration at the shallow bottom of the oil pan is suppressed. The vibration at the deep bottom is suppressed by a large amount of stored lubricating oil.

According to the second aspect of the present invention, the oil holding wall also serving as the stopper holds the lubricating oil in the shallow portion, so that the oil layer between the oil pan and the inner pan is reliably formed, and the lubricating oil is formed. Oil-based damping action is obtained.
Here, if the communication hole is provided as in claim 3, when the engine is stopped, all the lubricating oil in the shallow portion flows into the deep portion.

Further, according to the present invention, the lubricating oil is positively supplied into the shallow portion by using the relief flow of the oil pump.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings.

1 to 3 show an embodiment of the present invention. The oil pan 1 is formed by press-forming a steel plate. The portion near the front end of the engine is a substantially rectangular deep bottom portion 1a, and the remaining portion is a shallow bottom portion 1b. Note that a stepped portion 1c that rises further upward is provided on the rear end side of the shallow portion 1b. The bottom surfaces of the deep bottom portion 1a and the shallow bottom portion 1b are substantially flat surfaces. A flange portion 2 is formed on an outer peripheral edge of the oil pan 1, and the flange portion 2 is bolted to a lower edge of a cylinder block (not shown).

The deep bottom 1a and the shallow bottom 1 of the oil pan 1
An oil holding wall 3 is fixed to the boundary with the oil pan 1 along the width direction of the oil pan 1. The oil retaining wall 3 is formed by bending a metal plate into a substantially V-shaped cross section and making it elongated in a rectangular shape. The flange portions provided on the deep bottom portion 1a side and the shallow bottom portion 1b side respectively have an oil pan 1 Both ends are welded to the left and right side walls of the oil pan 1 while being welded to the bottom wall. That is, the oil holding wall 3
The deep bottom portion 1a and the shallow bottom portion 1b are partitioned at an appropriate height.

An inner pan 4 having a rectangular shallow dish shape is accommodated in a shallow bottom portion 1b of the oil pan 1 partitioned by the oil retaining wall 3. The inner pan 4 is formed of a steel sheet press-formed product or a hard synthetic resin-formed product, and has a bottom wall shaped along the bottom wall surface of the shallow bottom portion 1 b of the oil pan 1. The side wall provided at a low height on the periphery has a cross-section curved along the side wall of the oil pan 1 surrounding the shallow bottom portion 1b and the wall surface of the oil holding wall 3 on the shallow bottom portion 1b side. The inner pan 4 is not fixed to the oil pan 1.

A baffle plate 5 for restraining the oil surface from swinging is fixed to the upper opening of the oil pan 1 by welding. The inner pan 4 is stored in the inner pan 4. Accordingly, excessive upward movement of the inner pan 4 is restricted, and there is no possibility of interference with a connecting rod, a crankshaft, or the like (not shown). The baffle plate 5 and the upper end of the oil retaining wall 3 are close to each other with a slight gap 6 (see FIG. 2), and the oil retaining wall 3 acts as a stopper to move the inner pan 4 forward, that is, the deep bottom portion 1a. Restricts movement to the side.

As shown in FIG. 3, the baffle plate 5 is provided with a plurality of oil drop holes 7 for allowing the lubricating oil dropped on the upper surface to flow downward, and the oil drop holes 7 are formed at the center of the shallow bottom portion 1b. While the individual oil drop holes 7A are relatively large, the oil drop holes 7B located at the front and rear ends of the shallow portion 1b and the oil drop holes 7C along the side wall of the oil pan 1 are formed in a narrow slit shape. Is formed. In addition, a strainer opening 8 through which an oil strainer (not shown) penetrates is provided in the upper central portion of the deep bottom portion 1a. The baffle plate 5 has a deep bottom portion 1a and a shallow bottom portion 1a.
A step portion 5a is formed along the boundary with the b side so that the shallow portion 1b side becomes higher.

As shown in FIG. 2, a communication hole 9 is formed in the center of the lower part of the oil retaining wall 3 to communicate between the inside of the shallow bottom 1b and the side of the deep bottom 1a. In this embodiment, since the oil holding wall 3 is formed of a metal plate bent in a substantially V-shaped cross section as described above, the communication hole 9 is actually formed on the deep bottom portion 1a side. It is formed on both the wall portion and the wall portion on the shallow bottom portion 1b side.

Next, the operation of the above embodiment will be described. The lubricating oil stored in the deep bottom portion 1a is sucked up by an oil pump (not shown) and is pressure-fed to various parts of the engine.
The lubricating oil used in each part is discharged from an oil return hole or the like on the upper surface of the crankcase, flows down the inner wall surface of the crankcase, and flows down to the oil pan 1. Then, a part thereof flows into the shallow bottom portion 1b through the oil drain hole 7 of the baffle plate 5. Oil droplets scattered in the crankcase also enter the shallow bottom portion 1b. For this reason, during the operation of the engine, the symbol L1 in FIG.
The lubricating oil is held up to the oil level position shown as. Therefore, a very thin oil layer is formed between the inner pan 4 and the oil pan 1 pressed against the oil pan 1 by its own weight. Even when the vehicle makes a sharp turn, since the opening areas of the oil drain holes 7B and 7C in the peripheral portion of the shallow bottom portion 1b are small, the lubricating oil is reliably held in the shallow bottom portion 1b. Also,
After the shallow portion 1b is filled with the lubricating oil, excess lubricating oil overflows from each oil drop hole 7 and is collected toward the deep portion 1a.
Since the baffle plate 5 has the stepped portion 5a, the lubricating oil once moved to the deep bottom portion 1a does not flow backward to the shallow bottom portion 1b.

When the bottom wall of the oil pan 1, especially the bottom wall of the shallow bottom portion 1b, vibrates due to the vibration input from the cylinder block side in the state where the oil layer is formed, the oil pan 1
A slight change in the distance between the inner pan 4 and the inner pan 4 occurs, and accordingly, the lubricating oil in the oil layer attempts to flow along the two surfaces. Therefore, the vibration energy is converted into the kinetic energy of the lubricating oil, and is attenuated by friction with each wall surface and friction between oils. As a result, vibrations that actually occur are greatly suppressed, and radiation noise is reduced. This damping effect acts on a plurality of membrane resonances like a damping element in a general vibration model, so that it is effective in a wide frequency range and can reduce radiated sound as a whole. In addition, since the lubricating oil is stored in the deep bottom portion 1a up to the oil level indicated by the reference numeral L2 in FIG. 1 during the operation of the engine, the sound radiation from the deep bottom portion 1a is reduced.

FIG. 8 is a characteristic diagram showing the radiation sound of the oil pan 1 in the configuration of this embodiment, specifically, the vibration level of the shallow bottom portion 1b in comparison with the conventional characteristic (broken line). It should be noted that the dashed line in FIG.
This is the characteristic when the lubricating oil is held to an appropriate depth inside. As is apparent from these comparisons, even if lubricating oil is simply retained in the shallow bottom 1b,
Although the radiated sound is reduced as compared with the conventional characteristic indicated by the broken line in which b is exposed inside the crankcase, the provision of the inner pan 4 and the formation of a thin oil layer as in the above-described embodiment provides a greater damping effect. The resulting radiated sound is further reduced.

In the above configuration, the communication hole 9 is formed in the oil holding wall 3.
Are open, all the lubricating oil in the shallow bottom 1b moves into the deep bottom 1a when the engine is stopped. Therefore, when replacing the lubricating oil, the entire lubricating oil in the crankcase can be reliably replaced. In addition, the accumulation of the lubricating oil in the shallow portion 1b is prevented, and the accumulation of sludge is suppressed. The oil retaining wall 3 also functions as a reinforcement for reinforcing the oil pan 1 and contributes to an improvement in the rigidity of the oil pan 1.

FIG. 4 shows an embodiment in which lubricating oil is actively supplied into the shallow bottom portion 1b in which the inner pan 4 is stored. This embodiment is applied to an internal combustion engine equipped with a turbocharger, and lubricating oil after forcibly lubricating the bearings of the turbocharger returns to the inside of the oil pan 1 via an oil return passage. The connector 11 for connection to the oil return passage is arranged on the side surface of the shallow bottom portion 1b. Therefore, the lubricating oil returning from the turbocharger is first supplied to the shallow portion 1b, overflows from here, and is collected in the deep portion 1a. Therefore, the lubricating oil is more reliably held in the shallow bottom portion 1b in which the inner pan 4 is stored, and direct contact between the inner pan 4 and the oil pan 1 without passing through the oil layer is prevented.

FIGS. 5 and 6 show an embodiment in which the lubricating oil is supplied into the shallow bottom portion 1b in which the inner pan 4 is housed by using a relief flow of an oil pump.
That is, the front cover 13 shown in FIG. 6 is attached to the front end face of the cylinder block 12 shown in FIG. 5, and the oil pump 14 is housed inside the front cover 13. Lubricating oil discharge port 16 communicating with oil gallery 15
Similarly, the relief passage 17 on the cylinder block 12 side
A relief oil discharge port 18 communicating with the front cover 13 is formed on each side edge of the front cover 13. A lubricating oil inlet through which lubricating oil flows through a strainer (not shown) is provided on the lower surface of the oil pump 14. A relief valve (not shown) is accommodated in a relief valve accommodating portion 19 integrated with the housing of the oil pump 14. The relief passage 17 formed on the cylinder block 12 side extends rearward of the engine, and a lubricating oil outlet 20 at the tip thereof is disposed above the shallow bottom portion 1b.

In the embodiment having the above construction, as shown in FIG. 7, when the engine speed exceeds a certain value, a relief valve (not shown) is gradually opened to prevent the oil pressure from excessively increasing. Part of the lubricating oil is relieved. Then, the relieved lubricating oil returns to the oil pan 1. At this time, the lubricating oil flows from the lubricating oil outlet 20 at the tip of the relief passage 17 to the shallow bottom portion 1b. Lubricating oil is reliably held.

Next, FIG. 9 shows an embodiment in which the oil retaining wall 3 has a different sectional shape. The oil retaining wall 3 is also formed by press-forming a metal plate.

FIG. 10 shows still another embodiment of the oil holding wall 3. In this embodiment, the oil holding wall 3
Is formed of a synthetic resin and is fixed to the bottom surface of the oil pan 1.

Although not shown, a bead may be formed on the bottom surface of the oil pan 1 along the boundary between the deep bottom portion 1a and the shallow bottom portion 1b, and this bead may be used as an oil holding wall. Further, a configuration in which a stopper is provided only in a part of the width direction of the oil pan 1 without forming a wall shape is also possible.

[0030]

As is apparent from the above description, according to the oil pan vibration damping structure for an internal combustion engine according to the present invention, the oil layer is formed in the shallow bottom where the radiated sound is larger than the deep bottom. Since the inner pan is brought into close contact with the inner pan, radiated sound can be effectively reduced with almost no increase in weight. In particular,
Since the inner pan is housed without being fixed to the oil pan, its structure is simple and a sufficiently thin oil layer can be stably secured even with a small amount of lubricating oil flowing down the inner wall of the crankcase, resulting in good vibration. A damping effect is obtained. Therefore, it is possible to achieve both reduction in the weight of the entire oil pan and reduction in noise.

If the shallow bottom in which the inner pan is housed is partitioned by the oil retaining wall, the lubricating oil is reliably held in the shallow bottom, and the oil pan between the inner pan and the oil pan is not interposed. Direct contact can be avoided more reliably.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along the line BB of FIG. 3 showing one embodiment of the present invention;

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is a plan view of the oil pan of this embodiment.

FIG. 4 is a perspective view showing an embodiment in which return lubricating oil from a turbocharger is introduced into a shallow bottom portion.

FIG. 5 is a perspective view showing a cylinder block according to an embodiment in which a relief flow is guided to a shallow portion.

FIG. 6 is a perspective view of a front cover in the embodiment.

FIG. 7 is a characteristic diagram showing a characteristic of a relief flow.

FIG. 8 is a characteristic diagram showing a vibration characteristic of the oil pan according to the present invention in comparison with a conventional one.

FIG. 9 is a sectional view showing a different embodiment of the oil retaining wall.

FIG. 10 is a sectional view showing still another embodiment of the oil retaining wall.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Oil pan 1b ... Shallow bottom part 3 ... Oil holding wall 4 ... Inner pan 5 ... Baffle plate 9 ... Communication hole 17 ... Relief passage

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-294611 (JP, A) Japanese Utility Model Showa 49-65850 (JP, U) Japanese Utility Model Showa 58-62112 (JP, U) Japanese Utility Model Showa 58- 84309 (JP, U) Actually open 57-132050 (JP, U) Actually open 62-87152 (JP, U) Actually open 54-25941 (JP, U) Actually open 2-135617 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F02F 7/00 F01M 11/00

Claims (4)

(57) [Claims] 1. An oil pan mounted on a lower surface of a cylinder block of an internal combustion engine and partially having a deep bottom for storing lubricating oil, and having a shallow bottom in the remaining portion, along the bottom wall surface of the shallow bottom. The inner pan having a bottom wall with a bent shape is accommodated in the shallow bottom without being fixed to the oil pan, and a stopper for preventing the inner pan from moving toward the deep bottom is provided on the oil pan side. Oil pan damping structure of an internal combustion engine. 2. An oil holding wall for holding lubricating oil is formed in a shallow bottom along a boundary between a deep bottom and a shallow bottom of an oil pan, and the oil holding wall is used as the stopper. The oil pan vibration damping structure for an internal combustion engine according to claim 1, wherein 3. An oil pan damping structure for an internal combustion engine according to claim 2, wherein a communication hole is formed in a lower portion of said oil holding wall. 4. The oil pump according to claim 2, wherein a lubricating oil outlet at an end of a relief passage of the oil pump is provided so as to supply lubricating oil into a shallow bottom part partitioned by the oil holding wall. An oil pan vibration damping structure for an internal combustion engine as described in the above.