The present disclosure relates to an apparatus and process for machining of back-up and work rolls such as utilized in steel rolling processes, and more specifically to workpiece holders of centerless roll grinding machines for machining of back-up and work rolls.
A heated slab as thick as several hundreds of millimeters, which is produced by continuous casting, etc., is rolled to a steel strip as thick as several to several tens of millimeters by a hot strip mill comprising a roughing mill and a finishing mill. The finishing mill usually comprises 5 to 7 four-high stands arranged in tandem. In the case of a seven-stand finishing mill, first to third stands are called “front stands,” and fourth to seventh stands are called “rear stands.”
The pressure and heat in a mill stand are so high that the rolls flex slightly. This would cause the steel sheet to be slightly thicker at the center than the edges. To compensate, the rolls are formed to be slightly fatter at the center than the edges. This is called a “crown” profile. A crown might be as small as a few thousands (0.001) of an inch. Other profiles are used. In modern mills, roll profiles can be very complicated.
Of course, the surfaces of the rolls must not have surface irregularities that produce undesirable surface quality of the steel strip. Imperfections in the roll surface will cause imperfections in the surface of the rolled sheet. An uneven shape of the roll causes unevenness in the rolled product, which at the very least means a waste of rolled material. Over a period of use, rolls undergo wear and deterioration in surface quality. From time to time the rolls need to be reshaped by machining or grinding.
In steel rolling, metal forming, and similar processes, gage variations which are induced in flat rolled sheet products by eccentricity of the back-up and/or work rolls, is a widespread problem which is growing in criticality as a result of increasing demand for improved control of gage variation and strip shape. Eccentricity is defined as the sum of out-of-roundness and concentricity errors. The gage thickness variation of the final formed sheet is directly dependent upon the radial variation of the rolls and the roll's concentricity errors. Minimizing thickness variation in the sheet products is critical to enabling the most efficient use of materials and energy to produce acceptable products.
Rolls are shaped and reshaped by a process known as “roll grinding.” Modern off-line roll grinders comprise a headstock that journals the roll and rotates the roll about its axis. A carriage moves parallel to the roll axis supporting a grinding wheel that rotates at several hundred RPM. A stream of water cools the grinding wheel and roll. The grinding wheel axis is held by an infeed mechanism that precisely moves the grinding wheel toward the roll.
Modern roll grinders are computer controlled. Grinding involves a number of steps from coarse fast grinding to slow finish grinding. This includes carefully bringing the grinding wheel to the roll and periodic measurement. The measurements are often continuous made by a high-precision computer controlled electronic caliper mounted on the roll grinder. It is desirable for the grinding operation to return the roll, within tolerance, to the desired profile and surface condition within the minimum time, removing the minimum amount of material from the surface of the roll.
In one aspect, the present disclosure provides a centerless roll grinding machine having a frame that extends laterally and longitudinally to be positioned under a generally cylindrical work roll having a narrower neck on each longitudinal end. A grinding wheel assembly includes a grinding wheel housing received on a first lateral portion of the frame for longitudinal and lateral movement. The grinding wheel assembly includes a grinding wheel presented on a second side of the grinding wheel housing that is opposite to the first side. The frame includes a vertical support extending from a second lateral portion. A lateral support is received by the vertical support of the frame and extending horizontally in the first direction to contact the second side of one neck of the work roll. A lower support is received by and extends generally upwardly from the frame displaced in the first lateral direction from a geometric center of the neck of the work roll to cooperate with the lateral support to provide a V-channel support to hold the work roll for rotation about a longitudinal axis. The lateral support includes a horizontal ram and a lateral support device. The lateral support device includes more than one bearing pad that are radially spaced along a side of the neck in opposition to the grinding wheel. Each pair of bearing pads is pivotally attached to an averaging link that is pivotally coupled to the horizontal ram to reduce horizontal displacements of the work roll caused by a radial variation in the neck.
As used herein, the term “roll” will be understood as including any of a wide variety of work rolls, back-up rolls, feed rolls, pressure rolls, or the like, used in the variety of industrial applications such as steel, aluminum, and paper handling and processing, and similar applications. Generally, such rolls featured relatively large diameters (e.g., 12-80 inches, or 30-200 cm) and can weigh more than 50 tons (45 tonnes), although the apparatus and method of the present invention has utility for measuring and machining rolls of virtually any size. As mentioned above, eccentricity of such rolls will be understood to mean the combination of the out-of-roundness and concentricity errors or total indicator run-out from mean axis of rotation of the roll.
As an example, the rolls might be made of air-hardened tool steel. In one or more embodiments, a slight crown (e.g., about 0.010 inches, or about 0.25 mm) may be preferred on the diameter of each roll to facilitate alignment of the rolls in a machine frame, to guarantee uniform loading and to prevent marking of the roll by heavy contact with an edge of a roll support.
The above summary contains simplifications, generalizations and omissions of detail and is not intended as a comprehensive description of the claimed subject matter but, rather, is intended to provide a brief overview of some of the functionality associated therewith. Other systems, methods, functionality, features and advantages of the claimed subject matter will be or will become apparent to one with skill in the art upon examination of the following figures and detailed written description.
The description of the illustrative embodiments can be read in conjunction with the accompanying figures. It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements. Embodiments incorporating teachings of the present disclosure are shown and described with respect to the figures presented herein, in which:
According to aspects of the present innovation,
According to one or more aspects of the present innovation,
The horizontal lateral support 502 includes an inner third tier averaging link 540 of the 4-stage support device 522 that is mounted to horizontal slide member (ram) 510 by proximal pin 542.
In one or more embodiments,
Averaging links translate a small fraction (e.g., about ⅛th) of the radial variation of the neck regardless of the shape or extent of the out-of-round errors of the neck. The averaging link system responds to varying radii of a non-round neck in a manner that will reduce (approximately an 8 times reduction) the horizontal motion of the neck's geometric center, regardless of the shape (the number of lobes) or extent of the radial variation that is encountered. The averaging link system acts as a passive mechanical analog computer that computes a moving average of 8 neck radii. This rounding action is fully automatic, requiring no monitoring or control action by a machine operator.
In one or more embodiments, the grinding apparatus may include one or more drive means (not shown) for rotating a roll or other workpiece about its longitudinal axis. In one or more embodiments, the drive means is provided in the form of one or more drive wheels for frictionally contacting the roll or other workpiece to impose rotational energy. In one or more embodiments, the drive means further comprises means for providing rotational energy (e.g., a drive motor), with a drive belt or chain transmitting such rotational energy to the drive wheels. In one or more embodiments, the outer surface of drive wheel include a friction surface such as soft polymer or the like to enhance the frictional interaction with a roll and to make the transfer of rotational energy more efficient.
The invention also involves a rotating grinding- or cutting tool, in particular a grinding wheel or grinding roller that has a body as in the present invention and at least one layer of abrasive material on one peripheral surface and/or at least one lateral surface of the body, this material can be cubic boron nitride (CBN) or diamond.
In one or more embodiments, the grinding apparatus may include using grinding oil or grinding emulsion as cooling lubricant. The apparatus for machining a cylindrical roll or workpiece of the present disclosure can be applied to a machining apparatus for performing finish machining, such as grinding, of an outer circumferential surface of a cylindrical workpiece on the basis of an inner circumferential surface after heat treatment of the workpiece.
In the detailed description of exemplary embodiments of the disclosure, specific exemplary embodiments in which the disclosure may be practiced are described in sufficient detail to enable those skilled in the art to practice the disclosed embodiments. For example, specific details such as specific method orders, structures, elements, and connections have been presented herein. However, it is to be understood that the specific details presented need not be utilized to practice embodiments of the present disclosure. It is also to be understood that other embodiments may be utilized, and that logical, architectural, programmatic, mechanical, electrical and other changes may be made without departing from general scope of the disclosure. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims and equivalents thereof.
References within the specification to “one embodiment,” “an embodiment,” “embodiments”, or “one or more embodiments” are intended to indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The appearance of such phrases in various places within the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Further, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but not other embodiments.
While the disclosure has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular system, device or component thereof to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiments disclosed for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
The description of the present disclosure has been presented for purposes of illustration and description but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the disclosure. The described embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.
This application claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Patent Application Provisional Application Ser. No. 63/053,301, entitled “CENTERLESS ROLL GRINDING MACHINE WITH REDUCED RADIAL VARIATION ERRORS,” filed Jul. 17, 2020, the contents of which are hereby incorporated by reference in their entirety for any purpose.
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Number | Date | Country |
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241070 | Oct 1987 | EP |
Entry |
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EP-241070-A translation (Year: 1987). |
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20220016737 A1 | Jan 2022 | US |
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63053301 | Jul 2020 | US |