GB1585982A

GB1585982A - Railcar axle

Info

Publication number: GB1585982A
Application number: GB1466678A
Authority: GB
Original assignee: Hawker Siddeley Canada Inc
Current assignee: Hawker Siddeley Canada Inc
Priority date: 1978-02-27
Filing date: 1978-04-13
Publication date: 1981-03-11

Description

(54) RAILCAR AXLE (71) We. HAWKER SIDDELEY CANADA LIMITED, a company organized under the laws of Canada, of 7 King Street East, Toronto. Ontario. Canada. do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed.

to be particularly described in and by the following statement: This invention relates to railroad car axles. and more particularly to hollow railroad car axles.

United States Patent No. 2.569.248.

issued September 25. 1951 to George L.

Miller, discusses in detail the disadvantages of conventional solid steel railroad car axles and also of the hollow axles which had been proposed to overcome the disadvantages of solid axles, Miller himself describes further forms of hollow axle said to overcome these problems. These latter axles mostly comprise two hollow forgings which are welded together end-to-end to form the axle.

although there is shown in Figure S. but not described in detail. an axle in which the two hollow forgings are joined bv a hollow tubular member. We are not aware of any commercial exploitation of the Miller axles.

and we believe the reason may be the necessitv for using forging containing deep and accurately formed cavities. together with the imponderable effect of the hollow core of the axle on such matters as wheel security. It is suggested that the hollow wheel seat will in fact improve wheel secur ity. but this would be difficult to establish without extensive trials whilst existing axles are alreadv satisfactory in this respect.

The principal object of the present invention is to provide the acknowledged advantages of a hollow axle in an axle structure which conforms as far as possible to tried and tested design features without introducing new possible points of weakness at highly stressed location. which is cheap to make and which achieves a substantial weight saving as compared with a conventional axle. and which required a minimum of special tooling and machinery for its construction.

According to the invention. a railcar axle comprises solid forged stub shaft portions each defining an axlebox journal at its outer end. a wheel seating of larger diameter than and inward of the journal. and a cup shaped facing flange at its inner end of larger diameter than the seating. the journal, seating and flange being spaced from one another. and a tubular cylindrical middle portion of the same diameter as the flanges of the stub axles and friction welded at its ends to the peripheries of said flanges so as to provide a closed chamber within the axle which ends axially inward of the wheel seatings.With this arrangement. the end portions of the axle incorporating the journals. the wheel seatings and the transitions adjacent thereto can be of entirely conventional design. thus avoiding the possibility of introducing any new cause of failure in these regions. whilst the strength improvement and most of the weight-saving characteristic of a hollow axle is still retained. Moreover, since the tubular central portion is quite lightly stressed. it mav be formed simply of a length of mass produced mild steel tubing of suitable diameter and wall thickness.

The friction welds joifliag the stub shaft portions and the middle portion may be produced by a friction welding process of either the continuous or inertia type. Friction welding has the advantages. in this application. of producing welds which are highlv uniform around their periphery.

which will reliably join dissimilar metals.

and which ensure a high degree of concen trinity of the welded parts. The invention thus extends to a method of forming a railcar axle which comprises forging solid stub shaft portions each defining an axlebox journal at an outer end, a wheel seating of larger diameter than and inward of the journal,and a cup shaped flange of larger diameter than the seating at the inner end of the flange, concentrically aligning each said stub shaft portion with its flange adjacent one end of a cylindrical tube of the same diameter as the flange, and relatively rotating each said stub shaft portion and said tube in circumferential frictional contact with one another so as to expend sufficient energy frictionally to weld together said flange of said shaft portion and said tube.

In order that the invention may be more readily understood, reference will now be made to the accompanying drawing in which the single figure shows a longitudinal view of an axle embodying the invention, partly in section.

The axle shown in the drawng comprises stub shaft portions 2 and a tubular cylindrical central portion 4. The portions are united by circumferential welds 6.

The stub shaft portions are solid forgings.

and except for the cup shaped flange 8 at the inner end of each forging. are designed in accordance with conventional configurations and metallurgical practice for the outer portions of railcar axles: thev incorporate conventional axlebox journals 10 and wheel seatings 12, as well as conventional transitions 14 spacing the journals 10 and seatings 12, and conventional transitions 16 between the seatings 12 and the central portion of the shaft. The onlv difference from conventional practice is the forging of the flange 8 at the inner end of the shaft portion in place of an integrally forged central portion connecting the two stub shaft portions. In accordance with usual practice. the seatings 12 are larger in diameter than the journals 10. and the flanges 8 are in turn larger in diameter than the seatings 12.Both the inner and outer surfaces of the flange 8 are smoothly curved so as to avoid excessive stress concentrations.

Because of its relatively large diameter.

the central portion 4 is quite iightly stressed.

and it is found that the solid forged central portion of a conventional axle. which would typically have a minimum diameter of 7.5 inches for a 100 ton freight car. may be replaced bv a mild steel tube of 12.75 inches diameter and 0.5 inch thickness. the flanges 8 being of course of the same diameter as the pipe. The resultant axle is not onlv stronger. but also substantially lighter.

approximate weights being 1124 lbs. for the conventional axle and 833 Ibs. for the axle embodying the invention. This represents a weight saving of 1164 Ibs. for a complete freight car. and it is to be noted that this reduction is particularly advantageous because it is entirely in the unsprung weight of the car. The weight saving is moreover achieved without the necessity for any critical portion of the axle structure being made hollow, or needing to be of unconventional design, the hollow space enclosed by the axle ending well inwards of the wheel seatings.

The tube used for the central portion may be seamless or welded steel pipe such as is used for pipelines and is readily available.

The use of welded pipe is preferred, since it is cheaper and its wall thickness is more comsistent, thus permitting used of a thinner gauge.

The welds 6 are formed by friction welding. In this process, the parts to be joined are concentrically aligned, relatively rotated, and brought into frictional contact along the circumference of the weld zone. In continuous friction welding, rotational drive is applied to one workpiece whilst holding the other until sufficient heat is generated at the weld zone to fuse the parts together. In inertia friction welding, one part. together with a high inertia holder. is spun up to a high speed before drive is removed and the parts are brought together, the kinetic energy of the spinning part and its holder being sufficient to complete the weld.The advantage of the technique for the present application is the circumferential consistency of the weld and the high degree of concentricitv maintained between the parts, as well as its suitability for joining workpieces of different metallurgical properties.

After completion of each friction weld, any flash is trimmed off whilst still relatively soft. and the welds are then stress relieved in known manner to ensure a smooth transition in the properties of the metal through the welded joint.

WHAT WE CLAIM IS: 1. A railcar axle comprising solid forged stub shaft portions each defining an axlebox journal at its outer end. a wheel seating of larger diameter than and inward of the journal. and a cup shaped facing flange at its inner end of larger diameter than the seating. the journal. seating and flange being spaced from one another. a tubular cylindrical central portion of the same diameter as the flanges of the stub axles. and friction welds joining the ends of the central portion to the peripheries of said flanges so as to provide a closed chamber within the axle which ends axially inward of the wheel seatings.

2. A railcar axle according to claim 1.

wherein the central portion is a length of mild steel tubing.

A A railcar axle according to Claim 1 substantially as hereinbefore described with reference to the accompanying drawing.

4. A method of forming a railcar axle which comprises forging solid stub shaft portions each defining an axlebox journal at

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. journal at an outer end, a wheel seating of larger diameter than and inward of the journal,and a cup shaped flange of larger diameter than the seating at the inner end of the flange, concentrically aligning each said stub shaft portion with its flange adjacent one end of a cylindrical tube of the same diameter as the flange, and relatively rotating each said stub shaft portion and said tube in circumferential frictional contact with one another so as to expend sufficient energy frictionally to weld together said flange of said shaft portion and said tube. In order that the invention may be more readily understood, reference will now be made to the accompanying drawing in which the single figure shows a longitudinal view of an axle embodying the invention, partly in section. The axle shown in the drawng comprises stub shaft portions 2 and a tubular cylindrical central portion 4. The portions are united by circumferential welds 6. The stub shaft portions are solid forgings. and except for the cup shaped flange 8 at the inner end of each forging. are designed in accordance with conventional configurations and metallurgical practice for the outer portions of railcar axles: thev incorporate conventional axlebox journals 10 and wheel seatings 12, as well as conventional transitions 14 spacing the journals 10 and seatings 12, and conventional transitions 16 between the seatings 12 and the central portion of the shaft. The onlv difference from conventional practice is the forging of the flange 8 at the inner end of the shaft portion in place of an integrally forged central portion connecting the two stub shaft portions. In accordance with usual practice. the seatings 12 are larger in diameter than the journals 10. and the flanges 8 are in turn larger in diameter than the seatings 12.Both the inner and outer surfaces of the flange 8 are smoothly curved so as to avoid excessive stress concentrations. Because of its relatively large diameter. the central portion 4 is quite iightly stressed. and it is found that the solid forged central portion of a conventional axle. which would typically have a minimum diameter of 7.5 inches for a 100 ton freight car. may be replaced bv a mild steel tube of 12.75 inches diameter and 0.5 inch thickness. the flanges 8 being of course of the same diameter as the pipe. The resultant axle is not onlv stronger. but also substantially lighter. approximate weights being 1124 lbs. for the conventional axle and 833 Ibs. for the axle embodying the invention. This represents a weight saving of 1164 Ibs. for a complete freight car. and it is to be noted that this reduction is particularly advantageous because it is entirely in the unsprung weight of the car. The weight saving is moreover achieved without the necessity for any critical portion of the axle structure being made hollow, or needing to be of unconventional design, the hollow space enclosed by the axle ending well inwards of the wheel seatings. The tube used for the central portion may be seamless or welded steel pipe such as is used for pipelines and is readily available. The use of welded pipe is preferred, since it is cheaper and its wall thickness is more comsistent, thus permitting used of a thinner gauge. The welds 6 are formed by friction welding. In this process, the parts to be joined are concentrically aligned, relatively rotated, and brought into frictional contact along the circumference of the weld zone. In continuous friction welding, rotational drive is applied to one workpiece whilst holding the other until sufficient heat is generated at the weld zone to fuse the parts together. In inertia friction welding, one part. together with a high inertia holder. is spun up to a high speed before drive is removed and the parts are brought together, the kinetic energy of the spinning part and its holder being sufficient to complete the weld.The advantage of the technique for the present application is the circumferential consistency of the weld and the high degree of concentricitv maintained between the parts, as well as its suitability for joining workpieces of different metallurgical properties. After completion of each friction weld, any flash is trimmed off whilst still relatively soft. and the welds are then stress relieved in known manner to ensure a smooth transition in the properties of the metal through the welded joint. WHAT WE CLAIM IS:

1. A railcar axle comprising solid forged stub shaft portions each defining an axlebox journal at its outer end. a wheel seating of larger diameter than and inward of the journal. and a cup shaped facing flange at its inner end of larger diameter than the seating. the journal. seating and flange being spaced from one another. a tubular cylindrical central portion of the same diameter as the flanges of the stub axles. and friction welds joining the ends of the central portion to the peripheries of said flanges so as to provide a closed chamber within the axle which ends axially inward of the wheel seatings.

2. A railcar axle according to claim 1.

wherein the central portion is a length of mild steel tubing.

an outer end, a wheel seating of larger diameter than and inward of the journal, and a cup shaped flange of larger diameter than the seating at the inner end of the flange, concentrically aligning each said stub shaft portion with its flange adjacent one end of a cylindrical tube of the same diameter as the flange, and relatively rotating each said stub shaft portion and said tube in circumferential friction contact with one another so as to expend sufficient energy frictionally to weld together said flange of said shaft portion and said tube.

5. A method of forming a railcar axle according to claim 5, substantially as hereinbefore described with reference to the accompanying drawings.