The present invention relates generally to joint welding, and more particularly to a tube joint structure and weld pattern with increased weld area and strength.
Welds are commonly used to join metallic structures. The strength of a weld joint is ordinarily a function of weld area and the materials used. In many applications, weld joints are the weakest parts of a structure. Support structures, for example, are typically designed for particular load requirements, and are often formed at least in part from rigid metallic posts, rods, and/or tubes joined together at weld joints. Although load requirements can place demands on all components of a support structure (e.g. weight support, vibration tolerance, stress tolerance, etc.), weld strength in particular is often the critical factor in determining the overall strength and integrity of a structure. Where load requirements demand higher overall structural strength, weld joints may need to be strengthened. Because welding is only possible at the interface of joined components, strengthening a weld by adding more depth of weld material has sharply diminishing returns. A degree of improvement to weld strength is often possible by using advanced materials, at additional cost.
In one embodiment, the present invention is directed toward a joint weld comprising a rod and a hollow tube. The rod has a cylindrical first end, and the hollow tube has a second end situated coaxially about a first axial length of the cylindrical first end. A plurality of circumferentially distributed scallops in the second end extend axially to at most a second axial length less than the first axial length to form an end pattern with varying axial extent as a function of circumferential position. The joint includes a weld along a perimeter of the end pattern, between the hollow tube and the rod.
In another embodiment, the present invention is directed toward a support strut comprising a welded-together strut head and strut body. The strut head has a cylindrical section with a rod radius. The strut body has a tubular portion with an inner radius slightly greater than the rod radius, in an assembled state. The tubular portion has a plurality of axially extending, circumferentially distributed scallops that define an end pattern with varying axial extent as a function of circumferential position. The weld between the strut head and body follows the end pattern.
In still another embodiment, the present invention is directed toward a method for joining a rod to a hollow tube. First, a plurality of circumferentially distributed, axially extending scallops are formed at an end of the hollow tube. A first length of the rod is inserted coaxially into the first end of the hollow tube, and the rod is welded to the hollow tube along a perimeter of the end of the hollow tube.
While the above-identified figures set forth one or more embodiments of the present disclosure, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale, and applications and embodiments of the present invention may include features and components not specifically shown in the drawings.
Embodiments of the present invention relate to a weld joint wherein a tubular section surrounds and is welded to a coaxially inner tube or cylinder. The tubular section has an end pattern with scallops and/or crenellations that lengthen the perimeter of the tubular section, and correspondingly increase the weld area available at the interface of the tubular section and the tube or cylinder.
Support frame 16 is a bracing and/or mounting assembly such as a permanent installation frame or a transportation frame for gas turbine engine 12. Support structure 14 supports gas turbine engine 12 via a plurality of structural connections through support struts 18, 20, and 22. Support struts 18, 20, and 22 can, for example, be rods, tubes, and/or posts attached to support frame 16 and casing 24 of gas turbine engine 12 via fixed or flexible joints. In the illustrated embodiment, support strut 18 is formed of at least two pieces joined by a weld, as described in greater detail below with respect to
In the illustrated embodiment, support strut 18 is an elongated support member configured to mate with trunnion 26, thereby securing support strut 18 to casing 24. More generally, however, embodiments of the disclosure can be used with any strut or element with a tubular section joined to a radially inner tube or cylinder by a weld.
As shown in
Strut body 112 is a post or tube having at least a tubular or hollow length at tubular region 114 configured to surround cylindrical section 104. In some embodiments strut body 112 can be a metallic tube or cylinder. In other embodiments, strut body 112 can be a solid rod that is hollow only in tubular region 114. Tubular region 114 is an axially terminal region of strut body 112 configured to mate with cylindrical section 104 of strut head 100. The terminal axial extent of tubular region 114 is defined by tube edge 120. In the depicted embodiment, tubular region 114 has an end pattern comprising a plurality of scallops 116 extending a scallop length LS (see
Support strut 18 is formed by joining strut head 100 to strut body 112. Cylindrical section 104 of strut head 100 has a radius close to but less than an inner radius of strut body 112 in tubular region 114, during installation. In some cases, however, tubular region 114 can have an inner radius less than or equal to the radius of cylindrical section 104 at a normal operating temperature. In such cases, in order to provide an interference fit, strut body 112 is heated to provide sufficient thermal expansion to allow cylindrical section 104 to fit within strut body 112 during installation. After installation, in either embodiment, the radius of cylindrical section 104 and the inner radius of tubular region 114 are both approximately equal to a weld radius RW, discussed hereinafter with respect to
During assembly, an installation length LI of cylindrical section 104 is inserted within strut body 112. Strut head 100 is then joined to strut body 112 via a weld along a perimeter of tubular region 114, and following the end pattern of tube edge 120 created by scallops 116, as described below with respect to
The following are non-exclusive descriptions of possible embodiments of the present invention.
A weld joint comprising: a rod with a cylindrical first end; a hollow tube with a second end situated coaxially about a first axial length of the cylindrical first end; a plurality of circumferentially distributed scallops in the second end, extending axially to at most a second axial length less than the first axial length to form an end pattern with varying axial extent as a function of circumferential position; and a weld along the perimeter of the end pattern between the hollow tube and the rod.
The weld joint of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:
A further embodiment of the foregoing weld joint, wherein the end pattern is a crenellated pattern, and the circumferentially distributed scallops are axially-extending slots. A further embodiment of the foregoing weld joint, wherein the crenellated pattern includes at least four grooves defining four crenellations.
A further embodiment of the foregoing weld joint, wherein the weld has a weld width, and each of the axially-extending slots has a circumferential slot width at least twice the weld width.
A further embodiment of the foregoing weld joint, wherein the end pattern is an arced pattern or sinusoidal pattern.
A further embodiment of the foregoing weld joint, wherein the weld has a weld length at least 1.5 times a circumference of the hollow tube.
A support strut comprising: a strut head with a cylindrical section having a rod radius; a strut body with a tubular portion with an inner radius slightly greater than the rod radius in an assembled state, the tubular portion having a plurality of axially extending, circumferentially distributed scallops that define an end pattern with varying axial extent as a function of circumferential position; a weld between the strut head and the strut body, following the end pattern of the strut body.
The support strut of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:
A further embodiment of the foregoing support strut, wherein the strut head includes an attachment section configured to allow connection to an adjacent piece.
A further embodiment of the foregoing support strut, wherein the strut head further comprises a ball bushing.
A further embodiment of the foregoing support strut, wherein the strut head tapers from the cylindrical section to the attachment section.
A further embodiment of the foregoing support strut, wherein end pattern is a crenellated pattern
A further embodiment of the foregoing support strut, wherein the strut body is a hollow cylindrical tube.
A further embodiment of the foregoing support strut, wherein the circumferentially distributed scallops have at most a first axial length, and further wherein the strut head extends into the strut body a second axial length greater than the first axial length.
A method for joining a rod to a hollow tube, the method comprising: forming a plurality of circumferentially distributed, axially extending scallops at an end of the hollow tube; inserting a first length of the rod coaxially into the first end of the hollow tube; welding the rod to the hollow tube along a perimeter of the end of the hollow tube.
The method of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:
A further embodiment of the foregoing method, wherein each of the plurality of circumferentially distributed scallops has at most a second axial length less than the first axial length.
A further embodiment of the foregoing method, wherein forming the scallops comprises forming axially-extending grooves that define crenellations in the first end of the hollow tube.
A further embodiment of the foregoing method, wherein welding the tube comprises depositing a weld with a thickness no greater than half a width of the grooves.
A further embodiment of the foregoing method, wherein forming the scallops comprises forming an arced pattern or sinusoidal pattern at the first end of the hollow tube.
A further embodiment of the foregoing method, wherein forming the plurality of scallops comprises machining away material from the hollow tube.
A further embodiment of the foregoing method, wherein forming the plurality of scallops comprises casting the hollow tube with a scalloped contour at the end of the hollow tube.
Any relative terms or terms of degree used herein, such as “substantially”, “essentially”, “generally”, “approximately” and the like, should be interpreted in accordance with and subject to any applicable definitions or limits expressly stated herein. In all instances, any relative terms or terms of degree used herein should be interpreted to broadly encompass any relevant disclosed embodiments as well as such ranges or variations as would be understood by a person of ordinary skill in the art in view of the entirety of the present disclosure, such as to encompass ordinary manufacturing tolerance variations, incidental alignment variations, alignment or shape variations induced by thermal, rotational or vibrational operational conditions, and the like.
While the invention has been described with reference to an exemplary embodiment(s), 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 invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.