Multi-cartridge cutting tool and railway wheel boring assembly

A multi-cartridge cutting tool includes a body with a plurality of cartridge-receiving pockets, and a plurality of insert-receiving cartridges mounted to a respective pocket. A round cutting insert is mounted to each cartridge. The pockets are formed at predetermined distances from a central, longitudinal axis of the body to form a first group and a second group of cutting inserts such that the cutting edges of the first group of cutting inserts and the cutting edges of the second group of cutting inserts are located at different axial and radial distances from the central, longitudinal axis of the body to perform different machining operations. The cutting tool may be used as part of a railway wheel boring assembly.

BACKGROUND OF THE INVENTION

Cutting tools with round cutting inserts, such as milling cutters, boring bars, and the like, may often manage a number of profiling operations from fine machining to rough machining. Usually, the round cutting inserts generate a fine surface at a particular feed rate because the round edge functions as a wiper. Currently, cutting tools include four round cutting inserts mounted onto the cutter body with two cutting inserts performing a rough cutting operation and the other two cutting insets performing a finish cutting operation. However, it has been observed with cutting tools having four round cutting inserts that the feed rates and the life of the cutting inserts are deficient for some machining applications and some particular materials to be machined. Thus, there is a need to provide a cutting tool that is capable of higher feed rates, while maximizing the life of the cutting insert.

BRIEF SUMMARY OF THE INVENTION

Briefly, according to an aspect of the invention, there is provided a multi-cartridge cutting tool comprising a body including at least five cartridge-receiving pockets, each cartridge-receiving pocket including a pair of side walls, a bottom wall and a back wall. The back wall of the cartridge-receiving pockets is located at a plurality of different radial distances, and the bottom wall of the cartridge-receiving pockets is located at a plurality of different axial distances. An insert-receiving cartridge is adapted to be mounted to a respective cartridge-receiving pocket. A cutting insert is adapted to be mounted to a respective insert-receiving cartridge, each cutting insert having a cutting edge, wherein a plurality of the cutting inserts are located at different axial and radial distances from a central, longitudinal axis of the body to perform a plurality of machining operations.

According to another aspect of the invention, there is provided a railway wheel boring assembly comprising a railway wheel support table, a plurality of wheel alignment holders supported by the railway wheel support table, and a multi-cartridge cutting tool. The multi-cartridge cutting tool comprises a body including at least five cartridge-receiving pockets, each cartridge-receiving pocket including a pair of side walls, a bottom wall and a back wall. The back wall of the cartridge-receiving pockets is located at a plurality of different radial distances, and the bottom wall of the cartridge-receiving pockets is located at a plurality of different axial distances. An insert-receiving cartridge is adapted to be mounted to a respective cartridge-receiving pocket. A cutting insert is adapted to be mounted to a respective insert-receiving cartridge, each cutting insert having a cutting edge, wherein the plurality of cutting inserts are located at different axial and radial distances from a central, longitudinal axis of the body to perform a plurality of machining operations.

According to yet another aspect of the invention, a method of removing material from a workpiece comprises the steps of:providing a multi-cartridge cutting tool with a body including at least five cartridge-receiving pockets, each cartridge-receiving pocket including a pair of side walls, a bottom wall and a back wall; the back wall of the cartridge-receiving pockets being located at a plurality of different radial distances, and the bottom wall of the cartridge-receiving pockets being located at a plurality of different axial distances; an insert-receiving cartridge adapted to be mounted to a respective cartridge-receiving pocket; and a cutting insert adapted to be mounted to a respective insert-receiving cartridge, each cutting insert having a cutting edge, a plurality of cutting inserts being located at different axial and radial distances from a central, longitudinal axis of the body to perform a plurality of machining operations; andmoving the cutting tool relative to the workpiece to perform the plurality of machining operations.

According to still yet another aspect of the invention, a method of boring a railway wheel hub comprises the steps of:providing a support table for supporting a railway wheel;providing a boring bar with a body including at least five cartridge-receiving pockets, each cartridge-receiving pocket including a pair of side walls, a bottom wall and a back wall; the back wall of the cartridge-receiving pockets being located at a plurality of different radial distances, and the bottom wall of the cartridge-receiving pockets being located at a plurality of different axial distances; an insert-receiving cartridge adapted to be mounted to a respective cartridge-receiving pocket; and a cutting insert adapted to be mounted to a respective insert-receiving cartridge, each cutting insert having a cutting edge, a plurality of cutting inserts being located at different axial and radial distances from a central, longitudinal axis of the body to perform a plurality of machining operations; andmoving the boring bar relative to the railway wheel to perform the plurality of machining operations, thereby boring the railway wheel.

DETAILED DESCRIPTION OF THE INVENTION

According to the principles of the invention, a cutting tool includes a body with an even number of cartridge-receiving pockets greater than four pockets, for example, six, eight, ten, twelve, and the like, proximate a cutting end of the body. It is possible that the cutting tool may have an odd number of pockets greater than four pockets, such as five, seven, nine, eleven, and the like. The pockets are spaced circumferentially equidistant with respect to each other. Each cartridge-receiving pocket including a pair of side walls, a bottom wall and a back wall. The back wall of the cartridge-receiving pockets is located at a plurality of different radial distances, and the bottom wall of the cartridge-receiving pockets is located at a plurality of different axial distances. An insert-receiving cartridge is adapted to be mounted to a respective cartridge-receiving pocket. A cutting insert is adapted to be mounted to a respective insert-receiving cartridge. A first group of cutting inserts comprises one-half of the cutting inserts adjacent to each other, and a second group of cutting inserts comprises the other one-half of the cutting inserts located diagonally opposite the first group. For cutting tools with an odd number of cutting inserts, a third group comprising a single cutting insert would be located between the first and second groups. The cutting edges of a first group and the second group are located at different axial and radial distances from a central, longitudinal axis of the body to perform different machining operations, such as a finish machining operation, semi-finish machining operation, semi-rough machining operation, rough machining operation, and the like. For cutting tools with an odd number of cutting inserts, the third group could perform the same machining operations as one of the cutting inserts of the first and second groups, or a different machining operation.

In an embodiment that is illustrated inFIGS. 1-5, the cutting tool10comprises a boring bar having a body12with eight cartridge-receiving pockets14that are equidistantly spaced at about forty-five (360/8=45) degrees with respect to each other and proximate a cutting end12aof the body12. Each cartridge-receiving pocket14includes a pair of opposing side walls14a,14b, a bottom wall14cand a back wall14d. As shown inFIG. 3, a longitudinal axis28of each pocket14is substantially parallel with a central, longitudinal axis18of the body12. A pair of threaded apertures16is formed so as to radially extend from the back wall14dof each pocket14toward the central, longitudinal axis18of the body12. In the illustrated embodiment, the threaded apertures16are aligned along the longitudinal axis28of the cartridge-receiving pocket14. A longitudinally-extending flute20is formed proximate to each cartridge-receiving pocket14to provide effective chip control. In the illustrated embodiment, each flute20has a concave-shaped or dish-shaped profile with respect to the outer surface of the body12. The body12includes a flange member22and a cylindrically-shaped motor connection23distal from the cutting end12afor mounting the cutting tool10to a drive motor, for example, a main motor section of a railway wheel boring assembly (FIG. 11). The flange member22includes a plurality of mounting bores24for enabling the cutting tool10to be mounted to the drive motor. In the illustrated embodiment, the cutting tool10has a total of ten mounting bores24. However, the invention is not limited by the number of mounting bores, and can be practiced with any desirable number of mounting bores that will be sufficient to mount the cutting tool10to the cutting machine.

As shown inFIG. 4, the back wall14dof four adjacent cartridge-receiving pockets14of the eight pockets14forming a first group is located from the central, longitudinal axis18of the body12by radial distances d1, d2, d3and d4, respectively. In the illustrated embodiment, the radial distance d1is larger than the radial distance d2, the radial distance d2is larger than the radial distance d3, and the radial distance d3is larger than the radial distance d4. The back wall14dof the other four adjacent cartridge-receiving pockets14forming a second group are also located at the four different radial distances d1, d2, d3and d4, respectively. As a result, the back wall14dof two cartridge-receiving pockets14in the first and second group located directly opposite each other are at approximately the same radial distance from the central, longitudinal axis18of the body12. It is noted that the side walls14aand14bof each pocket14have a different depth from the outer surface26of the body12because each cartridge-receiving pocket14is not radially aligned with the central, longitudinal axis18of the body12.

In addition to the back wall14dof the cartridge-receiving pockets14of the first group are located at four different radial distances d1, d2, d3and d4with respect to the central, longitudinal axis18of the body12, and the bottom wall14cof the cartridge-receiving pockets14of the first group are located at four different axial distances a1, a2, a3and a4from an end face22aof the flange member22of the body12. Specifically, the bottom wall14cof four adjacent cartridge-receiving pockets14in the first group are located at four different distances a1, a2, a3and a4with respect to an end face22aof the flange member22of the body12, as shown inFIG. 3. Similarly, the other four adjacent cartridge-receiving pockets14in the second group are also located at the four different axial distances a1, a2, a3and a4. As a result, the bottom wall14cof two cartridge-receiving pockets14of the first and second groups located directly opposite each other are at approximately the same axial distance from the end face22aof the flange member22of the body12.

Referring now toFIGS. 6-9, the cutting tool10also includes a plurality of insert-receiving cartridges30adapted to be received in the cartridge-receiving pockets14of the body12. In the illustrated embodiment, each cartridge30is substantially identical to each other. Each cartridge30is mounted to its respective pocket14by a pair of mounting screws33(FIG. 1) that are inserted through apertures34in the cartridge30and threadingly received in the threaded apertures16of the body12. In the illustrated embodiment, the apertures34are substantially aligned along the longitudinal axis28of the cartridge-receiving pocket14, similar to the threaded apertures16of the body12. Each cartridge30includes a pair of substantially parallel side walls30a,30b, a bottom wall30cand a back wall30d. When mounted in the cartridge-receiving pocket14of the body12, the side walls30a,30bof the cartridge30contact the side walls14a,14bof the pocket14, the bottom wall30cof the cartridge30contacts the bottom wall14cof the pocket14, and the back wall30dof the cartridge30contacts the back wall14dof the pocket to securely hold the cartridge30in place.

Each insert-receiving cartridge30includes an insert-receiving pocket36adapted to have a cutting insert38mounted thereto. As shown inFIG. 10, the cutting insert38is a conventional round cutting insert having an upper surface40that terminates in a circular cutting edge42, and a bottom surface44that engages a bottom wall36a(FIG. 7) of the pocket36when the insert38is mounted to the pocket36. The insert38also includes a frusto-conical side wall46interconnecting the upper surface40and the bottom surface44. A screw hole48(shown in phantom) is centrally disposed through the body of the insert38for receiving a threaded clamping screw50(FIG. 1). An optional shim52may be positioned between the bottom wall36aof the pocket36and the cutting insert38. In one embodiment, the cutting insert38provides a negative rake angle when mounted to the insert-receiving pocket36. However, the invention can be practiced with the cutting insert38having a positive rake angle when mounted to the insert-receiving pocket36. It will be appreciated that the invention is not limited by the shape of the cutting insert, and that the invention can be practiced with other desirable insert shapes, such as square, rectangular, triangular, and the like.

Referring now toFIG. 1, the four different radial distances d1, d2, d3and d4from the central, longitudinal axis18at which the back wall14dof the cartridge-receiving pockets14in each group are formed, and the four different axial distances a1, a2, a3and a4at which the bottom wall14cof the cartridge-receiving pockets14in each group are formed with respect to the end face22aof the body positions the cutting edge of each cutting insert38at a predetermined radial and axial location with respect to the central, longitudinal axis18of the body12when the insert-receiving cartridge30is mounted in the cartridge-receiving pocket14.

Specifically, the cutting edge42of the cutting inserts38mounted to two opposite cartridge-receiving pockets14at the axial distance a1and the radial distance d1in the first and second groups has the largest radial distance r1from each other for performing finish machining of the workpiece (not shown). The cutting edge42of the cutting inserts38mounted to two opposite cartridge-receiving pockets14at the axial distance a2and the radial distance d2in the first and second groups has the second largest radial distance r2from each other for performing semi-finish machining of the workpiece. The cutting edge42of the cutting inserts38mounted to two opposite cartridge-receiving pockets14at the axial distance a3and the radial distance d3in the first and second groups has the third largest radial distance r3from each other for performing semi-rough cutting of the workpiece. The cutting edge42of the cutting inserts38mounted to two opposite cartridge-receiving pockets14at the axial distance a4and the radial distance d4in the first and second groups has the smallest radial distance r4from each other for performing rough machining of the workpiece. As a result, the cutting tool10of the illustrated embodiment of the invention provides for two cutting edges42for performing finish machining, two cutting edges42for performing semi-finish machining, two cutting edges42for performing semi-rough machining, and two cutting edges42for performing rough machining.

In operation, the cutting tool10is moved relative to a workpiece (not shown). For example, the cutting tool10may move linearly along a central axis of the workpiece as the workpiece rotates, or the cutting tool10may rotate about the central, longitudinal axis18as the workpiece moves linearly along its central axis.

During the different machining operations, the workpiece presents a plurality of different surface conditions. One surface condition is a pre-machined surface prior to the commencement of any machining operation thereon. Other surface conditions include, but are not limited to, a roughened surface, a semi-roughened surface, a semi-finished surface, and a finished surface.

In one embodiment, the cutting tool10comprises a boring bar and the workpiece comprises a railway wheel70. The railway wheel70includes a central hub section72, a plate74that extends from the hub section72to a flange76and a tread78. The railway wheel70is typically comprised of cast steel, but could also be comprised of forged steel. The railway wheel60can have a diameter of about 28 inches to about 42 inches, and can weigh between about 400 lbs. and about 900 lbs.

Referring now toFIGS. 11 and 12, a railway wheel boring assembly is shown generally at60according to an embodiment of the invention. The railway wheel boring assembly60includes a main motor section62and the boring bar10that is capable of being mounted to the main motor section62. The boring bar10can be rotated relative to the railway wheel70, for example, the boring bar10can be rotated in a counterclockwise direction by the main motor section62. The railway wheel boring assembly60also includes a support table64for supporting the railway wheel70, as shown inFIG. 11. Support table ribs66and support alignment holders68are movably supported on the support table64. The support alignment holders68are moved inwardly to engage the tread78and center and securely hold the railway wheel70on the support table64during the machining operation.

The cutting tool10moves downwardly while being rotated by the main motor section62to bring the cutting inserts38into contact with the hub section72of the railway wheel70. The hub section72is bored by the cutting tool10such that an opening80is formed by the cutting tool10as the cutting tool10is lowered into and through the railway wheel70, thereby placing the cutting inserts38into contact with the entire length of the hub section72.

In the illustrated embodiment in the cutting tool10with eight cutting inserts28(two groups with four cutting inserts in each group), the first cutting insert to engage the surface of the railway wheel70is the cutting insert38mounted in the cartridge-receiving pocket14at the axial distance a4and the radial distance d4to perform the roughing machining of the railway wheel70. This cutting insert38removes material from the railway wheel70to a first specific depth based on the axial distance a4, which also results in that portion of the railway wheel70having the roughened surface with a specified surface roughness.

The next cutting insert38to engage the surface of the railway wheel70is the cutting insert38mounted in the cartridge-receiving pocket14at the axial distance a3and the radial distance d3and performs the semi-roughing machining of the railway wheel70. This cutting insert38removes material from the railway wheel70to a second specific depth based on the axial distance a3, which also results in that portion of the railway wheel70having the semi-roughened surface with a specified surface roughness.

The next cutting insert38to engage the surface of the railway wheel70is the cutting insert38mounted in the cartridge-receiving pocket14at the axial distance a2and the radial distance d2and performs the semi-finishing machining of the railway wheel70. This cutting insert38removes material from the railway wheel70to a third specific depth based on the axial distance a2, which also results in that portion of the railway wheel70having the semi-finished surface with a specified surface roughness.

The last cutting insert38to engage the surface of the railway wheel70is the cutting insert38mounted in the cartridge-receiving pocket14at the axial distance a1and the radial distance d1and performs the finishing machining of the railway wheel70. This cutting insert38removes material from the railway wheel70to a fourth specific depth based on the axial distance a1, which also results in that portion of the railway wheel70having the finished surface. The four cutting inserts38in the second group then engage the railway wheel70to produce a finished product that has a specified surface roughness and dimension.

Tests of the cutting tool10were conducted on the railway wheel70, and the cutting tool10provided unexpected results. Specifically, the cutting tool10using eight cutting inserts performed at faster feed rates and cut with less force as compared to a conventional cutting tool using four cutting inserts. In addition, the cutting tool10using eight cutting inserts demonstrated improved chip control and evacuation as compared to the convention cutting tool using four cutting inserts. Further, the life expectancy of the cutting inserts38of the cutting tool10was over ten times the life expectancy of cutting inserts used in a conventional cutting tool, such as a conventional boring bar with only four cutting inserts (two roughing and two finishing).

It will be appreciated that the principles of the invention can be applied to a cutting tool having a different number of insert-receiving cartridges. For example, the principles of the invention can be practiced with a cutting tool using a total of six insert-receiving cartridges, or more than eight insert-receiving cartridges.

It will also be appreciated that the cutting tool of the invention, in addition to the boring bar shown inFIG. 1, may also be a turning tool, and the like.

The documents, patents and patent applications referred to herein are hereby incorporated by reference.