JP2001295619A - Oil pan vibration control structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the oil pan vibration control structure at a low cost which is fittable directly to an optional part of the oil pan and capable of optionally adjusting the inertia mass, a spring constant and the damping property. SOLUTION: The oil pan vibration control structure of this invention is formed by fitting a dynamic vibration absorber 13, which is formed of a spring plate 2 having a prescribed spring constant and bonded to a surface of an oil pan 14, a mass 1 bonded to the spring plate 2 and having the mass for generating the inertia force and an elastic body 7, having the damping work and pinched by the spring plate 2 and the oil pan 14, so as to resonate with a different phase angle from the natural frequency of the oil pan, when the oil pan is vibrated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil pan for an internal combustion engine for an automobile.

[0002]

2. Description of the Related Art An oil pan of a general automobile internal combustion engine is mounted on a lower surface of a cylinder block. Due to the explosion of the engine, the piston and the crankshaft make a periodic motion and generate vibration. The engine vibration is transmitted from the cylinder block to the oil pan as excitation energy. As a result, the oil pan is vibrated, generating a large radiated sound. Various oil pans have conventionally been proposed to reduce this radiated sound.

[0003] For example, in order to suppress the vibration of the oil pan, a proposal has been adopted in which a rigid bead is provided in the oil pan, or the material itself is a damping steel plate.

In Japanese Patent Application Laid-Open No. 9-280109, an inner pan made of a steel plate is provided inside an oil pan, and a gap serving as an oil layer is formed between the two. When the oil pan vibrates up and down, the oil in the gap attempts to move along the surface of the inner pan, and at that time a damping force F is generated, thereby reducing the oil pan noise.
There has been proposed a vibration damping structure having a so-called two-panel structure of an oil pan main body and an inner panel.

In the engine oil pan structure disclosed in Japanese Patent Application Laid-Open No. 10-288088, an oil pan 14 fixed to a lower portion of a cylinder block 21 is provided as shown in FIG. An elastic member 24 that contacts the wall surface, a pressing member 23 that presses the elastic member 24 against the wall surface, and an elastic member 24 that is attached to the cylinder block.
A so-called dynamic vibration absorber has been proposed, which comprises a pressure member 23 and a support member 22 for holding the pressure member 23. The pressure member 23 has an adjusting means capable of adjusting the pressing force of the elastic member 24. I have.

[0006]

However, in an oil pan provided with a rigid bead that suppresses vibration, the resonance frequency of the oil pan shifts from a low frequency range to a high frequency range due to an increase in surface rigidity. Therefore, there is no dissipation of vibration energy, and there is no vibration reduction effect in all frequency ranges. For this reason, conventionally, it has been mainly employed for the purpose of preventing resonance vibration in the normal rotation range of the engine, and there has been a problem that the effect of reducing the oil pan sound-insulation generated due to the surface vibration of the oil pan is small.

Conventionally, a damping steel sheet has a resin film laminated between two or three steel sheets. However, when a deep drawing of an oil pan is performed, this film is affected by processing stress. There is a problem that the expected vibration damping performance is not exhibited because the film loses and breaks and the film is not uniformly distributed over the entire oil pan after the oil pan is formed. Furthermore, since the value of the loss coefficient varies depending on the temperature due to the temperature dependency inherent to the resin, for example, when the oil pan is sufficiently warmed during engine operation, the value of the loss coefficient is high, and the vibration damping performance is high. The vibration of the oil pan is reduced and the sound radiated from the oil pan is reduced.However, if the oil pan is not sufficiently warm immediately after starting the engine, the value of the loss coefficient is small, There is a problem that the vibration performance is not sufficiently exhibited and the sound radiation from the oil pan is not reduced.

In the oil pan having a two-layer structure proposed in Japanese Patent Application Laid-Open No. 9-280109, although the temperature dependency is less than that of the damping steel sheet, the oil damping performance is inferior. The vibration suppression effect is not sufficient, and the sound radiation reduction effect from the oil pan is small. Further, conventionally, the surface shape of an oil pan obtained by pressing a thin plate is slightly wavy, and there is a problem that two steel plates cannot be formed accurately and in a targeted gap relationship. As a result, there is a problem that desired vibration damping performance is not exhibited and surface vibration of the oil pan is not sufficiently suppressed. Further, it is necessary to separately mold the inner pan and the outer pan, and there is a problem of increased cost due to an increase in the number of dies and processing steps.

[0009] Further, Japanese Patent Application Laid-Open No. 10-28808 shown in FIG.
In the vibration damping structure of the conventional oil pan proposed in Japanese Patent Publication No. 8, a supporting member is extended from a cylinder block to a side surface of the oil pan, and a pressing member is attached to an end of the supporting member.
The pressure member presses the elastic member against the side surface of the oil pan. For example, at a certain frequency, if the vibration surface to be countermeasured is vibrating in the secondary vibration mode, the vibration surface has two antinodes with large amplitudes, but effectively vibrates. In order to suppress it, it is necessary to attach an elastic member to the belly part. In this case, there are two parts with large amplitudes that become the belly.
For each antinode, a supporting member, a pressing member, and an elastic member are required. As a result, the cost is large and the cost is high. In addition, auxiliary parts are generally attached to the periphery of the cylinder block and the oil pan. Therefore, there is a space problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to directly connect an arbitrary portion of a vibrating oil pan, and to provide an inertia mass, a spring constant, and a damping. It is an object of the present invention to provide an inexpensive oil pan vibration damping structure capable of arbitrarily adjusting the characteristics and effectively suppressing vibration with a simple structure.

[0011]

Means for Solving the Problems Claim 1 according to the present invention.
The described oil pan damping structure is a spring plate (2) joined to a surface of an oil pan (14) and having a predetermined spring constant.
A mass (1) joined to the spring plate (2) and having a mass to generate an inertial force; and a spring plate (2) having a damping action.
When the oil pan vibrates, the dynamic vibration absorber (13) constituted by the elastic body (7) sandwiched between the oil pan (14) and the oil pan (14) resonates at a phase angle different from the natural frequency of the oil pan. It is characterized by being mounted as described above.

Further, the oil pan damping structure according to claim 2 is
The spring constant of the spring plate (2) can be set arbitrarily.
2. The spring plate according to claim 1, wherein the spring plate is formed in a hat shape with a shallow bottom, and a corner portion of the spring plate is provided with an arc-shaped flexure. It is.

Further, the oil pan vibration damping structure of the third aspect is
The front portion of the spring plate (2) is bent into an L shape to provide a claw (6), and a U-shaped slit (4) is provided on the upper surface of the spring plate (2), while the elastic body (7) is provided. A groove (10) is provided on the side of the elastic body (7), and a boss (8) is provided on the upper part of the elastic body (7), so that the claw (6) is fitted into the insertion groove (10) of the elastic body (7) and a spring is provided. The boss (8) of the elastic body (7) is fitted in the slit (4) of the plate (2). According to the present invention, the elastic body (7) can be easily attached.

Further, the oil pan vibration damping structure of claim 4 is
A stopper (9) is provided on the upper surface of the elastic body (7), and when the elastic body (7) is inserted between the spring plate (2) and the oil pan (14), the stopper (9) becomes a spring. The elastic member (7) comes into contact with an end portion (5) of the plate to prevent the elastic member (7) from falling off.

[00015]

When the vibration propagates to the oil pan, the shallow bottom portion (17) and the side portion (18) of the oil pan vibrate according to the resonance frequency of the oil pan. In the vibration damping structure of the present invention, the spring plate (2) whose spring constant can be arbitrarily adjusted is connected to the oil pan (1).
An elastic body (7) having a damping action is fitted between the inside of the spring plate (2) and the oil pan (14), and the surface of the spring plate (2) is joined. A mass (1) having a mass that generates an inertial force is joined to the portion to form a dynamic vibration absorber (13), and a spring constant of the system,
The inertial mass and the damping coefficient can be set arbitrarily. When the oil pan vibrates, the dynamic vibration absorber (13) is formed to resonate at a phase angle different from the natural frequency of the oil pan (optimal tuning). As a result, the vibration energy due to the resonance vibration of the oil pan can be reliably attenuated by the dynamic vibration absorber (13). Further, for example, it is also possible to optimally tune only a specific frequency having the highest vibration level among the resonance frequencies of a plurality of oil pans. In this case, it is sufficient to form the minimum necessary dynamic vibration absorber, The size of the vibration structure can be reduced, and the maximum oil pan vibration suppression performance can be obtained with an inexpensive vibration suppression structure.

Further, the vibration damping structure of the present invention can be formed at an arbitrary position on the surface of the oil pan, and the vibration of the oil pan can be reliably suppressed. As a result of suppressing the vibration of the oil pan, the noise radiated from the surface of the oil pan is suppressed, and the noise can be reduced. In addition, as a secondary advantage, it is possible to prevent the oil pan itself from being broken due to the resonance vibration of the oil pan, to improve the durability of the oil pan, and to improve the reliability of the engine itself.

[00017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An oil pan damping structure according to the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view taken along the line AA in FIG. 2, and shows an oil pan vibration damping structure according to claims 1 and 2 of the present invention.
FIG. 2 is a plan view of the oil pan vibration damping structure of the present invention. As shown in FIG. 1, in a first embodiment according to the present invention, a spring plate (2) having a substantially hat-shaped cross section is joined to a surface portion of an oil pan (14). The oil pan is made of, for example, thin steel, and is formed by sheet metal pressing. Spring plate (2)
Is also made of sheet steel, formed by sheet metal pressing, and joined to an oil pan by spot welding or the like. The spring plate (2) has a hat shape with a substantially shallow bottom in its cross section. The spring plate (2) increases or decreases the plate thickness, and as shown in FIG. The spring constant can be arbitrarily set, for example, by setting (3) (second embodiment according to claim 2). The mass (1) is joined to the surface of the spring plate (2). The mass (1) is formed of, for example, a steel plate, and is joined to the surface of the spring plate (2) by spot welding, overlay welding, or the like. The mass (1) has a mass for generating an inertial force with respect to the surface vibration of the oil pan.

The elastic body (7) is formed of, for example, elastic rubber or elastic elastomer. The elastic body (7) is sandwiched between the spring plate (2) and the oil pan (14). The elastic body (7) is sufficiently pressed against the surface of the oil pan (14) by the spring plate (2).

In the oil pan damping structure according to the present invention, a dynamic vibration absorber (13) is formed by the spring plate (2), the mass (1), and the elastic body (7). The spring plate (2) adjusts the natural frequency of the vibration absorber system to be optimally tuned to the natural frequency of the oil pan.
, The mass of the mass (1), the spring constant due to the deflection of the elastic body (7), and the internal damping characteristics are determined. The internal damping characteristic of the elastic body (7) is selected based on, for example, a value such as a loss coefficient.

FIG. 3 is a cross-sectional view taken along the line BB in FIG. 2 and shows a vibration damping structure for an oil pan according to a third aspect of the present invention. FIG. 4 is a cross-sectional view of the oil pan vibration damping structure according to the present invention, taken along line CC in FIG. FIG. 5 is an assembly view and a perspective view of the oil pan vibration damping structure according to the present invention. A third embodiment of the present invention will be described with reference to FIGS. A spring plate (2) formed in a hat shape with a substantially shallow bottom has a claw (6) provided by bending a front portion thereof into an L-shape and a U-shape on the upper surface of the spring plate (2). Slit (4) is provided.

On the other hand, a groove (10) is provided on the side of the elastic body (7), and a boss (8) is provided on the upper part of the elastic body (7). The elastic body (7) is inserted from the open cross-sectional direction of the spring plate (2) as shown in FIGS. At this time, the elastic body (7) is connected to the oil pan (1).
Spring plate (2) so as to be sufficiently pressed against the surface of (4)
And is slightly bent by the pressing pressure. Therefore, when the elastic body (7) is inserted, the slit (6) of the spring plate (2) serves as a guide, and the boss (8) of the elastic body (7) is inserted. Further, the claw (6) of the spring plate (2) fits into the insertion groove (10) of the elastic body (7), and the elastic body (7) is securely inserted at the aimed position, and can be easily attached. .

[0002] A stopper (9) is provided on the upper surface of the elastic body (7). The stopper (9) is inserted in a bent state, and, after being attached, has a structure in which the stopper (9) hooks on the end (5) of the spring plate (2). Therefore, when the oil pan vibrates or the engine itself vibrates up, down, left, and right, it is possible to reliably prevent the elastic body (7) from falling off. The pawl (6) of the spring plate (2) is formed so as to be sufficiently pressed against the elastic body (7). For this reason, when the oil pan vibrates, the spring plate (2) and the elastic body (7) can more reliably move integrally, and together with the mass (1) joined to the spring plate (2), The vibration performance of the dynamic vibration absorber (13) is stabilized.

In a dynamic vibration absorber of a spring-mass system, when the frequency of vibration propagating to an oil pan changes according to the number of revolutions of an engine, the dynamic vibration absorber and the oil pan resonate at a certain frequency, Conversely, there is a problem that surface vibration of the oil pan is amplified. In the dynamic vibration absorber of the present invention, since the dynamic vibration absorber (13) is provided with the elastic body (7) having a damping action, even when the frequency is as described above, the spring plate (2) and the mass (1 ), Spring of elastic body (7)
By optimally designing the mass-damping characteristics, it is possible to perform optimal tuning that can suppress the surface vibration of the oil pan. Specifically, the dynamic vibration absorber (13) is designed to resonate at a phase angle different from the resonance vibration of the oil pan.

Next, embodiments of the present invention will be described. FIG. 6 is a partial sectional perspective view showing an attached state of the oil pan vibration damping structure according to the present invention. The dynamic vibration absorber (13) of the present invention can be arbitrarily attached to a portion of the oil pan where vibration of the oil pan surface is large, such as a shallow bottom portion or a side portion. Further, a method of setting the mounting position of the dynamic vibration absorber (13) of the present invention will be described based on an example in which an experimental modal analysis is performed by a hammering test in a state where the oil pan is mounted on the engine.

FIG. 8 shows an experimental modal analysis model of the shallow bottom portion (17) and the side portion (18) of the oil pan. When a hammering test was performed on the oil pan while the oil pan was mounted on an engine, a frequency response function as shown in FIG. 9 was obtained at the shallow bottom center point. Here, attention was paid to the outstanding vibration peaks # 1 to # 3, and an experimental modal analysis was performed. FIG. 10 shows the analysis result. According to the analysis results, vibration mode shapes corresponding to the frequencies appear at the shallow bottom portion (17) and the side portion (18) of the oil pan. Here, a part having the largest vibration amplitude is defined as an antinode, and a part having the least vibration amplitude is defined as a node. The dynamic vibration absorber (13) in the oil pan vibration damping structure of the present invention has the object of suppressing the surface vibration of the oil pan, and is attached to the antinode of the vibration mode shape of the countermeasure frequency.

FIG. 11 shows a dynamic vibration absorber (13) for each of the shallow bottom portion (17) and left and right side portions (18) of the oil pan shown in FIG. 7 shows the noise reduction effect at 60 cm below the oil pan when the camera is attached. Comparing the dynamic vibration absorber (solid line) and without the dynamic vibration absorber (dashed line), the overall value (A characteristic correction)
As a result, a noise reduction effect of about 4 dBA was obtained.

[00027]

As described in detail above, according to the present invention,
A surface vibration of the oil pan can be suppressed with a simple structure, and an oil pan that is easy to manufacture and has excellent durability can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view taken along line AA in FIG. 2, and shows an oil pan vibration damping structure according to claims 1 and 2 of the present invention.

FIG. 2 is a plan view of the oil pan vibration damping structure of the present invention.

FIG. 3 is a cross-sectional view taken along the line BB in FIG. 2, showing a vibration damping structure for an oil pan according to the third embodiment of the present invention.

FIG. 4 is a sectional view taken along line CC in FIG. 2;

FIG. 5 is an assembly view and a perspective view of an oil pan vibration damping structure according to the present invention.

FIG. 6 is a partial cross-sectional perspective view showing an attached state of an oil pan vibration damping structure according to the present invention.

FIG. 7 shows a vibration damping structure of a conventional oil pan.

FIG. 8 shows an experimental modal analysis model of a shallow portion and a side portion of an oil pan.

FIG. 9 shows a frequency response function at a shallow bottom center point of the oil pan shown in FIG. 8;

10 shows experimental results of an experimental modal analysis of the oil pan shown in FIG. 8, and shows # in the frequency response function shown in FIG.
Vibration mode shapes corresponding to 1 to # 3.

FIG. 11 is a noise characteristic diagram showing a noise reduction effect when the dynamic vibration absorber of the present invention is attached to a shallow bottom portion and a side portion of the oil pan shown in FIG.

[Explanation of symbols]

1 mass 2 spring plate
3 Flexure 4 Slit 5 End
6 Claw 7 Elastic body 8 Boss
9 Stopper 10 Insertion groove 11 Joint
12 Joint 13 Dynamic vibration absorber 14 Oil pan
15 Inside surface 16 Outside surface 17 Shallow bottom
18 side part 19 belly 20 sections
21 Cylinder block 22 Support member 23 Pressurizing member
24 elastic members

Claims (4)

[Claims] 1. A spring plate (2) joined to the surface of an oil pan (14) and having a predetermined spring constant, and a mass (1) joined to the spring plate (2) and having a mass generating an inertial force. When the oil pan vibrates, the dynamic vibration absorber (13) constituted by a spring plate (2) having a damping action and an elastic body (7) sandwiched between the oil pan (14) is moved. An oil pan damping structure characterized by being mounted so as to resonate at a phase angle different from the natural frequency of the oil pan. 2. The spring plate (2) is formed in a hat shape with a shallow bottom so that the spring constant of the spring plate (2) can be set arbitrarily. The oil pan vibration damping structure according to claim 1, wherein an arc-shaped flexure (3) is provided. 3. A front portion of the spring plate (2) is bent into an L-shape to provide a claw (6) and a U-shaped slit (4) on the upper surface of the spring plate (2). A groove (10) is provided on the side of the elastic body (7), and a boss (8) is provided on the upper part of the elastic body (7), and the claw (6) is attached to the elastic body (7).
The boss (8) of the elastic body (7) is fitted in the slit (4) of the spring plate (2) and the fitting groove (10). Item 2
The described oil pan damping structure. 4. A stopper (9) is provided on the upper surface of the elastic body (7), and the elastic body (7) is attached to the spring plate (2) and the oil pan (1).
When inserted between (4) and (4), the stopper (9) comes into contact with the end (5) of the spring plate to prevent the elastic body (7) from falling off. The oil pan damping structure according to claim 1, 2, or 3.