Claims:1) A device for offset machining of tilt Pads with high degree of accuracy and surface finish on a conventional non-CNC machining center, the said device comprising:
- a calibrated slider (2) having a base plate (2’) supporting plates (P1, P2) connected to each other through lead screw (12);
- a slider hand-wheel (13) connected to the lead screw (12) through which hand motion can be imparted to slide plate (P2) over plate (P1) to create an offset with respect to turn table center;
- a slider lock screw (14) to lock relative position of said plates (P1, P2);
- a stand plate (1) mounted on the plate (P2) through a nut (3) on which (1) a subject workpiece Pad (4) is mounted for machining;
- a dummy pad (9) mounted on the stand plate (1) to provide ready reference for correct measurement of inner and outer radii of pad (4);
- a slot located at the middle of the stand plate (1) periphery to measure the thickness and width of Pad without disturbing the job setting.
2) The device for offset machining of tilt Pads with high degree of accuracy and surface finish on a conventional non-CNC machining center as claimed in claim 1, wherein the stand plate (1) is mounted on the plate (P2) through a nut (3) on which (1) a subject workpiece pad (4) is mounted using stud (5), Jack bolt (7), Pad holder (6) and Nut (8) for machining.

3) The device for offset machining of tilt Pads with high degree of accuracy and surface finish on a conventional non-CNC machining center as claimed in claim 1 or 2, wherein the dummy pad (9) is mounted on the stand plate (1) using stud (10), dummy pad holder (11) and Nut (8) to provide ready reference for correct measurement of inner and outer radii of pad (4) for quality inspection during and after machining.
4) The device for offset machining of tilt Pads with high degree of accuracy and surface finish on a conventional non-CNC machining center as claimed in the claims 1-3, wherein relative position of plate (P2) with respect to Plate (P1) can be locked at any position with the help of slider lock screw (14).

5) A method for offset machining of pads of tilt pad journal bearing using device as claimed in claim 1 comprising of the steps of:-

- mounting of the device on turntable of a vertical borer that spigot of lower plate (P1) of calibrated slider is tightly fitted in the central hole of turn table to ensure the error free operation;
- placement of bolts into T slots of the turntable and fitting of the plate (P1) by fastener including bolts and nuts, once the spigot of lower plate (P1) gets inserted into central hole of the turntable;
- carrying out centering of said stand plate (P1) with respect to the lower plate (P1) and turntable by dial gauge. , Description:FIELD OF THE INVENTION
[001] The present invention relates to a device and method for offset machining of pads of tilt pad journal bearing. Offset pads are used in the exciters, generators, turbines, motors and other rotating equipment. Inner and Outer radii of tilt pads are offset and needs special fixing arrangement for machining these radii. More particularly the invention relates to a device which has been developed to hold the pad during machining of its inner and outer radii which are offset to each other in spite of being concentric.
BACKGROUND OF THE INVENTION
[002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[003] Tilted Pad journal bearings uses pads which rest on pivots. A typical Tilted Pad Journal Bearing (B) with tilted pad (4) is shown in figure 1. These pads are free to rock or slide thereby producing the "tilt" motion. A tilting pad bearing is an example of a fluid film bearing, which uses an oil wedge to support a load without shaft-to-bearing contact. The main advantage that tilt pad bearings have over all fixed-geometry bearings is that there are no significant destabilizing cross-coupling forces, which cause oil whirl instability. Also, they are very robust, which means they are able to be designed for optimal rotor dynamics.
[004] These bearings have the ability to tilt to accommodate the forces being developed in the hydrodynamic oil film, and therefore operates with an optimum oil-film thickness for the given load and speed. This ability to operate over a large range of loads is especially useful in high-speed gear reductions with various combinations of input and output shafts. Another important advantage of the tilting-pad journal bearing is its ability to accommodate shaft misalignment. Because of its relatively short length-to-diameter ratio, it can accommodate minor misalignment quite easily.
[005] Tilted pad journal bearings typically include plurality of tilt pads. The pivot type is selected based on requirements for life of the pivot, stiffness, ease of pivot tilt in one or more directions, and industry requisites. Common pivot types include point contact, line contact, ball and socket, and Flexure Pivot.
[006] The present invention is related to manufacture a line contact pivot by offset machining of inner and outer radii of Pads. This off setting operation makes the pad thicker in the center of pad arc and thinner in the outer ends of pad arc and this thicker portion will act as a pivot of line contact in the assembly of bearing.
[007] In view of the above it is clear that the machining of Pad plays an important role in the functional performance of the bearing, hence machining of Pad needs to be considered as a critical goal and attended carefully. A typical picture of Pad is shown in figure 2. It can be seen that these Pads are thicker at its mid-section and thinner towards the outer faces because of offset centers of pad’s inner and outer radii. Given the complexity of maintaining the profile accuracy of highest degree that too with close tolerances, these type of profile only can be manufactured on a CNC machine as per prior art practice. However, machining a component on CNC machine is not only expensive but also engages the machine too thereby, bar other critical line manufacturing items to be out on hold.
[008] However, to manufacture such pads on a conventional manual machine such as a vertical borer or the likes, work holding attachments would be required and a work methodology needs to be established to enable the same quality of finished job as compared to a CNC machine used in prior art. Present invention is related to develop an attachment which is necessarily required to machine such asymmetric component with highest degree of accuracy on conventional machining centers.
[009] Thus there exists a need of method and means for offset machining of pads of tilt pad journal bearing on conventional manual machines which are less resource expensive as compared to a CNC machine, wherein such CNC machine can be utilized to machine other components of complex nature which cannot be transferred to a manual machine by virtue of their profiles which are impossible to create manually or jobs which require mandatory spindle movement in more than 3-axis.
OBJECTS OF THE INVENTION
[010] The principal objective of this invention is to provide a device and method for offset machining of pads of tilt pad journal bearing which is simple in construction.
[011] An object of the invention is to provide a device and method for offset machining of pads of tilt pad journal bearing which overcomes disadvantages of prior art(s).
[012] Another object of the invention is to provide a device and method for offset machining of pads of tilt pad journal bearing with a high degree of accuracy.
[013] Still another object of this invention is to provide a device and method for offset machining of pads of tilt pad journal bearing with provision of offsetting and holding of work piece with respect to machine center as well as with provisions of measurement without disturbing the setting of the job.
[014] Yet another object of this invention is to provide a device and method for offset machining of pads of tilt pad journal bearing to produce the good quality pad with required accuracy and tolerances to ensure the pad dimensions as well as assembly clearances to perform its intended function.
[015] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.
SUMMARY OF THE INVENTION
[016] One or more drawbacks of conventional systems and process are overcome, and additional advantages are provided through the apparatus and a method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be part of the claimed disclosure.
[017] According to this invention, there is provided a device for offset machining of tilt Pads with high degree of accuracy and surface finish on a conventional machining center such as vertical borer. Said means comprising a calibrated slider (2) having a base plate (2’) supporting plates (P1, P2) connected to each other through lead screw (12). A slider hand-wheel (13) is connected to the lead screw (12) through which hand motion can be imparted to slide plate (P2) over plate (P1) to create an offset with respect to turn table center. A slider lock screw (14) is provided to lock relative position of plates (P1, P2). A stand plate (1) is mounted on plate (P2) through threaded means nut (3) on which the subject workpiece Pad (4) is rigidly mounted for machining using various threaded means such as stud (5), Jack bolt (7), Pad holder (6) and Nut (8). A dummy pad (9) is mounted on the stand plate (1) using stud (10), dummy pad holder (11) and Nut (8) to provide ready reference for correct measurement of inner and outer radii of pad (4) for quality inspection during and after machining. A slot is placed at the middle of stand plate (1) periphery to measure the thickness and width of Pad without disturbing the job setting.
[018] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
[019] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.
[020] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[021] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein: -
Figure 1 illustrates typical view of a tilted pad bearing (B) according to the present invention.
Figure 2 illustrates a tilt pad (4) as used in a tilted pad bearing (B), in accordance with the present invention.
Figure 3 illustrates isometric view of proposed device for offset machining of pads of tilt pad journal bearing mounted with Pad, in accordance with the present invention.
Figure 4 illustrates exploded view of the proposed device in accordance with the present invention.
[022] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAIL DESCRIPTION OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS OF PREFERRED EMBODIMENTS
[023] While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.
[024] Although embodiments for the present subject matter have been described in language specific to package features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/device of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.
[025] The present invention pertains to a technology regarding a device and method for offset machining of pads of tilt pad journal bearing.
[026] Now, reference may be made to fig. 3 and 4. As shown in figure 3, 4 the proposed device comprises of different components, out of which a key component is a calibrated slider (2) which further comprises a base plate (2’) supporting lower plate (P1) and upper plate (P2). These Plates (P1 & P2) are connected with the help of a lead screw (12). This Lead screw (12) is connected with slider hand-wheel (13) which rotates through hand motion on a circular scale. When hand wheel (13) is rotated, the plate (P2) slides over the plate (P1) and such motion produces an offset with respect to turn table center. Such a displacement of Plate (P2) can be read on circular scale. Once the correct offset is reached, relative position of plate (P2) with respect to Plate (P1) can be locked at any position with the help of slider lock screw (14).
[027] At this locked relative position of said plates (P1, P2), stand plate (1) is mounted on plate (P2) and fixed on it through threaded means such as a central nut (3). The stand plate (1) is the member on which the subject work piece Pad (4) is to be rigidly mounted for machining. The work piece Pad (4), as shown in figure 1,2, is mounted on stand plate (1) with the help of stud (5), Jack bolt (7), Pad holder (6) and Nut (8). Also, a Dummy pad (9) is mounted on the stand plate (1) with the help of stud (10), dummy pad holder (11) and Nut (8). A slot in the middle of the stand plate (1) periphery is provided so as to measure the thickness and width of Pad without disturbing the setting of job.
Operation of present invention
[028] This whole arrangement as discussed above is mounted on the turntable of a vertical borer in such a way that spigot of lower plate (P1) of calibrated slider is tightly fitted in the central hole of turn table to ensure the error free operation. Once spigot of lower Plate (P1) got inserted into central hole of the turn table, bolts are put into T slots of turntable and plate (P1) becomes tightly fitted with the help of fasteners including bolts & nuts. With the help of dial gauge, the centering of said stand plate with respect to lower plate (P1) as well as turntable is carried out.
[029] With such an arrangement as described hereinabove, required offset values can be set for machining.
[030] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[031] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
[032] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particulars claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.
[033] The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
[034] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[035] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[036] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.