JPH07332054A - Oil pan vibration damping structure of internal combustion engine and discharging method for lubricant - Google Patents

Abstract

PURPOSE:To smooth discharge of lubricant in a clearance of a double structure- type oil pan. CONSTITUTION:An oil pan 1 is formed by a steel plate, and a drain cock 11 is provided on the bottom of a deep bottom part on the front edge. The inner pan 3 is so formed as to be a little smaller than the oil pan 1 and formed into a similar shape, so that a thin oil layer 4 may be formed between it and the oil pan 1. The inner pan 3 is not fixed to the oil pan 1 and sank in oil by its own weight. The drain cock 11 is arranged on an expansion part 17 formed by partially expanding the oil pan 1 downward, and the tip opening edge 14b of a weld nut 14 is positioned lower than the bottom wall surface of the oil pan 1 on the peripheral edge of the expansion part 17, thereby lubricant between the oil pan 1 and the inner pan 3 is quickly discharged. Moreover, the inner pan 3 may be lifted by inserting a jig through the weld nut 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping structure for an oil pan attached to the lower surface of a cylinder block of an internal combustion engine and a method for discharging lubricating oil thereof.

[0002]

2. Description of the Related Art In many internal combustion engines typified by automobile internal combustion engines, an oil pan having a shallow bottom portion and a deep bottom portion is attached to the lower surface of a cylinder block. It is structured so that it is sucked up by and pumped to each part. Here, the oil pan generally has a thin structure in which a metal plate is press-molded, and therefore, there is a problem in that the vibration of the film causes the vibration of the engine to generate a relatively large radiated sound.

Therefore, in the past, Japanese Patent Laid-Open No. 3-2946
As disclosed in Japanese Patent Publication No. 11 etc., the oil pan has a double structure of an outer oil pan and an inner oil pan, and a gap between the oil pan and the oil pan is filled with lubricating oil to vibrate due to energy damping action due to deformation of the oil layer. A low noise oil pan that suppresses the noise has been proposed. In this case, when the outer oil pan vibrates, the oil layer formed between the outer oil pan and the inner oil pan expands and contracts, and the vibration energy is attenuated by the viscous action of the lubricating oil.

[0004]

However, in the above-mentioned conventional structure, the inner oil pan is fixed to the inner side of the outer oil pan with a slight gap maintained, so that the structure becomes complicated and the working precision and Costs are likely to increase because welding accuracy is also required. The thinner the oil layer sandwiched between the outer oil pan and the inner oil pan is, the greater the energy damping effect can be obtained. However, in the structure in which the inner oil pan is fixed as described above, the gap between the two is reduced. There is a limit to how thin it can be made, and sufficient vibration reduction cannot be achieved. Therefore, the noise reduction effect is lower than the weight increase due to the addition of the inner oil pan,
There was a problem.

Moreover, if a large opening is formed in the inner oil pan corresponding to the drain cock provided at the bottom of the oil pan, the rigidity of the inner oil pan will be reduced.
The energy damping effect is further reduced.

Further, if the gap between the inner oil pan and the outer oil pan is set to be sufficiently small in order to enhance the energy damping action, it becomes difficult to discharge the lubricating oil in the gap when replacing the lubricating oil. Therefore, sludge easily accumulates in the gap. In particular, when the weld nut for the drain cock is arranged on the inner side surface of the outer oil pan, the lubricant is apt to remain in the gap due to being blocked by the weld nut.

[0007]

Therefore, the invention according to claim 1 provides an inner pan having a wall surface along the inner wall surface of the oil pan so as to form a slight gap between the inner pan wall surface including at least the bottom surface. , Is arranged inside the oil pan to form a thin oil layer between the inner pan wall surface and the oil pan inner wall surface, and partially bulges a part of the bottom of the oil pan downward to swell around the drain cock hole. And a drain cock weld nut is provided inside the bulging portion, and a lubricating oil discharge hole having a diameter smaller than that of the drain cock bolt is formed in the inner pan portion corresponding to the drain cock hole. It is characterized by that.

Particularly, in the invention of claim 2, the height position of the tip opening edge of the weld nut is lower than the oil pan bottom wall surface of the peripheral edge of the bulging portion.

According to the third aspect of the invention, a part of the inner pan including the lubricating oil discharge hole is formed so as to bulge inward.

Further, in the invention of claim 4, an inner pan having a wall surface along the inner wall surface of the oil pan so as to form a slight gap with the inner wall surface of the oil pan including at least the bottom surface is arranged inside the oil pan. Then, a thin oil layer is formed between the inner pan wall surface and the oil pan inner wall surface, and a part of the bottom of the oil pan is partially bulged downward to provide a bulge portion surrounding the drain cock hole, and this bulge The weld nut for the drain cock is arranged inside the portion, and the jig contact portion that can contact the jig inserted through the screw hole of the weld nut is provided in the inner pan portion above the drain cock hole. The feature is that it is provided.

According to a fifth aspect of the present invention, the inner pan having a wall surface along the inner wall surface of the oil pan is formed inside the oil pan so as to form a slight gap between the inner wall surface and the inner wall surface of the oil pan including at least the bottom surface. Then, while forming a thin oil layer between the inner pan wall surface and the oil pan inner wall surface,
A part of the bottom of the oil pan is partially inflated downward to provide a bulging part surrounding the drain cock hole, and a drain cock weld nut is arranged inside the bulging part.
A method for discharging lubricating oil in an oil pan damping structure for an internal combustion engine, in which a drain cock bolt is screwed onto the weld nut, wherein a jig is inserted through a screw hole of the weld nut after removing the drain cock bolt. The jig is characterized in that the inner pan is pushed up by this jig to increase the distance from the bottom wall of the oil pan.

Further, in the invention of claim 6, the jig has a tubular shape, and a lubricating oil introducing portion is formed in an opening on a side surface of the tip.

[0013]

The inner pan settles in the oil due to its own weight, whereby the inner wall surface of the oil pan and the inner pan wall surface come close to each other with a slight gap. Lubricating oil intervenes in this gap, whereby a thin oil layer is formed between the wall surfaces. When the oil pan vibrates in this state, the oil layer expands and contracts with a minute change in the distance between the two. That is, the lubricating oil tends to flow along the wall surface in the thin oil layer, and the viscosity of the lubricating oil provides the energy damping action. This suppresses the vibration of the oil pan. Here, since the lubricating oil discharge hole of the inner pan has a small diameter, the rigidity of the inner pan is not significantly reduced, and a good energy damping action can be obtained.

On the other hand, when the drain cock bolt is removed to discharge the lubricating oil, the lubricating oil in the inner pan is discharged through the lubricating oil discharge hole, and the lubricating oil existing in the gap between the inner pan and the oil pan is also removed. It is discharged to the outside. At this time, since the drain cock is in the bulging portion that bulges downward, the lubricating oil present in the gap between the inner pan and the oil pan is smoothly guided to the drain cock and is quickly discharged.

In particular, in the structure of claim 2, since the screw hole of the weld nut is opened below the bottom wall surface of the oil pan, the lubricating oil is reliably discharged without remaining on the oil pan.

Further, according to the third aspect of the present invention, the lubricating oil discharge hole portion of the inner pan is bulged inward, so that the decrease in rigidity of the inner pan due to the opening of the hole is suppressed.

According to the structure of claim 4, when discharging the lubricating oil, the inner pan can be pushed up by inserting the jig through the screw hole of the weld nut. As a result, the lubricating oil is promptly discharged from the gap between the inner pan and the oil pan.

Similarly, in the lubricating oil discharging method of the fifth aspect, the jig is inserted from the screw hole of the weld nut and the inner pan is pushed up, whereby the lubricating oil is quickly discharged from the gap between the inner pan and the oil pan. It

Particularly, when the inner pan is pushed up by using the jig, the lubricating oil in the gap flows into the jig from the lubricating oil introducing portion and is discharged through the tubular jig.

[0020]

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

1 to 4 show a first embodiment of the present invention. The oil pan 1 is formed by press-forming a steel plate, and 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. 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 the outer peripheral edge portion, and the flange portion 2 is bolted to the lower edge of the cylinder block (not shown).

The oil pan 1 contains an inner pan 3 formed by press-forming a steel plate. Like the oil pan 1, the inner pan 3 has a deep bottom portion 3a and a shallow bottom portion 3b, and has a shape along the inner wall surface of the oil pan 1 as a whole. That is, the oil pan 1 has a bottom wall 3c and a side wall 3d that are substantially similar to each other so that a slight gap may occur between the respective wall surfaces when fitted in the oil pan 1. The size is slightly smaller than the shape. The inner pan 3 is not particularly fixed to the oil pan 1, and when it is settled in the oil in the oil pan 1, a thin oil layer 4 is defined between the bottom surface and the side wall surface of the oil pan 1. It has become. In particular, each is formed so that the bottom outer wall surface of the oil pan 1 and the bottom inner wall surface of the inner pan 3 are in close contact with each other as much as possible.

A baffle plate 5 is fixed to the opening of the upper surface of the oil pan 1 by welding so as to suppress the swing of the oil surface. Below the baffle plate 5, that is, between the bottom surface of the oil pan 1 and the baffle plate 5. Inner bread 3 is housed in. As a result, excessive movement of the inner pan 3 is restricted, and there is no risk of interfering with the connecting rod 6 or the crankshaft 7 (see FIG. 2), for example. The baffle plate 5 is provided with a plurality of oil drop holes (not shown) for letting the lubricating oil dropped on the upper surface thereof flow downward, but a part of the oil drop holes is provided near the side edge of the oil pan 1. Thus, the lubricating oil is dropped into the oil layer 4 between the side wall surface of the oil pan 1 and the side wall 3d of the inner pan 3. Therefore, even if the oil level 8 of the oil pan 1 becomes lower than the upper edge of the inner pan 3 during engine operation, the lubricating oil is reliably retained in the oil layer 4.

As shown in FIG. 1, a drain cock 11 is detachably arranged at the bottom of the deep bottom portion 1a of the oil pan 1 for discharging the lubricating oil. A lubricating oil discharge hole 12 is formed in a portion of the inner pan 3 corresponding to the drain cock 11.

FIG. 3 is an enlarged view of the drain cock 11 portion. The drain cock hole 13 is formed in the bottom wall of the oil pan 1.
Is formed and the drain cock hole 13 is formed.
Weld nut 14 inside the oil pan 1
Are welded, and the drain cock bolt 15 is detachably screwed into the screw hole 14a of the weld nut 14. Then, a seal member 16 such as a copper washer is arranged between the flange portion 15a of the drain cock bolt 15 and the oil pan 1 to seal the drain cock hole 13.

Here, a part of the bottom wall of the oil pan 1 including the drain cock hole 13 is a bulging part 17 which is partially bulged downward as shown in the drawing. This bulge 17
Is a substantially flat bottom portion 1 that bulges in a substantially circular shape in a plan view.
7a and a tapered portion 17b having a substantially conical surface. The drain cock hole 13 is opened at the center of the bottom portion 17a. The depth of the bulging portion 17 is set to be slightly larger than the height of the weld nut 14 arranged inside the bulging portion 17. That is, as shown in FIG. 4, the height position of the tip opening edge 14 b of the weld nut 14 is lower than the oil pan 1 bottom wall surface 18 at the peripheral edge of the bulging portion 17.

The inner pan 3 covering the upper surface of the bulging portion 17 is formed substantially flat in this embodiment, and the above-mentioned lubricating oil discharge hole 12 is opened above the weld nut 14. The lubricating oil discharge hole 12 is located concentrically with the weld nut 14, and is formed with a diameter smaller than the diameter of the screw hole 14a, that is, the diameter of the drain cock bolt 15.

Next, the operation of the above embodiment will be described. In the configuration in which the inner pan 3 is disposed in the oil pan 1 via the thin oil layer 4 as described above, when the bottom wall and the side wall of the oil pan 1 vibrate due to the vibration input from the cylinder block side, A slight change in the distance from the inner pan 3 occurs, and the oil layer 4 expands and contracts accordingly. That is, the lubricating oil in the oil layer 4 tries to flow along the two surfaces.
Therefore, the vibration energy is converted into the kinetic energy of the lubricating oil and is attenuated by the viscosity of the lubricating oil. Therefore, the vibration that actually occurs is significantly suppressed, and the radiated sound is reduced.
In particular, in the above configuration, since the inner pan 3 is settled in the oil in a non-fixed state, the thickness of the oil layer 4 is not affected by welding accuracy and the like as compared with the case where the inner pan 3 is welded to the oil pan 1. Can be thin enough. Moreover, with respect to the oil layer 4 between the bottom surface of the oil pan 1 and the bottom wall 3c of the inner pan 3, the inner pan 3 is strongly pressed against the inner wall surface of the oil pan 1 because the weight of the inner pan 3 acts.
Since the oil flows in the thin oil layer 4 generated by this,
A greater energy damping effect is obtained. It should be noted that this damping effect is effective in a wide frequency range as with the damping element in a general vibration model, and the radiated sound can be reduced as a whole. Here, FIG. 5 shows inner bread 3
As shown in the figure, the greater the rigidity of the inner pan 3 is, the more the radiated sound can be reduced. However, in the above-mentioned configuration, the lubricating oil discharge hole that causes the rigidity decrease. Since 12 is small, the decrease in rigidity is small, and therefore the vibration noise can be further reduced.

Further, as shown in FIG. 6, as the inner pan 3 and the oil pan 1 are brought into close contact with each other to make the oil layer 4 thinner, the radiated sound can be reduced, but in the above configuration, the bottom surface of the inner pan 3 and the oil pan 1 are reduced. And can be sufficiently close. Even if the bottom surface of the inner pan 3 is in close contact with the bottom surface of the oil pan 1 in this way, the oil layer 4 can be opened by opening the drain cock 11 when replacing the lubricating oil.
Lubricating oil is quickly discharged including inside. That is,
When the drain cock bolt 15 is loosened and removed from the weld nut 14, the lubricating oil in the inner pan 3 is discharged to the outside through the lubricating oil discharge hole 12 and the screw hole 14a. Further, the lubricating oil between the inner pan 3 and the oil pan 1 is quickly collected in the bulging portion 17 which is relatively lower, and is discharged to the outside through the screw hole 14 a of the weld nut 14. In particular, the tip opening edge 14b of the weld nut 14
However, since it is at a position lower than the oil pan 1 bottom wall surface 18 on the periphery of the bulging portion 17, finally, the lubricating oil is reliably discharged to the liquid level position indicated by the symbol L in FIG. It does not remain on the wall.

Next, FIG. 7 shows a second embodiment of the present invention. In this embodiment, the bulging portion 1 on the oil pan 1 side
The configurations of 7 and the drain cock 11 are the same as those of the first embodiment described above, but the bulging portion 19 is provided on the inner pan 3 so as to face the weld nut 14. The bulging portion 19 of the inner pan 3 bulges inward of the inner pan 3 as opposed to the bulging portion 17 of the oil pan 1, and has a substantially circular bottom surface 19a and a substantially flat bottom portion 19a. It has a tapered portion 19b having a substantially conical surface. And
The lubricating oil discharge hole 12 is opened at the center of the bottom portion 19a. That is, the bulging portion 19 is formed so as to surround the lubricating oil discharge hole 12.

By providing the bulging portion 19 so as to surround the lubricating oil discharge hole 12 in this way, the rigidity of the inner pan 3 made of a steel plate, particularly the rigidity around the lubricating oil discharge hole 19, is improved, and as described above, It is possible to avoid a decrease in effect due to a decrease in rigidity.

FIG. 8 shows a lubricating oil discharging method in which the jig 21 is used to accelerate the discharging of the lubricating oil in the structure of the second embodiment. This jig 21
Is made of a metal tube having a diameter slightly smaller than that of the screw hole 14a of the weld nut 14, and a flange portion 22 extending in the radial direction is integrally provided at the base end thereof. A plurality of introduction portions 23 are formed. When draining the lubricating oil, after removing the drain cock bolt 15, the screw hole 1 of the weld nut 14 is removed.
The tip portion of the jig 21 is inserted through 4a, and is abutted against the inner pan 3 and pushed upward as shown in the drawing. As a result, the inner pan 3 is lifted upward, so that the distance between the bottom wall 3c of the inner pan 3 and the bottom wall of the oil pan 1 is increased, and the lubricating oil between the two is inside the bulging portion 17 around the drain cock 11. To get together easily. Then, the lubricating oil collected in the bulging portion 17 enters the jig 21 from the lubricating oil introducing portion 23 of the jig 21, and is discharged to the outside through the inside of the tubular jig 21. Therefore, the lubricating oil in the oil layer 4 can be easily and surely discharged, and the working time for discharging the lubricating oil can be shortened.

As described above, in the embodiment shown in FIGS. 7 and 8, by forming the lubricating oil discharge hole 12 of the inner pan 3 to have a smaller diameter than the jig 21, the periphery of the lubricating oil discharge hole 12 abuts the jig. It becomes part 24. This lubricating oil discharging method can be applied to the above-described configurations of FIGS. 3 and 4 as well, and in this case also, the periphery of the lubricating oil discharging hole 12 becomes the jig contact portion 24. The lubricating oil discharge hole 12 is formed to have a larger diameter than the jig 21, and
It is also possible to provide a jig contact portion in the shape of a tongue, for example, at a part of the opening edge. Further, the jig 21 is not necessarily limited to the tubular shape, and may be formed in an appropriate shape as long as it is a rod-like shape capable of pushing up the inner pan 3.

[0034]

As is apparent from the above description, claim 1
According to the oil pan damping structure of the internal combustion engine according to the present invention, since the inner pan is settled without being fixed, it is possible to easily manage the thickness of the gap and the like, and it is possible to configure at low cost and to stabilize a sufficiently thin oil layer. Therefore, a good vibration damping action can be obtained. Moreover, by reducing the diameter of the lubricating oil discharge hole,
It is possible to suppress the reduction of the vibration damping effect due to the formation thereof. Then, when the lubricating oil is replaced, the lubricating oil in the oil layer is quickly collected in the bulging portion as the drain cock is opened.
Even if the gap between the bottom wall of the oil pan and the bottom wall of the inner pan is made extremely small, the lubricating oil between the two is reliably and promptly discharged. Therefore, the work time for discharging the lubricating oil can be shortened and the accumulation of sludge can be prevented.

In particular, according to the second aspect of the invention, it is possible to reliably prevent the residual lubricating oil from remaining on the bottom wall surface of the oil pan.

According to the third aspect of the invention, the rigidity around the lubricating oil discharge hole of the inner pan is increased, which is more advantageous in terms of the vibration damping effect.

Further, according to the structure of claim 4, the inner pan can be lifted up in the oil pan by using the jig when replacing the lubricating oil, and the discharging of the lubricating oil can be promoted.

According to the lubricating oil discharge method of claim 5,
Even when the inner pan bottom wall and the oil pan bottom wall are configured to be in close contact with each other, the inner pan can be lifted and the lubricating oil between the two can be easily and surely discharged when the lubricating oil is replaced.

Further, according to the method of claim 6, since the lubricating oil passes through the jig, the work of pushing up the inner pan by the jig becomes easy.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part of an engine showing a first embodiment of the present invention.

FIG. 2 is a transverse sectional view of the same.

FIG. 3 is an enlarged cross-sectional view of part A in FIG. .

FIG. 4 is an enlarged cross-sectional view with a drain cock bolt removed.

FIG. 5 is a characteristic diagram showing a change in radiated sound depending on the rigidity of the inner pan.

FIG. 6 is a characteristic diagram showing changes in radiated sound depending on the thickness of an oil layer.

FIG. 7 is a sectional view similar to FIG. 3, showing a second embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a state when lubricating oil is discharged using a jig.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Oil pan 3 ... Inner pan 4 ... Oil layer 11 ... Drain cock 12 ... Lubricant oil discharge hole 13 ... Drain cock hole 14 ... Weld nut 15 ... Drain cock bolt 17 ... Swelling part 19 ... Swelling part 21 ... Jig 23 ... Lubricant introduction section

Claims (6)

[Claims] 1. An inner pan having a wall surface along the inner wall surface of the oil pan so as to form a slight gap with the inner wall surface of the oil pan including at least the bottom surface is disposed inside the oil pan, and A thin oil layer is formed between the inner wall surface of the oil pan and a part of the bottom of the oil pan is partially expanded downward to provide a bulging portion surrounding the drain cock hole, and the drain cock is provided inside the bulging portion. An oil pan damping structure for an internal combustion engine, comprising: a welding nut for use; and a lubricating oil discharge hole having a diameter smaller than that of a drain cock bolt formed in an inner pan portion corresponding to the drain cock hole. 2. The oil pan control of the internal combustion engine according to claim 1, wherein the height position of the tip opening edge of the weld nut is lower than the oil pan bottom wall surface of the peripheral edge of the bulging portion. Swing structure. 3. The oil pan damping structure for an internal combustion engine according to claim 1, wherein a part of the inner pan including the lubricating oil discharge hole is formed so as to bulge inward. 4. An inner pan having a wall surface along the inner wall surface of the oil pan so as to form a slight gap with the inner wall surface of the oil pan including at least the bottom surface is disposed inside the oil pan, and the inner pan wall surface and A thin oil layer is formed between the inner wall surface of the oil pan and a part of the bottom of the oil pan is partially expanded downward to provide a bulging portion surrounding the drain cock hole, and the drain cock is provided inside the bulging portion. And a jig contact portion capable of contacting a jig inserted through the screw hole of the weld nut is provided in the inner pan portion above the drain cock hole. Oil pan damping structure for internal combustion engine. 5. An inner pan having a wall surface along the inner wall surface of the oil pan so as to form a slight gap with the inner wall surface of the oil pan including at least the bottom surface is arranged inside the oil pan, and A thin oil layer is formed between the inner wall surface of the oil pan and a part of the bottom of the oil pan is partially expanded downward to provide a bulging portion surrounding the drain cock hole, and the drain cock is provided inside the bulging portion. A method for discharging lubricating oil in an oil pan damping structure for an internal combustion engine, in which a weld nut for use is provided and a drain cock bolt is screwed onto the weld nut, the weld nut being removed after the drain cock bolt is removed. A jig is inserted through the screw hole of the internal combustion engine, and the jig is used to push up the inner pan to increase the distance from the bottom wall of the oil pan. Lubricant discharge method pan damping structure. 6. The method for discharging lubricating oil according to claim 5, wherein the jig has a tubular shape, and a lubricating oil introducing portion is formed in an opening on a side surface of the tip.