Lubrication ring for a mechanical expander for sizing large pipes

Abstract

A lubrication ring for a mechanical expander (1) for sizing large pipes comprises a conventionally manufactured ring (12) made of steel, in particular construction steel. Fluid bores are provided in the ring (12). A part (13) of the lubrication ring (6) is manufactured by an additive manufacturing technology.

Claims

1. A mechanical expander (1) for sizing pipes, comprising: a wedge (2), the wedge (2) being movable relative to segments (4) that are pressed radially outward against an inside of the pipes during sizing; a draw bar (3) for moving the wedge (2), the draw bar (3) being connected to the wedge (2) by a nut (5); a washer (7) and a lubrication ring (6) stacked between the nut (5) and the wedge (2), wherein the lubrication ring (6) comprises a ring (12) made of solid steel; fluid bores provided in the ring; and an additive manufactured part (13) made of fused metal powder layers, wherein the ring (12) made of solid steel is arranged proximal to the wedge (2) and the additive manufactured part (13) is arranged proximal to the washer (7), and wherein the additive manufactured part (13) includes at least one enclosed lubricant channel which extends from a face proximal to the washer to the fluid bores in the ring (12).

2. The mechanical expander according to claim 1, wherein the additive manufactured part (13) consists of a high-strength steel.

3. The mechanical expander according to claim 1, wherein the lubrication ring is configured for a mechanical expander for sizing pipes having a diameter of 14 inches or less.

4. The mechanical expander according to claim 1, wherein the additive manufactured part (13) includes circumferential common rails (14) to guide a lubricant.

5. The mechanical expander according to claim 1, wherein the additive manufactured part (13) functions as a dual line distributor (11).

6. The mechanical expander according to claim 1, wherein the additive manufactured part (13) includes two lubricant channels which extend from the face proximal to the washer to the fluid bores in the ring (12), wherein each of the two lubricant channels has a single opening in the face proximal to the washer and is in fluid communication with one of two circumferential common rails (14).

7. A method for the manufacturing a lubrication ring of the mechanical expander as in claim 1, comprising the following steps: machining the ring (12) from solid steel; aligning and mounting of the ring (12) as a blank in a printer build space; applying metal powder layers and fusing the metal powder layers with the aid of a laser on the blank.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, a preferred exemplary embodiment of the lubrication ring is described and explained in more detail on the basis of the attached drawings.

(2) FIG. 1 shows a sectional view through a previously known expander with a lubrication ring in accordance with the invention.

(3) FIG. 2 shows a spatial view of a lubrication ring according to the prior art.

(4) FIG. 3 shows the lubrication ring from FIG. 2 in a partially cut open view with the indicated steps for drilling the bores.

(5) FIG. 4 shows a spatial view of the lubrication ring in accordance with the invention from FIG. 1 or the lubrication ring as a hybrid component, as the case may be.

DETAILED DESCRIPTION

(6) The expander 1 shown in FIG. 1 comprises a wedge 2, which can be moved relative to oppositely shaped segments 4 via a draw bar 3, such that the segments 4 are pressed radially outwards in order to deform or size a pipe (not shown) from the inside.

(7) The wedge 2 has lubrication channels (not shown) that transport the lubricant into the gap between the wedge 2 and the segments 4.

(8) The wedge 2 is connected to the draw bar by a nut 5. A washer 7 and then a lubricating ring 6 are arranged as a stack between the nut 5 in the pulling direction. The lubricant is fed from a supply journal 8 via external lines 9 to channels of the washer 7. The channels in the washer 7 are connected in axial direction to channels 10 of the lubrication ring 6. Dual line distributors 11 (not shown in FIG. 4), which are supplied for the control of the lubricant flow, are attached to the lubricating ring 6.

(9) FIG. 2 and FIG. 3 show a previously known lubrication ring manufactured in a conventional manner. FIG. 3 illustrates how fluid bores or lubrication channels were previously inserted into the lubrication ring 6 through bores.

(10) The previously known lubrication ring 6′ in accordance with FIG. 2 can be provided in the expander according to FIG. 1 as an alternative to the lubrication ring 6 in accordance with the invention according to FIG. 4, or the lubrication ring 6 in accordance with the invention can replace the conventional lubrication ring 6′, if necessary with the additional adaptation of the washer 7.

(11) The lubricating ring 6 in accordance with the invention according to FIG. 4 comprises a conventionally manufactured part 12 in the form of a ring, whose shape in this area largely corresponds to the corresponding part of the lubricating ring 6′ according to FIG. 2. A part 13 manufactured by additive manufacturing connects in the axial direction to the conventionally manufactured part 12. The additive manufactured part 13 is turned towards the washer 7 and rests against it. Thus, the lubrication ring 6 according to FIG. 4 is designed as a hybrid component. The conventionally manufactured part 12 is made of construction steel. The additive manufactured part 13 consists of high-strength steel.

(12) In the additive manufactured part 13, two circulating common rail lines 14 are provided for the distribution of the lubricant, among others to the dual line distributors 11.

(13) Additive manufacturing: Invention report—Lubrication ring as hybrid component

(14) In the manufacture of large pipes, they are sized for roundness and dimensional accuracy after internal and external seam welding with the aid of the mechanical expander 1. During each expansion process, a high surface pressure and thus friction between the surfaces of the segments and the wedge arises. The friction is reduced by a defined lubrication. In order to guide the lubricant to the appropriate points, the lubrication ring serves as a lubricant distributor and conductor.

(15) In particular with expander tools 1 for small pipe diameters (for example, 14″ and smaller), conventional manufacturing reaches its limits. The reason for this is the small installation space in the lubrication ring 6′, which makes positioning and manufacturing of the fluid bores more difficult.

(16) Additive manufacturing technology opens up new possibilities. However, the often filigree structures associated with additive manufacturing are difficult to apply, in particular in heavy mechanical engineering. This is because very rough operating conditions often prevail and high forces are required for plastic deformation, which leads to a solid construction of the components.

(17) The solid design was also taken into account in the product development process. The result is a new lubrication ring 6 with a hybrid design, combining the conventional with the additive manufactured design. The basis for the layer-by-layer application is a steel ring 12, in which the first bores for fluid transfer to the wedge 2 are already being produced by conventional means. The ring 12 is aligned and mounted in the printer build space. The ring is then assembled using additive manufacturing technology. With the compact arrangement of the fluid channels, the height to be applied only amounts to 70 mm. Compared to the original design, the maximum dimensions have been reduced by 10% in the outer diameter and by almost 30% in the total component height, which at the same time leads to a reduction in the size of the surrounding components. This is because, with the aid of additive manufacturing technology, channels 10, 14 can be manufactured completely independently of the contour of the production tools and can be designed very compactly in a small installation space.

(18) The novel design is characterized by the two circumferential common rails 14. These supply the individual channels to the dual line distributors 11, in which an exactly defined quantity of lubricant is then discharged. The lubricating oil supply for the two common rails 14 takes place via only two channels 10, which has a great advantage with regard to the number of necessary seals or the number of possible leakage points. This is because the number of leakage points is reduced by 17%. This also eliminates the need for special seals. Furthermore, the lubricant supply via only two channels 10 simplifies the design of the adjacent components, just like the conventionally manufactured washer. The design of the AM area is defined in such a manner that the effort required for subsequent post-processing is kept to a minimum. For this purpose, all angles in the printing direction are selected such that the need for support structures is eliminated. Reworking for the seat of the dual line distributor 11 is also kept as low as possible.

(19) The combination of conventional and additive methods is not only technically convincing, but also economically convincing, and will play an important role in heavy mechanical engineering in the future.

LIST OF REFERENCE SIGNS

(20) 1 Expander 2 Wedge 3 Draw bar 4 Segments 5 Nut 6 Lubrication ring 6′ Conventional lubrication ring 7 Washer 8 Supply journal 9 External lines 10 Channels of the lubrication ring 11 Dual line distributor 12 Conventionally manufactured part, ring made of steel 13 Part manufactured by additive manufacturing 14 Common rail lines