US3643488A

US3643488A - Rolling mill

Info

Publication number: US3643488A
Application number: US882135A
Authority: US
Inventors: Erich J F E Bretschneider
Original assignee: Siemag Siegener Maschinenbau GmbH
Current assignee: Siemag Siegener Maschinenbau GmbH
Priority date: 1968-12-07
Filing date: 1969-12-04
Publication date: 1972-02-22
Anticipated expiration: 1989-02-22
Also published as: DE1813331A1

Abstract

This invention has to do with a universal planetary rolling mill in which clusters of rolls are rotated to swing successive rolls into the path of the stock to be rolled.

Description

lUIlhE 40405 WEWET fireilsrhneimler 1 lFelh, 22., 11972 {54] RUILLHNG MIULIL [72] Inventor: Erich .ll. lF. lE. lllr'etschheirlner, Buderich, [56] References Chm Germany UNITED STATES PATENTS [73] Assgneei g f g Mamimm (MW, 2,932,997 4/1960 Sendzimir ..72/190 1 many 2,710,550 6/1955 Senclzimir..... ..72/191 11 [22] Filed: Dec. 4, 1969 3,439,519 4/1969 Gerding ..72/ 190 X [21] Appl' mzws Primary Examiner-Milton S. Mehr Attorney-Norman S. Blodgett [30] [Fair-elm filpphwltlm P1401 143 @1110 Dec. 7, 1960 Germany .1 1s 13 331.8 {571 ABWMCT This invention has to do with a universal planetary rolling mill 1191, 72/249 in which clusters of rclls are rotated to swing successive rolls Klim- I into the path of the tock to be rolled [58] lliellall ulfiwrch ..72/194, 191, 190,198, 184,

72/249 ill) Claims, 5 Drawing Figures mmmmm 1972 3mm MEH sum E OF 5 PMENIEBFEB22 m2 dag sum or 5 mortars MTLIL BACKGROUND OF THE INVENTION It is common practice to use planetary rolling mills when large reductions are to be achieved with a single pass. The prior art planetary rolling mills have been equipped with a support roller or large diameter and with a number of working rollers of smaller diameter which operate in one plane only. Such mills may be used for rolling of some metal stock, but are not usable for the reduction of blooms. The working of blooms in accordance with the common method requires a number of passes to reduce the cross section in two dimensions. Especially when large reductions are required, it is a disadvantage that the two roller sets for working the two dimensions cannot operate in the same plane normal to the direction of rolling. Furthermore, it has proven to be a disadvantage that, when a small feed speed is used with large cross section, cracking takes place because of burning. Therefore, a minimum feed of around 4 inch/second has to be maintained, which again limits the entrance cross section of the stock to approximately 4 inch by 4 inch for the desired rolling heat and commonly used exit speed. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.

It is, therefore, an outstanding object of the invention to provide a rolling mill for producing substantial stock reduction without cracking.

Another object of this invention is the provision of a rolling mill for working blooms and the like at high speed.

A further object of the present invention is the provision of a rolling mill for reducing stock as much as 9 percent without the need for supplementary feed means.

It is another object of the instant invention to provide a rolling mill for deforming stock cross section from a large square to a small circle.

A still further object of the invention is the provision of a rolling mill for reducing blooms to a round rod without the use of a reversing drive or discontinuous operation.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

SUMMARY OF THE INVENTION In general, the invention consists of a rolling mill for attenuating elongated stock having a base with two spaced vertical housings and having a plurality of frames joining the housings and grouped around the path of stock movement. A cluster of rolls is associated with each frame and each roll is driven about a major axis substantially spaced from the path of the stock and also about its own axis. The algebraic sum of the speed of the roll due to rotation about the minor axis is such as to produce a desired stock speed.

BRIEF DESCRIPTION OF THE DRAWINGS The character of the invention, however, may be best understood by reference to one of its structural forms, as illustrated by the accompanying drawings, in which:

FIG. it is a side elevational view of a rolling mill embodying the principles of the present invention,

FIG. 2 is a sectional view of the mill taken on the line II-II of FIG. ll,

FIG. 3 is a vertical sectional view of the mill taken in a transverse plane.

FIG. 4 is a horizontal sectional view, and

FIG. 5 is a diagrammatic view of the roll pass sequence during attenuation of the stock.

DESCRIPTION OF THE PREFERRED EMBODIMENT achieves also a desired depth effect. The rolling stock is fed continuously and the movable parts themselves operate continuously. This task is brought about by a planetary rolling mill which preferably leaves out support rolls and has working rolls arranged on shafts which are supported in carrier arms. By the use of individual carrier arms and working rolls of sufficient stability (and, therefore, of large diameter per shaft), it is necessary to provide only three working rolls by providing the required space. Therefore, the number of roll passes is restricted to three for each revolution of the roller carrier. The large roller diameter, however, results in the desired depth effect and permits also the separate drive of the working rolls as well as the profiling of the rollers to influence the desired exit cross section in a manner which is not possible on the known universal planetary rolling mills. The required output is achieved with a limited number of revolving working rolls and the achieved speed in comparison to the rolling stock is very high in every case and so prevents the danger of cracking by burning.

It was determined to be of importance that the working rolls be driven with opposed rotation compared to the roll carriers, so that the algebraic sum of the linear speed of the roll due to its rotation and that due to the motion of the roll carrier equal the desired feed speed of the rolling stock. This feed speed may be arbitrarily low, since the speed with which the working rollers are moved in comparison to the rolling stock can be selected so high that the cracking by burning is definitely prevented. The rotation of the working rolls and the roll car riers is brought about by one prime mover, so that the adjusted relationship of rotation speed and consequently the automatically adjusted feed speed of the rolling stock is maintained at a predetermined value. It was recognized to be of advantage to divert the drive for the working rolls from the roll carrier through a planetary gear system which is adjusted to the required basic transmission ratio. To the third member of this planetary gear system is connected a control motor which in troduces an additional adjustable moving component. In this way it is possible to adjust the feed speed of the rolling stock. A simple design of the rolling mill results by which the roller carriers rotate within their own frames, wherein the latter are supported by stands. The stands are design as pinion housings which are driven from one main drive shaft through universal couplings connected to the individual frames. One stand transmits the drive to the roll carriers and the other stand provides for the transmission of the drive movement to the working rolls.

The roll carriers are each provided with a gear which shall transmit the drive power to the working rolls. In the preferred embodiment, the gear is arranged on a shaft which lies in a tubular shaft extending from the roll carrier. The shafts are driven by gearing of variable selective ratios and are arranged within one of the driving arms. This gear drive with such variable gear ratios is a planetary gear train wherein the third member is driven selectively by a control motor to permit, by introduction of an additional moving component, the change of the output speed. The working rolls are provided with a profile. For the achievement of cross sections of approximately circular shape at the outlet, this profile is designed as a symmetrically, tlat wedge-shaped recess where the center area is rounded to a radius which corresponds to the desired exit diameter of the stock.

Referring first to FIG. ii, the rolling mill is shown as having a base from which extend housing It and 2 designed as pinion housings. The housing 2 has a pinion 3 arranged on drive shaft 3 which engages a gear 5 and, consequently, drives also a gear 6. The latter transfers movement to four gears 7. The

gears

5 and 6 drive bevel gears 9 through universal couplings It as well as the parts located within a gear housing 110.

The arrangement and design of the housing ll is similar to that the housing 2. The gears arranged within the housing are driven by a pinion mounted on the main drive shaft M by engaging these gear wheels. The drive shaft M is driven by a motor (not shown). Eevel gears lib located within the gear housing litll are put into motion by the: gears in the housing ll through universal couplings 115.

Between the housings l and 2 is arranged a planetary gear system 11 whose ring gear 12 is connected to the main drive shaft 14 and its output portion is connected with the shaft 3. Within the ring gear 12 of the planetary gear system ill and around the sun gear move planet pinions which are supported within the output portion. The planet pinions are designed for the desired gear reduction which is in a ratio of 4:1 in the preferred embodiment. The ring gear 12 is rotatably supported and is driven by control motor 13. It has proven to be of advantage to use as control motor a high-speed motor with correspondingly lower output which is driving the ring gear 12 through a reduction gear.

As can be seen in FIGS. 1 and 3, the bevel gear 9 drives a bevel gear 17 located on a tubular shaft 18 extending from a roll carrier 19 and serves to rotate this roll carrier. The roll carrier is designed with three pair of fork-shaped carrier arms 20 in which are mounted shafts 21 on which are arranged the live rolls. A bevel gear 16 is driven by the universal coupling 15 and engages the bevel gear 23 which is mounted on a shaft 24 lying in the tubular shaft 18 and carries a gear 25. The gear 25 engages three gears 26 mounted on shafts 21 and so is able to drive the live rolls 22. A roll carrier 19 lies within each frame 27. These frames each contain one of the gear housings l and are supported by shoulders 28 extending from the housings l and 2. The rolling stock or workpiece 29 to be reduced is introduced through a front opening in the housing I through a ring-shaped recess in which is supported a gearwheel centered on a hollow shaft and the shoulder 28; the rolling stock leaves through a corresponding opening in the housing 2.

The rolling operation brought about by the rolling mill of the invention is explained clearly in connection with FIG. 4. The workpiece 29 has a square shape and is introduced on the corner to move from left to right. It is to be rolled down from a dimension of 100x100 mm. to a dimension of 30x30 mm. This does not reflect the upper limit of the dimensions; with the chosen dimensions of the mill (especially the size of the live rolls 22), the working of rolling stock of 140x140 mm. is possible, and with increased size of the live rolls, even greater profiles could be worked.

In FIG. 4, the frames 27 are shown in section; for simplification and for a clearer picture, the gears and the stands are omitted; also omitted is the roll carrier with its live rollers between the rolling stock and the observer. In the phase of operation of FIG. 4, the live roll 32, supported by carrier arm 30 of the roll carrier 19 engages the rolling stock 29 in the viewing direction. The roll is shown in an operating position approximately at the center of the shape-reducing area 31 of the rolling stock. The roll carriers 19, which cause the effective force components parallel to the drawing plane, are in such a position that the gaps between their carrier arms 20 face the stock. The shaping area 31 is of such a width that the the live live roll 32 in working position may pass the shaping area without being restricted by the carrier arms of the two vertical roll carriers 19. During rotation of all roll carriers in the direction of arrows 33 to 35, the live roll pairs always alternate and are guided through the shaping area 31 of rolling stock 29 in a manner that the live rolls of the oppositely arranged roll carriers are always effective at the same time.

Through the separate drives of roll carriers and live rolls, which are activated by the roll carrier 19 through

universal joints

8 and 15, it is possible to synchronize the speed of the roll carriers and the live rolls in such a way that the area of the live roll which is in contact with the rolling stock activates slow feeding. There is no danger of cracking through burning, because the liver rolls are not only activating a slow feeding, but are turning themselves within the shaping area 31 and are guided over the rolling stock with such a high speed that such cracking by burning is definitely prevented. Through the alternate action of the live roll areas as displaced 90 relative to each other, the rolling stock is rolled out alternately during one cycle of the roll carriers. This occurs first in the horizontal direction and thereafter in the vertical direction until every one of the live rolls has taken part in the action, so that the introduced square cross section is reduced, so that wire bars with square cross section are leaving the rolling stand considerably reduced in cross section.

The feed speed may be adjusted from the exterior of the mill for any desired value. The resulting reduction by this different drive branches and by the planetary gear system H is brought about in such a way that, with stationary sun gear 12, an average feed speed of the rolling stock 29 is achieved. By the operation of the control motor 13 in the direction of rotation, it is possible to increase the average feed speed. By reversing it, the feed speed may be lowered below the average speed. By corresponding control of the control motor speed, any feed speed may be introduced. With this method, it is possible to adjust the shaping procedure to the physical properties of the material of the rolling stock to be rolled. By the use of higher feed speed, every pass of one live roll pair results in a greater reduction and so corresponds to a greater depth effect. On the other hand, with sensitive material, a limitation in working of the material may be desired; this can be achieved by a reduction of the feed speed. The surfaces effected by the pass of one roll pair are close together within the shaping area and the corresponding material reduction is brought about in accordance with the desired lower working operation.

The energy consumption of the control motor is small because the motor adds only a small amount of the operating energy transmitted to the live rolls. By the use of high-speed motors and large speed reduction, only a small space is necessary.

FIG. 5 shows a bloom 41 which is worked by the live rolls 37 driven and operated with a universal planetary roll mill stand built in accordance with this invention. The live rolls 37 are designed with a profile'BS which has the shape of a flat doublewedge recess (facing conical surfaces) and its root or valley 39 is rounded in such a way that its radius corresponds to the radius of the final desired cross section.

To illustrate the continuous shaping operation, four cross sections 41 to 44 are taken in the shaping zone 4th of the rolling stock; each is shown with the corresponding live rolls. The cross section 41 of the rolling stock has a square shape and its corners are supported by the root 39 of the profile 38 of the live rolls 37 and are the first to be exposed to the shaping operations. In the following cross section 12, the contact sections of the live rolls 37 and also the following pair of rolls 45 have moved closer together and the rolling stock cross section is developing in the direction of an octagonal shape, wherein the four comers have already been rounded with the final radius. During the continuous pass to the area of cross section 4-3, a further shaping occurs by which the octagonal shape is maintained, but its area is largely reduced. The final cross section 44 appears very close to the circular shape. It is, therefore, possible not only to reduce square or rectangular rolling stock to a square or rectangular exit cross section, but also, within a wide range, to achieve selective exit cross sections without abandoning the important advantage of a planetary mill, namely, the exceptional large cross section reduction available within the rolling stand. The universal planetary rolling mill, therefore, is suitable where large cross section reductions are to be made within two areas in one operation, or where only low entrance speeds are present. The larger diameter of the live rolls permits the omission of special drive stands, and permits the shaping operation to start evenly at the head of the rolling stock. The introduction of the rolling stock to the mill is made considerably easier. The introduction of the additional control motor permits a simple, sure, and constant determination of the desired feed, because the control operation is concerned with only one part of the speed and only a negligible part of the driving power is obtained from this motor.

As a consequence of the clean rolling operation, the work requirement is considerably small. It is possible to reduce substantially blooms and billets in a single stand with a continuous operation to the desired dimensions without the use of an expensive and generally not fully usable, continuously blooming train, and without operating the stands with reverse drive, and without stopping and starting large masses, as in discontinuous operation.

It is obvious that minor changes may be made in the form and construction of the invention without departing from the material spirit thereof. it is not, however, desired to confine the invention to the exact form herein shown and described, but it is desired to include all such as properly come within the scope claimed.

The invention having been thus described, what is claimed as new and described to secure by Letters Patent is:

l. A rolling mill for attenuating an elongated bloom or the like, comprising a. a base having two spaced, parallel housings extending therefrom,

b. four frames extending between the housings, the frames extending perpendicularly to the housings and being grouped around the path of the bloom to form a boirlilre configuration,

c. a cluster of rolls associated with a roll carrier mounted on each frame, each carrier being rotated about a major axis substantially spaced from the said path and each roll being entirely supported by the carrier for rotation about its own minor axis,

cl. means driving each carrier to bring its rolls successively adjacent the said path, and

e. means driving each roll to bring about deformation of the workpiece when it is adjacent the said path.

2. A rolling mill as recited in claim ll, wherein the rolls are driven in the opposite direction to that of the carrier, so that the algebraic sum of the peripheral speed of a roll and the speed due to the rotation of the carrier is equal to the desired rate of longitudinal feed of the workpiece.

3. A rolling mill as recited in claim li, wherein the means driving the carriers and the means driving the rolls are operated from a main drive shaft.

i. A roiling mill as recited in claim El, wherein the main drive shaft operates through a planetary gear system for rotation of the carriers at different speeds than the rolls, and wherein the said different speed of rotations is produced by use of a controi motor connected to the planetary gear system.

55. A rolling mill as recited in claim il, wherein each roll is provided with a formed groove, the groove having symmetrical double frustoconical surfaces with the root rounded to the radius of the desired exit cross section of the workpiece.

ti. A rolling mill as recited in claim ll, wherein the rotation of the roll carriers about their major axes are synchronized so that rollers of one set of opposed carriers arrive adjacent the said path at the same time and the rollers of the other set of opposed carriers not only arrive at the same time, but also between the times of arrival of successive roll pairs of the said one set, so that roll pairs contact the workpiece alternately in planes apart.

'7. A rolling mill as recited in claim ll, wherein each of the housings contains four pinion gears connected to be driven together, wherein each gear is connected through a spindle and universal couplings to one of the roll carriers.

ii. A rolling mill as recited in claim "I, wherein each roll carrier includes a main gear rotatable about the major axis, and secondary gears mounted on the individual rolls and in driving contact with the main gear.

9. A rolling mill as recited in claim it, wherein the main gear is mounted on the shaft which rotates within a tubular shaft fixed to the roll carrier, the two shafts being driven at different speeds, the difference between the speeds being adjustable.

iii. A rolling mill as recited in claim 9, wherein the speeds are adjustable by virtue of a planetary gear system, having a ring gear driven by a control motor.

Claims

1. A rolling mill for attenuating an elongated bloom or the like, comprising a. a base having two spaced, parallel housings extending therefrom, b. four frames extending between the housings, the frames extending perpendicularly to the housings and being grouped around the path of the bloom to form a boxlike configuration, c. a cluster of rolls associated with a roll carrier mounted on each frame, each carrier being rotated about a major axis substantially spaced from the said path and each roll being entirely supported by the carrier for rotation about its own minor axis, d. means driving each carrier to bring its rolls successively adjacent the said path, and e. means driving each roll to bring about deformation of the workpiece when it is adjacent the said path.

2. A rolling mill as recited in claim 1, wherein the rolls are driven in the opposite direction to that of the carrier, so that the algebraic sum of the peripheral speed of a roll and the speed due to the rotation of the carrier is equal to the desired rate of longitudinal feed of the workpiece.

3. A rolling mill as recited in claim 1, wherein the means driving the carriers and the means driving the rolls are operated from a main drive shaft.

4. A rolling mill as recited in claim 3, wherein the main drive shaft operates through a planetary gear system for rotation of the carriers at different speeds than the rolls, and wherein the said different speed of rotations is produced by use of a control motor connected to the planetary gear system.

5. A rolling mill as recited in claim 1, wherein each roll is provided with a formed groove, the groove having symmetrical double frustoconical surfaces with the root rounded to the radius of the desireD exit cross section of the workpiece.

6. A rolling mill as recited in claim 1, wherein the rotation of the roll carriers about their major axes are synchronized so that rollers of one set of opposed carriers arrive adjacent the said path at the same time and the rollers of the other set of opposed carriers not only arrive at the same time, but also between the times of arrival of successive roll pairs of the said one set, so that roll pairs contact the workpiece alternately in planes 90* apart.

7. A rolling mill as recited in claim 1, wherein each of the housings contains four pinion gears connected to be driven together, wherein each gear is connected through a spindle and universal couplings to one of the roll carriers.

8. A rolling mill as recited in claim 7, wherein each roll carrier includes a main gear rotatable about the major axis, and secondary gears mounted on the individual rolls and in driving contact with the main gear.

9. A rolling mill as recited in claim 8, wherein the main gear is mounted on the shaft which rotates within a tubular shaft fixed to the roll carrier, the two shafts being driven at different speeds, the difference between the speeds being adjustable.

10. A rolling mill as recited in claim 9, wherein the speeds are adjustable by virtue of a planetary gear system, having a ring gear driven by a control motor.