JP2003287074A - Shock absorber for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shock absorber for a vehicle equipped with a damping device of new structure wherein effectively vibration transmission from the wheel side to the body side in the suspension mechanism is reduced with simple structure. <P>SOLUTION: The damping device 18 is constituted that an independent mass member 44 which is non-adhesive and independently displaceable on a cylinder 24 or a piston rod 26 of the shock absorber 10 for a vehicle and the independent mass member 44 is elastically contacted to the cylinder 24 or the piston rod 26 repeatedly. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vehicle shock absorber used for a suspension mechanism of an automobile, a trailer, a motorcycle, a railroad vehicle, and the like, and particularly to suppress vibration transmission from a wheel side member constituting a suspension mechanism to a body side member. ,
The present invention relates to a new shock absorber for a vehicle, which has a simple structure and can suppress the traveling vibration of a body side member.

[0002]

2. Description of the Related Art Conventionally, in a vehicle such as an automobile, vibration is applied to a body, a panel, a steering wheel, various levers, etc. due to an exciting force input from a wheel side being transmitted to a vehicle body side. Generation of muffled sound is likely to be a problem. Therefore, when such a vibration on the vehicle body side becomes a problem, for example, by installing a vibration-proof connecting member such as a suspension bush at a connecting portion of the suspension mechanism such as an arm or a rod that is connected to the body side. I am dealing with it.

In order to obtain a high level of vibration damping performance, various structures have been proposed as a vibration damping coupling member for such a suspension. For example, a vibration damping effect is obtained based only on the elasticity of a rubber elastic body. In addition to the solid type anti-vibration connecting member as described above, there is also a structure having a structure in which a liquid is enclosed inside to obtain an anti-vibration effect based on the resonance action of the liquid.

However, even if such an anti-vibration connecting member for suspension is adopted, it is still possible to obtain a sufficient anti-vibration effect against vibrations caused by an exciting force input from the wheel side in an automobile or the like. It is difficult at present, especially in the suspension mechanism, since spring rigidity is required in order to ensure the running stability of the vehicle. There was a limit to improving the vibration performance. A liquid-filled type anti-vibration connecting member has also been proposed, but since the frequency range in which the anti-vibration effect based on the resonance action of the liquid is effectively exhibited is narrow, many vibration forces are input from the wheel side. However, the suspension mechanism including the frequency component has a problem that it is difficult to stably obtain an effective anti-vibration effect.

[0005]

The present invention has been made in view of the circumstances as described above, and its problem to be solved is to apply an exciting force exerted from a wheel side to a body side during traveling of a vehicle. It is an object of the present invention to provide a vehicle shock absorber equipped with a novel vibration damping mechanism which has a simple structure and is inexpensive, which can effectively reduce the resulting vibration over a wide frequency range.

[0006]

Aspects of the present invention made to solve such problems will be described below. The constituent elements used in each of the following aspects can be used in any combination as much as possible. Further, the aspects and technical features of the present invention are not limited to those described below, but are described in the entire specification and the drawings, or the invention idea that can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized based on this.

That is, as a result of detailed verification and examination by the present inventor of the mechanism of vibration transmission from the wheel side to the body side in the suspension mechanism, wheel side members such as suspension arms and suspension rods and subframes and main bodies Vibration transmission from the wheel side to the body side through a shock absorber that is mounted between the body side member and exerts a damping force on the operation of the suspension mechanism is transmitted from the wheel side through the rigid member such as the suspension arm or suspension rod to the body side. It has been confirmed that it is a factor that cannot be ignored compared with the vibration transmission to the shock absorber, and that the vibration transmission through this shock absorber is due to the resonance phenomenon of the shock absorber itself. It became clear that is large. Then, as a result of the inventor's extensive studies based on such knowledge, the vibration damping means having a specific structure relates to the vibration transmission from the wheel side to the body side through the shock absorber without impairing the function of the shock absorber. It has been found that a very effective reduction effect can be exerted, whereby the invention relating to a vehicle shock absorber can be completed.

The feature of the first aspect of the present invention made to solve the above problems is that a cylinder is attached to one of a body side member and a wheel side member of a vehicle and a piston is provided to the other side. By attaching the rod,
In a shock absorber for a vehicle mounted on a suspension mechanism, a non-adhesive independent mass member that can be independently displaced is attached to the cylinder or the piston rod, and the independent mass member is the cylinder or the piston rod when vibration is input. It is to be repeatedly and elastically abutted against.

In the vehicle shock absorber having the structure according to the present embodiment, when the vibrations input from the wheels to the suspension mechanism are applied to the shock absorber during traveling of the vehicle, the shock absorber is vibrated. The independent mass member is displaced like a jump with respect to the cylinder or the piston rod, and the independent mass member is elastically brought into contact with the cylinder or the piston rod. As a result, the vibration induced in the cylinder or the piston rod is positively reduced, and the vibration transmitted from the wheel side to the body side through the shock absorber can be effectively reduced.

Particularly, in the shock absorber for a vehicle according to this aspect, it is only necessary to assemble an independent mass member which can be independently displaced with respect to a cylinder or a piston rod, and there is no need for a special actuator or liquid encapsulation. It has a simple structure, is easy to manufacture, and can be constructed compactly. It does not impair the original function of the shock absorber, and there is no particular need to change the design of the entire suspension mechanism including the installation space. Therefore, it has extremely high practicality and versatility.

In this embodiment, the independent mass member is
The whole or part of it can be made of various materials such as rubber elastic body, synthetic resin material, metal, etc. However, when the independent mass member is made of a rigid material such as metal, the independent mass member and the cylinder or piston. By disposing the elastic material layer on at least one contact surface of the rod, elastic contact of the independent mass member can be advantageously realized. That is, since the independent mass member is elastically brought into contact with the cylinder or the piston rod, a small amplitude (energy) is generated based on the elasticity of the elastic material forming the contact surface, preferably the rubber elastic body. However, the independent mass member is efficiently displaced relative to the cylinder or the piston rod, so that the damping effect based on the contact of the independent mass member with the cylinder or the piston rod is reduced to small amplitude vibration. On the other hand, it can be effectively demonstrated.

Furthermore, in this embodiment, the independent mass member is disposed so as to be independently displaceable with respect to the cylinder or the piston rod, and the independent mass member is elastic directly to the cylinder or the piston rod. Because they are not connected and are physically independent,
The displacement of the independent mass member can be freely generated without being restricted by the cylinder or piston rod, and as a result,
Based on the contact of the independent mass member with the cylinder or the piston rod, the displacement of the independent mass member is effectively generated with respect to the vibration of the cylinder or the piston rod in a wide frequency range or a plurality of frequency ranges. The vibration damping effect as described above can be effectively exhibited. And this means that there are multiple input vibration frequencies in question,
Alternatively, it is extremely effective in reducing the transmission vibration to the body side through the changing suspension mechanism.

In this embodiment, the independent mass member is
It may be a single piece or a plurality of pieces, and it may be designed so that it can be brought into contact with either the cylinder or the piston rod. It also uses multiple independent mass members that are brought into contact with the cylinder and piston rod, respectively. May be. The independent mass member may directly contact the cylinder or the piston rod, but in addition, for example, a suspension spring fixed to the cylinder or the piston rod or a seat for the suspension spring. Etc., or a contact member may be specially provided in the cylinder or the piston rod so that the independent mass member can contact more efficiently.

In this embodiment, the independent mass member is
It is desirable to make contact with the cylinder or piston rod in the direction of the problematic vibration, for example, in the axial or orthogonal direction of the cylinder or piston rod depending on the vibration input direction. Will be done.
In particular, when vibration in the direction perpendicular to the axis is a problem, consider the vibration mode of the shock absorber so that the independent mass member is brought into contact with the vicinity of the part where the vibration mode at resonance is antinode. Desirably, for example, when the primary vibration mode becomes a problem, it is desirable that the independent mass member is brought into contact with a substantially central portion in the axial direction of the shock absorber.

According to a second aspect of the present invention, the independent mass member is an annular shape that extends continuously around the central axis of the cylinder or the piston rod over the entire circumference in the circumferential direction. It is characterized in that the piston rod is disposed in an externally inserted state. In such a mode, by detaching the annular independent mass member from the cylinder or the piston rod, it is possible to advantageously prevent the independent mass member from being detached or dropped from the cylinder or the like. Further, it becomes easy to set a large mass of one independent mass member, and the degree of freedom in design can be improved.

According to a third aspect of the present invention, in the vehicle shock absorber according to the first aspect, a plurality of the independent mass members are independently provided around the central axis of the cylinder or the piston rod. The plurality of independent mass members are elastically repeatedly abutted against the cylinder or the piston rod in a direction substantially orthogonal to the central axis when vibration is input. . In the present mode as described above, an effective damping effect is exhibited against vibrations in a plurality of directions orthogonal to the central axis of the shock absorber.

A fourth aspect of the present invention is the vehicle shock absorber according to the third aspect, which is fixedly provided on the cylinder or the piston rod to support the independent mass member from vertically below. It is characterized in that the supporting surface to be pressed is an inclined surface which is inclined vertically downward toward the central axis. In this aspect, in the stationary state, the plurality of independent mass members are held in contact with the cylinder or the piston rod based on the guiding action of the supporting surface, and therefore, at the time of vibration input. The exciting force can be advantageously transmitted from the cylinder or the piston rod to the independent mass member, so that the jumping displacement of the independent mass member is more advantageously produced.

Further, a fifth aspect of the present invention is the vehicle shock absorber according to any one of the first to fourth aspects, wherein a hollow housing for accommodating the independent mass member is provided in the cylinder or the cylinder. It is characterized in that the independent mass member is elastically repeatedly abutted against the inner surface of the housing at the time of vibration input by being fixedly provided on the piston rod. In this aspect, the contact surface of the independent mass member in the cylinder or the piston rod can be advantageously formed, and the independent mass member can be more efficiently contacted with the cylinder or the piston rod. Become. In addition, the housing can be made to have a substantially hermetically sealed structure, whereby problems such as obstruction of the vibration damping effect due to intrusion of foreign matter between the contact surface and the independent mass member can be avoided. The housing may be integrally formed with the cylinder or the piston rod, or the housing formed with another member may be fixed to the cylinder or the piston rod. There, the housing is made of a rigid material such as metal so that the independent mass member can be stably supported and vibrations of the cylinder and the piston rod can be efficiently applied to the independent mass member as an exciting force when necessary. Preferably formed.

A sixth aspect of the present invention is the shock absorber for a vehicle according to the fifth aspect, wherein a reciprocating movable distance of the independent mass member between contact surfaces formed by the inner surface of the housing is set. In each of the directions substantially parallel to the direction substantially orthogonal to the central axis of the cylinder or the piston rod, 0.1 mm to 1.6 mm is set. In this aspect,
By bringing the independent mass member into contact with the cylinder or the piston rod on both sides in the reciprocating displacement direction in the problematic vibration input direction, it becomes possible to more efficiently obtain the desired damping effect. Moreover, since the displacement of the independent mass member is limited even in the direction orthogonal to the vibration input direction, which is a problem, the independent mass member is guided in the vibration input direction, and the displacement state is stabilized.
It is possible to further improve the vibration damping effect based on the target contact.

Further, a seventh aspect of the present invention is the vehicle shock absorber according to any one of the first to sixth aspects, wherein when vibration is input, the vibration is approximately with respect to the center axis of the cylinder or the piston rod. A first contact surface on which the independent mass member is elastically repeatedly abutted in the orthogonal direction, and the independent mass member is elastically repeatedly abutted in a direction substantially parallel to the central axis at the time of vibration input. It is characterized in that a second abutting surface to be pressed is fixedly provided on the cylinder or the piston rod. In this aspect, the damping effect based on the contact of the independent mass member can be effectively exerted on each of the axial and orthogonal vibrations transmitted through the shock absorber. The damping effect as a whole can be improved.

An eighth aspect of the present invention is the shock absorber for a vehicle according to any one of the first to seventh aspects, wherein the independent mass member is elastically repeatedly abutted upon vibration input. It is characterized in that the contact surface is provided in the vicinity of the protruding end of the piston rod of the cylinder. In this aspect, the adverse effect of the independent mass member on the expansion / contraction operation of the piston rod with respect to the cylinder due to the sliding movement of the piston can be avoided. Moreover, since the contact surface of the independent mass member is finally positioned near the antinode in the axial direction in the primary vibration mode which is likely to cause a problem in the shock absorber, the vibration damping effect based on the contact of the independent mass member is achieved. Can be exerted more efficiently.

Further, a ninth aspect of the present invention is the vehicle shock absorber according to any one of the first to eighth aspects, wherein the piston rod is provided to the other of the body side member and the wheel side member. Of the contact surface on which the independent mass member is elastically repeatedly abutted at the time of vibration input at the portion protruding further outward beyond the mounting portion of Is provided. According to this aspect, it is possible to advantageously form the contact surface of the independent mass member with respect to the piston rod without adversely affecting the expansion / contraction operation of the piston rod with respect to the cylinder. Moreover, by disposing the independent mass member at the tip portion of the piston rod, it is possible to easily secure a relatively large disposition space due to the suspension structure. For example, it is possible to set the mass of the independent mass member to a larger value. Also, the vibration damping effect and the design flexibility can be improved.

A tenth aspect of the present invention is the shock absorber for a vehicle according to any one of the first to ninth aspects, wherein the independent mass member is in contact with the cylinder or the piston rod at the time of vibration input. At least one of the contact surfaces has a Shore D hardness of 80 or less. In such an aspect, the contact noise of the independent mass member can be reduced, and the displacement of the independent mass member based on the elasticity of the contact surface can be efficiently exhibited. The vibration damping effect for small-amplitude vibration) can be further improved. The Shore D hardness is AST
Shore D hardness of M standard D2240 is referred to, and Shore D hardness is more preferably set to 20-40.

Furthermore, in order to reduce the contact noise when the independent mass member comes into contact with the cylinder or the piston rod, and to further improve the damping effect due to the contact of the independent mass member with the cylinder or the piston rod. Means that the compression elastic modulus is set to preferably 1 to 10 ⁴ MPa, more preferably 1 to 10 ³ MPa at the contact portion of the independent mass member with respect to the cylinder or the piston rod, and the loss tangent (tan δ ) Is preferably 1 × 10 ⁻³ or more,
It is more preferably 0.01 to 10.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, some embodiments of the present invention will be described in detail with reference to the drawings in order to clarify the present invention more specifically.

First, FIG. 1 is a schematic explanatory view showing a shock absorber 10 as a first embodiment of the present invention in a mounted state, in which the shock absorber 10 is an absorber main body constituting a cylinder mechanism. 12
Against the coil spring 14 and the bump stopper 16
In addition to the structure, a specific vibration damping device 18 is provided, and is mounted between the main body 20 as a body side member and the suspension arm 22 as a wheel side member to swing the suspension arm 22. On the other hand, it exerts a damping force.

More specifically, the absorber body 12 is conventionally known, and a piston rod 26 is fixed to a piston that is slidably mounted on a cylindrical cylinder 24, and the piston rod 26 is fixed to the piston rod 26. 26 for cylinder 2
4 has a structure in which it projects upward from the axially upper end portion on the central axis. Although not explicitly shown in the drawings, a predetermined damping force is exerted on the expansion and contraction operation of the piston rod 26 with respect to the cylinder 24 based on the flow resistance of the oil enclosed in the cylinder 24 and the like. ing.

The lower end of the cylinder 24 in the axial direction is
Via the vibration-proof bush 28, the suspension arm 22
On the other hand, the axial upper end portion (protruding tip end portion) of the piston rod 26 is attached via the upper support 30.
It can be attached to the main body 20.
As a result, the absorber body 12 is mounted between the suspension arm 22 and the main body 20, and exerts a damping force when the suspension arm 22 swings. As the vibration-proof bushing 28 and the upper support 30, any conventionally known ones can be adopted, and therefore the description thereof is omitted here.

The shock absorber 1 of this embodiment is also used.
No. 0 constitutes a strut-type suspension mechanism, and a spring lower seat 32 that spreads outward in the direction perpendicular to the axis at an axially intermediate portion is fixed to the cylinder 24 while the main body 20 An upper spring seat 34 is fixedly mounted on the upper side of the lower spring seat 32 so as to face the lower spring seat 32 at a predetermined distance in the vertical direction. The coil spring 14 externally fitted to the shock absorber 10 is assembled in a state of being axially sandwiched between the lower spring seat 32 and the upper spring seat 34, and the elastic force of the coil spring 14 is increased. However, the suspension arm 22 is made to act as an elastic supporting force of the body for the wheel.

A dust cover 38 having a bellows tube shape having a diameter smaller than that of the coil spring 14 is externally inserted and assembled to the absorber body 12, and the dust cover 38 is suspended from the spring upper seat 34. hand,
By being arranged between the absorber body 12 and the coil spring 14, the entire length of the piston rod 26 protruding from the cylinder 24 is covered with the dust cover 38.

Further, a bump stopper 16 having a generally thick and generally cylindrical shape is externally inserted and assembled to the piston rod 26 of the absorber body 12. As the bump stopper 16, any well-known one can be adopted, and although not described in detail here, it is formed of an elastic material such as a rubber elastic body or urethane foam, and faces the cylinder 24 and the main body 20. It is arranged in between. When a large load is applied in the bounding direction of the absorber body 12 and the piston rod 26 is largely displaced in the contracting direction with respect to the cylinder 24, the bump stopper 16 moves axially between the cylinder 24 and the main body 20. By being compressed, swinging of the suspension arm 22 is buffered.

Further, the absorber body 12 is equipped with a vibration damping device 18 at the protruding portion of the piston rod 26 at the axially upper end of the cylinder 24.

As shown in FIGS. 2 to 4, the vibration damping device 18 is provided with an annular housing 42 having a hollow structure. In the housing 42, a plurality of independent mass members as independent mass members are provided. It is configured by housing the mass 44. Here, the housing 42 includes an upper annular metal member 46 having an inverted L-shaped cross-sectional shape and extending continuously in the circumferential direction, and a lower annular metal member 48 having an L-shaped cross-sectional shape continuously extending in the circumferential direction. And the cylindrical parts 50, 52 of the upper and lower annular metal fittings 46, 48
Are fitted and fixed to each other, and the annular plate portions 54 and 56 of the upper and lower annular metal fittings 46 and 48 are opposed to each other at a predetermined distance in the axial direction. That is, the housing 42 is a hollow annular body that continuously extends in the circumferential direction with a U-shaped cross section that opens to the inner peripheral surface.
In addition, the upper and lower annular metal fittings 46, 48 are provided with respective cylindrical portions 50, 5
Covering rubbers 58 and 60 are adhered and formed on almost the entire surface except the fitting surface of the second fitting surface, whereby the entire inner peripheral surface of the housing 42 is covered with the covering rubbers 58 and 60.

In particular, in the lower annular metal fitting 48, the thickness of the portion of the covering rubber 60 attached to the upper surface of the annular plate portion 56 is made thicker toward the outer peripheral side,
The inner bottom surface as a support surface of the housing 42 is a tapered inclined surface 62 that is inclined inward in the radial direction. In addition, on the annular plate portions 54 and 56 that form the upper and lower wall portions of the housing 42, locking projections 64 that project at a predetermined height toward the axially opposite sides at the opening edge portions on the inner peripheral side of the housing 42, respectively. , 66 are formed in an annular shape continuously in the circumferential direction. The locking protrusions 64 and 66 are formed by the covering rubbers 58 and 60. The annular opening window 68 formed on the inner peripheral side of the housing 42 is narrower than the hollow inside of the housing 42, and is formed with an axial opening width smaller than the axial inner dimension of the housing 42. Has been done.

Further, a plurality of (six in this embodiment) independent masses 44 are housed in the inner space 70 which is the hollow interior of the housing 42, and are arranged on one circumference around the central axis. Has been done. Further, in the inner space 70 of the housing 42, a plurality of vertical walls 72 for partitioning, which project inward in the radial direction from the outer peripheral wall portion, are fixed at a predetermined interval in the circumferential direction (six in this embodiment). These vertical walls 72 prevent adjacent independent masses 44, 44 from directly abutting each other. In the present embodiment, a plurality of vertical walls 72 are integrally formed with the covering rubber 60 and fixed to the lower annular metal fitting 48.

The plurality of independent masses 44 are all the same, and a cushion rubber layer having a constant thickness is formed on the entire surface of the spherical mass body 74 made of metal or the like. As a result, 76 is attached to form a spherical outer peripheral surface as a whole. In particular, the independent mass 44
Is smaller than the inner dimension of the inner space 70 of the housing 42 in the axial direction and the direction perpendicular to the axis, and is adjacent to the vertical wall 7.
It is formed with an outer diameter dimension smaller than the facing distance between 2, 72, and can be displaced independently of the housing 42 within the inner space 70 by a predetermined distance in the axial direction of the housing 42 and the direction perpendicular to the axis. It is said that.

Furthermore, the outer diameter dimension of the independent mass 44 is made larger than the axial opening width dimension of the opening window 68 of the internal space 70 in the housing 42 by a predetermined amount, and the vertical relationship forming the opening window 68 is increased. By contacting the stop projections 64 and 66, the independent mass 44 is prevented from coming out of the opening window 68. Also, the independent mass 44 is
When positioned inside the inner space 70, a part of the independent mass 44 projects radially inward from the opening window 68 and projects further radially inwardly than the inner circumferential surface of the housing 42. It is designed to be punished. Here, in the present embodiment, since the bottom surface of the inner space 70 of the housing 42 is the inclined surface 62, the independent mass 44 placed on the inclined surface 62 is opened in an open window. The part 68 is held in a state of being partially projected inward in the radial direction.

Thus, the vibration damping device 18 having such a structure has the absorber main body 1 as shown in FIG.
2 is externally inserted into the piston rod 26, and is mounted and fixedly mounted on the axial upper end surface of the cylinder 24 with the central axes of the cylinder 24 and the piston rod 26 and the central axis of the housing 42 aligned. There is. There, the housing 42 may be secured to the top surface of the cylinder 24 by gluing or the like, or, as shown in FIG.
Fitting cylinder portion 78 extending axially downward from the housing 42
May be provided, and the housing 42 may be fixed to the cylinder 24 by externally fitting the fitting tubular portion 78 to the upper end portion of the cylinder 24.

Although the outer diameter of the piston rod 26 of the absorber body 12 is smaller than the inner diameter of the housing 42, the independent mass 44 projected from the opening window 68 of the housing 42 is formed on the outer peripheral surface of the piston rod 26. It is set so that they can be brought into contact with each other. That is, in the mounted state of the vibration damping device 18, the independent mass 44 has upper and lower locking protrusions 64, 66 at the innermost moving end in the inner space 70 as shown in FIG. It is defined not by the contact with the piston rod 26 of the absorber body 12 but by the contact with the piston rod 26. As is apparent from this, in the present embodiment, the independent mass is formed by the outer peripheral surface of the piston rod 26 and the cylindrical portion 52 covered with the covering rubber 60 of the lower annular metal member 48 forming the outer peripheral wall portion of the housing 42. A first contact surface is formed on which 44 is brought into contact with the absorber body 12 in the direction perpendicular to the axis thereof. In addition, a second contact in which the independent mass 44 is brought into contact in the axial direction of the absorber body 12 by the annular plate portions 54 and 56 covered with the covering rubbers 58 and 60 of the upper and lower annular metal fittings 46 and 48 in the housing 42. The surface is formed.

The size of the difference between the inner size of the inner space 70 of the housing 42 and the outer diameter of the independent mass 44 is not particularly limited, and free displacement of the independent mass 44 is allowed. In this embodiment, in particular, the displacement amounts of the independent mass 44 in the axial direction and the orthogonal direction to the axial direction of the independent mass 44 when the vibration damping device 18 is mounted on the absorber body 12 are not limited to the above ranges. Is the piston rod 2
As a reciprocating movable distance between the two moving ends, which is limited by abutting against 6, it is 0.1 to 1.6 mm, more preferably 0.1.
It is set to be ~ 1.0 mm. That is, by setting such a reciprocal movable distance, the independent mass 44 can be brought into contact with the housing 42 or the piston rod 26 on both sides in the moving direction at the time of vibration input.

As is apparent from the above description, in the present embodiment, the independent mass 44 is formed by the cushioning rubber layer 76 of the independent mass 44 and the covering rubbers 58 and 60 of the housing 42.
Of the piston rod 26 and the cylinder 24 are directly or indirectly contacted with each other. Then, the cushioning rubber layer 76 and the covering rubber 5 that form these contact surfaces
Nos. 8 and 60 preferably have a Shore hardness of 80 or less according to ASTM standard D2240 or have a compression elastic modulus of 1 to 10 in order to reduce the hitting sound at the time of contact and to obtain an effective vibration damping effect. It is desirable that the pressure is ⁴ MPa. Also,
For the same purpose, it is desirable that the loss tangent (tan δ) be 10 ⁻³ or more.

The shock absorber 10 having such a structure is subjected to an oscillating force between the suspension arm 22 and the main body 20 when the vehicle travels while being mounted on the vehicle as described above. For example, as a vibration that causes a serious problem, a vibration of a primary resonance mode is exerted on the absorber body 12 due to an exciting force in a direction perpendicular to the axis as shown by a virtual line in FIG. That is, when such a resonance phenomenon of the absorber body 12 itself occurs, the vibration input from the suspension arm 22 is amplified and transmitted to the main body 20, so that a vibration problem is likely to occur.

In the shock absorber 10, the piston rod 26 constituting the absorber main body 12 is vibrated, so that the vibration damping device 18 holds the piston rod 26 in contact with the independent piston rod 26. The vibrating force is exerted on the mass 44. Then, the independent mass 44 is displaced like a jump in the axis-perpendicular direction with respect to the piston rod 26, and is repeatedly hit and abutted against the outer peripheral surface of the piston rod 26 in the axis-perpendicular direction. As a result, an effective damping effect is exerted on the piston rod 26 by hitting the independent mass 44.
By suppressing the resonant vibration of itself, the vibration transmission from the wheel side to the body side through the absorber body 12 can be effectively reduced.

In particular, in this embodiment, the bottom surface of the housing 42 supporting the independent mass 44 is made into the inclined surface 62, and the contact state of the independent mass 44 with the piston rod 26 is advantageously developed. The jumping independent displacement of the mass 44 and the hitting against the piston rod 26 are more advantageously developed, and the vibration reducing effect is more effectively exerted.

Moreover, in this embodiment, even when the independent mass 44 is displaced outward in the radial direction, the housing 42 is
Since the cylinder 24 is hit against and abuts against the cylinder 24 via the outer peripheral wall portion, the damping effect on the absorber body 12 can be exerted even by such abutment.

Further, in this embodiment, even when the cylinder 24 vibrates in the axial direction, the vibrating force is exerted on the independent mass 44 from the housing 42 which is vibrated integrally with the cylinder 24, and the independent mass 44 is vertically moved. It is made to jump and displace, and hits against the cylinder 24 through the housing 42 to come into contact therewith. Therefore, based on such abutment,
It is possible to obtain an effective damping effect against the axial vibration of the absorber body 12.

Further, in this embodiment, the housing 42
Since the inner space 70 of the independent mass 44 is partitioned by a plurality of vertical walls 72 and the interference between the independent masses 44 is also avoided, the jumping displacement of each independent mass 44 is stably generated, and thereby, the purpose. The vibration damping effect can be obtained more stably.

Incidentally, in the shock absorber 10 having the structure according to the present embodiment as described above, the vibration damping device 1 is used.
In order to verify the vibration damping effect of 8, the vibration level of the main body 20 without the vibration damping device 18 and the vibration level of the main body 20 with the vibration damping device 18 mounted were measured, It was confirmed that the vibration level (vibration acceleration spectrum) in the resonance frequency range of about 130 Hz was improved by about 3 dB. The actual measurement is carried out by hammering the mounting portion of the cylinder 24 of the shock absorber 10 to the suspension arm 22 and detecting the vibration acceleration of the mounting portion of the piston rod 26 to the main body 20 with a pickup.
The measurement value was evaluated by the detection value of (m / s ² ) / N. In addition, the vibration damping device 1
In the state where 8 is not mounted, the vibration damping device 18 with all the independent masses 44 removed is used.

Next, FIG. 6 shows a shock absorber 80 as a second embodiment of the present invention. The following embodiments all show another specific example of the vibration damping device, and since the same absorber body 12 as the first embodiment can be adopted, The same reference numerals as those in the first embodiment will be used for the members and parts having the same structures as those in the first embodiment, and only the characteristic parts will be illustrated and described.

That is, the vibration damping device 82 employed in the shock absorber 80 according to the second embodiment has a large-diameter annular block shape having an inner diameter larger than the outer diameter of the cylinder 24 of the shock absorber 80. It has a housing body 84 having. This housing body 8
4, an annular groove 86 having a constant rectangular cross section and extending over the entire circumference in the circumferential direction is formed so as to open upward in the axial direction. An annular plate-shaped lid 88 is superposed and fixed on the axial upper surface of the housing body 84, so that the opening of the concave groove 86 is covered with the lid 88 to form the housing 90. The housing body 84 and the lid 88 are preferably formed of metal or a hard synthetic resin material.

In short, the housing 90 of the vibration damping device 82 of the present embodiment has a ring-shaped internal space 92 having a structure that is substantially sealed from the external space. In addition, a plurality of independent masses 94 having the same structure as the independent mass (44) of the first embodiment are accommodated and arranged. In addition, in the housing 90, as in the first embodiment, vertical walls 96 that prevent the interference of the adjacent independent masses 94, 94 by partitioning the inner space 92 in the circumferential direction are mutually predetermined in the circumferential direction. It is fixed so that it is located at a distance.

In addition, each independent mass 94 has a housing 90.
However, they are not bonded or elastically connected to each other and are completely positioned independently of each other, and a jumping displacement independent of the housing 90 is allowed in the space partitioned by the adjacent vertical walls 96, 96 in the internal space 92. So each independent mass 9
The outer diameter dimension of 4 is the same as in the first embodiment.
It is set to be smaller than the inner size of the space partitioned by the adjacent vertical walls 96, 96 in 2 in the axial direction and in the direction perpendicular to the axis by a predetermined amount.

In the vibration damping device 82, the housing 90 is externally inserted into the cylinder 24 of the absorber body 12, and is fixedly fixed to the axially upper end of the cylinder 24. The cylinder 24 of the housing 90
For example, the upper end portion of the cylinder 24 can be press-fitted and fixed to the housing 90 in the shape of an annular block, or can be welded. In addition, for example, as shown in FIG. 7 or FIG. 8, the housing 90 is divided at one or two locations on the circumference, and the divided location is connected and fixed by a tightening bolt 98, so that the housing 90 is fixed. It may be clamped and fixed to the outer peripheral surface of the cylinder 24.

As is apparent from the above description, in the present embodiment, the inner peripheral surface of the inner space 92 of the housing 90 is provided with the recessed groove 86 which is positioned to face in the radial direction.
The inner and outer peripheral surfaces form a first contact surface, and the bottom surface of the recessed groove 86 and the lower surface of the lid 88 that are axially opposed to each other form a second contact surface.

Also in the shock absorber 80 according to the second embodiment having the vibration damping device 82 having such a structure, the independent mass 9 is held in the internal space 92 when the vibration is input.
By making the jumping displacement of 4 and hitting and abutting against the housing 90, an effective vibration damping effect is exerted on the absorber body 12 as in the first embodiment. Further, particularly in this embodiment, the independent mass 94
The internal space 9 in which the installation area of is substantially cut off from the external space
Since it is configured by 2, it is possible to prevent foreign matter and the like from entering between the contact surfaces of the independent mass 94 and the housing 90, and it is possible to more stably obtain the desired vibration damping effect.

Next, FIG. 9 shows a shock absorber 100 as a third embodiment of the present invention.

The vibration damping device 102 employed in the shock absorber 100 as the third embodiment has a substantially rectangular box-shaped housing body 106 having a rectangular recess 104 that opens upward. . As shown in FIG. 10, the recess 104 of the housing body 106 has a central portion in the longitudinal direction of the recess 104 partitioned by partition walls 108, and pockets each having a substantially cubic shape are formed on both sides of the partition wall 108. The parts 110, 110 are formed.
Then, a rectangular plate-shaped lid body 112 is overlapped and fixed on the upper surface of the housing body 106, so that the openings of the pocket portions 110, 110 are covered with the lid body 112 to form a housing 114. The housing body 106, the partition wall 108, and the lid 112 are preferably formed of a metal or a hard synthetic resin material.

In short, the housing 114 of the vibration damping device 102 of the present embodiment is provided with the internal cavities 116, 116 each having a cubic shape and having a structure that is substantially sealed from the external space. Internal void space 116,1
The independent masses 118, 118 having the same structure as the independent mass (44) of the first embodiment are housed and arranged in the inside of 16. It should be noted that, as in the first embodiment, each independent mass 118 is capable of jumping displacement independently of the housing 114 inside the internal space 116.

In the vibration damping device 102, the housing 114 has the piston rod 26 of the absorber body 12.
Fixed against. That is, the piston rod 26
Is fixed to the upper support 30 by a fixing nut 120 at its upper end in the axial direction, and the upper end of the piston rod 26 is projected further upward than the mounting portion to the upper support 30. The housing 114 is fixed to the protruding tip of the piston rod 26. The housing 114 has the piston rod 26 at the center of the bottom wall of the recess 104.
Is fixed to the piston rod 26 such that the bottom surface of the recess 104 spreads out in a direction substantially perpendicular to the axis of the piston rod 26. in short,
A pair of internal cavities 116, 116 are located on both sides of the central axis of the piston rod 26, and the pair of independent masses 118, 1 are symmetrically arranged with the piston rod 26 in between.
18 is provided.

The shock absorber 100 according to the third embodiment provided with the vibration damping device 102 having such a structure.
Also, at the time of vibration input, the vibration of the piston rod 26 is exerted on the housing 114 to be vibrated, so that the independent masses 118, 11 inside the inner spaces 116, 116.
8 is displaced like a jump and hits against the housing 114 including the partition wall 108 to come into contact with the housing 114, so that an effective vibration damping effect is exerted on the absorber body 12 as in the first embodiment.

Next, FIG. 11 shows a shock absorber 130 as a fourth embodiment of the present invention.

The vibration damping device 132 employed in the shock absorber 130 according to the fourth embodiment is provided with an annular independent mass 134 as a whole. The independent mass 134 has a structure in which a cushion rubber 138 is adhered and formed to cover the entire outer peripheral surface of a ring-shaped mass body 136 continuously extending in the circumferential direction with a constant rectangular cross section. There is. The cushion rubber 138 is integrally formed with a contact portion 140 that projects downward in the axial direction of the mass body 136 in a chevron section.

The independent mass 134 has an inner diameter larger than the outer diameter of the piston rod 26 of the absorber body 12 by a predetermined amount, and the diameter of the protruding tip portion of the abutting portion 140. However, the outer diameter of the cylinder 24 of the absorber body 12 is reduced by a predetermined amount.

The independent mass 134 is externally attached to the piston rod 26 of the absorber body 12 and assembled. Under such an assembled state, the abutting portion 140 is attached to the axial upper end surface 142 of the cylinder 24. Are abutted against each other and supported. In the present embodiment, the first contact surface and the second contact surface are formed by the axial upper end surfaces of the piston rod 26 and the cylinder 24.

The shock absorber 130 according to the fourth embodiment provided with the vibration damping device 132 having such a structure.
Also, when the vibration is input, the vibration of the cylinder 24 in the absorber body 12 is directly exerted on the independent mass 134 to be excited, whereby the independent mass 134 is displaced in a jumping manner with respect to the cylinder 24. By striking and abutting against, the effective vibration damping effect is exerted on the absorber body 12 as in the first embodiment. In the present embodiment, the independent mass 134 is directly abutted and vibrated on the piston rod 26 of the absorber body 12 in the axis-perpendicular direction even when vibration in the axis-perpendicular direction is exerted. Independent mass 1
Since 34 abuts against the piston rod 26 in the axis-perpendicular direction and is brought into contact with the piston rod 26, an effective vibration damping effect can be exhibited even with respect to vibration in the axis-perpendicular direction.

The embodiments of the present invention have been described in detail above, but these are merely examples, and the present invention is
The specific description in these embodiments is not to be construed as limiting in any way, and can be carried out in a mode in which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. Further, it goes without saying that all such embodiments are included in the scope of the present invention without departing from the spirit of the present invention.

For example, in the vibration damping device 18 shown in the first embodiment, the independent masses 44 are formed in a plurality in the axial direction of the piston rod 26 by integrally forming the housing 42 by stacking a plurality of stages in the axial direction. You may make it contact | abut at a location. Further, a plurality of the vibration damping devices 82 shown in the second embodiment may be mounted at a plurality of positions in the axial direction of the cylinder 24.

In the first to third embodiments,
The number of independent masses 44, 94, 118 adopted is not limited to the number of the first to third embodiments. Furthermore, the outer peripheral surfaces of the independent masses 94 and 118 have a cushioning rubber layer 76.
The inner surfaces of the inner cavities 92 and 116 in the housings 90 and 114 do not need to be covered with the covering rubber.

Further, when a plurality of independent masses 44, 94 are adopted as in the first and second embodiments, the vertical walls 72, 96 in the housings 42, 90 do not necessarily have to be provided.

In the second embodiment, the inner peripheral surface of the housing 90 is superposed on the outer peripheral surface of the cylinder 24, but the outer peripheral surface of the cylinder 24 and the housing 9 are overlapped with each other.
An elastic material may be interposed between the opposing surfaces of the inner peripheral surface of 0, and the housing 90 may be elastically connected to the cylinder 24 by the elastic material to form a sub-vibration system for the absorber main body 12, which is the main vibration system. .

The specific structure of the shock absorber used in the present invention is not particularly limited,
For example, the present invention can be similarly applied to a shock absorber of a type in which the coil spring 14 is not externally mounted.

[0072]

As is apparent from the above description, in the shock absorber having the structure according to the present invention, the resonance of the shock absorber itself is caused by the direct or indirect contact of the independent mass member with the cylinder or the piston rod. Vibration is suppressed, which can advantageously improve the vibration state of the vehicle due to the transmission of vibrations from the wheel side to the body side through the suspension mechanism.

[Brief description of drawings]

FIG. 1 is an explanatory diagram schematically showing the overall structure of a shock absorber for a vehicle as a first embodiment of the present invention.

FIG. 2 is an explanatory longitudinal sectional view showing an enlarged main part of the shock absorber shown in FIG.

FIG. 3 is a detailed explanatory view showing a part of FIG. 2 in a further enlarged manner.

4 is a sectional view taken along line IV-IV in FIG.

5 is an explanatory longitudinal sectional view corresponding to FIG. 2, showing another example of the mounting structure of the vibration damping device in the shock absorber shown in FIG.

FIG. 6 is an explanatory longitudinal sectional view corresponding to FIG. 2, showing a main part of a shock absorber for an automobile as a second embodiment of the present invention.

FIG. 7 is a cross-sectional view in the direction perpendicular to the axis, showing an example of the mounting structure of the vibration damping device in the shock absorber shown in FIG.

8 is a cross-sectional view in the direction perpendicular to the axis, showing another example of the mounting structure of the vibration damping device in the shock absorber shown in FIG.

FIG. 9 is a vertical cross-sectional explanatory view corresponding to FIG. 2, showing a main part of a shock absorber for an automobile as a third embodiment of the present invention.

10 is a cross-sectional view taken along line XX in FIG.

FIG. 11 is an explanatory longitudinal sectional view corresponding to FIG. 2, showing a main part of a shock absorber for an automobile as a fourth embodiment of the present invention.

[Explanation of symbols]

10 shock absorber 12 absorber body 18 Vibration control device 20 main body 22 Suspension arm 24 cylinders 26 Piston rod 42 housing 44 Independent Mass 70 Internal void 74 mass 76 cushioning rubber layer

Claims (10)

[Claims] 1. A shock absorber for a vehicle mounted on a suspension mechanism by mounting a cylinder on one of a body side member and a wheel side member of a vehicle and mounting a piston rod on the other side, the cylinder or the piston rod. On the other hand, a shock absorber for a vehicle in which an independent mass member that is non-adhesive and can be independently displaced is assembled so that the independent mass member is elastically repeatedly abutted against the cylinder or the piston rod at the time of vibration input. . 2. The independent mass member is an annular shape that continuously extends around the central axis of the cylinder or the piston rod over the entire circumference in the circumferential direction, and is externally attached to the cylinder or the piston rod. Claim 1 which is arranged
The shock absorber for a vehicle according to item 1. 3. A plurality of the independent mass members are arranged independently of each other around a center axis of the cylinder or the piston rod, and the plurality of independent mass members are substantially orthogonal to the center axis when a vibration is input. 2. The shock absorber for a vehicle according to claim 1, wherein the shock absorber is elastically repeatedly abutted against the cylinder or the piston rod in a predetermined direction. 4. A support surface fixedly provided on the cylinder or the piston rod for supporting the independent mass member from vertically below is an inclined surface inclined vertically downward toward the central axis. The vehicle shock absorber according to item 3. 5. A hollow housing for accommodating the independent mass member is fixedly provided to the cylinder or the piston rod, and the independent mass member is elastically repeated with respect to the inner surface of the housing when vibration is input. The vehicle shock absorber according to any one of claims 1 to 4, wherein the shock absorber is brought into contact with the shock absorber. 6. A reciprocating movable distance of the independent mass member between contact surfaces formed by an inner surface of the housing is substantially parallel to a direction substantially orthogonal to a central axis of the cylinder or the piston rod. In each of,
The shock absorber for a vehicle according to claim 5, wherein the shock absorber has a thickness of 0.1 to 1.6 mm. 7. A first contact surface on which the independent mass member elastically repeatedly abuts in a direction substantially orthogonal to the central axis of the cylinder or the piston rod at the time of vibration input, and at the time of vibration input. 7. A second contact surface, on which the independent mass member is elastically repeatedly contacted in a direction substantially parallel to the central axis, is fixedly provided on the cylinder or the piston rod. The vehicle shock absorber according to claim 1. 8. The contact surface for elastically repeatedly contacting the independent mass member at the time of vibration input is provided in the vicinity of the protruding side end of the piston rod of the cylinder. The vehicle shock absorber described. 9. The piston rod is made to project further outward beyond a mounting portion to the other of the body side member and the wheel side member, and further projected outwardly beyond the mounting portion. The shock absorber for a vehicle according to any one of claims 1 to 7, wherein a contact surface is provided at a portion where the independent mass member is elastically repeatedly contacted when vibration is input. 10. The vehicle shock according to claim 1, wherein at least one of the contact surfaces of the independent mass member and the cylinder or the piston rod when a vibration is input has a Shore D hardness of 80 or less. Absorber.