JP2007030670A - Tandem axle suspension device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tandem axle suspension device which can adjust the axle weight distribution acting on a driving shaft and a driven shaft only by changing a laminated elastic body without changing the related parts, improve traveling performance of the vehicle, and enhance versatility. <P>SOLUTION: A spring constant in the vertical direction of the laminated elastic body 7 of the side corresponding to the driving shaft 9 is set to a value higher than the spring constant in the vertical direction of the laminated elastic body 7 of the side (rear side) corresponding to the driven shaft 11, and the spring constant in the horizontal direction of the laminated elastic body 7 of the side corresponding to the driving shaft 9 is set to a value approximately equal to the spring constant in the horizontal direction of the laminated elastic body 7 of the side corresponding to the driven shaft 11, and the axle weight control for the driving shaft 9 and the driven shaft 11 is performed by changing the inclination angle θ<SB>1</SB>and the number of lamination of an elastic member 5 and a plate 6 in the laminated elastic body 7 of the side (front side) corresponding to the driving shaft 9 while keeping the inclination angle θ<SB>0</SB>and the total length H of both mounting surfaces. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tandem axle suspension system.

  For large vehicles such as buses and trucks, tandem axles with the rear axle (rear axle) as the drive shaft and driven shaft are common, but in vehicles with the rear axle as the tandem axle, the load is doubled. It can be distributed on one axle, and the overall load capacity can be improved.

  FIG. 6 shows a conventional example of a suspension (suspension device) for supporting a tandem axle as described above. Reference numeral 1 denotes a vehicle body frame extending in the longitudinal direction of the vehicle, and a trunnion bracket 2 attached to the vehicle body frame 1. The laminated elastic body 7 in which the elastic members 5 and the plates 6 are alternately laminated is disposed so as to be inclined in a V shape between the center beam 4 and the center bracket 4 attached to the center portion of the equalizer beam 3 in the front-rear direction. A driving axle 8 is connected to the front end of the equalizer beam 3, and a driving shaft 9 is rotatably supported on the driving axle 8, and a driven axle 10 is connected to the rear end of the equalizer beam 3. The driven shaft 11 is rotatably supported by the driven axle 10.

The laminated elastic body 7 generally uses rubber as the elastic member 5 and uses a metal plate as the plate 6, and the plates 6 disposed at both ends in the laminating direction are arranged on the inclined surface (inclination angle θ ₀ ) of the trunnion bracket 2. Are attached to the inclined surface (inclination angle θ ₀ ) of the center bracket 4 using fastening members such as bolts and nuts (not shown).

  In FIG. 6, reference numeral 12 denotes a drive wheel that rotates about the drive shaft 9, and 13 denotes a driven wheel that rotates about the driven shaft 11.

  In the tandem axle suspension device as shown in FIG. 6, the load applied from the vehicle body frame 1 side is borne by the compression and shear deformation of the laminated elastic body 7.

Examples of the general technical level related to the tandem axle suspension system as described above include Patent Document 1 and Patent Document 2.
JP 2000-62423 A JP-A-9-136521

  However, in the tandem axle suspension system having the drive shaft 9 and the driven shaft 11 as shown in FIG. 6, the load (axial weight) acting on the drive shaft 9 is dispersed. The grounding load to be reduced is reduced, and when the vehicle is empty (during light load), there is a problem that the startability of the vehicle is reduced.

  In order to solve such problems, the axial load distribution acting on the drive shaft 9 and the driven shaft 11 is changed, for example, by changing the length of the equalizer beam 3 in the front and rear direction so that the drive shaft 9 side becomes larger. It is conceivable to change the spring constant of the laminated elastic body 7 provided.

  However, as described above, when the length of the equalizer beam 3 before and after is changed, almost all layouts and parts must be changed accordingly, and completely different parts are designed and manufactured for each vehicle type. The necessity arises and the versatility is low.

  On the other hand, in order to simply increase the spring constant in the compression direction of the laminated elastic body 7, it is generally known to increase its cross-sectional area or shorten its overall length. In order to simply increase the spring constant in the direction, it is generally known to increase the number of plates 6, but when the total length of the laminated elastic body 7 changes, the components related to it are still changed. As described above, it is necessary to design and manufacture completely different parts for each vehicle type, and it is inevitable that versatility is reduced.

  In view of such circumstances, the present invention can adjust the axle load distribution acting on the drive shaft and the driven shaft only by changing the laminated elastic body without changing the related parts, thereby improving the running performance of the vehicle. It is an object of the present invention to provide a tandem axle suspension device that can be improved and can also improve versatility.

In the present invention, a laminated elastic body in which an elastic member and a plate are alternately stacked is disposed between a body frame and a tandem axle having a drive shaft and a driven shaft in a pair of front and rear inclined positions corresponding to the drive shaft and the driven shaft. In the tandem axle suspension system configured to bear the load applied from the body frame side by compression and shear deformation of the laminated elastic body,
By changing the inclination angle and the number of laminations of the elastic member and the plate in at least one laminated elastic body while maintaining the inclination angle and the total length of the mounting surfaces on both ends, the vertical direction of the laminated elastic body on the side corresponding to the drive shaft is changed. The spring constant is set higher than the vertical spring constant of the laminated elastic body on the side corresponding to the driven shaft, and the horizontal spring constant of the laminated elastic body on the side corresponding to the drive shaft is set on the side corresponding to the driven shaft. The present invention relates to a tandem axle suspension device characterized in that it is substantially equal to the spring constant in the horizontal direction of the laminated elastic body and is configured to perform axial load control on the drive shaft and the driven shaft.

  According to the above means, the following operation can be obtained.

  When configured as described above, it is possible to avoid a reduction in the ground load acting on the drive wheel due to the axle load control on the drive shaft and the driven shaft by changing the spring constant of the laminated elastic body. In addition, it is possible to improve the startability of the vehicle at the same time, and by simply changing the laminated elastic body, it is not necessary to change the dimensions and layout of the related parts. Therefore, versatility can be greatly improved.

  In the tandem axle suspension device, the laminated elastic body may be a laminated rubber in which rubber and metal plates are alternately laminated.

  According to the tandem axle suspension device of the present invention, the axle load distribution acting on the drive shaft and the driven shaft can be adjusted only by changing the laminated elastic body without changing the related parts, and the running performance of the vehicle As a result, it is possible to achieve an excellent effect of improving versatility.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an example of an embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 6 denote the same components, and the basic configuration is the same as the conventional one shown in FIG. However, as shown in FIG. 1, the feature of the illustrated example is that the inclination angle θ ₁ of the elastic member 5 and the plate 6 in the laminated elastic body 7 on the side (front side) corresponding to the drive shaft 9 and the number of laminated layers are as follows. Is changed while maintaining the inclination angle θ _{0 and the} total length H of the both end mounting surfaces, the vertical spring constant of the laminated elastic body 7 on the side corresponding to the drive shaft 9 is changed to the side corresponding to the driven shaft 11 ( The horizontal elastic constant of the laminated elastic body 7 on the side corresponding to the drive shaft 9 is set higher than the vertical spring constant of the laminated elastic body 7 on the rear side) and the laminated elastic body on the side corresponding to the driven shaft 11. 7 is substantially equal to the horizontal spring constant of 7, and is an axis with respect to the drive shaft 9 and the driven shaft 11. It lies in that configured to perform the control.

In the case of the illustrated example, the thickness of the plates 6 disposed at both ends in the laminating direction of the laminated elastic body 7 is gradually changed from one end side to the other end side to form a wedge shape, and the orientation of each plate 6 is changed. The staggered angle of the elastic member 5 and the plate 6 is set to θ ₁ without changing the tilt angle θ ₀ of the both end mounting surfaces of the laminated elastic body 7 by staggering.

Here, the example shown in FIG. 1 is schematically represented as shown in FIG. 2, and a member (equalized with the equalizer beam 3) supported by two springs (corresponding to the laminated elastic body 7) having spring constants k ₁ and k _2. The balance equation when the loads f ₁ and f ₂ are applied to both ends (corresponding to the drive shaft 9 and the driven shaft 11) and the amount of deflection is δ is:
[Equation 1]
f ₁ + f ₂ = δ · (k ₁ + k ₂ )
[Equation 2]
(L−x) · k ₁ · δ + (L + x) · k ₂ · δ = 2 · L · f ₂
From [Formula 1] to [Formula 3]
δ = (f ₁ + f ₂ ) / (k ₁ + k ₂ )
From [Equation 3] and [Equation 2], [Equation 4]
(L−x) · k ₁ + (L + x) · k ₂ = 2 · L · (k ₁ + k ₂ ) · f ₂ / (f ₁ + f ₂ )
From [Equation 4], the relationship between the spring constants k ₁ and k ₂ is
[Equation 5]
k ₁ = k ₂ · {L · (f ₁ −f ₂ ) + x · (f ₁ + f ₂ )} / {L · (−f ₁ + f ₂ ) + x · (f ₁ + f ₂ )}
It becomes.

At this time, if the load distribution (shaft load distribution) is set to, for example, f ₁ : f ₂ = 10: 7, that is, f ₁ = 1 and f ₂ = 0.7, the spring constant k ₁ , between the k _2,
[Equation 6]
_{k 1 = k 2 · (0.3} · L + 1.7 · x) / (- 0.3 · L + 1.7 · x)
It would be good if this relationship is established.

On the other hand, the compression direction spring constant k _c ^* and the shear direction spring constant k _s ^* of one elastic member 5 constituting the laminated elastic body 7 are the vertical and horizontal directions of the single elastic member 5 as shown in FIG. , If the height dimension is a, b, h,
[Equation 7]
k _c ^* = (3 + 6.580 · S ² ) · G · (a · b / h)
(Where S is the shape factor, and S = a · b / {2 · (a + b) · h},
G is a transverse elastic modulus of rubber as the elastic member 5 of the laminated elastic body 7. )
[Equation 8]
k _s ^* = 1 / (1 + 1/3 × h ² / a ² ) × G · (a · b / h)
When the number of laminated rubbers constituting the laminated elastic body 7 is n, the compression direction spring constant k _c ^* and the shear direction spring constant k _s ^* of the laminated elastic body 7 are
[Equation 9]
k _c = k _c ^* / n
[Equation 10]
k _s = k _s ^* / n
It becomes.

The vertical spring constant k _y and the horizontal spring constant k _x when the laminated elastic body 7 is disposed at an inclination angle θ as shown in FIG.
[Equation 11]
k _y = k _c · cos ² θ + k _s · sin ² θ
[Equation 12]
k _x = k _c · cos ² (90−θ) + k _s · sin ² (90−θ)
It becomes.

Now, the longitudinal dimension a, the lateral dimension b, the height dimension h, the lateral elastic modulus G, the number n of laminations, and the inclination angle θ (θ ₀ , θ ₁ ) of one elastic member 5 constituting the laminated elastic body 7 are required. When the shape ratio S, the vertical spring constant k _{y, the} horizontal spring constant k _{x and the} like are obtained from the above [Equation 7] to [Equation 12], the result is as shown in FIG. In [Equation 6],
L = 660 [mm]
x = 282 [mm]
If the layout of
k ₁ : k ₂ = 2.4: 1
The ratio before and after the vertical spring constant k _y , that is,
13827: 5817 ≒ 2.4: 1
The load distribution (shaft load distribution) is f ₁ : f ₂ = 10: 7
It becomes possible to set to.

  As described above, since the spring constant of the laminated elastic body 7 on the side corresponding to the drive shaft 9 (front side) is changed, the axial load control for the drive shaft 9 and the driven shaft 11 can be performed. The ground contact load acting on the drive wheel 12 can be avoided from being reduced, and the vehicle startability can be improved when the vehicle is idle (light load). Moreover, only by changing the laminated elastic body 7, It is not necessary to change the dimensions and layout of the parts such as the equalizer beam 3 and the center bracket 4 related to it, and it is not necessary to design and manufacture completely different parts for each vehicle type, which can greatly increase versatility. It becomes.

  Thus, the axial load distribution acting on the drive shaft 9 and the driven shaft 11 can be adjusted only by changing the laminated elastic body 7 without changing the related parts such as the equalizer beam 3 and the center bracket 4. The driving performance can be improved, and versatility can be improved.

Note that the tandem axle suspension device of the present invention is not limited to the illustrated example described above, and the inclination angle and the number of layers of the elastic member 5 and the plate 6 in the laminated elastic body 7 on the side corresponding to the driven shaft 11 are determined. The horizontal spring constant of the laminated elastic body 7 on the side corresponding to the drive shaft 9 and the lamination on the side corresponding to the driven shaft 11 are changed while maintaining the inclination angle θ _{0 and the} total length H of the both end mounting surfaces. While the spring constant in the horizontal direction of the elastic body 7 is substantially equal, the vertical spring constant of the laminated elastic body 7 on the side corresponding to the driven shaft 11 is set to the vertical of the laminated elastic body 7 on the side corresponding to the drive shaft 9. The spring constant in the vertical direction of the laminated elastic body 7 on the side corresponding to the drive shaft 9 is relatively reduced in the vertical direction of the laminated elastic body 7 on the side corresponding to the driven shaft 11. For example, it may be higher than the spring constant. Of course, various changes can be made without departing from the scope of the present invention.

It is a side view which shows an example of the form which implements this invention. It is the schematic which shows an example of the form which implements this invention typically. Is a perspective view showing a direction of compression spring constant k _c ^* and shear directions spring constant k _s for one of the elastic members constituting the laminated elastic body ^* in an example of the mode for carrying out the present invention. It is a schematic diagram showing a vertical spring constant k _y and horizontal spring constant k _x when the laminated elastic body in an example of the mode for carrying out the present invention has been arranged obliquely. Various dimensions of the laminated elastic body in an example of the mode for carrying out the present invention, specific values, such as vertical spring constant k _y and horizontal spring constant k _x is a diagram illustrating in tabular form. It is a side view which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Body frame 2 Trunnion bracket 3 Equalizer beam 4 Center bracket 5 Elastic member 6 Plate 7 Laminated elastic body 9 Drive shaft 11 Drive shaft 12 Drive wheel 13 Drive wheel H Total length k _y Vertical spring constant k _x Horizontal spring constant θ ₀ Inclination Angle θ ₁ Tilt angle

Claims (2)

A laminated elastic body in which elastic members and plates are alternately stacked is disposed between the vehicle body frame and a tandem axle having a drive shaft and a driven shaft so that the pair of front and rear are inclined corresponding to the drive shaft and the driven shaft. In the tandem axle suspension device configured to bear the load applied from the vehicle body frame side by compression and shear deformation of the laminated elastic body,
By changing the inclination angle and the number of laminations of the elastic member and the plate in at least one laminated elastic body while maintaining the inclination angle and the total length of the mounting surfaces on both ends, the vertical direction of the laminated elastic body on the side corresponding to the drive shaft is changed. The spring constant is set higher than the vertical spring constant of the laminated elastic body on the side corresponding to the driven shaft, and the horizontal spring constant of the laminated elastic body on the side corresponding to the drive shaft is set on the side corresponding to the driven shaft. A tandem axle suspension system characterized in that it is substantially equal to the horizontal spring constant of the laminated elastic body and is configured to perform axial load control on the drive shaft and driven shaft.   The tandem axle suspension apparatus according to claim 1, wherein the laminated elastic body is a laminated rubber in which rubber and metal plates are alternately laminated.

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