JP2007100889A - Strut mount - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To absorb great external force exerted from a shock absorber and absorb slight high-frequency vibration which may occur during high speed travel. <P>SOLUTION: This strut mount comprises an outside fitting 9 mounted on a vehicle body, an inside fitting 4 mounted on a piston rod 2 of the shock absorber, and a rubber elastic body 7 to be pressed into a storage portion of the outside fitting in the state of being formed on the outer periphery of the inside fitting integrally with the inside fitting when mounted between the outside fitting and the inside fitting. Between the outside fitting and the rubber elastic body, a soft layer 8 is mounted which has a higher loss factor and lower density than the rubber elastic body. Thus, the soft layer absorbs slight high-frequency vibration and the rubber elastic body absorbs great external force. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a strut mount for mounting a shock absorber constituting a suspension mechanism of a vehicle on a vehicle body.

Some vehicles, such as automobiles, have a strut-type suspension mechanism formed of a shock absorber or the like between a wheel and a vehicle body. In the strut type sun suspension mechanism, a shock absorber is mounted on the vehicle body via a strut mount.
Most strut mounts press-fit a rubber elastic body that is integrated with the inner metal fitting into the outer metal fitting housing, and a metal plate that prevents the dropout from being placed in the opening of the housing to prevent the inner metal fitting and rubber elastic. It is configured to prevent the body from falling off the outer fitting. In addition, an outer plate is attached to the outer periphery of the rubber elastic body and the outer plate is press-fitted into the outer metal fitting in order to firmly support the rubber elastic body integrated with the inner metal fitting to the outer metal fitting. Have been proposed to support this. In the strut mount having such a configuration, since the input from the road surface enters the inner cylinder fitting attached to the inner periphery of the rubber elastic body, and external force is transmitted from the vehicle body side through the outer plate provided on the outer periphery, the rubber elasticity A large shear stress is generated in the body, and there is a problem in terms of durability of the rubber elastic body. In order to cope with such a problem, there has also been proposed a structure in which a stopper cushion is interposed between the rubber elastic body and the outer metal fitting to reduce the shearing force applied to the rubber elastic body (for example, Patent Document 1). 2).
JP 2001-65626 A JP 2001-82530 A

By the way, the rubber elastic body used in the above-described conventional strut mount is usually desired to have a high spring constant for a large input. Is difficult to absorb with shock absorbers and coil springs, so it has a low dynamic spring constant and a high loss factor in order to absorb these vibrations and improve riding comfort. Required. However, having these high spring constants and having a low dynamic spring constant and a high loss factor are in a contradictory relationship, and it has been very difficult to satisfy these simultaneously.
In particular, in recent years, the weight of the vehicle body has increased significantly in order to improve safety and comfort, and along with this, the external force applied to the strut mount has increased and the required performance has also increased. While maintaining a high static spring constant, it is required to achieve both a low spring constant and a high loss coefficient at the same time.

Further, in the conventional strut mounts described above, since the rubber elastic body is attached to the outer metal fitting using the outer plate, it is difficult to reduce the size as much as the space for accommodating the outer plate is secured. Further, although the stopper cushion is interposed between the rubber elastic body and the outer metal fitting, the problem of deterioration of the durability of the rubber elastic body due to the great shear stress is not completely solved.
In addition, since a gap is formed between the outer metal fitting and the rubber elastic body, when a large external force is applied that causes the stopper cushion to fully compress, the external force cannot be absorbed by the stopper cushion, and the rubber elastic body and the outer There has been a problem that there is a possibility that an abnormal noise such as a hitting sound or a rubbing sound may be generated due to a momentary contact displacement between the metal fitting or the stopper cushion.

The present invention has been made in view of the above circumstances, and can absorb even when a large external force is applied from a shock absorber, and also absorbs minute high-frequency vibration that tends to occur during high-speed running and the like. An object of the present invention is to provide a strut mount that can be used.
Another object of the present invention is to provide a strut mount that can be made compact and can improve durability.
Furthermore, the other object of this invention is to provide the strut mount which prevents generation | occurrence | production of unusual sounds, such as a hitting sound and a rubbing sound.

The present invention employs the following means in order to solve the above problems.
The strut mount according to the present invention includes an outer metal fitting attached to a vehicle body, an inner metal fitting attached to a piston rod of a shock absorber, and a state in which the inner metal fitting is integrally formed on the outer periphery of the inner metal fitting. In a strut mount comprising a rubber elastic body interposed between the outer metal fitting and the inner metal fitting by being press-fitted into a storage portion of the outer metal fitting, between the outer metal fitting and the rubber elastic body. A soft layer having a loss factor higher than that of the rubber elastic body and having a low density is interposed.

In this strut mount, a soft layer having a loss factor higher than that of the rubber elastic body and having a low density is interposed between the outer metal fitting and the rubber elastic body. As a result, a soft layer with a low dynamic spring constant and a high loss factor absorbs minute high-frequency vibrations because of its softness and low density, while it does not absorb large external forces from a shock absorber. The rubber elastic body is appropriately deformed and absorbed.
In this way, the soft layer deforms and absorbs the vibration mainly for minute high-frequency vibrations, and the large elastic force mainly deforms the relatively rigid rubber elastic body for large external forces. To absorb.

In the strut mount according to the present invention, the outer metal fitting includes an outer metal fitting body in which the storage portion is formed, and the rubber elastic body that is disposed in the opening portion of the storage portion and press-fitted into the storage portion. It has the fall prevention plate which prevents the fall of a soft layer.
In this strut mount, the rubber elastic body is supported in a press-fit state in the storage portion. However, even if a force stronger than the support force is applied from the shock absorber to the rubber elastic body, the rubber elastic body etc. The rubber elastic body or the like is prevented from falling out of the storage portion and falling off.

The strut mount according to the present invention is characterized in that the soft layer is formed at an end portion on at least one side in the axial direction of the piston rod in the rubber elastic body.
In this strut mount, a force is often applied from the piston rod or the vehicle body along the axial direction of the piston rod. In this case, a compressive force or a tensile force acts on the soft layer instead of a shearing force. This type of soft layer has a sufficient proof strength compared to the action of a shearing force, particularly when a compressive force is applied. By effectively utilizing this sufficient proof stress, durability of the soft layer can be improved.

The strut mount according to the present invention is characterized in that the soft layer is formed of a foam material.
Since this strut mount uses an easily available and inexpensive foam material, a soft layer having a low dynamic spring constant and a high loss factor can be produced easily and at low cost.

The strut mount according to the present invention is characterized in that the soft layer is formed of urethane.
Since this strut mount uses urethane which is easy to obtain and inexpensive, a soft layer having a low dynamic spring constant and a high loss factor can be produced easily and at low cost.

Further, the strut mount according to the present invention is characterized in that the rubber elastic body is press-fitted into the storage portion with its radially outer peripheral surface being in direct contact with the inner peripheral surface of the storage portion.
In this strut mount, the rubber elastic body is brought into direct contact with the inner peripheral surface of the storage portion and press-fitted into the storage portion. Compactness can be achieved by the thickness of the other members.

Further, the strut mount according to the present invention is characterized in that the rubber elastic body is press-fitted into the storage portion with the soft layer formed on a radially outer peripheral surface thereof.
In this strut mount, a rubber elastic body is press-fitted into the storage portion via the soft layer, and the soft layer can be interposed between the rubber elastic body and the storage portion, so that the rubber elastic body and the storage portion are It is possible to fill the gap that tends to occur with the soft layer. As a result, when there is a gap between the rubber elastic body and the storage portion, it is possible to prevent the generation of abnormal sounds such as a hitting sound and a rubbing sound that tend to occur between the two.

Moreover, the strut mount according to the present invention is characterized in that the soft layer is press-fitted into the storage portion with pre-compression.
In this strut mount, since the soft layer is pre-compressed and set in the storage portion, a gap is not easily formed between the soft layer and the storage portion. The occurrence of abnormal noise such as can be prevented.
The strut mount according to the present invention is characterized in that the drop-off prevention plate is fixed to the outer metal fitting main body at the periphery thereof.
In this strut mount, the drop-off prevention plate is fixed to the outer metal fitting body at the periphery, so that the force applied to the drop-off prevention plate can be transmitted to the outer metal fitting body via a rubber elastic body, etc. The strength of the outer bracket can be increased.

According to the present invention, in the strut mount, a soft layer having a lower loss coefficient and a lower density than the rubber elastic body is interposed between the outer metal fitting or the inner metal and the rubber elastic body. As a result, a soft layer with a low dynamic spring constant and a high loss factor absorbs minute high-frequency vibrations because of its softness and low density, while it does not absorb large external forces from a shock absorber. The rubber elastic body is appropriately deformed and absorbed.
In this way, the soft layer deforms and absorbs the vibration mainly for minute high-frequency vibrations, and the large elastic force mainly deforms the relatively rigid rubber elastic body for large external forces. Can be absorbed. In addition, the rigidity of the rubber elastic body can be increased by arbitrarily increasing the hardness of the rubber elastic body in order to cope with a large external force without considering the absorption of high-frequency vibrations in this way, so that the durability can be improved accordingly. it can.

  A first embodiment according to the present invention will be described with reference to FIGS. The strut mount 1 of the present embodiment is used as an upper mount for connecting a shock absorber constituting a part of a strut type suspension mechanism to a vehicle body of an automobile. The shock absorber includes a cylinder portion having a built-in piston and a piston rod 2 connected to the piston and projecting outward from the cylinder portion, and a coil spring 3 is fitted on the outer peripheral side of the piston rod 2.

  A strut mount 1 is attached via a bolt 10 to a fender apron or the like of the vehicle body. A piston rod 2 is connected to the strut mount 1, whereby a shock absorber constituting a part of the suspension mechanism is attached to the vehicle body via the strut mount 1.

  An inner metal fitting 4 is disposed at the center of the strut mount 1. The inner metal fitting 4 is composed of a cylindrical portion 4a and an outer flange portion 4b formed so as to expand outward at one end (upper end in FIG. 1) of the cylindrical portion, and a through hole 4c is formed in the central portion. ing. The tip of the piston rod 2 of the shock absorber is inserted through the through hole 4c. A portion of the piston rod 2 that protrudes upward from the inner metal fitting 4 is formed with a male screw portion 2 a, and a nut 5 is screwed into the male screw portion 2 a, whereby the piston rod 2 is connected to the inner metal fitting 4.

  A rubber elastic body 7 is vulcanized and formed integrally with the inner metal fitting 4 on the outer circumference of the inner metal fitting 4 so as to surround the outer flange portion 4b of the inner metal fitting 4 from both the upper and lower surfaces and the outer peripheral side. And the soft layers 8 and 8 are attached to the up-and-down both ends of the rubber elastic body 7, respectively. The soft layer 8 may be integrally formed with the rubber elastic body 7 at the same time when the rubber elastic body 7 is formed by vortexing.

As shown in FIGS. 2 and 3, the rubber elastic body 7 is formed in a substantially truncated cone shape that gradually narrows downward, and a plurality of concave portions 7a extending in the axial direction are formed in the outer peripheral portion. It is formed with an interval, and thereby has a non-circular shape in plan view in which axial rotation is restricted. At the upper and lower ends of the rubber elastic body 7, a soft layer 8 having a predetermined height is formed with the same ridge line as the rubber elastic body 7 so as to be continuous with the rubber elastic body 7.
Here, the soft layer 8 is formed on the upper and lower ends of the rubber elastic body 7, that is, on the end of the piston rod 2 in the axial direction so as to overlap with the rubber elastic body 7. A so-called sandwich structure is formed by 8 and the central rubber elastic body 7.
The soft layer 8 is made of a material having a loss factor higher than that of the rubber elastic body 7 and a low density, such as foaming urethane or soft rubber.
The shape of the rubber elastic body 7 is not necessarily formed in a truncated cone shape, and may be formed in a cylindrical shape without a cone. Further, the concave portion 7a is not necessarily required, and an annular shape without unevenness can be applied to the present invention.

In the strut mount 1, an outer metal fitting 9 is coaxially arranged on the outer peripheral side of the inner metal fitting 4, and the outer metal fitting 9 is connected to the vehicle body via a bolt 10.
The outer metal fitting 9 is disposed in an outer metal fitting body 11 formed with a storage portion 9a for supporting the rubber elastic body 7 and the soft layer 8 in a press-fitted state, and an opening portion of the storage portion 9a, and is press-fitted into the storage portion 9a. The rubber elastic body 7 and the soft layer 8 are prevented from falling off. The storage portion 9a is formed in a substantially truncated cone shape that gradually narrows toward the lower side, corresponding to the shape of the rubber elastic body and the upper and lower soft layers 8, and includes the rubber elastic body 7 and the soft layer. 8 is press-fitted so as to directly contact the inner peripheral surface of the storage portion 9a without using other members such as an outer plate.

The outer metal fitting body 11 includes a bottomed cylindrical portion 11a that defines the storage portion 9a, and an outer flange portion 11b that extends outward from the upper end of the gardened cylindrical portion 11a. On the other hand, the drop-off prevention plate 12 is formed in a substantially disc shape having a recess 12a at the center, and a hole 12aa through which the tip of the piston rod 2 is inserted is formed at the center of the recess 12a. The drop-off prevention plate 12 is appropriately fixed by, for example, its periphery in a state where the rubber elastic body 7 and the soft layer 8 are press-fitted into the storage portion 9a and then pressed against the outer metal fitting body 11 from the opening side of the storage portion 9a. A plurality of portions are fixed to the outer metal fitting body 11 by spot welding.
Insertion holes 11ba and 12b are formed in the outer peripheral portions of the outer flange portion 11b and the drop-off prevention plate 12, respectively. By inserting the bolt 10 into these insertion holes 11ba and 12b, the outer metal fitting body 11 is connected to the vehicle body. Has been.

  Here, as described above, since the rubber elastic body 7 and the soft layer 8 are press-fitted into the storage portion 9a, the lower soft layer 8 in FIG. 1 is pre-compressed with respect to the storage portion 9a. It is set with. Further, the total height Ha of the rubber elastic body 7 and the upper and lower soft layers 8 (see FIG. 3) is larger than the depth Hb of the storage portion 9a (see FIG. 1) by an amount corresponding to pre-compression. Therefore, when the rubber elastic body 7 and the soft layer 8 are press-fitted into the storage portion 9a and then closed from the upper side by the drop-off prevention plate 12, the upper soft layer 8 in FIG. It is set in the outer metal fitting 11 in a state of being compressed.

  The pre-compression amount of the upper and lower soft layers 8 is set according to the use conditions of the strut mount 1, the hardness of the rubber elastic body 7, the spring constant of the soft layer 8, etc., for example, from the piston rod 2 of the shock absorber. Even when the soft layer 8 is deformed by receiving an external force, the pre-compression amount is set such that no gap is generated between the soft layer 8 and the outer metal fitting 9.

   As shown in FIG. 1, a bearing 13 is attached to the strut mount 1 on the lower side of the outer flange portion 11 b of the outer metal fitting 9. The lower end of the bearing 13 is in contact with the upper end portion of the coil spring 3 that is compressed with the cylinder portion. Below the outer metal fitting 9, an upper sheet 14 is attached coaxially with the outer metal fitting 9, and this upper sheet 14 is engaged with the upper end of the bump stopper.

   When attaching the strut mount 1 configured as described above to the vehicle body, the outer flange portion 11b of the outer metal fitting body 11 is abutted against the lower surface side of the attachment portion of the vehicle body via the drop-off prevention plate 12, and in this state, The bolt 10 is inserted from below into the insertion hole 11ba of the outer flange portion 11b, the insertion hole 12b of the drop-off prevention plate 12, and the insertion hole of the vehicle body, and a nut is screwed into the tip of the bolt 10 until a predetermined fastening torque is generated. . Thereby, the strut mount 1 can be fastened and fixed to the mounting portion of the vehicle body, and the shock absorber can be mounted on the vehicle body via the strut mount 1.

Next, the operation of the strut mount 1 configured as described above will be described.
In the strut mount 1 of this embodiment, the soft layers 8 are provided at the upper and lower end portions of the rubber elastic body 7, respectively, and the soft layer 8 has a higher loss factor and lower density than the rubber elastic body 7. As a result, the soft layer 8 has a higher loss coefficient and a lower dynamic spring constant than the rubber elastic body 7. Therefore, minute high-frequency vibrations that tend to occur during high-speed traveling or the like and that are input from the piston rod 2 to the strut mount 1 can be effectively absorbed by the soft layer 8 being appropriately deformed.

   On the other hand, when the input load from the piston rod 2 of the shock absorber to the strut mount 1 suddenly increases due to the vehicle overcoming a step such as a curb stone, the rubber mainly having higher rigidity than the soft layer 8 is mainly used. The elastic body 7 is appropriately deformed to absorb the large input load.

FIG. 4 shows the relationship between the displacement amount along the axial direction of the piston rod 2 and the input load in this case. In FIG. 4, the horizontal axis represents the amount of displacement along the axial direction of the piston rod 2, and the vertical axis represents the input load from the piston rod 2 to the strut mount 1.
In this figure, the alternate long and two short dashes line indicates the amount of displacement along the axial direction of the piston rod of the conventional strut mount that does not have a soft layer between the inner metal fitting and the outer metal fitting and is interposed only with a rubber elastic body. And the input load.

   As can be seen from FIG. 4, the strut mount 1 according to the present embodiment can effectively utilize the characteristics of both the rubber elastic body 7 and the soft layer 8, and therefore can have a large characteristic linear region Z. In addition, since the rigidity of the rubber elastic body 7 can be arbitrarily increased to cope with a large input load without considering the absorption of high-frequency vibration in this way, the rubber elastic body 7 and thus the rigidity can be increased accordingly. The durability of the strut mount 1 can be improved.

In the strut mount 1 having the above-described configuration, the soft layer 8 is formed at the upper and lower ends of the rubber elastic body 7, that is, the axial end of the piston rod 2, and the piston rod 2 and the vehicle body are connected to the piston rod 2. For the force applied along the axial direction, not the shearing force but the compressive force or the tensile force acts on the soft layer 8. This kind of soft layer 8 has a sufficient proof strength compared to the action of a shearing force, particularly when a compressive force is applied, so that the sufficient proof strength in the soft layer 8 can be used effectively, resulting in a strut. The durability of the mount 1 can be improved.
Further, when the soft layer 8 is formed only on the upper and lower ends of the rubber elastic body 7 as shown in FIG. 1, the strut mount 1 allows only a predetermined amount of movement of the piston rod 2 in the axial direction. While allowing, for example, the front-rear and left-right movements orthogonal to the axial direction of the piston rod can be supported relatively rigidly, an ideal strut mount 1 can be obtained.

  Moreover, in the strut mount 1 having the above-described configuration, when the soft layer 8 is formed of, for example, urethane foam, the soft layer 8 can be made of an easily obtainable and inexpensive material. The strut mount 1 can be produced.

  In the strut mount 1 having the configuration, the rubber elastic body 7 is press-fitted into the storage portion 9a by directly contacting the radially outer peripheral surface thereof with the inner peripheral surface of the storage portion 9a without using other members such as an outer plate. Therefore, as compared with the case where the other member is used to set the outer metal fitting 9, it is possible to reduce the size by the thickness of the other member.

  Further, in the strut mount 1 having the configuration, the soft layer 8 is pre-compressed and press-fitted into the storage portion 9a. Therefore, even when the soft layer 8 is deformed by applying force, the soft layer 8 and the storage portion 9a It is difficult to generate a gap between them, and therefore, it is possible to further prevent the generation of abnormal noise such as a hitting sound caused by the presence of a gap between the two.

The present invention is not limited to the above-described embodiment, and can be appropriately changed in design without departing from the spirit of the invention.
For example, in the said embodiment, the rubber elastic body 7 is provided so that the outer flange part 4b of the inner metal fitting 4 may be enclosed, and the soft layer 8 is provided in the upper-lower end part of this rubber elastic body 7, respectively, but it is restricted to this. Instead, as shown in FIG. 5, a soft layer 8 a may be provided on the outer peripheral portion of the rubber elastic body 7, and the soft layer 8 a may be connected to the upper and lower soft layers 8.
Moreover, in the said embodiment, although the soft layer 8 was each provided in the upper-lower end part of the rubber elastic body 7, it is not restricted to this, The soft layer 8 is provided only in either one side of an upper-lower end part. Also good.
Furthermore, when the vehicle body attachment portion has a drop-off prevention function, it goes without saying that the object of the present invention can be achieved and the effect can be obtained even with a configuration without the drop-off prevention plate.

It is sectional drawing which shows the strut mount of embodiment of this invention. It is a top view of the rubber elastic body and soft layer which are used with the strut mount of the embodiment of the present invention. It is a half sectional view of a rubber elastic body and a soft layer used in a strut mount of an embodiment of the present invention. It is a figure which shows the characteristic of the strut mount of embodiment of this invention. It is sectional drawing which shows other embodiment of the strut mount of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Strut mount 2 Piston rod 3 Coil spring 4 Inner metal fitting 7 Rubber elastic body 8 Soft layer 9 Outer metal fitting 11 Outer metal fitting body 12 Fall-off prevention plate

Claims (9)

An outer bracket attached to the car body,
An inner bracket attached to the piston rod of the shock absorber,
A rubber elastic body interposed between the outer metal fitting and the inner metal fitting by being press-fitted into a housing portion of the outer metal fitting while being integrally formed with the inner metal fitting on the outer circumference of the inner metal fitting. In a strut mount comprising:
A strut mount, wherein a soft layer having a loss factor higher than that of the rubber elastic body and having a low density is interposed between the outer metal fitting and the rubber elastic body.   The outer metal fitting is disposed at the outer metal fitting body in which the storage portion is formed, and the opening portion of the storage portion, and the rubber elastic body press-fitted into the storage portion and the drop-off prevention for preventing the soft layer from falling off. The strut mount according to claim 1, further comprising a plate.   3. The strut mount according to claim 1, wherein the soft layer is formed at an end portion on at least one side of the piston rod in the axial direction of the rubber elastic body.   The strut mount according to any one of claims 1 to 3, wherein the soft layer is formed of a foam material.   The strut mount according to any one of claims 1 to 4, wherein the soft layer is made of urethane.   The strut mount according to any one of claims 1 to 5, wherein the rubber elastic body is press-fitted into the storage portion with a radially outer peripheral surface thereof being in direct contact with an inner peripheral surface of the storage portion.   The strut mount according to any one of claims 1 to 5, wherein the rubber elastic body has the soft layer formed on a radially outer peripheral surface thereof and is press-fitted into the storage portion.   The strut mount according to any one of claims 1 to 7, wherein the soft layer is pre-compressed and press-fitted into the storage portion.   The strut mount according to any one of claims 2 to 8, wherein the drop-off prevention plate is fixed to the outer metal fitting main body at a peripheral portion thereof.

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