JP2665402B2 - Leaf spring manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a leaf spring used for a suspension spring of an automobile or the like.

[0002]

2. Description of the Related Art A steel suspension spring used for a suspension system of a vehicle such as an automobile is strongly required to be reduced in weight, and various measures for reducing the weight have been taken. For example, if the leaf spring is used with high stress by increasing the hardness and increasing the tensile strength, it will help to reduce the weight. However, the toughness of the leaf spring is reduced due to the increase in hardness, and the notch sensitivity of the leaf spring surface is increased, so that the durability may be reduced. In order to avoid this, by including in the leaf spring manufacturing process a thermomechanical treatment that combines heat treatment such as rolling and quenching,
Performing tempering has been studied by the present inventors.

[0003] Leaf springs tempered by thermomechanical treatment are:
For example, the toughness is enhanced by the refinement of the crystal grains or the uniformity of the direction of the structure, and this makes it possible to cope with high stress. In order to reduce the weight, a tapered leaf spring that can equalize the stress distribution in the longitudinal direction of the leaf spring is also effective. Furthermore,
In the case of a stacked leaf spring device, the number of leaf springs can be reduced,
This is effective in reducing the weight.

In view of the above, recently, there has been a tendency to manufacture tapered leaf springs using a leaf spring material having a large thickness. In addition, in order to obtain the above-mentioned thermomechanical effect, it is necessary to also roll the central portion (the maximum thickness portion) of the tapered leaf spring in the longitudinal direction. Therefore, a tapered leaf spring is obtained by rolling the entire length of the leaf spring material in the longitudinal direction.
However, in this case, since the final rolling reduction becomes large, a certain measure is required for the rolling mill.

FIG. 4 shows an example of a conventional taper leaf spring manufacturing apparatus 2. As shown in FIG. This conventional apparatus 2 comprises a furnace 3 for heating a leaf spring material 1, a high-pressure water descaler 4 for removing an oxide scale on the surface of the material 1, and a pair of edge rolls arranged in the width direction of the material 1. 5 (only one is shown), and a variable roll 6 capable of variably setting the amount of reduction.

A first conventional method (rolling in one pass) using the above-mentioned conventional apparatus 2 is a method in which a leaf spring material 1 discharged from a furnace 3 is preliminarily expanded by an edge roll 5 to a width corresponding to a widened portion. Adjust the width to the width pattern. after that,
Rolling in the thickness direction is performed by the variable roll 6, and after being rolled into a predetermined tape shape, it is cut into a predetermined length. FIGS. 5A, 5B, and 5C schematically show changes in the shape of the leaf spring material 1 when the above-described first conventional method is performed. That is, the leaf spring material 1 having the shape shown in FIG.
The width is adjusted to the shape shown in FIG. 5B, and the tape is further formed into a tapered shape shown in FIG.
In each drawing, a is the side shape of the material 1, b is the planar shape,
c represents the front shape.

As a second method using the above-mentioned conventional apparatus 2, a method of rolling in two passes is also conceivable. FIG. 6 shows a shape change of the leaf spring material 1 when the second conventional method is performed. The second conventional method uses an edge roll 5
Is the same as in the first conventional method up to the width shifting step by
The material 1 is widened to the shape shown in FIG. 6 (B). In the subsequent tape rolling process using the variable roll 6, first, as shown in FIG. As described above, the parallel rolling is performed to a predetermined plate thickness, and in the second pass, the moving direction of the material 1 is reversed, and as shown in FIG.
Rolling is performed. Therefore, in the second conventional method, the leaf spring material 1 reciprocates on the variable roll 6.

[0008]

In the case of the first conventional method using the above-mentioned conventional apparatus 2, since the final shape is completed in one pass by the variable roll 6, the roll diameter, load and torque are increased. Therefore, the size of the entire rolling equipment increases, and the equipment cost increases significantly. Also, since the width of the leaf spring material 1 is large, the edge roll 5 must be large. And the edge roll 5 and the variable roll 6
With the increase in size, the distance between peripheral equipment before and after the rolling mill becomes longer, so that taper processing of a short material becomes impossible.

On the other hand, in the case of the above-mentioned second conventional method, in order to finish the final product by reversing the variable roll 6 in the first pass and the second pass, a peripheral portion for reciprocating the material 1 is used. Equipment and its control are complicated, and production tact is greatly reduced. In addition, since rolling is performed twice at the exit side of the edge roll 5, it is difficult to predict the amount of width expansion of the raw material 1, and there is a problem that the dispersion of the plate width of the final product becomes large. In the case of performing a thermomechanical treatment, it is necessary to quench the steel immediately after rolling, so that the conventional method, which requires a long time in the rolling process, is not suitable.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a leaf spring manufacturing apparatus capable of forming a tapered leaf spring by adding a simple structure and at the same time, expecting a working heat treatment effect of the leaf spring. It is in.

[0011]

SUMMARY OF THE INVENTION A leaf spring manufacturing apparatus according to the present invention, which has been developed to achieve the above object, comprises: a flat roll for rolling a heated leaf spring material in parallel to a predetermined thickness; An edge roll which is arranged on the outlet side of the roll and rolls both side edges of the above-mentioned leaf spring material in the plate width direction to adjust the width to a predetermined plate width pattern; And a variable roll for forming the leaf spring material into a predetermined tape shape by rolling in the thickness direction.

[0012]

The steel plate spring material is heated by a furnace to, for example, an austenitizing temperature, the scale is removed after the furnace is released, and is then parallel-rolled to a predetermined thickness by the flat roll. Here, the predetermined thickness is a thickness at which the variable roll can bite or a thickness of a parallel plate thickness portion (maximum plate thickness portion) at the center in the longitudinal direction of the taper leaf spring. The material rolled in parallel by the flat roll is narrowed by the edge roll by an amount that allows for an increase in the sheet width during tape rolling by the variable roll. Thereafter, the material is rolled into a predetermined tape shape by a variable roll in one pass.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. A leaf spring manufacturing apparatus 10 shown in FIG. 1 includes a heating furnace 1 for heating a steel leaf spring material 1.
1, a high-pressure water descaler 12 and an upper roll 13a and a lower roll 13b arranged in the thickness direction of the leaf spring material 1 in this order on the outlet side of the heating furnace 11.
3, a pair of edge rolls 14 (only one is shown) arranged on both sides in the width direction of the leaf spring material 1, and the leaf spring material 1
And a variable roll 15 composed of an upper roll 15a and a lower roll 15b arranged in the thickness direction of FIG. The heating furnace 11 can heat the leaf spring material 1 to a temperature at which the heat treatment can be performed. The high-pressure water descaler 12 has a function of removing the oxide scale on the surface of the leaf spring material 1.

The flat roll 13 has a predetermined thickness of the leaf spring material 1 by the upper roll 13a and the lower roll 13b, that is, the maximum thickness of the tapered leaf spring 1 'to be formed at a longitudinally intermediate portion. Parallel rolling is performed to a thickness corresponding to the portion 18. The flat roll 13 is made of a leaf spring material 1 having a thickness greater than the maximum plate thickness that can be bittened and determined by the roll diameter of the variable roll 15.
It is only necessary to have a function of performing parallel rolling to a thickness at which the variable roll 15 can bite. Therefore, the roll diameter, rolling load and rolling torque of the flat roll 13 may be small. A leaf spring material 1 is provided on the outer periphery of the edge roll 14.
A groove having a shape corresponding to both right and left side edges (so-called rounded edge portion) is provided over the entire circumference.

The variable roll 15 is a variable rolling mechanism 21 having a hydraulic servo cylinder or the like capable of variably setting the rolling amount.
And a sensor 22 for detecting the position of the leaf spring material 1 in the longitudinal direction, etc., based on a command from a control unit 23 using a microcomputer or the like. The desired tape rolling is performed by successively changing the amount of reduction in accordance with this. The variable roll 15, the roll diameter, the rolling load, and the torque may be smaller than when the flat roll 13 is not provided (for example, the conventional device illustrated in FIG. 4).

Next, the operation of the leaf spring manufacturing apparatus 10 having the above configuration will be described. FIGS. 2A to 2D show this device 1
0 shows a shape change of the leaf spring material 1 when rolling is performed using 0. In each figure, a represents a side shape, b represents a planar shape, and c represents a front shape.

The leaf spring blank 1 is discharged from the furnace 11 in a state where the leaf spring material 1 is heated to a temperature at which a thermomechanical treatment can be performed. Then, the scale is removed by the descaler 12. FIG. 2A shows an example of the shape of the leaf spring material 1 before rolling. The leaf spring material 1 is parallel-rolled to a predetermined thickness by a small-diameter flat roll 13 as shown in FIG. Is done. The predetermined thickness in the present embodiment refers to the thickness of the maximum plate thickness portion (parallel plate thickness portion) 18 in the middle portion in the longitudinal direction of the tapered leaf spring 1 'as the final product.

After the parallel rolling by the flat roll 13 is completed, the width is shifted by the edge roll 14. In this case, as shown in FIG. 2C, the width is adjusted in a pattern that allows for an increase in the width of the plate due to the subsequent taper rolling in the thickness direction.

The rolled leaf spring material 1 is rolled into a predetermined tape shape by a variable roll 15 having a diameter larger than that of the flat roll 13 and then cut into a predetermined length. The leaf spring 1 'of the final product as shown in FIG. In the variable roll 15, the position sensor 2
2, the longitudinal position of the leaf spring material 1 detected is tracked. Based on this position signal, the amount of reduction is controlled by a control program stored in the control unit 23 in advance, and the desired taper is controlled. Rolling to a shape is performed.

In the variable roll 15, substantially no rolling of the middle portion in the longitudinal direction of the leaf spring 1 ', that is, the maximum thickness portion 18 is performed. However, since the maximum plate thickness portion 18 is previously parallel-rolled at a certain area reduction ratio by the flat roll 13 described above, a desired working heat treatment effect is exerted over the entire longitudinal direction of the leaf spring 1 ', and high strength is obtained. Thus, a strong taper leaf spring 1 'can be obtained.

Material 1 rolled by flat roll 13
Is a material having a thickness exceeding the maximum thickness that can be bitten by the variable roll 15, and a material having a thickness less than the maximum thickness is not substantially rolled by the flat roll 13 and the lower roll 13 is not rolled.
It may just pass over b. Therefore, the rolling reduction of the flat roll 13 is, for example, about 15 to 20%, which is sufficient. The roll diameter, rolling load, and torque of the flat roll 13 need only be small, and only need to have the function of parallel rolling. Is possible.

In the apparatus 10 of this embodiment, since the flat rolls 13 are preliminarily parallel-rolled by the flat rolls 13 to the plate thickness of the maximum plate thickness portion 18 at the middle portion in the longitudinal direction of the leaf spring 1 ', the variable roll 15 It is sufficient that the diameter is smaller than that of the conventional method, and the rolling load and the torque are small.
Further, since there is no unnecessary movement such as reversing the moving direction of the material as in the above-described second conventional method, the production tact does not decrease.

Using the taper leaf spring 1 'shown in FIG. 3 as a model and rolling by the apparatus 10 of this embodiment,
Comparing the case of rolling by the first conventional method using the above-described conventional apparatus 2, as shown below, the roll diameter, rolling load and rolling torque of the apparatus 10 of this embodiment are smaller than those of the apparatus of this embodiment. It was confirmed that. Incidentally, one example of the dimensions of the model in FIG. 3 is L1 = L3 = L5 = 100 mm, L2 = L4
= 400 mm, t1 = 32 mm, t2 = 16 mm, the material size is t0 = 40 mm, and the plate width is 100 mm. Conventional device (see Fig. 4)

Edge roll 5 [Roll diameter 210 mm, rolling load 42 ton
, Rolling torque 3.2 ton] variable roll 6 [roll diameter 550 mm, rolling load 273 ton]
n, Rolling torque 21.7ton] Flat roll 13 [Roll diameter 250mm] Edge roll 14 [Roll diameter 150mm, Rolling load 24ton]
, Rolling torque 1.4 ton] variable roll 15 [roll diameter 370 mm, rolling load 197 ton]
n, rolling torque 10.1ton]

The above-described leaf spring manufacturing apparatus 10 is suitable for manufacturing a tapered leaf spring. However, in some cases, the leaf spring manufacturing apparatus 10 may be used to manufacture a leaf spring having the same thickness in the longitudinal direction. Can also be produced.

[0026]

According to the present invention, since the flat roll is previously rolled in parallel, the leaf spring material can be accurately rolled into a desired tape shape in one pass on a variable roll. There is a large allowable range of sheet thickness that can be tape-rolled on the same line from thin to thick. Also,
The reliability of the edge roll has been improved, and the failure of the entire apparatus has been extremely reduced.

According to the present invention, the roll diameter, the rolling load, and the torque may be smaller than those of the conventional apparatus, so that the rolling equipment can be downsized and the equipment cost can be reduced.
In addition, the production tact is shorter than in the case of two-pass rolling using a conventional apparatus, which is advantageous when performing a thermomechanical treatment, and also reduces the production cost.

Further, the variation in the thickness and width of the taper leaf spring, which is the final product, is reduced, the plate bending (warpage and bending in the longitudinal direction) is extremely reduced, and the round edge portion is formed by the edge roll. The curved surface became extremely smooth, and the durability of the leaf spring itself was improved.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing a leaf spring manufacturing apparatus according to one embodiment of the present invention.

FIGS. 2A to 2D are diagrams showing, in the order of steps, a shape change of a raw material when a leaf spring is manufactured using the apparatus shown in FIG.

FIG. 3 is a side view showing a shape model of the taper leaf spring.

FIG. 4 is a side view schematically showing a conventional leaf spring manufacturing apparatus.

FIGS. 5A to 5C are diagrams showing a shape change of a leaf spring material according to a first conventional method in the order of steps.

FIGS. 6A to 6D are diagrams showing a change in shape of a leaf spring material according to a second conventional method in the order of steps.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... leaf spring material, 1 '... taper leaf spring, 10 ... leaf spring manufacturing apparatus, 11 ... furnace, 13 ... flat roll, 14 ... edge roll, 15 ... variable roll.

Claims (1)

(57) [Claims] 1. A leaf spring manufacturing apparatus for rolling a leaf spring material into a predetermined shape, comprising: a flat roll for rolling a heated leaf spring material in parallel to a predetermined thickness; and a flat roll at an outlet side of the flat roll. An edge roll which is arranged and rolls the both side edges of the leaf spring material in the plate width direction to adjust the width to a predetermined plate width pattern, and the width of the leaf spring material adjusted so that the amount of reduction can be adjusted. And a variable roll for forming a predetermined tape shape by rolling in a thickness direction.