JPH07293328A - Vibration damping structure for oil pan of internal combustion engine - Google Patents

Abstract

PURPOSE:To effectively reduce radiation noise generated from an oil pan by means of an oil layer between the oil pan and an inner pan and suppress generation of abnormal noises caused by vibration of the inner pan at the starting time. CONSTITUTION:An oil pan 1 made of a steel plate has an oil holding wall 3 along a boundary between its deep bottom 1a and its shallow bottom 1b. An inner pan 4 is housed in the shallow bottom 1b partitioned by the oil holding wall 3 in a non-fixed condition, while a thin oil layer is formed between the inner pan 4 and the inner wall surface of the oil pan 1. A communication hole is opened on a center part of a lower portion of the oil holding wall 3 so as to drop lubricating oil into the deep bottom part 1a at the stopping time of an engine. A temperature sensing stopper 6 made of strip bimetal is arranged on a side wall of the inner pan 4. The temperature sensing stopper 6 is extended to the side of the oil pan 1 together with temperature lowering, and press-fitted to the oil pan 1 to fix the inner pan 4.

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.

[0002]

2. Description of the Related Art In many internal combustion engines represented by automobile internal combustion engines, a lower surface of a cylinder block is provided with a relatively deep oil pan in which lubricating oil is stored and is sucked up by an oil pump to be pumped to respective parts. It is composed. 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, the conventional method has been used.
As disclosed in Japanese Patent No. 41, Japanese Unexamined Patent Publication No. 3-294611, etc., an oil pan has a double structure of an outer plate and an inner plate, and a gap between the two is filled with lubricating oil to flow the oil layer. A low-noise oil pan has been proposed in which vibration is suppressed by the energy damping action of the.

[0004]

However, in the above-mentioned conventional structure, the inner plate is fixed to the inner side of the outer plate while keeping a slight gap, so that the structure is complicated and the working accuracy is required. Therefore, the cost is likely to increase. Also, the thinner the thickness of the oil layer, that is, the smaller the gap between the outer plate and the inner plate, the greater the energy damping effect associated with the oil flow can be obtained.
With the configuration in which the inner plate is fixed as described above, not only can the gap not be made so thin, but also the effect of pressing the inner plate against the oil layer cannot be utilized, so that the flow of the lubricating oil in the oil layer A large energy damping effect cannot be obtained. Therefore, there is a problem that the noise reduction effect is lower than the weight increase due to the addition of the inner plate.

When the inner plate forming the oil layer is not fixed and is placed along the outer plate, the oil layer between the two is lost during a long-term stop of the engine, and at the time of subsequent starting, The inner plate and the outer plate may come into contact with each other to generate abnormal noise. In particular,
At the shallow bottom of the oil pan, the lubricating oil tends to flow down to the deep bottom after the engine is stopped, so the oil layer is likely to be lost during the stop.

[0006]

Therefore, the present invention provides an inner pan having a wall surface along the oil pan inner wall surface so as to form a slight gap between the oil pan inner wall surface including at least a part of the bottom surface. It is placed inside the oil pan without fixing it to the oil pan, and on the side wall of the inner pan,
The present invention is characterized in that one or more temperature-sensitive stoppers that project toward the oil pan at normal temperature and retract at high temperatures are provided, and the inner pan is fixed to the oil pan by the temperature-sensitive stoppers at normal temperature.

Particularly in claim 2, an oil holding wall for holding the lubricating oil is formed in the shallow bottom portion along the boundary between the deep bottom portion and the shallow bottom portion of the oil pan, and the oil holding wall is partitioned by the oil holding wall. The inner pan is arranged along the inside of the shallow bottom.

According to a third aspect of the present invention, the oil pan comprises an oil pan main body and a sub tank welded and fixed to a lower surface of the oil pan main body. An inner pan having an opening corresponding to the opening of the sub tank is provided in the oil pan main body. It is characterized in that it is arranged along the inner side of.

Further, in claim 4, at least a pair of temperature-sensitive stoppers are arranged so as to face each other.

[0010]

When the engine is in operation, lubricating oil and oil droplets scattered in the crankcase are constantly supplied to the inside of the oil pan along the inner wall surface of the crankcase. Then, the inner pan tries to come into pressure contact with the bottom surface of the oil pan due to its own weight. Therefore, the inner wall surface of the oil pan and the outer surface of the inner pan are close to each other via the thin oil layer. When the oil pan tries to vibrate in this state, the oil layer expands and contracts with a minute change in the distance between the two, and an energy damping action is obtained. This suppresses the vibration of the oil pan. In particular, the pressure of the oil layer between the inner pan and the bottom surface of the oil pan increases due to the weight of the inner pan, and the lubricating oil flows while the pressure is high, so that energy attenuation is further increased.

When the ambient temperature returns to room temperature after the engine is stopped, the temperature-sensitive stopper on the side wall of the inner pan projects toward the oil pan and presses against the oil pan. Therefore, when the engine is started next time, the inner pan is fixed to the oil pan, and no interference sound is emitted.

According to the second aspect of the present invention, the lubricating oil is positively retained in the shallow bottom portion by the oil retaining wall, and the oil layer between the oil pan and the inner pan is reliably formed during engine operation. .

According to the third aspect of the invention, the lubricating oil flows down from the oil pan body to the sub-tank side after the engine is stopped, but when the ambient temperature returns to room temperature, the inner pan is fixed by the temperature-sensitive stopper.

According to the fourth aspect of the present invention, when the temperature returns to room temperature, the inner pan is fixed substantially at the center by the pair of temperature-sensitive stoppers arranged to face each other. That is, the gaps are substantially evenly secured on both sides, and after the engine is started, the lubricating oil quickly flows in between the inner pan and the oil pan.

[0015]

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 3 show an 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. A step portion 1c that rises further upward is provided on the rear end side of the 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 of the oil pan 1, and the flange portion 2 is bolted to the lower edge of a cylinder block (not shown).

A deep bottom portion 1a and a shallow bottom portion 1 of the oil pan 1
An oil retaining wall 3 is fixed along the width direction of the oil pan 1 at the boundary with b. The oil retaining wall 3 is the step portion 1
It is formed in an elongated rectangular shape so as to form a weir having substantially the same height as c, and is welded to the bottom wall surface and the side wall surface of the oil pan 1, respectively. That is, this oil retaining wall 3
Thus, the deep bottom portion 1a and the shallow bottom portion 1b are partitioned at substantially the same height as the step portion 1c.

Inside the shallow bottom portion 1b of the oil pan 1 partitioned by the oil holding wall 3 and the step portion 1c, an inner pan 4 having a rectangular shallow dish shape is accommodated. The inner pan 4 is made of a press-formed product of a steel plate, and has a bottom wall formed along the bottom wall surface of the shallow bottom portion 1b of the oil pan 1. In addition, the side wall provided at a low height on the periphery thereof has a curved cross section 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. They are close to each other leaving a large gap. The inner pan 4 is not fixed to the oil pan 1.

A baffle plate (not shown) is fixed to the upper opening of the oil pan 1 by welding in order to prevent the oil surface from swinging. The baffle plate is below the baffle plate, that is, the bottom surface of the oil pan 1. The inner pan 4 is accommodated in the space. As a result, excessive movement of the inner pan 4 upward is restricted, and there is no risk of interfering with, for example, a connecting rod or a crankshaft (not shown). Further, the gap between the baffle plate and the upper end of the oil retaining wall 3 is smaller than the height of the inner pan 4, and the forward movement of the inner pan 4, that is, the movement toward the deep bottom portion 1a side is restricted.

Further, as shown in FIG. 2, a communication hole 5 is formed in the center of the lower portion of the oil retaining wall 3 for communicating the inside of the shallow bottom portion 1b with the side of the deep bottom portion 1a. This is for discharging the lubricating oil in the shallow bottom portion 1b at the time of replacing the lubricating oil, and the opening area thereof is appropriately set so that the lubricating oil accumulates in the shallow bottom portion 1b during engine operation. . Since it is necessary to discharge the lubricating oil in the inner pan 4 at the time of replacing the lubricating oil, an oil discharging hole (not shown) of an appropriate size is formed in the bottom of the inner pan 4.

Temperature-sensitive stoppers 6 are arranged on the four side walls of the inner pan 4, respectively. The temperature-sensitive stopper 6 is made of a flat-belt-shaped bimetal, and a recess 7 having a depth corresponding to the plate thickness is formed on the side wall of the inner pan 4, and an end portion of the bimetal fitted and arranged in the recess 7 is formed. Is welded to the inner pan 4. This temperature-sensitive stopper 6
When the temperature is high (for example, 80 ° C. or higher), the shape retreats toward the inner side of the inner pan 4 as shown in FIG.
In the following, it is configured so as to be deformed into a shape protruding outward as shown in FIG. The temperature-sensitive stopper 6 may be made of shape memory alloy.

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 pressure-fed to each part 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 along the inner wall surface of the crankcase, and flows down to the oil pan 1. Then, a part of it passes through the oil drain hole of the baffle plate (not shown) and the shallow bottom part 1
It also flows into b. Oil droplets scattered in the crankcase also enter the shallow bottom portion 1b. Therefore, during the engine operation, the lubricating oil is positively retained in the shallow bottom portion 1b partitioned by the oil retaining wall 3. Further, since the lubricating oil temperature is high at the stage when the engine warm-up is completed, the temperature-sensitive stopper 6
Is retracted as shown in FIG. Therefore, the inner pan 4 becomes unfixed and settles in the oil, and a very thin oil layer is formed between the inner pan 4 and the oil pan 1 that are pressed against the oil pan 1 by their own weight. .

When the bottom wall of the oil pan 1, particularly the bottom wall of the shallow bottom portion 1b, vibrates due to the film vibration due to the vibration input from the cylinder block side with the oil layer thus formed, the oil pan 1
A slight change occurs in the distance between the inner pan 4 and the inner pan 4, and the oil layer expands and contracts accordingly. That is, the lubricating oil in the oil layer tends 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 friction with each wall surface and the friction between the oils. Therefore, the vibration that actually occurs is significantly suppressed, and the radiated sound is reduced. Since this damping action acts on a plurality of membrane resonances similarly to the damping element in a general vibration model, it has an effect in a wide frequency range, and radiated sound can be reduced as a whole.
In particular, since the weight of the inner pan 4 acts on the oil layer of the bottom wall, a greater vibration damping effect can be obtained as the lubricating oil moves in the oil layer. Since a relatively large amount of lubricating oil is stored in the deep bottom portion 1a even during engine operation, this reduces the sound emitted from the deep bottom portion 1a.

Further, in the above structure, the oil retaining wall 3 is provided with the communication hole 5
Is open, so that when the engine is stopped, all of the lubricating oil in the shallow bottom portion 1b moves into the deep bottom portion 1a (the oil surface position when the engine is stopped is indicated by symbol L1). Therefore, when replacing the lubricating oil, the entire lubricating oil in the crankcase can be reliably replaced. In addition, the retention of the lubricating oil in the shallow bottom portion 1b is prevented, and the accumulation of sludge is suppressed.

Here, the temperature-sensitive stopper 6 of the inner pan 4
When the temperature of the lubricating oil reaches room temperature, it bulges outward and presses against the oil pan 1 as shown in FIG. Therefore, the inner pan 4 is fixed to the oil pan 1. Therefore,
Even if the oil film between the inner pan 4 and the oil pan 1 is lost due to a long-term stop, the inner pan 4 does not move until the lubricating oil is sufficiently warmed at the next start, and the inner pan 4 does not move. The generation of abnormal noise due to the vibration of In particular, in the above-described embodiment, the temperature sensitive stoppers 6 are arranged on the four sides of the inner pan 4, and these hold the inner pan 4 at a position where a gap is maintained substantially at the center of the shallow bottom portion 1b, that is, at the four sides. Therefore, after starting, the lubricating oil quickly flows in through the gaps between the respective parts, and the oil layer between the inner pan 4 and the oil pan 1 can be secured.

Next, FIGS. 4 and 5 show different embodiments of the present invention. In this embodiment, the oil pan 1
The oil pan main body 11 is formed by pressing a steel plate, and the sub tank 12 is fixed to the front end of the oil pan main body 11 and is a separate member. Oil pan body 1
In No. 1, the whole is formed relatively shallow, and a substantially rectangular opening 13 is formed in a portion near the front end of the engine. The sub-tank 12 is fixed to the bottom surface of the oil pan body 11 by welding so as to surround the opening 13. The sub-tank 12 constitutes a tank portion 14 for storing the lubricating oil.
Communicates with the inside of the oil pan body 11 through the opening 13. The bottom wall surface of the oil pan body 11 is a substantially flat surface. A flange portion 15 is formed on the outer peripheral edge portion of the oil pan body 11.

Inside the oil pan body 11, an inner pan 4 formed by pressing a steel plate is housed.
The inner pan 4 has a shape along the inner wall surface of the oil pan body 11. That is, it has a bottom wall and a side wall having a shape along the bottom wall surface and the side wall surface of the oil pan main body 11, and a slight gap may be generated between the respective wall surfaces in a state where the bottom wall and the side wall are overlapped in the oil pan main body 11. The overall size is slightly smaller than the inner wall surface shape of the oil pan body 11. The bottom of the oil pan body 1
An opening 16 is formed to match the first opening 13. The inner pan 4 is not fixed to the oil pan main body 11 as in the above embodiment, and is in a state of being able to freely move up and down. A baffle plate (not shown) is attached to the upper opening of the oil pan body 11 to prevent excessive movement such that the inner pan 4 and the crankshaft interfere with each other.

On the four side walls of the inner pan 4,
As in the above-mentioned embodiment, the temperature-sensitive stopper 6 made of bimetal is provided. On two sides along the longitudinal direction of the inner pan 4, two temperature-sensitive stoppers 6 are provided at the front and rear, and the inner pan 4 as a whole has six temperature-sensitive stoppers 6.

Also in this embodiment, when the temperature of the lubricating oil is high, the temperature-sensitive stopper 6 is retracted so that the inner pan 4 can move freely through the oil layer.
The vibration of No. 1 can be effectively suppressed. Also, after the engine is stopped,
Although the lubricating oil flows into the sub-tank 12, the temperature-sensitive stopper 6 bulges outward as the temperature of the lubricating oil decreases, and the inner pan 4 is fixed to the oil pan main body 11. No abnormal noise is generated due to vibration.

[0030]

As is apparent from the above description, according to the oil pan damping structure for the internal combustion engine of the present invention, the inner pan is housed in the oil pan without being fixed, and a thin oil layer is secured between the inner pan and the inner pan. Since it was done, the configuration becomes simple,
Vibration noise can be reduced at low cost. In addition, it is easy to control the gap between the oil pan and the oil layer, and especially at the bottom part, it is possible to stably secure a sufficiently thin oil layer due to the weight of the inner pan, and increase the pressure. Therefore, the damping action is further enhanced. Further, after the engine is stopped, the inner pan is fixed to the oil pan by the temperature-sensitive stopper, so that there is no fear that the inner pan will vibrate and generate an abnormal noise at the next start.

If the shallow bottom portion in which the inner pan is accommodated is defined by the oil retaining wall, the lubricating oil can be reliably retained in the shallow bottom portion.
It is possible to more reliably avoid direct contact between the inner pan and the oil pan without an oil layer.

Further, according to the third aspect of the invention, the inner pan can be formed so as to widely cover the oil pan main body excluding the sub-tank portion, and the radiated sound of the oil pan main body can be greatly suppressed.

Further, if the temperature-sensitive stoppers are arranged to face each other as in the fourth aspect, a gap can be secured on both sides of the inner pan, and the lubricating oil will flow in quickly at the time of starting.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

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

FIG. 3 is an explanatory view showing a state (a) at a high temperature of the temperature sensitive stopper and a state (b) at a normal temperature.

FIG. 4 is a plan view showing another embodiment of the present invention.

FIG. 5 is a partially cutaway sectional view of this embodiment.

[Explanation of symbols]

 1 ... Oil pan 3 ... Oil holding wall 4 ... Inner pan 6 ... Temperature-sensitive stopper 11 ... Oil pan main body 12 ... Sub tank

Claims (4)

[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 a part of the bottom surface, without fixing the inner pan to the oil pan. In addition to being placed inside, the sidewall of the inner pan overhangs to the oil pan side at normal temperature and is equipped with one or more temperature-sensitive stoppers that retract at high temperature. An oil pan damping structure for an internal combustion engine, characterized in that 2. An oil holding wall for holding lubricating oil is formed in the shallow bottom along the boundary between the deep bottom and the shallow bottom of the oil pan, and the inside of the shallow bottom partitioned by the oil holding wall. An inner pan is arranged along the inner surface of the inner pan.
An oil pan damping structure for an internal combustion engine as described. 3. The inner pan having an opening corresponding to the opening of the sub-tank is formed along the inner side of the oil pan main body, the inner pan including an oil pan main body and a sub-tank fixed to the lower surface of the oil pan by welding. The oil pan damping structure for an internal combustion engine according to claim 1, wherein 4. At least one pair of temperature-sensitive stoppers are arranged so as to face each other.
An oil pan damping structure for an internal combustion engine according to any one of 1.