JP2019069731A - Tandem axle suspension device - Google Patents

Abstract

To provide a tandem axle suspension device capable of reducing stroke amount until vertical movement of a shackle is regulated during braking.SOLUTION: A tandem axle suspension device 10 includes a swing mechanism 30 to which a rear end 21b of a first leaf spring 21 and a front end 22a of a second leaf spring 22 are connected. The swing mechanism 30 has a walking beam 31 having a swing shaft section 34, a shackle 32 having an upper side shaft section 39 to which the first leaf spring 21 is rotatably connected and a lower side shaft section 38 to which the walking beam 31 is rotatably connected, and a stopper 33 which regulates vertical movement of the shackle 32. The shackle 32 has a first regulation piece 51 which abuts on the stopper 33 during traveling and a second regulation piece 52 which moves upward from the first regulation piece 51 by rotation of the shackle 32 around the lower side shaft section 38 during braking and has a tip surface abutting on the stopper 33.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tandem axle suspension system for attaching front and rear axles aligned in the front-rear direction of a vehicle to a frame of the vehicle.

  In a large automobile such as a truck, as in Patent Document 1, for example, it acts on the front axle and the rear axle as a suspension system for attaching the front axle and the rear axle aligned in the longitudinal direction of the vehicle to the side frame of the vehicle. In many cases, a tandem axle suspension system capable of holding the shaft weight at a constant ratio is employed.

  Such a tandem axle suspension comprises a first leaf spring supporting one end of a front axle, a second leaf spring supporting one end of the rear axle, a rear end of the first leaf spring and a second leaf spring. And a rocking mechanism connecting the front end.

  An example of a tandem axle suspension is a walking beam suspension. The rocking mechanism of the suspension system is configured such that the walking beam connected to the frame via a rocking shaft extending in the width direction of the vehicle and each of the walking beam and the rear end of the first leaf spring are rotatably connected And a shackle. The swing mechanism also includes a stopper that restricts upward movement of the shackle when the shackle abuts.

Unexamined-Japanese-Patent No. 10-157430

  By the way, load movement toward the front of the vehicle occurs in the vehicle at the time of braking, such as at the time of operation of the foot brake. By such load movement, a rotational force acts on the first leaf spring to displace the rear end portion obliquely upward on the front side of the vehicle. The rotational force causes the shackle to move upward, but the ratio adjustment of the axial weight via the walking beam between the front axle and the rear axle is performed until the upward motion is restricted by the stopper.

  However, in order to effectively apply the braking force to the vehicle, it is preferable that the ground load on the front wheels be large. In this regard, the adjustment of the axial load ratio at the time of braking described above reduces the ground contact load on the front wheels and increases the ground load on the rear wheels. Therefore, at the time of braking, in order to suppress the movement of the ground contact load due to the swing of the walking beam, it is preferable that the stroke amount which is the displacement amount of the shackle to the upper side of the vehicle until the upward movement is restricted. On the other hand, when traveling, it is preferable from the viewpoint of ride comfort and traveling stability that the stroke amount be large so that the ratio adjustment of the shaft weight by the swinging of the walking beam is increased.

  An object of the present invention is to provide a tandem axle suspension system capable of reducing the stroke amount until the upper motion of the shackle is restricted at the time of braking.

  A tandem axle suspension system for solving the above problems is a tandem axle suspension system for attaching a front axle and a rear axle to a frame of a vehicle, the first leaf spring extending in the longitudinal direction of the vehicle to support the front axle A second leaf spring extending in the front-rear direction of the vehicle behind the first leaf spring to support the rear axle, a rear end of the first leaf spring and a front end of the second leaf spring And a swing mechanism connected to the rear part, the swing mechanism extending in the width direction of the vehicle between the rear end of the first leaf spring and the front end of the second leaf spring A walking beam having a shaft and pivotable with respect to the frame, a lower shaft to which the walking beam is rotatably connected, and a rear end of the first leaf spring A shackle having an upper shaft portion rotatably connected, and a stopper positioned above the shackle to restrict the upward movement of the shackle, the shackle being the shackle when the vehicle travels The first restricting surface that contacts the stopper by the upward movement, and the upward movement of the first restricting surface due to the rotation of the shackle around the lower shaft when the vehicle is braked And a second restriction surface that abuts on the

  According to the above configuration, at the time of braking, the upward movement of the shackle is restricted by the second restricting surface moved upward with respect to the first restricting surface abutting on the stopper. As a result, the stroke amount can be made smaller than in the configuration in which the upward movement of the shackle during braking is restricted by the first restriction surface.

It is preferable that the tandem axle suspension apparatus of the said structure is larger than the said 1st control surface in a said 2nd control surface in distance from the said upper side axial part.
At the time of braking, the shackle pivots about the lower shaft so as to move the first restricting surface to the front of the vehicle. Therefore, by configuring as described above, the second restricting surface can be disposed above the first restricting surface at the time of braking. In addition, the amount of shackle stroke at the time of braking can be made smaller.

  In the tandem axle suspension of the above configuration, the shackle extends from the upper shaft along the direction in which the lower shaft and the upper shaft are aligned, and has a first restriction surface at its tip. It is preferable to have a piece and a second restriction piece extending from the upper shaft toward the rear side of the vehicle with respect to the first restriction piece and having the second restriction surface at its tip.

  According to the above configuration, the first restricting surface and the second restricting surface are set to separate surfaces separated from each other where there is no boundary portion. As a result, the degree of freedom of the shapes of the first and second restricting surfaces is improved.

In the tandem axle suspension system having the above configuration, the shackles have a pair of support portions that support the upper shaft portion and the lower shaft portion facing each other in the width direction of the vehicle, and the pair of support portions It is preferable that each have the said 1st control piece and the said 2nd control piece.
According to the above configuration, it is possible to disperse the load acting on the shackle when the shackle abuts on the stopper.

  In the tandem axle suspension of the above configuration, the stopper has an abutting surface on which the first restricting surface and the second restricting surface abut, and the abutting surface and the second restricting surface are flat. Preferably, the contact surface and the second control surface are in surface contact with each other when the vehicle is braked.

  According to the above configuration, after the abutment surface of the stopper abuts on the second regulation surface of the shackle, the deviation between the abutment surface and the second regulation surface is suppressed. Further, the reproducibility of the relative position between the stopper and the shackle in the restricted state at the time of braking can be enhanced.

1 is a side view showing a side structure of an embodiment of a tandem axle suspension system. The side view which shows the side structure of a rocking mechanism. The front view which shows an example of the front structure of a shackle. The side view which shows an example of the side structure of a shackle. The side view which shows the state where the upper motion of the shackle was controlled at the time of driving | running | working. The side view which shows the state by which the upper motion of the shackle was controlled at the time of damping | braking.

One embodiment of a tandem axle suspension system will be described with reference to FIGS. 1 to 6.
As shown in FIG. 1, a walking beam type tandem axle suspension system 10 (hereinafter simply referred to as the suspension system 10) extends in the longitudinal direction of the vehicle and is opposed to the pair of side frames 11 in the width direction of the vehicle It is provided separately for each of the frames 11).

  The suspension device 10 includes a first leaf spring 21 supporting one end of the front axle 12, a second leaf spring 22 supporting one end of the rear axle 13, and a rear end 21b of the first leaf spring 21 and a first And a swing mechanism 30 for connecting the front end portion 22 a of the two leaf spring 22.

  The first leaf spring 21 extends in the front-rear direction of the vehicle, and supports the front axle 12 to which the front wheel 14 is connected at a central portion. The front end portion 21 a of the first leaf spring 21 is rotatably connected to the bracket 23 fixed to the frame 11 via a shaft portion 24 extending in the width direction of the vehicle. The rear end 21 b of the first leaf spring 21 is rotatably connected to the swing mechanism 30.

  The second leaf spring 22 is located rearward of the first leaf spring 21 in the vehicle. The second leaf spring 22 extends in the front-rear direction of the vehicle, and supports the rear axle 13 corresponding to the rear wheel 15 at a central portion. The front end 22a of the second leaf spring 22 is rotatably connected to the swing mechanism 30 via a shaft 25 extending in the width direction of the vehicle. The rear end 22 b of the second leaf spring 22 is connected to a bracket 26 fixed to the frame 11 via a shackle 27.

  The shackle 27 is disposed to extend in the vertical direction of the vehicle, and is rotatably connected to the bracket 26 via a shaft portion 28 extending in the width direction of the vehicle. Further, in the shackle 27, the rear end portion 22b of the second leaf spring 22 is rotatably connected via a shaft portion 29 extending in the width direction of the vehicle. The shackle 27 rotates with respect to the bracket 23 centering on the shaft portion 28 so as to follow the rotation around the shaft portion 25 of the second leaf spring 22 and the elastic deformation of the second leaf spring 22. It pivots with respect to the rear end 22 b of the second leaf spring 22 about the portion 29. As a result, the shackle 27 absorbs changes in the relative position between the bracket 26 and the rear end 22 b of the second leaf spring 22 due to the rotation or elastic deformation of the second leaf spring 22.

The rocking mechanism 30 includes a walking beam 31, a shackle 32, and a stopper 33. FIG. 2 shows the side structure of the rocking mechanism as viewed from the outside of the vehicle.
As shown in FIG. 2, the walking beam 31 has a swing shaft 34 extending in the width direction of the vehicle. The walking beam 31 is swingably connected to a bracket 35 fixed to the frame 11 via a swing shaft portion 34. The walking beam 31 has a first arm 36 extending from the swinging shaft 34 toward the first leaf spring 21 and a second arm 37 extending from the swinging shaft 34 toward the second leaf spring 22. The lower end of the shackle 32 is connected to the end of the first arm 36, and the front end 22a of the second leaf spring 22 is rotatably connected to the end of the second arm 37 via the shaft 25. There is.

  The shackle 32 has a lower shaft portion 38 extending in the width direction of the vehicle, and an upper shaft portion 39 located above the lower shaft portion 38 and extending in the width direction of the vehicle. The shackle 32 is pivotally connected to the first arm 36 of the walking beam 31 via the lower shaft 38. The shackle 32 is rotatably connected to the rear end 21 b of the first leaf spring 21 via the upper shaft 39. The shackle 32 has a lower shaft 38 relative to the first arm 36 of the walking beam 31 so as to follow the pivoting about the shaft 24 of the first leaf spring 21 and the elastic deformation of the first leaf spring 21. , And with respect to the rear end 21b of the first leaf spring 21 about the upper shaft 39. As a result, the shackle 32 absorbs a change in the relative position of the first arm 36 of the walking beam 31 and the rear end 21 b of the first leaf spring 21 due to the rotation or elastic deformation of the first leaf spring 21.

  The stopper 33 is located above the shackle 32 and is fixed to, for example, the bracket 35. The stopper 33 has an abutting surface 33 a that restricts the upward movement of the shackle 32 when the shackle 32 abuts. The contact surface 33a is a flat surface extending along a surface direction orthogonal to the vertical direction of the vehicle.

  In addition, as shown in FIG. 1, the suspension system 10 attenuates the vertical vibration of the front axle 12 with respect to the frame 11, and the second shock absorber attenuates the vertical vibration of the rear axle 13 with respect to the frame 11. It has 42 and so on.

  In the suspension system 10 having such a configuration, the walking beam 31 swings as the front axle 12 and the rear axle 13 move up and down, so that the axial weight acting on the front axle 12 and the rear axle 13 is a certain ratio. It is possible to hold

Next, the shackle 32 will be described in detail with reference to FIGS. 3 and 4. FIG. 4 shows the side structure of the shackle 32 as viewed from the outside of the vehicle.
As shown in FIG. 3 and FIG. 4, the shackle 32 is produced by subjecting a base material formed of a steel member such as cast iron or carbon steel to various kinds of machining. The shackle 32 has a pair of support portions 44 supporting the lower shaft portion 38 and the upper shaft portion 39 so as to face each other in the width direction of the vehicle.

  Each of the pair of support portions 44 has a plate-like shape extending in the surface direction orthogonal to the width direction of the vehicle. One of the pair of support portions 44 is an outer side support portion located outside in the width direction of the vehicle, and the other of the pair of support portions 44 is an inner side support portion located inside in the width direction of the vehicle. The lower shaft hole 47 in which the lower shaft portion 38 is inserted and the upper shaft portion 39 are inserted in the width direction of the vehicle. And an upper shaft hole 48.

  The shackle 32 has a connecting portion 49 that integrally connects the pair of support portions 44. The connecting portion 49 has a plate-like shape, and integrally connects the portion between the upper shaft hole 48 and the lower shaft hole 47 in each of the pair of support portions 44. The connecting portion 49 is positioned between the rear end 21 b of the first leaf spring 21 and the first arm 36 of the walking beam 31 in a state where the shackle 32 is connected to the first leaf spring 21 and the walking beam 31. It is arranged.

  Each of the pair of support portions 44 has a first restriction piece 51 projecting from a portion where the upper shaft hole 48 is formed in a direction in which the lower shaft hole 47 and the upper shaft hole 48 are arranged. The front end surface of the first restricting piece 51 is set to the first restricting surface 51 a. The first restricting surface 51 a is formed in a curved surface shape along the circumference of a virtual circle C passing through the tip of the first restricting piece 51 with the upper axial hole 48 as the center in a side view of the vehicle. The first restricting surface 51a is in contact with the contact surface 33a of the stopper 33 when the shackle 32 moves upward as the front axle 12 and the rear axle 13 move up and down while the vehicle is traveling. Regulate the movement.

  Each of the pair of support portions 44 has a second restricting piece 52 that protrudes obliquely upward in the rear side of the vehicle from a portion where the upper shaft hole 48 is formed in a side view of the vehicle. The second restricting piece 52 has a shape that narrows toward a portion closer to the end in a side view of the vehicle, and the end face is set to the second restricting surface 52a. The second restricting surface 52a is located outside the imaginary circle C passing through the tip of the first restricting surface 51a described above. That is, the second restricting surface 52a is located at a position at which the distance to the upper shaft hole 48, in other words, the distance to the upper shaft 39, is larger than that of the first restricting surface 51a. The second restricting surface 52 a moves upward beyond the first restricting surface 51 a by rotation of the shackle 32 about the lower shaft 38 during braking of the vehicle, and makes surface contact with the contact surface 33 a of the stopper 33. Regulate the upward movement of the shackle 32. The second restricting surface 52a is a flat surface which is inclined so as to be positioned lower toward the rear side of the vehicle when the vehicle is in a stopped state.

  The operation of the above-described tandem axle suspension system 10 will be described with reference to FIGS. 5 and 6. In FIG. 5 and FIG. 6, the shackle 32 at the time of a stop of a vehicle is shown with the dashed-two dotted line.

  As shown in FIG. 5, when the front axle 12 moves upward when the vehicle travels, the first leaf spring 21 displaces the rear end 21 b upward around the shaft 24 that supports the front end 21 a. Rotate. In addition, the first leaf spring 21 elastically deforms so as to displace the rear end 21b to the rear of the vehicle. Then, the first leaf spring 21 swings the walking beam 31 via the shackle 32 so that the first arm 36 of the walking beam 31 is displaced upward. At this time, the shackle 32 pivots toward the rear of the vehicle about the lower shaft 38 with respect to the first arm 36 of the walking beam 31, and with respect to the rear end 21 b of the first leaf spring 21. And pivots about the upper shaft 39. When the shackle 32 is displaced upward by the stroke amount L1 which is the upward displacement amount, the first restricting surface 51a abuts on the contact surface 33a of the stopper 33, whereby the upward movement is restricted.

  On the other hand, as shown in FIG. 6, when the vehicle is braked, a rotational force F acts on the first leaf spring 21 to displace the rear end 21b obliquely upward on the front side of the vehicle. The first leaf spring 21 is pivoted by the rotational force F so that the rear end 21b is displaced upward about the shaft 24 supporting the front end 21a, and the rear end 21b is inclined forward of the vehicle. It elastically deforms so as to move upward. Then, the first leaf spring 21 swings the walking beam 31 so as to displace the first arm 36 of the walking beam 31 upward through the shackle 32, that is, to move the shackle 32 upward. With the rotation and elastic deformation of the first leaf spring 21, the shackle 32 rotates the rear end 21 b of the first leaf spring 21 about the upper shaft 39 and rotates the lower shaft 38 about the lower shaft 38. The upper shaft 39 is pivoted to move toward the front of the vehicle. The rotation of the shackle 32 moves the second restricting surface 52a upward above the first restricting surface 51a, and the second restricting surface 52a eventually abuts on the contact surface 33a of the stopper 33 to move the shackle 32 upward. Is regulated. Therefore, as compared with a configuration in which the upward movement of the shackle 32 is restricted by the first restriction surface 51a coming into contact with the contact surface 33a of the stopper 33 at the time of braking of the vehicle, the contact surface of the first restriction surface 51a and the stopper 33 The upward movement of the shackle 32 is restricted by a stroke amount L2 which is smaller by a distance ΔL to 33a.

According to the tandem axle suspension system 10 of the above embodiment, the following effects can be obtained.
(1) The upper movement of the shackle 32 is restricted by the first restricting surface 51a at the time of traveling, and is restricted by the second restricting surface 52a moving upward than the first restricting surface 51a at the time of braking. This makes it possible to reduce the stroke amount at the time of braking while securing the stroke amount at the time of traveling.

  (2) The second restricting surface 52 a is located outside the virtual circle C passing the foremost end of the first restricting surface 51 a around the upper shaft 39. According to such a configuration, when the shackle 32 pivots about the lower shaft portion 38 at the time of braking, the second restricting surface 52a can be disposed above the first restricting surface 51a. Further, the amount of rotation of the shackle 32 until the second restricting surface 52a is disposed above the first restricting surface 51a is reduced, and the stroke amount L2 of the shackle 32 at the time of braking can be further reduced.

  (3) Each of the support portions 44 constituting the shackle 32 is a first restricting piece having a first restricting surface 51 a which protrudes from the upper shaft portion 39 along the direction in which the lower shaft portion 38 and the upper shaft portion 39 are arranged. 51 and a second restricting piece 52 that protrudes rearward and obliquely upward from the upper shaft portion 39 toward the rear side of the vehicle with respect to the first restricting piece 51.

  According to such a configuration, the first restricting surface 51a and the second restricting surface 52a are set on mutually separated and independent surfaces where there is no boundary portion. Therefore, there is no need to consider mechanical strength at the boundary between the first restricting surface 51a and the second restricting surface 52a in designing the shapes of the first restricting surface 51a and the second restricting surface 52a. The degree of freedom of the shapes of the first restricting surface 51a and the second restricting surface 52a is improved.

  (4) The shackle 32 has the 1st control surface 51a and the 2nd control surface 52a in each of a pair of support part 44. As shown in FIG. Thereby, the impact load acting on the shackle 32 when the first restricting surface 51 a abuts on the stopper 33 can be relaxed. In addition to the impact load acting on the shackle 32 when the second restricting surface 52a abuts on the stopper 33, the continuous load received by the shackle 32 in a state where the second restricting surface 52a abuts on the stopper 33 It can be dispersed. As a result, the mechanical strength required of the shackle 32 can be suppressed.

  (5) The contact surface 33a of the stopper 33 and the second restriction surface 52a of the shackle 32 are flat with each other, and the contact surface 33a and the second restriction surface 52a are in surface contact with each other when the vehicle is braked. According to such a configuration, it is possible to suppress the deviation between the contact surface 33a and the second restricting surface 52a after the upward movement of the shackle 32 is restricted at the time of braking. As a result, since the restriction state of the shackle 32 by the second restriction surface 52a is easily maintained, it becomes more difficult to adjust the ratio of the shaft weight at the time of braking. In addition, the reproducibility of the relative position between the stopper 33 and the shackle 32 in the restricted state at the time of braking can be enhanced, and in designing the suspension device 10, the design condition at the time of braking can be easily specified.

In addition, the said embodiment can also be changed suitably as follows and can also be implemented.
The second restricting surface 52a may not be a flat surface, but may have a curved surface shape extending in the extending direction of the second restricting piece 52, for example.

The contact surface 33a of the stopper 33 may not be a flat surface, but may be a curved surface having a curved shape in a side view of the vehicle, for example.
The shackle 32 may have a configuration in which the second restricting surface 52 a is provided on only one of the pair of support portions 44.

-The 1st control surface 51a and the 2nd control surface 52a may be composition which adjoins in one continuous surface which is a curved surface which overlaps with virtual circle C, for example in side view of vehicles.
The second restricting surface 52a may be moved upward above the first restricting surface 51a and abut on the stopper 33 by the rotation of the shackle 32 about the lower shaft portion 38. Therefore, the distance from the upper shaft portion 39 may be the same between the first restricting surface 51a and the second restricting surface 52a, and the second restricting surface 52a is smaller than the first restricting surface 51a. It is also good.

  DESCRIPTION OF SYMBOLS 10 ... Tandem axle suspension system, 11 ... Frame, 12 ... Front axle, 13 ... Rear axle, 14 ... Front wheel, 15 ... Rear wheel, 21 ... 1st leaf spring, 21a ... Front end part, 21b ... Rear end part , 22: second leaf spring, 22a: front end, 22b: rear end, 23: bracket, 24, 25: shaft, 26: bracket, 27: shackle, 28, 29: shaft, 30: rocking mechanism 31: walking beam, 32: shackle, 33: stopper, 33a: abutment surface, 34: rocking shaft, 35: bracket, 36: first arm, 37: second arm, 38: lower shaft, 39: upper shaft portion, 41: first shock absorber, 42: second shock absorber, 44: support portion, 47: lower shaft hole, 48: upper shaft hole, 49: connection portion, 51: first restriction piece, 51a ... first Regulating surface, 52 ... second restriction piece, 52a ... second restriction surface.

Claims (5)

A tandem axle suspension system for attaching a front axle and a rear axle to a frame of a vehicle, comprising:
A first leaf spring extending in the longitudinal direction of the vehicle to support the front axle, and a second leaf spring extending rearward of the vehicle behind the first leaf spring to support the rear axle A swing mechanism connected to a rear end of the first leaf spring and a front end of the second leaf spring;
The swing mechanism has a swing shaft portion extending in the width direction of the vehicle between a rear end portion of the first leaf spring and a front end portion of the second leaf spring, and swings with respect to the frame Shackle having a possible walking beam, a lower shaft to which the walking beam is rotatably connected, and an upper shaft to which the rear end of the first leaf spring is rotatably connected; And a stopper for restricting the upward movement of the shackle,
The shackle is a first restricting surface that comes in contact with the stopper by the upward movement of the shackle when the vehicle is traveling, and the rotation of the shackle around the lower shaft when the vehicle is braked. (1) A tandem axle suspension system comprising: a second control surface which moves above the control surface and contacts the stopper. The tandem axle suspension according to claim 1, wherein a distance from the upper shaft portion is larger in the second control surface than in the first control surface. The shackle extends from the upper shaft along a direction in which the lower shaft and the upper shaft are arranged, and has a first restriction piece having the first restricting surface at its tip;
The tandem axle suspension system according to claim 1 or 2, further comprising: a second restriction piece extending from the upper shaft toward the rear side of the vehicle with respect to the first restriction piece and having the second restriction surface at a tip end. . The shackles have a pair of support portions that face each other in the width direction of the vehicle to support the upper shaft portion and the lower shaft portion.
The tandem axle suspension system according to claim 3, wherein each of the pair of support portions includes the first restriction piece and the second restriction piece. The stopper has an abutting surface on which the first restricting surface and the second restricting surface abut,
The contact surface and the second control surface are flat surfaces,
The tandem axle suspension system according to any one of claims 1 to 4, wherein the abutment surface and the second restriction surface are in surface contact when the vehicle is braked.

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