JPH04228206A - Leaf spring manufacturing equipment - Google Patents

Abstract

PURPOSE:To form tapered leaf springs in accurate shapes by using comparatively simple rolling equipment. CONSTITUTION:This equipment which rolls a leaf spring blank 1 to a prescribed tapered shape, is comprised of a small flat roll 13 which rolls the heated blank 1 in parallel rolling to a prescribed thickness, an edge roll 14 which is arranged on the exit side of the flat roll 13 to edge the blank to a prescribed breadthwise pattern by rolling both edges of the blank 1 to the direction of the width, and a variable roll 15 which controls a rolling reduction and forms the blank 1 to the prescribed tapered shape by rolling the blank in the thickness direction.

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 leaf springs used in automobile suspension springs and the like.

0002

2. Description of the Related Art There is a strong desire to reduce the weight of steel suspension springs used in suspension systems of vehicles such as automobiles, and various measures have been taken to reduce the weight. For example, making leaf springs highly hard and increasing their tensile strength will help reduce weight if used under high stress. However, increasing the hardness lowers the toughness of the leaf spring and increases the sensitivity to notches on the surface of the leaf spring, which may reduce durability. In order to avoid this, by including processing heat treatment that combines heat treatment such as rolling and quenching in the leaf spring manufacturing process,
The present inventors are researching the use of thermal refining.

[0003] A leaf spring tempered by processing heat treatment is
For example, by making the crystal grains finer or aligning the orientation of the structure, the material becomes tougher and can handle higher stress. Further, 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 stacked leaf spring devices, the number of leaf springs can be reduced,
This is effective in reducing weight.

[0004] From the above-mentioned viewpoints, there has recently been a tendency to manufacture tapered leaf springs using thicker leaf spring materials. Moreover, in order to obtain the above-mentioned processing heat treatment effect, it is necessary to also roll the longitudinal center portion (maximum plate thickness portion) of the tapered leaf spring. 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, the final reduction ratio is large, so the rolling equipment must also take appropriate measures.

FIG. 4 shows an example of a conventional tapered leaf spring manufacturing apparatus 2. As shown in FIG. This conventional device 2 includes a furnace 3 that heats the leaf spring material 1, a high-pressure water descaler 4 that removes oxidized scale from the surface of the material 1, and a pair of edge rolls arranged in the width direction of the material 1. 5 (only one of which is shown), and a variable roll 6 whose rolling reduction amount can be variably set.

A first conventional method using the conventional device 2 (
In the method of rolling in one pass), the leaf spring material 1 taken out of the furnace 3 is aligned in advance with an edge roll 5 into a sheet width pattern commensurate with the width expansion. Thereafter, rolling is carried out in the thickness direction using variable rolls 6, and after rolling into a predetermined tapered 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 implemented. That is, the leaf spring material 1 having the shape shown in FIG. 5(A) is rolled by the edge roll 5 as shown in FIG.
The width is adjusted to the shape of , and the tapered shape shown in FIG. 5(C) is finished by the variable roll 6. In addition, in each figure, a is the side shape of the material 1, b is the planar shape,
c represents the front shape.

[0007] Furthermore, as a second method using the conventional apparatus 2 described above, a method of rolling in two passes can also be considered. FIG. 6 shows the change in shape of the leaf spring material 1 when this second conventional method is implemented. The second conventional method is the edge roll 5
The process up to the width adjustment process is the same as the first conventional method,
The material 1 is width-aligned into the shape shown in FIG. 6(B), but in the subsequent taper rolling process using the variable rolls 6, the material 1 is first rolled into the shape shown in FIG. 6(C) in the first pass. Parallel rolling is performed to a predetermined thickness as shown in FIG.
Pa rolling is performed. Therefore, in the second conventional method, the leaf spring material 1 reciprocates around the variable roll 6.

[0008]

[Problems to be Solved by the Invention] In the case of the first conventional method using the conventional device 2 described above, in order to finish the final shape in one pass with the variable roll 6, the roll diameter, load, and torque are increased. As a result, the entire rolling equipment becomes larger and the equipment cost increases significantly. Further, since the width of the leaf spring material 1 increases, it is necessary to use a large edge roll 5 as well. And edge roll 5 and variable roll 6
As rolling mills become larger, the distance between peripheral equipment before and after the rolling mill becomes longer, making it impossible to taper short materials.

On the other hand, in the case of the second conventional method described above, in order to finish the final product by reversing the variable roll 6 between the first and second passes, the surrounding area for reciprocating the material 1 is Equipment and its control will become more complex, and production tact will drop significantly. Further, since rolling is performed twice on the exit side of the edge roll 5, it becomes difficult to predict the amount of width expansion of the material 1, and there are problems such as increased variations in the width of the final product. Further, when carrying out processing heat treatment, it is necessary to quench the material immediately after rolling, so this conventional method, which requires a long rolling process, is unsuitable.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a leaf spring manufacturing apparatus that can form a tapered leaf spring by adding a simple configuration and can also be expected to have the effect of processing heat treatment of the leaf spring. It is in.

[0011]

[Means for Solving the Problems] A leaf spring manufacturing apparatus of the present invention developed to achieve the above object includes a flat roll for parallel rolling a heated leaf spring material to a predetermined thickness, and a flat roll for parallel rolling a heated leaf spring material to a predetermined thickness. Edge rolls are placed on the exit side of the spring roll and roll both edges of the leaf spring material in the width direction of the plate to create a predetermined width pattern. A variable roller that forms a predetermined tapered shape by rolling the leaf spring material in the thickness direction.
It is equipped with

0012

[Operation] A steel leaf spring material is heated in a furnace to, for example, a temperature at which it becomes austenite, and after being taken out of the furnace, the scale is removed and then parallel rolled to a predetermined thickness by the flat rolls. The predetermined thickness herein refers to the plate thickness that the variable roll can bite into, or the thickness of the parallel plate thickness section (maximum plate thickness section) at the longitudinal center of the tapered leaf spring. The material parallel-rolled by the flat rolls is aligned by the edge rolls by an amount that allows for an increase in the width of the material during tapering rolling by the variable rolls. Thereafter, the material is rolled into a predetermined tapered shape in one pass by variable rolls.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3. A leaf spring manufacturing apparatus 10 shown in FIG. 1 includes a heating furnace 1 that heats a steel leaf spring material 1.
1, a high-pressure water descaler 12, and a flat roll 1 consisting of an upper roll 13a and a lower roll 13b arranged in the thickness direction of the leaf spring material 1, in order on the exit side of the heating furnace 11.
3, a pair of edge rolls 14 (only one is shown) arranged on both sides of the leaf spring material 1 in the width direction, and the leaf spring material 1
It is provided with variable rolls 15 including an upper roll 15a and a lower roll 15b arranged in the thickness direction of the roll. The heating furnace 11 can heat the leaf spring material 1 to a temperature higher than that at which processing heat treatment is possible. The high-pressure water descaler 12 has the function of removing oxidized scale from the surface of the leaf spring material 1.

The flat roll 13 uses an upper roll 13a and a lower roll 13b to form the leaf spring material 1 into a predetermined thickness, that is, the maximum thickness of the tapered leaf spring 1' at the longitudinal intermediate portion to be formed. Parallel rolling is performed until the plate thickness corresponds to section 18. This flat roll 13 is used to roll the leaf spring material 1, which has a thickness greater than the maximum plate thickness determined by the roll diameter of the variable roll 15, up to a plate thickness that the variable roll 15 can bite into. It is sufficient to have the function of parallel rolling. Therefore, the roll diameter, rolling load, and rolling torque of the flat roll 13 may be small. Grooves having shapes corresponding to the left and right edges (so-called round edges) of the leaf spring material 1 are provided on the outer periphery of the edge roll 14 over the entire circumference.

The variable roll 15 is equipped with a variable rolling mechanism 21 including a hydraulic servo cylinder or the like that can variably set the rolling volume, a sensor 22 for detecting the longitudinal position of the leaf spring material 1, and the like. By sequentially changing the amount of reduction according to the longitudinal position of the leaf spring material 1 based on instructions from the control unit 23 using a microcomputer or the like,
The desired taper rolling is performed. The variable roll 15 has different roll diameter, rolling load, and
The torque may be small.

Next, the operation of the leaf spring manufacturing apparatus 10 having the above structure will be explained. FIGS. 2(A) to 2(D) show this device 1
2 shows the 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 frontal shape.

The leaf spring material 1 is heated in the furnace 11 to a temperature at which processing heat treatment is possible, and then taken out of the furnace 11. The scale is then removed by the descaler 12. FIG. 2(A) shows an example of the shape of the leaf spring material 1 before rolling,
This leaf spring material 1 is parallel-rolled to a predetermined thickness by a small-diameter flat roll 13, as shown in FIG. 2(B). The predetermined thickness in this embodiment refers to the thickness of the maximum plate thickness portion (parallel plate thickness portion) 18 at the longitudinally intermediate portion of the tapered leaf spring 1' which is the final product.

After the parallel rolling by the flat rolls 13 is completed, width adjustment is performed by the edge rolls 14. In this case, as shown in FIG. 2(C), width adjustment is performed in a pattern that takes into account the increase in sheet width due to taper rolling in the sheet thickness direction that will be performed thereafter.

The flat spring material 1 is rolled into a predetermined tapered shape by a variable roll 15 having a larger diameter than the flat roll 13, and then cut into a predetermined length, as shown in FIG. The final product, leaf spring 1', as shown in (D) is completed. In this variable roll 15, the position sensor 22
The longitudinal position of the leaf spring material 1 detected by Rolling is performed.

The variable roll 15 does not substantially roll the longitudinally intermediate portion of the leaf spring 1', that is, the maximum plate thickness portion 18. However, since the maximum plate thickness portion 18 has been parallel-rolled in advance with a certain degree of area reduction by the flat rolls 13 mentioned above, the desired processing heat treatment effect is exerted over the entire longitudinal direction of the leaf spring 1', resulting in high strength. Thus, a strong tapered leaf spring 1' can be obtained.

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

In the apparatus 10 of this embodiment, the flat roll 13 is used to roll the leaf spring 1' in parallel to the thickness of the maximum thickness part 18 at the longitudinally intermediate part. A smaller diameter is sufficient than in the conventional method, and the rolling load and torque are also smaller. Further, since there is no unnecessary movement such as reversing the moving direction of the material as in the second conventional method described above, the production tact does not decrease.

When the tapered leaf spring 1' shown in FIG. 3 is modeled and rolled by the apparatus 10 of this embodiment,
Comparing the case of rolling according to the first conventional method using the conventional apparatus 2 described above, 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 10 of this embodiment. This was confirmed. An example of the dimensions of the model in Fig. 3 is L1 = L3 = L5 = 100 mm.
, L2 = L4 = 400 mm, t1 = 32 mm,
t2 = 16mm, and the material size is t0 = 40m
m, and the board width is all 100 mm. Conventional device (
(See Figure 4)

Edge roll 5 [Roll diameter 210 mm, rolling load 42 tons, rolling torque 3.2 tons] Variable roll 6 [Roll diameter 550 mm,
[Rolling load 273 tons, rolling torque 21.7 tons] This embodiment device Flat roll 13 [Roll diameter 250 mm]
Edge roll 14 [Roll diameter 150 mm, rolling load 24 tons, rolling torque 1.4 tons] Variable roll 15 [Roll diameter 370 mm,
Rolling load 197 tons, rolling torque 10.1 tons]

The above-mentioned leaf spring manufacturing apparatus 10 is suitable for manufacturing tapered leaf springs, but in some cases, this leaf spring manufacturing apparatus 10 may be used to manufacture leaf springs having equal thickness in the longitudinal direction. It is also possible to manufacture

[0026]

Effects of the Invention According to the present invention, since parallel rolling is performed in advance using flat rolls, the leaf spring material can be accurately rolled into a desired tapered shape in one pass with variable rolls. There is a wide allowable range of plate thicknesses that can be taper rolled on the same line, from thin to thick. Also,
The reliability of the edge roll has improved, and the number of failures of the entire device has been drastically reduced.

According to the present invention, the roll diameter, rolling load, and torque may be smaller than those of conventional equipment, so the rolling equipment can be downsized and the equipment cost can be kept low. In addition, the production tact is shorter than in the case of two-pass rolling using conventional equipment, which is advantageous when carrying out processing heat treatment, and the production cost is also lower.

Furthermore, the variation in plate thickness and plate width of the final product, the tapered plate spring, is reduced, plate bending (warping and bending in the longitudinal direction) is also extremely reduced, and the round edge part due to edge rolls is reduced. The curved surface has become extremely smooth, and the durability of the leaf spring itself has been improved.

[Brief explanation of the drawing]

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

2A to 2D are diagrams showing changes in the shape of a material in the order of steps when manufacturing a leaf spring using the apparatus shown in FIG. 1;

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

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

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

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Leaf spring material, 1'... Tapered leaf spring, 10... Leaf spring manufacturing device, 11... Furnace, 13... Flat roll, 14... Edge roll, 15... Variable roll.

Claims (1)

[Claims] 1. A leaf spring manufacturing device for rolling a leaf spring material into a predetermined shape, comprising: a flat roll for parallel rolling the heated leaf spring material to a predetermined thickness; an edge roll which rolls both edges of the leaf spring material in the board width direction to bring it closer to a predetermined board width pattern; and an edge roll whose rolling amount is adjustable and which brings the width of the leaf spring material closer together. 1. A leaf spring manufacturing apparatus comprising: a variable roll for forming a leaf spring into a predetermined tapered shape by rolling the leaf spring in the thickness direction.