JPH0581322B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of manufacturing a different diameter bar such as a different diameter steel bar whose outer diameter differs depending on the position in the axial direction by processing a cylindrical material.

[Prior art] Steel bars with different diameters have different outer diameters depending on the position in the axial direction. Conventionally, the outer diameter of a round steel bar is changed in the axial direction by hot forging, and the outer surface is made into a stepped shape. It was manufactured by molding and cutting it to a predetermined size.

This method has the disadvantage that noise is generated by intermittent hammering during hot forging.

A helical roll processing method is available as a method for manufacturing steel bars of different diameters that overcomes this difficulty. This method involves placing three
The tip of the cylindrical material 35 is caught between the rolls 31, 31, 31, and the tip is placed in the chuck 34.
In this method, a steel bar 36 of different diameters is manufactured by pulling out the material 35 after sandwiching the material 35, and changing the distance between the roll and the pass line according to the axial position of the material 35.

In addition, for example, Japanese Unexamined Patent Publication No. 50-49157 discloses a method and apparatus for hot forging of a circular body using concentrated pressure, and Japanese Patent Publication No. 48-32497 discloses a step forming method using cold forging. The attached shaft manufacturing apparatus is shown. Furthermore, Japanese Patent Publication No. 41-17850 discloses a roll forming method.

[Problem that the invention seeks to solve]

In the case of the conventional method shown in FIG.
Since the shaft 31a supporting the steel bar 1 is of a cantilever type, the shaft 31a etc. are bent during machining, resulting in poor dimensional accuracy of steel bars of different diameters.
There was a problem in that the length that can be drawn is determined by the equipment, making it impossible to manufacture long steel bars 36 of different diameters.

Furthermore, according to the method and apparatus for hot forging of a circular body using concentrated pressure disclosed in JP-A-50-49157, the intersecting angle is 0 and defects such as internal cracks are likely to occur.

In the stepped shaft manufacturing apparatus using cold forging shown in Japanese Patent Publication No. 48-32497, the rolls for forming the material are supported on a cantilever, and the cross angle of the rolls is negative, so the mill rigidity is low and the roll The axial flow of the material is suppressed due to the shape of the molded product, resulting in poor dimensional accuracy of the molded product. Moreover, it is necessary to grasp the material with a chuck on the exit side, making it impossible to manufacture long molded products.

The stepped shaft manufacturing device using cold forging disclosed in Japanese Patent Publication No. 17850/1977 has an inclination angle of 0° for the pressing rotor, and the target outer diameter of the stepped shaft can be maintained by holding the material. Since the stepped shafts are manufactured by adjusting the hydraulic cylinders, there is a problem that it is not possible to continuously manufacture long stepped shafts.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for manufacturing bars of different diameters with good dimensional accuracy and regardless of length.

[Means for solving problems]

The present invention uses an inclined rolling mill that allows the material to advance in the axial direction by itself by processing the material, supports it in a roll support type, and adjusts the distance between the roll and the pass line using a hydraulic mechanism. The above-mentioned distance is adjusted when processing the material using this method.

That is, the method for manufacturing bars of different diameters according to the present invention is a method of processing a cylindrical material to produce bars of different diameters whose outer diameters differ depending on the position in the axial direction. or four cone-shaped rolls having exit surfaces whose diameters are gradually reduced toward the exit side, the shafts of each roll being supported on both sides of the rolls, and the intersection angle γ of the shafts of the rolls, The inclination angle β is γ
>0°, 3°<β<20°, and 5°<γ+β<25°, using an inclined rolling mill in which the distance between the roll and the pass line can be adjusted hydraulically. When processing the material, the processing length is calculated and controlled based on the roll rotation speed, and the distance between the roll and the pass line is adjusted to achieve the target outer diameter and axial length. It is characterized by manufacturing diameter bars.

[Effect]

In the present invention, the shaft of the cone-shaped roll is supported on both sides, and the intersection angle γ and the inclination angle β of the roll shaft are γ>0°, 3°<β<20°, and 5° ＜γ+β＜
The material is rolled with rolls set in a 25° range to reduce its diameter, and the material is further rolled.
The processing length is calculated and controlled by the roll rotation speed, and during rolling, the distance between the roll and the pass line is adjusted using hydraulic control to achieve the target outer diameter and axial length. Become. Therefore, bars with different diameters that have excellent dimensional accuracy and are free from surface and internal defects can be manufactured regardless of length.

〔Example〕

Hereinafter, the present invention will be specifically explained based on the drawings regarding the case where three cone-shaped rolls are used. 1st
The figure is a side sectional view of an inclined rolling mill showing the implementation state of the present invention together with a block diagram (a view taken along the - line in Figure 2), Figures 2 and 3 are its front and rear views, and Figure 4 is a side view showing the vicinity of the rolls (in the figure, rolls 1 and 2 are a sectional view taken along the - line in FIG. 5); FIG. 5 is a front view taken along the - line in FIG. 4;
FIG. 6 is a side view showing the inclination angle β, and 10 in the figure.
indicates a cylindrical material. After the material 10 is heated to a predetermined temperature in a heating furnace (not shown), it is spirally transferred in the axial direction (in the direction of the open arrow) by a transfer device (not shown), and is rolled into a cross-type material that can be rolled at a high workability. The steel bar is rolled and reduced in diameter in an inclined rolling mill 20 by changing the reduction stepwise according to its position in the axial direction, thereby forming a different diameter steel bar 11, which is then cooled in a cooling device (not shown). It is sent further downstream.

The inclined rolling mill 20 has three cone-shaped rolls 1, 2, and 3 facing around the pass line (see Fig. 2), and the axes 1e, 2e, and 3e of each roll 1, 2, and 3.
The inlet and outlet sides of the rolls 1, 2, and 3 are rotatably supported by inlet jocks 23, 23, 23 and outlet jocks 24, 24, 24, respectively. , 23, 23 and the outlet chocks 24, 24, 24 are holes formed in the rotary housing 21 and the fixed housing 22, and the base ends of the support rods 23a, . . . and 24a, . (see FIGS. 2 and 3).
In other words, the rolls 1, 2, and 3 are of a dual-support type.

Hydraulic cylinders 25 and 26 are installed at the base ends of the entrance chock 23 and the exit chock 24 of each of the three rolls.
A cylinder rod is attached thereto, and the cylinder tubes of hydraulic cylinders 25 and 26 are fixed to a rotary housing 21 and a fixed housing 22, respectively. The distance between the entrance chock 23 and the pass line and the distance between the exit chock 24 and the pass line are adjusted by hydraulic cylinders 25 and 26, respectively. Therefore, the distance between the roll and the pass line is adjusted by adjusting the distance between the pass line and the entry and exit jocks that support both axial ends of the roll.

A cylinder rod of a hydraulic cylinder 27 is attached to the rotating housing 21, and a cylinder tube of the hydraulic cylinder 27 is fixed to the stationary housing 22. The rotary housing 21 is rotated relative to the fixed housing 22 by a hydraulic cylinder 27.

The hydraulic cylinders 25, 26, and 27 are each provided with a rolling control device 40 that controls the flow rate and pressure of pressure oil supplied thereto. The rolling control device 40 includes an input setting device 41 for inputting the dimensions of the material 10, the dimensions of the different diameter steel bar 11, etc.
The signal set to be input is given to the arithmetic and control unit 42. Based on the input signal, the arithmetic and control unit 42 determines the control amounts for the pressure and flow rate of the pressure oil supplied to the three sets of hydraulic cylinders 25 and 26 provided for each roll and the hydraulic cylinder 27 for rotating the rotary housing, and controls the same. The signal is sent to three sets of hydraulic cylinders 25, 2.
6 and another hydraulic cylinder 27, respectively, are provided to servo amplifiers 44, . . . through subtracters 43, . The servo amplifiers 44, . . . adjust the opening degrees of servo valves 45, . Supply to 27.

Each servo valve 45,... is provided with a speed displacement meter 46,..., which specifies the oil amount and sends the measurement signal to the servo amplifier 44,... to determine the flow rate of the pressure oil. controlled.

Moreover, pressure sensors 47,... are attached to the hydraulic cylinders 25, 26, 27, and the pressure sensors 47,... measure the pressure of the hydraulic oil in the hydraulic cylinders,
The measurement signal is sent to the subtractor 4 via the pressure amplifier 48.
3, pressure control is performed. Furthermore, position sensors 49 are attached to the entry and exit jocks 23 and 24 operated by the hydraulic cylinders 25 and 26, and to the cylinder rod of the hydraulic cylinder 27, respectively. Chiyotsuku 2
3, 24 and the amount of advance and retraction of the cylinder rod, and provides a measurement signal to the arithmetic and control unit 42. If the input signals from the position sensors 49, . . . differ from the set values for the advance and retraction amounts of the cylinder rod, the arithmetic and control unit 42 supplies compensation signals to the servo amplifiers 44, . ，
26.

The three cone-shaped rolls 1, 2, and 3 have gorge portions 1a, 2a, and 3a in the center (see FIG. 4),
The entrance side of the material 10 with this gorge as a boundary has entrance surfaces 1b, 2b whose diameter is gradually reduced toward the shaft end.
3b, and further includes reeling parts 1c, 2c, 3c whose diameters are gradually enlarged toward the outlet end, followed by outlet surfaces 1d whose diameters are gradually reduced,
It is equipped with 2d and 3d.

Note that in the reeling parts 1c, 2c, and 3c, the distance from the pass line is made to match the distance between the gorge part and the pass line.

The cone-shaped rolls 1, 2, and 3 having such shapes all have their entrance surfaces 1b, 2b, and 3b connected to the material 10.
The intersection point O between the axis Y-Y and the plane including the gorge parts 1a, 2a, and 3a (hereinafter referred to as the roll setting center) is
They are placed on the same plane perpendicular to the pass line XX of the material 10 and positioned at approximately equal intervals around the pass line XX. and each roll 1,
2 and 3 axis center line Y-Y is around the roll setting center,
In relation to the pass line XX of the material 10, the front shaft end is on the pass line XX as shown in FIG.
The shafts are crossed (inclined) by an intersecting angle γ so as to approach toward the material 10, and as shown in FIGS. It is tilted.

The crossing angle γ and the inclination angle β are adjusted by advancing and retracting the cylinder rods of the three hydraulic cylinders 25, 26, and 27, respectively. In particular, the crossing angle γ is mainly adjusted by the hydraulic cylinders 25 and 26, and the inclination angle β is adjusted mainly by the hydraulic cylinders. 27, respectively.

However, β and γ are within the ranges specified below for rolling purposes.

0°<γ<15° 3°<β<20° 5°<γ+β<25° The above values of β and γ are determined based on the dimensions of the material 10 and the different diameter steel bar 11, and the relationship between the two is determined by the arithmetic and control device. 42 as a table, and when the dimensions of the material 10 and the different diameter steel bar 11 are input, the arithmetic and control unit 42 can read out β and γ from the table.

By selecting the roll crossing angle γ and the inclination angle β in this way, the mill rigidity increases. Moreover, the axial movement of the material is not inhibited by the roll shape, and the dimensional accuracy of the formed bar material of different diameters is increased.

Furthermore, in the present invention, the machining length is calculated and controlled based on the roll rotation speed, and the intersection angle is set to a positive (γ
>0°). This is because by setting γ>0°, it is possible to prevent the roll from slipping during processing, and the length that the material will travel can be accurately predicted.

The reason why roll slip can be prevented can be explained from the relative speed between the material speed during processing and the roll circumferential speed. That is, when considering the material speed and circumferential speed at portions A to B of 1 where the roll and material are in contact in FIG. 10, the material speed is increased from the input side to the output side. If the peripheral speed of the material at point A on the entry side and point B on the exit side are V _A and V _B , respectively,
From the condition of constant volume, π/4d ₀ ²・V _A = π/4d ₁ ²・V _B d ₀ and d ₁ are the diameters of the material inlet and outlet sides, respectively.
d ₀ > d ₁ . Therefore, V _A < V _B.

On the other hand, when γ > 0° as shown in Figure 10a, the circumferential speed of the roll is small on the entry side and large on the exit side, so the speed on the exit side is increased, and both the material and the roll tend to speed up, preventing slipping. It is. This not only allows the length of the material to be accurately predicted, but also has the advantage that twisting does not occur at the roll contact area.

On the other hand, when γ<0° as shown in Fig. 10b, the peripheral speed of the roll becomes decelerated as it moves from the material input side to the material output side, and the tendency is opposite to the speed increase tendency of the material, causing the roll to slip. . Note that when γ=0, the roll circumferential speed is the same on the entrance and exit sides, so slips still occur.

Next, β < 20° and γ + β < 25° are set because the present invention employs an inclined rolling mill with double-supported cone-shaped rolls, so the chock holding the rolls is larger than the above-mentioned limit angle range. This is because they interfere with each other and the inclined rolling mill can only be used within the above range.

The rolls 1, 2, and 3 are connected to a drive source (not shown) and are driven to rotate in the same direction as shown by arrows in FIG. 5, and the hot material 10 caught between these rolls is It is moved in the axial direction while being rotationally driven around the core wire, that is, it is caused to move in a spiral manner.

A tachometer generator 50 is attached to the shaft 1e of the roll 1, and a length signal detected by the tachometer generator 50 is sent to an arithmetic and control unit 42 to measure the rolled length.

Optical thermometers 51 and 52, such as radiation thermometers, are provided with temperature measuring fields facing the moving areas of the different diameter steel bars 11 above and downstream of the rolls 1, 2, and 3, respectively. 52 measures the temperature of the material 10 and the temperature of the different diameter steel bar 11, and sends the measurement signals to the rolling control device 4.
0 to the arithmetic and control unit 42.

When the temperatures at the entrance and exit sides of the roll are input, the arithmetic and control unit 42 estimates the deformation resistance of the material 10 based on this, and performs an analytical analysis using the estimated value and the finite element method set in advance. Based on the mill stiffness curve obtained from
The amount of advance/retreat change is calculated based on the input signal from the position sensor 49 at that time, that is, the signal related to the amount of advance/retreat of the entry and exit jocks 23, 24 at that time, and a control signal corresponding to the calculated value is applied to each Output to the servo amplifiers 44, . . .

The method of the present invention, which is carried out using the inclined rolling mill configured as described above, will be explained below.

First, the dimensions of the steel bar with different diameters shown in Fig. 7, namely, the outer diameter of the large diameter part: D ₀ , the length of the large diameter part: L ₀ , the outer diameter of the small diameter part: D ₁ , and the length of the small diameter part: L ₁ , angle formed with the axis of the inclined surface whose diameter decreases from the large diameter part to the small diameter part: α ₁ ,
Angle between the axial center of the inclined surface whose diameter expands from the small diameter part to the large diameter part: α ₂ , the number of small diameter parts and large diameter parts, and material 1
The outer diameter, length, etc. of 0 are input from the input setting device 41 to the arithmetic and control device 42.

The arithmetic and control unit 42 stores the input signal and calculates β when rolling the small diameter portion based on the input signal and the table set therein in advance.
The setting value of γ is read out, and the control signal is given to all the servo amplifiers 44,... to the hydraulic cylinders 25, 2.
Adjust the amount of movement of each cylinder rod 6 and 27. As a result, β and γ become set values, and the distance between the pass line and the roll becomes D ₁ /2.

When this operation is completed, the rolls 1, 2, and 3 are rotated, and the material 10 is fed. As a result, the material 10 is rolled to form a small diameter portion having an outer diameter _D1 .

Based on the signal from the tachogenerator 50, the arithmetic and control unit 42 determines that when the compression length of the large diameter portion reaches _L1 ,
Thereafter, when rolling a predetermined length, both the entry and exit jocks 23 and 24 are moved back and forth by the same amount in proportion to the rolling length. This forms an inclined surface with an angle α ₂ . However, the amount of chock movement does not match (D ₀ −D ₁ )/2. Here, the reason will be explained.

Originally, the setting of the mill is done by the opening degree of the inlet and outlet chock and the relative rotation angle of the inlet and outlet housings, and the predetermined roll inclination angle, crossing angle, and set outer diameter at the gorge part are obtained. . However, controlling three set values simultaneously is complicated and impractical. The description here is based on the assumption that the input and output chock are moved by the same amount at the same time. Therefore, in this case, even if the chock is moved by the same amount (t) on the inlet and outlet sides, the outer diameter set at the gorge will not change by 2t.
An example is shown in FIG.

In FIG. 8, the horizontal axis represents the amount of movement of the chock in the opening direction from the reference position, and the vertical axis represents the amount of increase in the outer diameter of the steel bar with different diameters, the amount of change in the inclination angle β, and the amount of change in the intersecting angle γ. It is a figure showing the relationship between four parties. As can be understood from this figure, when the chock is moved in the opening direction from a certain setting value, β and γ increase as shown by the broken line and the dashed-dotted line, respectively.
Even if you move away from the pass line and increase the chock opening by 20mm on the input and exit sides, the amount of increase in outer diameter (solid line)
is not 20mm, but has a slightly smaller outer diameter. Therefore, when changing from D ₁ to D ₀ ,
The moving distance of the chock is (D ₀ - D ₁ )/2+Δt (Δt:
positive variable). However, Δt is determined by functions such as the reference setting outer diameter D ₁ , the roll inclination angle/intersection angle, and the relative positional relationship between the gorge portion and the choke.

Then, due to some reason during the process, the moving amount of the chock is (D ₀ - D ₁ )/based on the signal from the position sensor 49.
When it reaches 2+Δt, it is kept constant. As a result, a large diameter portion having an outer diameter of D ₀ is formed.

Thereafter, when the rolling length of the large diameter portion becomes L ₀ based on the signal from the tachometer generator 50, the arithmetic and control unit 42 determines that the distance between the pass line and the roll becomes D ₁ /2 when the rolling length of the large diameter portion is subsequently rolled for a predetermined length. Both the entrance and exit jocks 23 and 24 are advanced by the same amount in a proportional relationship according to the rolling length so that. This forms an inclined surface with an angle α ₁ .

Then, when the distance between the pass line and the roll reaches D ₁ /2 based on the signal from the position sensor 49,
D ₁ /2 is maintained constant, and the same control is thereafter repeated depending on the number of small diameter portions and large diameter portions.

In the above embodiment, the initial reference setting value is set to the small diameter portion, but in the present invention, the reference setting value may be set to the large diameter side, or may be set to an arbitrary position in between.

The steel bar 11 of different diameter manufactured in this way has almost no deflection in the shafts 1e, 2e, 3e due to the use of double-supported rolls 1, 2, 3.
Further, since the pressure reduction is controlled by hydraulic pressure for reasons described later, the dimensional accuracy is excellent.

The reason for performing the above-mentioned hydraulic reduction control is that the moment of inertia is large in the conventional electric reduction method that combines an electric motor, reduction gear, and reduction screw, and the power transmission efficiency of the reduction screw is low. This is to solve the problem of poor response speed.

In the above example, the steel bar is manufactured using an inclined rolling mill equipped with three rolls, but the present invention is not limited to this. It is possible to manufacture steel materials with different diameters such as

[Numerical example] Using a material with an outer diameter of 50mmφ, there are 3 small diameter parts and 4 large diameter parts, D ₀ : 40mmφ, D ₁ : 20mmφ,
A numerical example will be shown when a different diameter steel bar with L ₀ : 30 mm, L ₁ : 200 mm, α ₁ and α ₂ : 45° was manufactured by the method of the present invention. The manufacturing conditions for the large diameter part are roll opening: 40mm.
φ, γ: 3°, β: 15°, roll rotation speed (rolling speed): 100 rpm (0.16 m/sec), and that of the small diameter part is roll opening: 20 mmφ, γ: 2.8°, β: 13°. Yes, and the amount of chock travel at that time was 10.5mm. Other conditions include the outer diameter of the gorge part of the roll:
120 mmφ, roll material: SCM445, heating temperature of material 10: 1200°C, material of material 10: S45C.

〔effect〕

As described in detail above, the present invention has three or four cone-shaped rolls facing around the pass line, each having an exit surface whose diameter is gradually reduced toward the exit side, and an axis of each roll. is supported on both sides of the roll, and the cross angle γ and the inclination angle β of the roll axes are γ
> 0°, 3° < β < 20°, and 5° < γ + β < 25°, and the distance between the roll and the pass line can be adjusted hydraulically using an inclined rolling mill. , proceed as the material is rolled;
This makes it possible to continuously manufacture bars of different diameters with good dimensional accuracy and no internal defects, regardless of their length.

In addition, on the exit side of the rolled material, a guide is generally provided to cover the material, making it difficult to measure the length of the material. You can detect the length with

Furthermore, since there is no slip in the rolls, defects due to twisting on the surface of the rolled material do not occur, and the present invention has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view (view taken along the - line in FIG. 2) showing the implementation state of the present invention, FIG.
The figure is a front view and a back view, FIG. 4 is a side view showing the vicinity of the roll, FIG. 5 is a front view taken along the - line in FIG. 4, FIG. 6 is a side view showing the inclination angle β, and FIG. An explanatory diagram of dimensions in manufacturing steel bars of different diameters. Figure 8 is an explanatory diagram of the relationship between the moving amount of the chock and the amount of change in outer diameter of the small diameter section and large diameter section of the steel bar of different diameters. Figure 9 is a diagram of the conventional technology. FIG. 10 is an explanatory diagram of circumferential velocity. 1, 2, 3...roll, 1e, 2e, 3e...
Shaft, 10...Material, 11...Different diameter steel bar, 23...
Entry side check, 24...Exit side check, 25,2
6, 27... Hydraulic cylinder.

Claims (1)

[Claims] 1 In a method of manufacturing different diameter bars by processing a cylindrical material and having an outer diameter that differs depending on the position in the axial direction, three or four bars facing around the pass line are gradually reduced in diameter toward the exit side. The shaft of each roll is supported on both sides of the roll, and the cross angle γ and inclination angle β of the roll shaft are such that γ>0° and 3°<β< 20° and 5°<γ+β<25
°
When processing the above-mentioned material, the processing length is calculated and controlled based on the number of roll rotations, using an inclined rolling mill in which the distance between the roll and the pass line can be hydraulically adjusted. 1. A method for manufacturing bars of different diameters, which comprises continuously producing bars of different diameters by adjusting the distance between a roll and a pass line so as to have an outer diameter and an axial length.