JP4925809B2 - bush - Google Patents

Description

  The present invention relates to a bush that connects a trailing arm in a trailing arm type suspension device to a vehicle body so as to be swingable.

  In a conventional trailing arm type rear suspension, a twist beam arranged with the width direction of the vehicle as a longitudinal direction, and a pair arranged with the longitudinal direction of the vehicle as a substantially longitudinal direction at both longitudinal ends of the twist beam. A trailing arm and a spindle projecting outward from the vehicle at each rear end of the trailing arm, and for supporting the trailing arm swingably on the vehicle body side on the front end side of the trailing arm The bushing axis is set parallel to the vehicle width direction (see, for example, Patent Document 1).

In recent years, as shown in FIG. 1, a trailing arm type rear suspension 102 in which an axis CL of a bush 100 is inclined with respect to the vehicle width direction has been developed (for example, see Patent Document 2). In this case, the axis CL of the bush 100 is inclined at an angle θ so that the vehicle outer side is behind the vehicle ( arrow b direction ) than the vehicle inner side in a vehicle plan view. In FIG. 1, arrow F indicates the front of the vehicle, arrow R indicates the right side of the vehicle, and arrow L indicates the left side of the vehicle. Reference numeral 104 indicates a twist beam, reference numeral 106 indicates a trailing arm, and reference numeral 108 indicates press-fitting of the bush 100. This is the bush press-fitting part.
JP-A-10-181326 JP 2002-127724 A

  For example, as shown in FIG. 7, an anti-vibration device as a first conventional example includes an elastic body 114 disposed between an inner cylinder 110 and an outer cylinder 112, and is provided on both axial sides of the elastic body 114. A currant portion 116 is formed, and on one side of the inner cylinder 110, a stopper 118 protruding radially outward is provided on the elastic body portion on the inner cylinder side to suppress the displacement in the front-rear direction.

  Further, in the conventional vibration isolator as the second example, as shown in FIG. 8, for example, the bottom portion of the curly portion 116 formed on the elastic body 114 has a large rounded shape to alleviate the distortion in the vicinity of the bottom portion. It is structural.

However, in the former structure (FIG. 7), the curvature radius r of the bottom portion of the curly portion 116 becomes small on the side where the stopper 118 is formed. When 114 deforms, there is a problem that local distortion increases at the bottom of the currant portion 116. In the latter (FIG. 8) structure, since there is no stopper, the displacement is large (compared to the former), and durability is improved. There is a problem that makes it difficult.
Even when such a conventional type bush is used in a rear suspension as shown in FIG. 1, the above-mentioned problems exist, and there has been a demand for solving these problems.

  In view of the above facts, an object of the present invention is to provide a bush that can obtain high durability when used in a trailing arm type rear suspension in which the axis of the bush is inclined with respect to the vehicle width direction. Is the purpose.

The invention according to claim 1 includes a twist beam arranged with the width direction of the vehicle as a longitudinal direction, and a trailing arm with the longitudinal direction of the vehicle as a longitudinal direction and respectively connected to both ends of the twist beam. The front end side of the trailing arm in the suspension device is slidably connected to the vehicle body side, and the center axis of the swing is inclined so that the vehicle inner side is more forward than the vehicle outer side with respect to the vehicle body width direction. A bush attached to the trailing arm, which is coaxially arranged on the inner peripheral side of the outer cylinder connected to the front end side of the trailing arm, and is swingably connected to the vehicle body side An inner cylinder, an elastic body disposed between the outer cylinder and the inner cylinder and elastically coupled to the outer cylinder and the inner cylinder, and a vehicle having at least an axis on an outer surface in the vehicle width direction of the elastic body First concave portions formed on both sides in the rear direction, and when arranged in a horizontal cross section along the axis, is disposed between the inner cylinder and the outer cylinder on the outer side in the vehicle width direction. When the total thickness of the elastic body measured in the direction orthogonal to the axis of the portion where the first curly portion of the elastic body is formed is compared between the vehicle front side and the vehicle rear side of the axis, the vehicle front side is thicker. When viewed in a cross section along the axis, the bottom portion of the first curly portion is formed in an arc shape, and the radius of curvature is larger on the vehicle rear side than the vehicle front side across the axis. It is a feature.

Next, the operation of the bush according to claim 1 will be described.
The bush according to claim 1 is attached to the trailing arm so that the central axis of the swing is inclined with respect to the vehicle body width direction so that the inside of the vehicle is ahead of the vehicle than the outside of the vehicle. The inner cylinder is connected to the vehicle body side, and the outer cylinder is connected to the trailing arm.

  When a vehicle longitudinal force from the trailing arm is input to the outer cylinder, the inner cylinder and the outer cylinder are relatively displaced in the vehicle longitudinal direction, and the elastic body on the vehicle front side of the inner cylinder is compressed, so that the first curly portion is compressed. , The elastic body on the vehicle rear side of the inner cylinder is stretched, and the gap of the first currant portion is expanded.

  When viewed in a horizontal section along the axis, the elastic body total thickness measured in the direction orthogonal to the axis of the portion where the first curly portion is formed on the outer side in the vehicle width direction is more Since it is thicker on the front side of the vehicle, when the outer cylinder is displaced toward the vehicle rear side and when the outer cylinder is displaced toward the vehicle front side, the case where the outer cylinder is displaced toward the vehicle rear side is more The relative displacement amount of the inner and outer cylinders can be made smaller than when displaced forward. That is, by changing the total thickness of the elastic body in this way, a function as a stopper when the outer cylinder is displaced to the vehicle rear side is born.

  Further, in the portion where the first curly portion on the vehicle rear side of the inner cylinder is formed, the total elastic body thickness is smaller than that on the vehicle front side of the inner cylinder, that is, the clearance dimension of the first currant portion is Since the inner cylinder is larger on the rear side than the vehicle front side, the width of the bottom portion of the first currant portion can be made larger on the rear side than the vehicle front side of the inner cylinder, and the outer cylinder is displaced toward the vehicle rear side. In this case, the first curly portion is in the direction in which the gap is enlarged on the vehicle rear side of the inner cylinder, but the distortion in the vicinity of the bottom portion can be reduced.

Thus, in the bush of claim 1, when a force is applied to move the outer cylinder toward the rear side of the vehicle during traveling, distortion of the bottom portion of the first currant portion is suppressed while suppressing excessive displacement. It is possible to suppress the conventional conflicting problems, and high durability can be obtained.
Further, when viewed in a cross section along the axis, the bottom portion of the first currant portion is formed in an arc shape, and the radius of curvature is larger on the vehicle rear side than the vehicle front side across the axis. When the force that displaces the rear side of the vehicle is input and the gap size of the first currant portion is enlarged, the distortion acting on the bottom portion of the first currant portion can be reduced.

According to a second aspect of the present invention, in the bush according to the first aspect, in the outer side portion of the elastic body in the vehicle width direction, the elastic body from the outer peripheral surface of the inner cylinder to the inner side surface of the first currant portion. Is thicker than the thickness of the elastic body from the inner peripheral surface of the outer cylinder to the outer surface of the first currant portion.

Next, the operation of the bush according to claim 2 will be described .
When considering the condition that the gap size of the first currant portion is not changed, the thickness of the elastic body attached to the inner cylinder is increased, and the thickness of the elastic body attached to the outer cylinder is relatively set. Two patterns are conceivable: a case where the thickness is reduced, and a case where the thickness of the elastic body attached to the inner cylinder is thin and the thickness of the elastic body attached to the outer cylinder is relatively thick.
When both are compared, when the outer cylinder is displaced toward the rear side of the vehicle, the strain acting on the elastic body can be reduced in the former, which is a preferable mode for improving durability.

According to a third aspect of the present invention, in the bush according to the first or second aspect, a concave second currant is formed on at least both sides in the vehicle front-rear direction of the axis on the inner surface of the elastic body in the vehicle width direction. The second curly portion of the elastic body is formed between the inner cylinder and the outer cylinder on the inner side in the vehicle width direction when viewed in a horizontal cross section along the axis. When the total elastic body thickness measured in the direction perpendicular to the axis of the portion is compared between the vehicle front side and the vehicle rear side of the axis, the vehicle rear side is thicker.

Next, the operation of the bush according to claim 3 will be described .
When viewed in a horizontal cross section along the axis, the total elastic body thickness measured in the direction orthogonal to the axis of the portion where the second curly portion is formed on the outer side in the vehicle width direction is more Since the thickness is increased on the rear side of the vehicle, the case where the outer cylinder is displaced toward the vehicle front side is longer when the outer cylinder is displaced toward the vehicle front side than when the outer cylinder is displaced toward the vehicle rear side. The relative displacement amount of the inner and outer cylinders can be made smaller than when displaced to the side. That is, by changing the total thickness of the elastic body in this way, a function as a stopper when the outer cylinder is displaced to the vehicle front side is born.

  Further, in the portion where the second currant portion on the vehicle front side of the inner cylinder is formed, the total elastic body thickness is smaller than the vehicle rear side of the inner cylinder, that is, the gap dimension of the second currant portion is Since the inner cylinder is larger on the front side than the vehicle rear side, the width of the bottom portion of the second currant portion can be made larger on the front side than the vehicle rear side of the inner cylinder, and the outer cylinder is displaced toward the vehicle front side. In this case, the second curly portion is in the direction in which the gap is enlarged on the vehicle front side of the inner cylinder, but the distortion in the vicinity of the bottom portion can be reduced.

In this way, in the bush of claim 3 , when a force is applied to move the outer cylinder toward the front side of the vehicle during traveling, distortion of the bottom portion of the second currant portion is suppressed while suppressing excessive displacement. It is possible to suppress the conventional conflicting problems and obtain high durability.

  As described above, according to the bush of the present invention, the conventional conflicting problems are solved, and the durability is high when used in the trailing arm type rear suspension in which the axis of the bush is inclined with respect to the vehicle width direction. Is obtained.

[First Embodiment]
Hereinafter, the bush 10 which concerns on the 1st Embodiment of this invention is demonstrated with reference to drawings.

FIG. 1 is a perspective view showing a trailing arm type rear suspension, and FIG. 2 shows a bush 10 attached to the vehicle right side (arrow R direction side) of the rear suspension in a horizontal section along an axis. It is. 3 is an arrow view of the bush 10 shown in FIG. 2 as viewed in the direction of arrow b , and FIG. 4 is an arrow view of the bush 10 shown in FIG. 2 as viewed in the direction of arrow a . Furthermore, FIG. 5 is an AA cross-sectional view of the bush 10 shown in FIG. In the figure, arrow F indicates the front direction of the vehicle, arrow B indicates the rear of the vehicle, arrow R indicates the right side of the vehicle, arrow L indicates the left side of the vehicle, and arrow IN indicates the inner side of the vehicle. Yes.

As shown in FIG. 2, the bush 10 includes a thin metal outer cylinder 12. The outer cylinder 12 is integrally formed with a flange 12B on the inner side in the vehicle width direction of the cylindrical portion 12A.
A cylindrical inner cylinder 14 is concentrically provided inside the outer cylinder 12. Note that the inner cylinder 14 of the present embodiment has a diameter that is slightly larger at the center than at both ends.
The length along the axial direction of the inner cylinder 14 is longer than that of the outer cylinder 12, and both end portions thereof protrude from both ends of the outer cylinder 12.

  Here, the outer cylinder 12 is press-fitted and fixed in a bush press-fit portion 108 provided at the front end portion of the trailing arm 106 shown in FIG. 1, and the inner cylinder 14 is attached to a bracket (not shown) provided on the vehicle body side. The bolts and nuts (not shown) penetrating the side are swingably connected.

  The bush 10 swings around a bolt that penetrates the inner cylinder 14, but the trailing arm 106 swings in the direction of arrow C around a virtual line FL passing through both bushes 10, as shown in FIG. Move

As shown in FIG. 2, the bush 10 includes a thick cylindrical rubber-like elastic body 16 that is disposed between the outer cylinder 12 and the inner cylinder 14 and elastically connects the outer cylinder 12 and the inner cylinder 14. I have.
The rubber-like elastic body 16 is vulcanized and bonded to the inner peripheral surface of the outer cylinder 12 and the outer peripheral surface of the inner cylinder 14.

  As shown in FIG. 2, the rubber-like elastic body 16 is formed with a first curly portion 18 having a concave ring shape surrounding the inner cylinder 14 on the outer side surface in the vehicle width direction, and also on the inner side surface in the vehicle width direction. A second curly portion 20 having a concave ring shape surrounding the inner cylinder 14 is formed.

The rubber-like elastic body 16 in the portion where the first curly portion 18 is formed is outside when the vehicle front side (arrow F direction side) and the vehicle rear side ( arrow b direction side ) of the inner cylinder 14 are compared. The thickness of the portion attached to the inner peripheral surface of the cylinder is substantially the same, but the thickness of the portion attached to the outer peripheral surface of the inner cylinder is formed thicker on the vehicle front side than on the vehicle rear side.

  Therefore, when viewed in a horizontal cross section, the total elastic body thickness measured in the direction orthogonal to the axis of the portion of the rubber-like elastic body 16 where the first curly portion 18 is formed is the vehicle front side and the vehicle rear side of the axis. When compared with the side, the vehicle front side is thicker.

  In the present embodiment, among the rubber-like elastic bodies 16 where the first curly portion 18 is formed, the thick portion on the front side of the vehicle that is fixed to the outer peripheral surface of the inner cylinder is referred to as the first stopper portion. We will call it 22. The first stopper portion 22 is opposed to the inner peripheral surface of the outer cylinder 12 in the vicinity of the outer end in the vehicle width direction, and when the outer cylinder 12 is displaced rearward of the vehicle, the outer periphery of the outer cylinder 12 in the vicinity of the outer end in the vehicle width direction. The inner peripheral surface is in contact with the first stopper portion 22 so that the amount of displacement is regulated.

  Further, when the bottom portion of the first stopper portion 22 is viewed in cross section, it is substantially semicircular, and the curvature radius R1b of the bottom portion located on the vehicle rear side of the inner cylinder 14 is the bottom portion of the inner cylinder 14 located on the vehicle front side. It is set to be larger than the curvature radius R1f.

  On the other hand, in the second currant portion 20, the shape of the inner cylinder 14 on the vehicle front side and the shape on the vehicle rear side are the same shape. Further, the width of the second currant portion 20 is formed wider than that of the first currant portion 18. The shape of the bottom portion of the second curly portion 20 is a substantially semicircular arc shape, and the curvature radius R2 thereof is set to be larger than the curvature radius R1b of the bottom portion of the first stopper portion 22 located on the vehicle rear side of the inner cylinder 14. ing.

  In addition, as shown in FIG. 3, the mark 26 which designates the direction at the time of vehicle mounting | wearing is provided on the side surface of the rubber-like elastic body 16. In the present embodiment, the bush 10 is press-fitted and fixed in the bush press-fit portion 108 so that the mark 26 faces the front of the vehicle.

(Function)
Next, the operation of the bush 10 according to this embodiment will be described.
When the vehicle travels and a force toward the rear of the vehicle (in the direction of arrow b ) is input to the trailing arm 106 of the rear suspension, the force is transmitted from the outer cylinder 12 to the rubber-like elastic body 16, and the rubber-like elastic body 16 is deformed. Thus, the outer cylinder 12 is displaced toward the vehicle rear side with respect to the inner cylinder 14.

  Thereby, the rubber-like elastic body 16 on the vehicle front side of the inner cylinder 14 is compressed and the gap between the first curly portions 18 on the vehicle front side of the inner cylinder 14 is reduced, and when an excessive force is input, The outer cylinder 12 abuts on the first stopper portion 22, and excessive displacement of the outer cylinder 12 can be suppressed.

  At this time, the rubber-like elastic body 16 on the vehicle rear side of the inner cylinder 14 is stretched and the gap of the first curly portion 18 on the vehicle rear side of the inner cylinder 14 is enlarged, but the bottom portion here has a curvature. Since the radius is set to be large, that is, the curvature radius R1b is set to be larger than the curvature radius R1f of the bottom portion located on the vehicle front side of the inner cylinder 14, the distortion near the bottom portion can be suppressed small.

  Further, in the second currant portion 20, since the curvature radius R2 of the bottom portion is set larger than the curvature radius R1b of the bottom portion of the first currant portion 18, only when the outer cylinder 12 is displaced to the vehicle rear side. In addition, even when the vehicle is displaced rearward, the distortion near the bottom can be kept small.

  Therefore, in the bush 10 of the present embodiment, when a force for moving the outer cylinder 12 to the rear side of the vehicle is input during traveling, distortion of the bottom portion of the first curly portion 18 is suppressed while suppressing excessive displacement. Since the distortion of the bottom portion of the second curly portion 20 can also be suppressed, high durability can be obtained.

  The trailing arm 106 swings around a virtual line FL passing through the bush 10. At this time, a circumferential shearing force acts on the rubber-like elastic body 16. This circumferential shear force also affects the durability of the rubber-like elastic body 16. Since the influence of the shearing force on the bottom portion of the first curly portion 18 is less when it is away from the swing center (imaginary line FL), the first stopper portion 22 is provided on the inner cylinder side, and the first curly portion 18 is provided. The present embodiment in which the bottom portion (the radius of curvature R1f) of the lens is separated from the oscillation center is a preferable mode.

  Note that the bush 10 on the left side of the vehicle is disposed symmetrically with respect to the bush 10 shown in FIG.

[Second Embodiment]
Hereinafter, the bush 10 which concerns on the 2nd Embodiment of this invention is demonstrated with reference to drawings. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.
As shown in FIG. 6, in the bush 10 of this embodiment, the shape of the rubber-like elastic body 16 in the vehicle width direction inner portion is different from that of the first embodiment.

  In this embodiment, the rubber-like elastic body 16 in the portion where the second currant portion 20 is formed adheres to the inner peripheral surface of the outer cylinder when the vehicle front side and the vehicle rear side of the inner cylinder 14 are compared. Although the thickness of the part which is attached is the same, the thickness of the part adhering to the inner cylinder outer peripheral surface is formed thicker on the vehicle rear side than on the vehicle front side.

Accordingly, when viewed in a horizontal cross section, the total elastic body thickness measured in the direction orthogonal to the axis of the portion where the second curly portion 20 of the rubber-like elastic body 16 is formed is the vehicle front side and the vehicle rear side of the axis. When compared with the side, the vehicle rear side is thicker.
In the present embodiment, the thick portion on the outer peripheral surface side of the inner cylinder and on the vehicle rear side in the rubber-like elastic body 16 where the second curly portion 20 is formed is hereinafter referred to as the second stopper portion 24. I will call it.

  The second stopper portion 24 faces the inner peripheral surface of the outer cylinder 12 in the vicinity of the inner end in the vehicle width direction, and the vehicle width of the outer cylinder 12 when the outer cylinder 12 is displaced forward (in the direction of arrow F). The inner peripheral surface in the vicinity of the outer end in the direction is in contact with the second stopper portion 24 so that the amount of displacement is regulated.

  Further, when the bottom of the second stopper portion 24 is viewed in cross section, it is substantially semicircular, and the curvature radius R2f of the bottom located on the vehicle front side of the inner cylinder 14 is the same as that of the first embodiment. The curvature radius R2b of the bottom located on the vehicle rear side of the vehicle is smaller than the curvature radius R2f due to the provision of the second stopper portion 24. However, if the radius of curvature R2b is too small, a large distortion occurs when the outer cylinder 12 is displaced in the rearward direction of the vehicle. Therefore, it is preferable that the radius of curvature R1b is approximately the same as the radius of curvature R1b of the first curly portion 18.

(Function)
Next, the operation of the bush 10 according to the present embodiment configured as described above will be described.
When a force toward the front of the vehicle (in the direction of arrow F) is input to the trailing arm 106 of the rear suspension, the force is transmitted from the outer cylinder 12 to the rubber-like elastic body 16, and the rubber-like elastic body 16 is deformed so that the outer cylinder 12 is The inner cylinder 14 is displaced forward of the vehicle.

  Thereby, the rubber-like elastic body 16 on the vehicle rear side of the inner cylinder 14 is compressed and the gap between the second curly portions 20 on the vehicle rear side of the inner cylinder 14 is reduced, and when excessive force is input, The outer cylinder 12 can be brought into contact with the second stopper portion 24 to suppress excessive displacement of the outer cylinder 12.

Therefore, in the bush 10 of the present embodiment, when a force for moving the outer cylinder 12 toward the front side of the vehicle is input during traveling, excessive displacement is suppressed and distortion of the bottom portion of the second curly portion 20 is suppressed. Therefore, high durability can be obtained even with respect to the input of a force for displacing the outer cylinder 12 toward the front side of the vehicle. That is, high durability can be obtained with respect to the input of force in the vehicle longitudinal direction.
In addition, although the center part expanded the diameter of the inner cylinder 14 of the said embodiment rather than the both ends, this invention is not restricted to this, A diameter may be constant over the full length.

It is a perspective view which shows the structure of the trailing arm type rear suspension which can apply the bush concerning this embodiment, and the conventional bush. It is a horizontal sectional view along the axis of a bush concerning a 1st embodiment. It is the arrow line view seen in the b direction of the bush shown in FIG. It is the arrow view seen from the a direction of the bush shown in FIG. It is a BB sectional view of the bush shown in FIG. It is a horizontal sectional view along the axis of a bush concerning a 2nd embodiment. It is sectional drawing of the bush which concerns on the conventional 1st example. It is sectional drawing of the bush which concerns on the 2nd example of the past.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bush 12 Outer cylinder 14 Inner cylinder 16 Rubber-like elastic body 18 1st currant part 20 2nd curly part 22 1st stopper part 24 2nd stopper part

Claims (3)

A front end side of a trailing arm in a suspension device having a twist beam arranged with the width direction of the vehicle as a longitudinal direction, and a trailing arm with the longitudinal direction of the vehicle as a longitudinal direction and connected to both ends of the twist beam, respectively And a bush attached to the trailing arm so that the center axis of the swing is inclined with respect to the vehicle body width direction so that the inner side of the vehicle is more forward than the outer side of the vehicle. There,
An outer cylinder connected to the front end side of the trailing arm;
An inner cylinder that is coaxially disposed on the inner peripheral side of the outer cylinder and is swingably connected to the vehicle body side;
An elastic body disposed between the outer cylinder and the inner cylinder and elastically coupled to the outer cylinder and the inner cylinder;
A concave first curly part formed on at least both sides of the vehicle longitudinal direction of the vehicle body in the vehicle width direction of the elastic body;
With
When viewed in a horizontal cross section along the axis, the portion perpendicular to the axis of the elastic body disposed between the inner cylinder and the outer cylinder on the outer side in the vehicle width direction is formed. an elastic body total thickness measured in the direction, when compared with the vehicle front side and the rear side of the axis, toward the vehicle front side rather thick,
When viewed in a cross section along the axis, the bottom of the first currant portion is formed in an arc shape, and the radius of curvature is larger on the vehicle rear side than the vehicle front side across the axis.
Bush characterized by that. In the vehicle width direction outer side part of the elastic body, the thickness of the elastic body from the outer peripheral surface of the inner cylinder to the inner side surface of the first currant part is from the inner peripheral surface of the outer cylinder to the first currant part. The bush according to claim 1, wherein the bush is thicker than the thickness of the elastic body up to the outer surface of the bush. On the inner side surface in the vehicle width direction of the elastic body, concave second currant portions formed at least on both sides in the vehicle front-rear direction of the axis are formed,
  When viewed in a horizontal cross section along the axis, the portion perpendicular to the axis of the second curly portion of the elastic body disposed between the inner cylinder and the outer cylinder on the inner side in the vehicle width direction 3. The bush according to claim 1, wherein when the total elastic body thickness measured in the direction is compared between the vehicle front side and the vehicle rear side of the axis, the vehicle rear side is thicker.