JP2003267020A - Leaf suspension device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a mounting to a frame side without damaging an effect of improving strength by refining a leaf spring made of modified ausforming steel. <P>SOLUTION: In a leaf suspension device, an axle 3 is suspended on the frame 1 with the leaf spring 14 made of the modified ausforming steel. The front end of the leaf spring 14 extends forward in a flat shape as it is, and is grappled and held by a clamp 16 mounted to a front bracket 15 on the frame 1 side. Thus, an eye need not to be molded at the front end of the leaf spring 14 and the leaf spring 14 need not to be reheated. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leaf suspension device.

[0002]

2. Description of the Related Art There are various types of suspensions used for suspending an axle on a frame. Among them, a leaf suspension device formed by stacking a plurality of leaf springs has a structure. It is easy to use, has high strength, is easy to maintain, and has high durability, and has been widely used in vehicles such as trucks.

FIG. 4 shows an example of a conventional leaf suspension system. In the figure, 1 is a frame of a vehicle, 2 is a leaf spring arranged in a stack in the front-back direction of the frame 1, and 3 is an axle composed of an I-beam. The axle 3 is connected to the lower surface of the central portion of the leaf spring 2 in the longitudinal direction via a U bolt 4.

The front end portion of the leaf spring 2 is wound upward to form an eye 5, and the eye 5 is tiltably wound around a horizontal pin 7 mounted on a front bracket 6 on the frame 1 side. Has been.

On the other hand, the rear end of the leaf spring 2 is wound upward to form an eye 8 like the front end, and the eye 8 of the shackle 10 mounted on the rear bracket 9 on the frame 1 side. The shackle 1 is wound around the horizontal pin 11 so as to be tiltable, and the expansion and contraction in the front-back direction due to the leaf spring 2 bending in an arc shape.
It is designed to be absorbed by a swing of 0.

The leaf spring 2 causes the U bolt 4 to move.
The bracket 12 is also fixed together with the U-bolt 4 at a position where the axle 3 is carried via the shock absorber 13. The tip of the bracket 12 and the frame 1 immediately above the bracket 12 are connected by the shock absorber 13. Has been done.

In such a conventional leaf suspension device, from the viewpoint of reducing the weight of the vehicle,
A high strength modified ausforming steel with toughness is used for the leaf spring 2.
We are trying to minimize the number of layers.

[0008] Here, the modified ausforming steel refers to a steel which has been subjected to a treatment method for enhancing the strength by working a steel in an austenitic state, and more specifically, it has a deep isothermal transformation curve. Regarding steel types that have a part, the steel treated by the method of heating the steel to an austenite structure and performing hot working, and then transforming it into a martensitic structure by quenching and then tempering it pointing.

[0009]

However, when the leaf spring 2 is made of such modified ausforming steel, it is desirable to roll it in a high temperature state where it is easily deformed and immediately quench it. Is designed to reheat the leaf spring 2 to make it easier to deform and then form the eyes 5 and 8,
The crystal grains that have been refined in the rolling process are the eyes 5, 8
There is a problem in that the effect of improving the strength due to the fine structure is diminished because it grows and becomes coarse by reheating in the step of molding.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to realize the attachment to the frame side without impairing the effect of improving the strength of the leaf spring made of modified ausforming steel due to the fine structure. It is intended to provide a leaf suspension device.

[0011]

The invention according to claim 1 of the present invention is a leaf suspension device in which an axle is suspended on a frame by a leaf spring made of modified ausforming steel. The front portion of the leaf spring is extended forward while maintaining a flat shape, and the front end portion of the leaf spring is held by the clamp mounted on the front bracket on the frame side.

By doing so, it is not necessary to form an eye on the front end of the leaf spring, and the front end of the leaf spring is left in a flat shape so that the clamp on the frame side holds the clamping force. Therefore, it is not necessary to reheat the leaf spring, and it is possible to avoid a phenomenon in which fine crystal grains grow and become coarse.

The invention according to claim 2 of the present invention is
A leaf suspension device in which the axle is suspended on a frame by a leaf spring made of modified ausforming steel, wherein the front end portion of the leaf spring is set thicker than other portions and the front end portion of the leaf spring is locally heated by induction heating. It is characterized in that an eye is formed by winding it upward while being heated, and the eye is tiltably wrapped around a horizontal pin mounted on a front bracket on the frame side.

In this way, since the front end of the leaf spring is locally heated to form the eye, coarsening of crystal grains is unavoidable at this front end. , By setting its thickness thicker than other parts, insufficient strength of the front end of the leaf spring is avoided, and it is not necessary to reheat the entire leaf spring, and most of the leaf spring is miniaturized. It is possible to avoid the phenomenon that the crystal grains are grown and coarsened.

The invention according to claim 3 of the present invention is
A leaf suspension device in which an axle is suspended on a frame by a leaf spring made of modified ausforming steel, wherein the front end portion of the leaf spring is formed in a lump shape and the front end portion of the leaf spring is perforated to form an eye. The present invention is characterized in that the eye is worked and the eye is fitted on a horizontal pin mounted on a front bracket on the frame side so as to be tiltable.

In this way, since the eye is machined by punching the front end portion of the leaf spring, it is not necessary to reheat the leaf spring, and a fine crystal is formed. The phenomenon in which grains grow and become coarse is avoided.

The invention according to claim 4 of the present invention is a sliding seat in which a rear end of a leaf spring is extended rearward in a flat shape and the rear end of the leaf spring is mounted on a rear bracket on the frame side. It is characterized by being held movably.

By doing so, it is not necessary to form an eye at the rear end of the leaf spring, and the rear end of the leaf spring remains flat and can be moved to the sliding seat on the frame side. It is not necessary to reheat the leaf spring because it is only required to hold the leaf spring, and it is possible to avoid the phenomenon that the fine crystal grains grow and become coarse.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a first embodiment for carrying out the present invention, and the portions denoted by the same reference numerals as those in FIG. 4 represent the same things.

In the first embodiment shown in FIG. 1, the axle 3 is suspended from the left and right leaf springs 14 on the frame 1. In the example shown here, the axle 3 is bent downward. A leaf spring 14 having an arcuate shape is adopted, and the axle 3 is connected to the lower surface of the central portion in the longitudinal direction via the U bolt 4.

The front end of the leaf spring 14 is
The flat shape extends forward and is held by the clamp 16 mounted on the front bracket 15 on the frame 1 side, while the rear end of the leaf spring 14 remains flat in the rearward direction. Extending to
A sliding seat 18 mounted on the rear bracket 17 on the frame 1 side is movably held.

Thus, the molding of the eye on the front end side which has been conventionally followed by the leaf spring 14 is abolished, and the clamp 16 is held by the clamp 16 on the frame 1 side. If the rear end is not formed with the eye and is held by the sliding sheet 18 on the frame 1 side so as to be movable, it is not necessary to form the eye on the front end and the rear end of the leaf spring 14. Since it is not necessary to reheat the leaf spring 14, it is possible to avoid the phenomenon that the fine crystal grains grow and become coarse.

The sliding seat 18 itself is conventionally used to hold the rear end of the leaf spring instead of the shackle, and the rear end of the leaf spring is slidably inserted. It is structured.

Therefore, according to the present embodiment, the leaf spring 14 made of modified ausforming steel is used.
Without sacrificing the effect of improving the strength due to the fine organization of
Since it is possible to mount the leaf springs 14 on the frame 1 side, it is possible to reduce the number of leaf springs 14 stacked and the plate thickness to obtain the same strength, thereby reducing the vehicle weight. (For example, in the illustrated example, suspension of the axle is realized by one leaf spring on each of the left and right sides).

FIG. 2 shows a second embodiment of the present invention. In this embodiment, the front end portion of the leaf spring 14 is set thicker than other portions, and then the front end of the leaf spring 14 is set. The part is heated by electromagnetic induction to be locally heated to be wound upward to form an eye 19, and the eye 19 is tiltably wound around a horizontal pin 20 mounted on the front bracket 15 on the frame 1 side. It has a different structure.

In this way, since the front end portion of the leaf spring 14 is locally heated to form the eye 19, the coarsening of the crystal grains can be avoided at this front end portion. However, by setting the thickness of the leaf spring 14 thicker than other portions, insufficient strength of the front end portion of the leaf spring 14 can be avoided, and it is not necessary to reheat the entire leaf spring 14, so that the leaf spring 1
It is possible to avoid the phenomenon in which the crystal grains that have become finer grow and become coarse in most of the portions of No. 4, and it is possible to obtain the same operational effect as in the case of the first embodiment described above.

FIG. 3 shows a third embodiment of the present invention, in which the front end of the leaf spring 14 is formed into a lump, and the front end of the leaf spring 14 is perforated to form a through hole. The eye 22 having 21 is machined, and the eye 2
2 has a structure in which a horizontal pin 20 mounted on the front bracket 15 on the frame 1 side is externally fitted to be tiltable.

Thus, in this way, the eye 22 is formed by perforating the front end portion of the leaf spring 14.
Since the leaf spring 14
There is no need to reheat the, it is possible to avoid the phenomenon that fine crystal grains grow and become coarse,
It is possible to obtain the same operational effects as in the case of the first embodiment described above.

The leaf suspension device of the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the scope of the present invention.

[0031]

According to the leaf suspension device of the present invention described above, the leaf spring can be attached to the frame side without impairing the effect of improving the strength by the fine organization of the leaf spring made of modified ausforming steel. Therefore, when obtaining the same strength, it is possible to reduce the number of leaf springs stacked and the plate thickness, and thus it is possible to reduce the weight of the vehicle.

[Brief description of drawings]

FIG. 1 is a side view showing a first embodiment of the present invention.

FIG. 2 is a side view showing a second embodiment of the present invention.

FIG. 3 is a side view showing a third exemplary embodiment of the present invention.

FIG. 4 is a side view showing a conventional example.

[Explanation of symbols]

1 frame 3 axles 14 Leaf spring 15 Front bracket 16 clamps 17 Rear bracket 18 sliding sheets 19 eyes 20 horizontal pins 21 through holes 22 eyes

Claims (4)

[Claims] 1. A leaf suspension device in which an axle is suspended on a frame by a leaf spring made of modified ausforming steel,
A leaf suspension device, wherein a front end portion of a leaf spring is extended forward in a flat shape and a front end portion of the leaf spring is held by a clamp mounted on a front bracket on a frame side. 2. A leaf suspension device in which an axle is suspended on a frame by a leaf spring made of modified ausforming steel,
The front end of the leaf spring is set thicker than other portions, and the front end of the leaf spring is locally heated by induction heating to be wound upward to form an eye, and the eye is mounted on the front bracket on the frame side. A leaf suspension device characterized by being tiltably wound around a horizontal pin. 3. A leaf suspension device in which an axle is suspended on a frame by a leaf spring made of modified ausforming steel,
The front end of the leaf spring is formed in a lump and the front end of the leaf spring is perforated to machine an eye,
A leaf suspension device in which the eye is externally tiltably fitted to a horizontal pin provided on a front bracket on the frame side. 4. The leaf spring has a rear end portion extending rearward in a flat shape, and the rear end portion of the leaf spring is movably held by a sliding seat mounted on a rear bracket on the frame side. The leaf suspension device according to claim 1, 2 or 3.