US3426414A

US3426414A - Sleeve roll

Info

Publication number: US3426414A
Application number: US555883A
Authority: US
Inventors: Takeshi Iseki; Kosho Koga; Seiji Ito
Original assignee: Kanto Special Steel Works Ltd
Current assignee: Kanto Special Steel Works Ltd
Priority date: 1963-07-22
Filing date: 1966-06-07
Publication date: 1969-02-11
Anticipated expiration: 1986-02-11
Also published as: BE682983A; GB1148457A; DE1527661A1

Description

Feb. 11, 1969 TAKESHIIISEKI T AL 3,426,414

SLEEVE ROLL Filed June 7. 1966 Sheet 4 of 2 F l (PRIO ART) f 1 KM 4 7 INVENTORS BY 9M K M ATTORNEYS FebQll, 1969 TA SH. ISEK. ET AL 3,426,414

SLEEVE ROLL Sheet 2 of 2 Filed June 7. 1966 FIG.5

FIG.6I

filed 4 7" Ora INVENTOR BY (DMM 2147 ATTORNEY United States Patent Ofiice 3,426,414 Patented Feb. 11, 1969 3,426,414 SLEEVE ROLL Takeslii Iseki, Fujisawa, and Kosho Koga and Seiji Ito, Chigasaki, Japan, assignors to Kanto Special Steel Works, Ltd., Fujisawa, Kanagawa Prefecture, Japan Filed June 7, 1966, Ser. No. 555,883 US. Cl. 29129 11 Claims Int. Cl. B21b 31/08; B21h 1/14; B21d 55/10; B21k 1/04 ABSTRACT OF THE DISCLOSURE A sleeve roll, comprising a rigid arbor having a barrel portion inwardly stepped so as to have step sides near both ends; a sleeve stepped inwardly so as to have a step side engaged with one step side of said arbor, having the other end portion internally threaded, said sleeve being shrink-fitted on said arbor; and an externally threaded metal ring screwed in the threaded portion of said sleeve tightly enough to be in contact with the other step side of said arbor and engaged with the arbor, the sleeve being under axial tension.

The present invention relates in generaly to an improvement in the backup roll for use on a rolling mill and more particularly to an improvement in the sleeve roll used as the backup roll for the rolling mill.

There have so far been two types of backup rolls for use on the rolling mills in iron works and the like. The first type of backup roll is a sleeve roll formed by shrinkage flt of a sleeve onto an arbor, while the second is not such a built-up roll but a solid roll, that is, a roll manufactured from a single piece of material. The sleeve roll is greatly deflected when subjected to a high impact load due to a mistake in rolling (misrolling) or another trouble during the rolling operation, so that there takes place a relative slip between the arbor and the shrunk sleeve, and even when the slip occurs within the elastic limits, the roll retains a residual deflection or remains slightly bent. Whereas the sleeve roll is beset with the above-mentioned drawback, the solid roll is of course free from such residual deflection as long as the deformation of the roll stays within the limits of elasticity. Thus, the sleeve roll is inferior in this respect to the solid roll. However, the sleeve roll is more economical, and, because of its better hardening property, it has a better wear resistance and may be less spalled. Therefore, in spite of having the above stated defect, the sleeve roll is highly though of as the backup roll for the rolling mill and employed actually for rolling.

The above described slip between the arbor and the sleeve is generally made up of one or more of the following three basic movements: (i) the relative slip in the axial direction, (ii) the relative slip of the sleeve along the circumference of the arbor due to the rotation, and (iii) the relative slip due to the deflection of the roll. On some occasions, a combination of two or all of said three movements may take place. (i) The relative slip in the axial direction is the slip of the sleeve relative to the arbor in the longitudinal direction. Known as a measure against this slip is the method disclosed in British Patent No.

with each other and mutually engaged when the sleeve is shrink-fitted onto the arbor. Also known is the method of placing a spring ring g in an end portion of the roll as shown in FIG. 4. (ii) The relative slip of the sleeve along the circumference of the arbor takes place owing to an insufiicient amount of interference taken for shrinkage fit and can be prevented from occurring if the interference is about as employed normally for the backup roll. (iii) The relative slip due to roll deflection is often caused when a great impact load which is far higher, for example upwards of three times higher, than the ordinary rolling load is exerted on the roll on account of a mistake in rolling or another trouble during the rolling operation as described before. The arbor of the sleeve roll is so sized as to be more flexible than the sleeve and therefore, when the arbor bends under such a high load, the arbor may slip very slightly (at) with regard to the sleeve in the direction shown by the arrow in FIG. 1. It is diflicult for the method of the aforesaid British Patent No. 514,327 or the like to prevent the relative slip due to roll deflection, since such a method as shown in FIG. 3 is no different from the case shown in .FIG. 1 in the respect that the arbor is bent so as to slip very slightly in respect to the sleeve in the direction of the arrow denoted by A and B. Nor is it possible to prevent the relative slip due to roll deflection by forceful shrink fit, because the interference can not be too great in view of the requirement that the stress caused in the sleeve by shrink fit must remain within a range where the sleeve is safe from splitting. Accordingly, when the impact load due to a trouble exceeds a limit, the sleeve roll never fails to have a relative microslip on account of the deflection. Although the microslip is of course due to the deformation of the arbor and the sleeve within the elastic limits, yet even after the roll is freed from the load or external force, the microslip can not be completely removed because of the existence of a frictional force between the arbor and the sleeve. The process is schematically shown in FIG. 2, where the initial nonload state of a sleeve roll is denoted by a, while b indicates the state of the roll bent by an abnormally great load. It should be noted here that the bending designated by b is purely elastic or contains no plastic deformation. The character 0 stands for the state of the roll released from the high load. In this state, a bending, though very small, remains as indicated by d. The residual bending d is such that even in the case of a roll having an arbor whose length is, for instance, four meters or so, the shift of the central spot is at most about 20 to microns, which is very much smaller than the displacements due to the relative slips represented by (i) and (ii). Nevertheless, the material rolled by a sleeve roll having such a slight residual deflection as mentioned above is periodically varied in thickness, so that, at the present time when a very high accuracy is required for producing rolled plate, the roll thus slightly bent must be discarded or the deflection must be removed at a huge cost. Although, as already stated, the slips represented by (i) and (ii) can be prevented by the method of British Patent No. 514,327 or the like, no effective method has been found for prevention of the relative microslip denoted by (iii) and the resultant residual bending.

The present invention contemplates the prevention of the above stated relative microslip from taking place between the arbor and the sleeve of a sleeve roll when the roll is abnormally bent, and the gist is that the arbor and the sleeve are stepped to a sufficiently large extent near one end of the sleeve roll and provided with a threaded tightening metal article at the other end of the roll so as to be tightly and firmly engaged with the metal article, thus being not allowed to have any such rela tive microslip due to roll deflection as stated above.

An object of the present invention is to provide a. backup sleeve roll which is so formed as to allow no relative slip to occur between the arbor and the sleeve when the sleeve roll is subjected to a high impact load due to a mistake in rolling or another trouble in the rolling operation, and is as rigid as a solid roll as well as being easy to manufacture and economical.

Another object of the present invention is to provide a means for fitting an arbor with a sleeve so as not to allow any relative slip to take place between the arbor and the sleeve when the resulting sleeve roll is given a high impact load by a mistake in rolling or another trouble during the rolling operation or to provide the construction of the assembly.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawing, in which:

FIG. 1 illustrates how a microslip occurs between the arbor and sleeve of a sleeve roll when the roll is bent;

FIG. 2 illustrates the deflection and residual bending of the sleeve roll;

FIG. 3 is a view in vertical section of an exemplary conventional sleeve roll;

FIG. 4 is a view in vertical section of another conventional type of sleeve roll;

FIG. 5 is a view in vertical section of a sleeve roll embodying the present invention; and

FIG. 6 is a view in vertical section of a part of the sleeve roll shown in FIG. 5.

The arbor and sleeve of a sleeve roll embodying the principle of the present invention is specially constructed with such a fitting relationship with each other as not to have the above-mentioned relative microslip when the sleeve roll is subjected to an external force which, if exerted on a sleeve roll that is a conventional built-up backup roll, may cause said microslip to take place with the consequent occurrence of a residual bending of the roll. Referring now to FIG. 5, the

numerals

1 and 2 denote the sleeve and arbor of a sleeve roll respectively. The sleeve 1 and the barrel portion of the arbor 2 are each stepped near one of the ends in such a way that the step sides 4 fit together and have a sufiiciently large size. The internal surface of the other end portion of the sleeve 1 is threaded so as to fit on a threaded metal ring 3, which in turn is fitted onto the arbor 2, so that the sleeve 1 is tightly engaged with the arbor 2 by screwing the metal ring 3 with the thread 6' into the sleeve 1. The internal surface of the sleeve 1 is also stepped just inside the threaded portion, the step side being designated by 7, while the arbor 2 is stepped so as to have a step side 5. The sleeve 1 is so formed as to be shrunk on the arbor 2 with a predetermined interference. It is recommended by way of example and not in a limiting sense to shrink-fit the metal ring 3 lightly onto the arbor 2. The metal ring is designed to be screwed in until its end 8 comes into forceful contact with the step side 5 of the anbor 2.

Next, the formation of thepresent sleeve roll will be described. First, the sleeve 1 is heated to an adequate temperature, preferably 150 to 350 degrees C., and the arbor 2 is inserted into the sleeve 1, which is then shrunk on the arbor 2, and thereafter the metal ring 3 is screwed into the sleeve 1; thus, the sleeve roll shown in FIG. 5 is formed. Furthermore, the sleeve 1 and arbor 2 making up the sleeve roll are firmly combined by employing the following forming procedure: The sleeve 1 in which the arbor 2 is inserted is cooled from the end opposite to the threaded portion 6 in FIG. 5 so that the step sides 4 to come into complete contact with each other. Next, the metal ring 3 with the thread 6', after being heated to the room temperature or a temperature somewhat lower than the temperature of the sleeve 1 is screwed into the right end portion of the sleeve 1 and tightened until the end 8 of the metal ring 3 is strongly pressed against the step side 5 of the arbor 2, while the temperature of the threaded portion 6 of the sleeve 1 is kept not much below the shrink-fit temperature or the threaded section 9 of the sleeve 1 once cooled is reheated up to a temperature close to and just below the initial shrink-fit temperature. Besides, the temperature of the metal ring 3, when screwed in, is left at the room temperature or heated to a temperature nearly halfway between the room temperature and the temperature of the threaded portion 6 of the sleeve 1. In the above case, the bore of the metal ring 3 is so sized as to be lightly shrunk or firmly fixed onto the arbor 2. In order to press the end 8 of the metal ring 3 forcefully against the step side 5 of the arbor 2, it is advisable to locate the step side 7 of the sleeve 1 in the same plane as the ring end 8 or inside said end 8 and it is more preferable to provide a small separation 10 between the step side 7 and the end 8 of the metal ring 3. After the metal ring 3 has been screwed in, the sleeve 1 and the metal ring 3 are cooled. It is preferable, in this case also, to cool the sleeve 1 gradually from left to right. When the temperatures of all components of the sleeve roll thus cooled approach the room temperature, the sleeve 1 is tightly shrunk on the arbor 2 and, the metal ring 3, while the metal ring 3, together with the step sides 4, serves to fix the sleeve 1 to the arbor 2 in the axial direction. Since the metal ring 3 is screwed in tightly, close contact is ensured, by an adequate pressure, between the step sides 4 of the arbor 2 and the sleeve 1 and between the step side 5 of the arbor 2 and the end 8 of the metal ring 3. Meanwhile, the inside surface of the female thread 6 formed on the internal surface of the sleeve 1 comes into close contact at an appropriate pressure with the outside surface of the male thread 6' formed on the metal ring 3.

With a sleeve roll manufactured as mentioned above, there occurs no relative microslip between the sleeve 1 and the arbor 2 even when an abnormally great external force causes the roll to bend as indicated by b in FIG. 2, unless the threads 6 and 6' of the sleeve 1 and the metal ring 3 respectively are destroyed. Accordingly, after the external force is removed, the deflection disappears just as in the case of a solid roll and the sleeve roll returns not to the state c in FIG. 2 but to the nonload state a.

In order to facilitate the operation of screwing the metal ring 3 into the sleve 1, it is advisable to prepare a solid metal article consisting of the metal ring 3 and a grip "section 11 as shown in FIG. 6 and to cut the metal article, after the metal ring 3 has been screwed in, along the dotted line 12 by means of a lathe to remove the grip section 11 from the metal ring 3.

Furthermore, the width 9' of the metal ring 3 to be screwed in is calculated in view of the resisting force against the relative microslip. Besides, the form of the thread 6 on the metal ring 3 may vary according to the conditions under which the roll is used, and a trapezoidal thread is a preferable type.

As apparent from the foregoing description, the sleeve 1 and arbor 2 of the sleeve roll embodying the present invention are stepped so that the size of the step sides 4 and 5 may be made s-ufiiciently large for the pressure exerted on the contact surfaces to be excessively high even in case of trouble, and by screwing the threaded metal ring 3 into the sleeve 1, the sleeve !1 is tightly fastened to the arbor 2 at the side steps 4 :and 5 thereof through the metal ring 3; therefore, the sleeve #1 shrunk on the arbor 2 is lengthwise tightly fixed to the arbor 2, so that the sleeve roll, even after having bent under a high impact load, is virtually free from any residual bending.

In a sleeve roll embodiment of the present invention, steel, low alloy steel, special alloy steel, cast steel and cast iron are mainly used for metal material making the arbor 2, sleeve 1 and metal ring 3.

Example Sleeve (forged from a high-carbonchrome-molybdenum steel):

Outer diameter mrn 1,250 Length m 2,000 Thread length 9 mm 60 Height of step side 4 mm 6 Distance from end to step side 4 mm 50 Shore hardness of external surface degrees 68 Shore hardness of internal surface do 40 interference 4 Heating temperature C 150 Arbor (forged from a nickel-chromemolybdenum steel):

Barrel diameter mm 850 Barrel length rnm 2,000 Height of step side 5 mm Metal ring (forged from a nickel-chromemolybdenum steel):

Outer diameter mm 898 Inner diameter mm 827.5 Interference $5 Thread length 9' (6 threads) mm 58 Shore hardness of external surface degrees 40 Tensile strength kg./mm. 9O Screw-in temperature C 70 With the sleeve roll thus sized, it may be considered that the resisting force of the metal ring against the microslip under consideration is equivalent to the shearing force required to break the six threads; therefiore, when this shearing force is compared with the frictional force in the circumferential direction in the case of the shrinkage fi-t of the threaded portion (60 mm.) of the sleeve [1 onto the threaded metal ring with an interference of /i as is the case with the conventional shrink fit, it is apparent that said shearing force is more than ten times the said frictional force, so that it will be well understood that the fixing force of the metal ring is extremely strong.

What is claimed is:

1. A sleeve roll, comprising a rigid arbor having a barrel portion inwardly stepped so as to have step sides near both ends; a sleeve stepped inwardly so as to have a step side engaged with one step side of said arbor, having the other end portion internally threaded, said sleeve being shrink fit-ted on said arbor; and an ex terna-l ly threaded metal ring screwed in the threaded portion of said sleeve tightly enough to be in contact with the other step side of said arbor and engaged with the arbor, the sleeve being under axial tension.

2. A roll according to claim 1 in which the size of the engaging step sides iormed on the arbor and the sleeve near one end of the roll is larger than the interference.

3. A roll accord-ing to claim -1 in which the threads formed in the sleeve and on the metal ring are trapezoidal in form.

4. A roll according to claim 1 in which the other step side of the arbor is in close contact with the metal ring and there is a space between the metal ring and the step side of the sleeve.

5. A method of making a sleeve roll which comprises the steps of shrink-fitting an arbor having a barrel portion stepped so as to have step sides near both ends with a sleeve stepped so as to have a step side to be engaged with one of the two step sides of the arbor and having the other end portion internally threaded, and then screwing an externally threaded metal ring into the threaded portion of the sleeve until the leading end of the metal ring comes into forceful contact with the other step side of said arbor, whereby the sleeve not only firmly engages the arbor in a radial direction but is also tightly fixed to the arbor under tension in the axial direction.

6. A method according to claim -5 in which the sleeve to be shrunk on the arbor is heated from to 360 degrees C.

7. A method according to claim 5 in which the metal ring is shrunk on the barrel of the arbor.

8. A method according to claim 5 in which the metal ring has a grip section thereon and the metal ring is screwed into the threaded portion of the sleeve by turning the grip section, and thereafter the grip section is cut off by means of a lathe.

9. A method according to claim 5 in which the metal ring is shrunk on the arbor after being heated to a temperature lower than that to which the sleeve is heated.

10. A method according to claim 5 in which the metal ring is screwed into the sleeve after the threaded section of the sleeve, after it has cooled, is reheated up to a temperature close to and just below the initial shrink-fit temperature.

11. A method according to claim in which, for the shrink-fit of the sleeve onto the arbor, the sleeve placed on the arbor is gradually cooled from the end opposite to the threaded portion.

References Cited UNITED STATES PATENTS 281,597 7/1883 Wilmot 29--'129. 5 476,552 6/ 1892' Pollard 29129.5 1,430,418 9/1922 Vedder 29- 1l17 1,514,505 11/1924 Conklin 29129 2,018,247 10/ 1935 Bigger-t et al 29 129. 5 2,215,424 9/1940 Klein 2-9129.5 2,367,088 1/ 1945 Benson 291 17 2,452,266 10/1948 Scharfi 29l2-9.5 2,732,232 1/ 1956 Whitfield 29-129 BILLY J. WILHITE, Primary Examiner.

US. 01. X.R.