INNER SURFACE OF A TUBE”

TECHNICAL FIELD

The present disclosure relates to the field of metal working technology. Particularly, but not exclusively, the present disclosure relates to forming or thickening portions of a tube. Further embodiments of the present disclosure disclose a mandrel assembly for thickening a brim portion on either ends of the tube from its inner surface keeping the outer surface same.

BACKGROUND OF THE DISCLOSURE

A tube is a hollow elongated member made from materials including, but not limited to, metal, polymers, composites and the like. The tubes, in general, may be made by process including but not limited to, rolling, extrusion, pultrusion, protrusion, and the like, where the tube may include a defined thickness based on application. The tube may be used in various fields of domestic, medical, fuel gas distributions, automotive and other applications, including air conditioning and refrigeration. For example, in the automotive applications such as two- wheelers, tubes may be used in frames, seating systems, fuel delivery components and automotive link arms require tubes to be welded to create an integrated frame. The tubes may be welded using various known welding methods such as MIG welding, flux-cored arc welding, TIG welding, stick welding and the like, depending on factors including, but not limited to, material of the tube, the size [that is, thickness and diameter] of the tube, profile of the tube joining region, and the like, based on structural configuration required for application of the tube. Further, welding of two or more tubes may result in different zones being formed at a weld juncture, where the different zones include fusion zone, weld interface, heat affected zone, and the like. In general, the fusion zone and the HAZ acts stress affected zones at the joining region of the two or more tubes, where such stress affected zones tend to increase stress concentration in the joining region, impacting structural properties of the two or more tubes. For example, the stress affected zones may reduce durability of the two or more tubes at the joining region for loads including, but not limited to, fatigue load, axial load, shear load, and the like, whereby reducing industrial applicability of the tubes.

To avoid formation of such stress affected zones in the joining regions, conventionally, dimensions of the tubes including, but not limited to, thickness, may be increased, where either overall thickness of the tubes may be increased or thickness at predetermined portions of the tube may be increased to address the stress concentration at the joining regions. The tubes with overall increased thickness may add unnecessary weight to the application, while the tubes with increased thickness at predetermined portions may overcome the limitations of the tubes with overall increased thickness. The tubes may be defined with a thickened portion at the joining regions of the two or more tubes [generally, at brim portion to address impact of the stress concentration]. In general, for applications including, but not limited to, automotive industry, one end of the tubes is defined with a thickened portion [or commonly referred to as increased thickness at a given portion] at a brim portion [or commonly referred to as free ends of the tubes] of the tube such that, the thickened portion of the tube may be joined at a free end of subsequent tube having no thickened portions. This way, by defining one end of the tube with the thickened portion, stress concentration at the joining region of two or more tubes may be minimized, while maintaining add-on weight to a minimum value.

Conventionally some processes have been developed and employed for producing tubes with thickened portion. Some of such conventional processes may be including, but not limited to, flexible rolling, swage auto-frettage process, tube drawing using position controlled mandrel methods, extrusion with special die setup and also internally and externally upsetting ends of the tube. The above said processes have several restraints such as higher investment in tooling and/or low productivity due to increased cycle time. In some of the conventional processes, a punch-die assembly is employed for thickening the brim portions of the tube, where the punch- die assembly may be configured to thicken brim portion in one of the sides of the tube at a time. Though the punch-die assembly may address some of the limitations of the conventional methods, operation of the punch-die assembly may be restricted to producing the thickened portion at one end of the tube, as the die may be concealed within the brim portion if both brim portions of the tube are thickened simultaneously.

The present disclosure is directed to overcome one or more limitations stated above.

SUMMARY OF THE DISCLOSURE

One or more shortcomings of the conventional process are overcome by process as claimed and additional advantages are provided through the provision of processes as claimed in the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

In one non-limiting embodiment of the disclosure, a mandrel assembly for thickening a brim portion of a tube is disclosed. The assembly includes a central core element, that is receivable by an inner surface of the tube. Further, a plurality of segments is disposable between the central core element and the inner surface of the tube. At least one end of each of the plurality of segments is defined with a forming region, wherein the brim portion of the tube is deformable along the forming region of the plurality of segments.

In an embodiment of the present disclosure, the forming region is defined at either ends of each the plurality of segments.

In an embodiment of the present disclosure, the plurality of segments is configured to surround the central core element about perimeter region and along length of the central core element.

In an embodiment of the present disclosure, each of the plurality of segments are detachably positioned on the central core element.

In an embodiment of the present disclosure, the forming region of each of the plurality of segments is defined with a tapered profile.

In an embodiment of the present disclosure, the central core element is a solid core.

In another non-limiting embodiment of the present disclosure, a method for assembling a mandrel assembly for thickening a brim portion of a tube is disclosed. The method includes steps of positioning a central core element about an internal surface of the tube. A plurality of segments is positioned between the central core and the inner surface of the tube. At least one end of each of the plurality of segments is defined with a forming region that aligns with the brim portion of the tube.

In an embodiment of the present disclosure, the method further includes positioning the central core element abutting the inner surface of the tube. Further, one segment of the plurality of segments is positioned between the central core element and the inner surface of the tube. Also, remaining segments of the plurality of segments are positioned around the perimeter of the central core element.

In an embodiment of the present disclosure, the method further includes steps of displacing the central core element axially from the plurality of segments and out from the tube. As the central core element is displaced from the tube, one segment of the plurality of segments collapses due to gravity and is retracted from the tube on. Lastly, retracting the remaining segments of the plurality of segments from the tube.

In an embodiment of the present disclosure, the central core element is axially displaced from the plurality of segments, to collapse one segment from engagement between the central core element and a top portion of the inner surface of the tube.

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 together combined to form a further embodiment of the disclosure.

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 FIGURES

The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

FIG.1 is a sectional view of a mandrel assembly employed for thickening brim portion in an inner surface of a tube, in accordance with an embodiment of the present disclosure.

FIG.2 illustrates a perspective view of the mandrel assembly of FIG.1. FIGs.3A-3D illustrates pictorial views of a press apparatus having the mandrel assembly for thickening brim portion in the inner surface of the tube, in accordance with an embodiment of present disclosure.

FIG.4 illustrates cross-sectional view of the tube that is plastically deformed in the inner surface of the tube using the mandrel assembly of FIG.l, in accordance with an embodiment of the present disclosure.

FIG. 5 illustrates a schematic representation of retracting of the mandrel assembly from FIG. 4, in accordance with an embodiment of the present disclosure.

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.

DETAILED DESCRIPTION

The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent processes do not depart from the scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure. Embodiments of the present disclosure discloses a mandrel assembly for thickening brim portion in an inner surface of a tube, particularly tubes that may be used in components of an automobile. The mandrel assembly includes a central core element, which is configured to rigidly support a plurality of segments on an outer surface and to accommodate the tube along its length. The plurality of segments are disposable between the central core element and the inner surface of the tube. Further, at least one end of each of the plurality of segments is defined with a forming region that is aligned about a specific end, where the brim portion of the tube is deformable along the forming region of the plurality of segments. Also, the mandrel assembly is disassembled/dismantled by displacing the central core element from the plurality of segments. Due to such displacement of the central core element, one segment of the plurality of segments collapses due to gravity, thereby allowing retraction of remaining segments of the plurality of segments. This way, the brim portion of the tube at both ends can be thickened and the mandrel assembly can be effortlessly retrieved from inside of the tube.

The terms “comprises”, “comprising”, or any other variations thereof used in the specification, are intended to cover a non-exclusive inclusion, such that an assembly that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or method. In other words, one or more elements in an assembly proceeded by “comprises... a” does not, without more constraints, preclude the existence of other elements or additional elements in the assembly.

Henceforth, the present disclosure is explained with the help of one or more figures of exemplary embodiments. However, such exemplary embodiments should not be construed as limitation of the present disclosure.

The following paragraphs describe the present disclosure with reference to FIGS.l to 4. In the figures, the same element or elements which have similar functions are indicated by the same reference signs.

FIGs.1 and 2 are exemplary embodiments of the present disclosure showing sectional view and perspective view of a mandrel assembly (100) for thickening portions of a tube (200). The mandrel assembly (100) may be employable in a press apparatus (300) (herein after referred to as “the apparatus”) [or generally referred to as punch unit] to enable thickening of sections about a brim portion (202) along an inner surface (201) of the tube (200). In an embodiment, the press unit may be including, but may not be limited to, a hydraulic press unit, a pneumatic press unit, a combination of the either of the two, and any other press unit that may be employable for thickening portions of the tube (200). The tube (200) may be of cross-sectional profdes including, but not limited to, triangle, square, rectangle, elliptical, and the like, while for illustration the tube (200) of the present disclosure is illustrated with circular or cylindrical profde. As shown in FIGs.l and 2, the mandrel assembly (100) includes a central core element

(1) and a plurality of segments (2) [or also referred to as die segments (2) of the mandrel assembly (100) for the press unit], where the plurality of segments (2) may be disposable around the central core element (1). Each of the central core element (1) and the plurality of segments (2) may include an elongated portion which may be dimensioned to be at least one of equal to, greater than or lesser than longitudinal dimension of the tube (200). Further, the central core element (1) and the plurality of segments (2) may be made from homogenous material or heterogeneous material, where the material may be including, but not limited to, metals, non-metals, polymers, reinforced substances, and the like. Additionally, the central core element (1) and the plurality of segments (2) may be structured to be rigid and may be either solid composition or may be hollow, based on material employed for making the central core element (1) and the plurality of segments (2).

Referring now to FIG.2, an outer section of the central core element (1) and interior portion of each of the plurality of segments (2) may be configured to complement one another at the interface therebetween. The interface between the plurality of segments (2) and the central core element (1) may be defined with tolerance along portions on the circumference or may be seamless, based on required portion for thickening of the tube (200). The plurality of segments

(2) may be defined with a forming region (3), where the forming region (3) may act as a pressure-acting-surface for the inner surface (201) of the tube (200). The forming region (3) of the plurality of segments (2) may be configured to allow thickening at defined portions of the tube (200). The forming region (3) may be defined at any section along the length of the plurality of segments (2) in order induce thickening at defined portion of the inner surface (201) of the tube (200). In an embodiment, the plurality of segments (2) may be assembled to align the forming region (3) at one end such that, the brim portion (202) of the tube (200) on at least one end may be deformable along the forming region (3) to induce thickened portion in the tube (200). In the illustrative embodiment, the forming region (3) is defined at both ends of the plurality of segments (2). The forming regions may be assembled at one side of each of the plurality of segments (2) or at different sides such that, thickening of the brim portion (202) of the tube (200) may be symmetric or asymmetric respectively, about a predetermined axis of the central core element (1). In an embodiment, the forming region (3) may be defined with at least one of depression pattern, bulge portion, a defined pattern [such as, knurled pattern, thread pattern] and/or a combination of each. In the illustrative embodiment, the forming region (3) is defined with a tapered profile [for example, a depression at ends of the segments (2)] on both sides of the plurality of segments (2), in order to thicken the inner surface (201) of the tube (200) at both ends, while one or some of the plurality of segments (2) may be defined with the forming region (3) in order to thicken. Also, the forming region (3) may be defined about a predetermined length of the plurality of segments (2).

In an embodiment, the plurality of segments (2) may include two or more segments (2), which may be configured to surround the central core element (1) about perimeter region and along length of the central core element (1). The two or more segments (2) of the plurality of segments (2) may be positioned on the central core element (1) about a reference section. For example, a reference line may be indicated on interface surface between the central core element (1) and the plurality of segments (2). Also, the central core element (1) may be defined with at least one of splines, keyways, grooves, and the like on the outer surface, to accommodate and restrain rotational motion of the two or more segments (2) on the central core element (1). In the illustrative embodiment, the plurality of segments (2) may include four segments (2), namely a first segment [also referred to as one segment (2a)] and second segment, third segment and fourth segment [also referred to as remaining segments (2b)] as 2a, 2b, respectively, as depicted in FIG.2. Further, one segment (2a) of the plurality of segments (2) may be positioned between the central core element (1) and the inner surface (201) of the tube (200) and, remaining segments (2b) of the plurality of segments (2) may be positioned relatively [for example, on either side of the one segment (2a) and subsequently adjacent thereto] around the perimeter of the central core element (1). This way each of the plurality of segments (2) may be assembled within the tube (200) and on the central core element (1).

Referring now to FIGs 3A-3D, which illustrates a schematic diagram of the apparatus (300), where the apparatus includes a first support member (301), a second support member (302) and a punch (303). The first support member (301) may be installed on a rigid platform [for example, the ground] where the apparatus may be mounted and, the second support member (302) may be selectively operable to be positioned proximal and/or distal from the first support member (301). Further, the central core element (1) may be longitudinally suspended [for example, connected or held] from the first support member (301) at one end, while the tube (200) may be inserted and secured [for example, by virtue of gravity and self-weight] about perimeter of the central core element (1) about the other end, as best seen in FIG. 3 A. Also, the second support member (302) may be operable by an operation element including, but not limited to, a hydraulic operation element, a pneumatic operation element, an electric operation element, a gear arrangement element, and the like, to displace [that is, vertically move] the second support member (302) for rigidly gripping the tube (200) and centrally [for example, concentrically or symmetrically] aligning the tube (200) about the central core element (1), defining a predetermined gap therebetween. In an embodiment, the second support member

(302) may be driven by the operational element to provide necessary force for firmly gripping the tube (200) about the central core element (1). In an embodiment, degree of alignment of the tube (200) about the central core element ( 1 ) may be configured vary thickening of the brim portion (202) of the tube (200), at its inner surface (201).

Turning now to FIG. 3B, upon aligning the tube (200) about the central core element (1), predetermined gap defined between the tube (200) and the central core element (1) may substantially be equal to thickness of the plurality of segments (2). Further, one segment (2a) of the plurality of segments (2) may be disposable between the inner surface (201) of the tube (200) and central core element (1). In the illustrative embodiment, the one segment (2a) of the plurality of segments (2) may be positioned at top section and at the center in the predetermined gap between the tube (200) and the central core element (1). Further, the remaining segments (2b) of the plurality of segments (2) may be positioned around the perimeter of the central core element (1), as best seen in FIG. 3C. Upon positioning and aligning the plurality of segments (2) and the tube (200) relative to the central core element (1), the tube (200) may be co-axially [also referred to as lateral direction] engaged by the punch (303) from either ends. The punch

(303) may be aligned such that, an outer edge of the punch (303) may be in-line [that is, having minimal tolerance therebetween] with an outer surface of the tube (200) in order to mitigate action of shear force at portions of the tube (200). Also, dimension of the punch (303) may be greater than thickness of the tube (200), in order to enhance deformation of the tube (200) at the brim portion (202) and mitigate piercing of the tube (200). In continuation, the punch (303) may be configured to exert pressure [for example, compressive pressure] about the brim portion (202) [or at lateral surface or perimeter] of the tube (200) to axially deform [or press] the tube (200) about its inner surface (201). The second support member (302) may restrict upward movement [or flow of the material] of the tube (200), whereby restricting deformation to the inner surface (201) of the tube (200) and maintaining external dimensions of the tube (200). The prolonged application of pressure by the punch (303) at the brim portion (202) on the inner surface (201) of the tube (200) may be complemented by an outward force imparted by the plurality of segments (2), as best seen in FIG.3D. Due to the combined pressure applied by the punch (303) and the plurality of segments (2), the brim portion (202) may be thickened about the inner surface (201) of the tube (200), where the thickening may resemble the profde defined on the outer surface of the plurality of segments (2), as best seen in FIG.2.

Additionally, thickness at the brim portion (202) of the tube (200) increases after the plastic deformation, as it takes the shape of the plurality of segments (2), as best seen in FIG. 4. Due to such increase in thickness at the inner surface (201) of the tube (200), the mandrel assembly (100) having the central core element (1) and the plurality of segments (2) within the tube (200) may get rigid, whereby the plurality of segments (2) may not be retrievable from inside of the tube (200). For retrieving the plurality of segments (2) from the tube (200), interface between the central core element (1) and the plurality of segments (2) may be defined to be a slideable such that, the central core element (1) may be displaced from such interface. The central core element (1) may be axially displaced [for example, pulled or pushed along the longitudinal axis of the tube (200)] by either operating the first support member (301) to extrude the central core element (1) from inside of the tube (200) or by employing a pull mechanism to draw out the central core element (1) from inside of the tube (200). The central core element (1) includes a provision such as, but not limited to, a recess, protuberance, protrusion, and the like, which may enable the central core element (1) to be axially retrieved from the plurality of segments (2) and the tube (200). The central core element (1) which may be surrounded by the plurality of segments (2) and the tube (200), from interior to exterior, respectively, may loosen rigidity of the assembly (100), upon retracting [or displacing]. Further, retraction of the central core element (1) may result in collapse of the one segment (2a) of the plurality of segments (2) due to gravity [or self-weight] . As the one segment (2a) of the plurality of segments (2) collapses, connection between the remaining segments (2b) of the plurality of segments (2) within the tube (200) may be fragile and may be individually retrieved from inside of the tube (200), as seen in FIG. 5.

In an embodiment, the punch (303) may be simultaneously from either ends of the tube (200) and may be driven by an external actuation source [not shown in figures], where the external actuation source may be driven by mechanisms such as, but not limited to, hydraulic mechanism, pneumatic mechanism, electrical means, and the like. Further, the pressure exerted by the punch (303) may plastically deform the brim portion (202) about internal surface of the tube (200) at its either ends.

The assembly (100) can simultaneously thicken the inner surface (201) of the brim portion (202) on both the ends of the tube (200), this ensures lower cycle time which improves the productivity in manufacturing plant. Further, the process has low operation cost over the conventional device due use of less tonnage equipment. Also, the tubes undergo strain hardening during the process, facilitating in increase in strength of the tube (200).

Equivalents

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, 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 description 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 particular 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, 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."

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 in the description.

Referral Numerals: