RU2253548C1 - Adaptable milling cutter - Google Patents

Abstract

FIELD: manufacturing processes in machine engineering, working surface of rolling of railway road transport wheel pairs.

SUBSTANCE: milling cutter includes body with radial grooves for mounting cutters engaging with damping member and having cutting tips of hard alloy secured to them. In order to enlarge manufacturing possibilities, radial grooves of body are trapezoidal ones; surfaces of grooves are lined with bronze porous self-lubricating plates that serve as sliding bearings. Said plates, except one lateral plate, are plane-parallel and they are fixed to body of milling cutter. Said lateral plate is in the form of movable wedge and it is designed for regulating gap between it and cutter by means of screw engaging with threaded opening whose axis passes in plane of touching of wedge lateral plate with body. Half of said threaded opening is drilled in plate and its other half is drilled in body; thread is cut only in opening half drilled in body. Cutting tips are circular ones and they are mechanically secured to cutters. Cutters may have trapezoidal contour reciprocal to contour of radial grooves of body; they are mounted by sliding fit and hold in body at one end by means of cover and at other end - by means of washer like corrugated spring and second cover. Both covers are secured to body by means of screws.

EFFECT: improved design of milling cutter.

3 cl, 7 dwg

Description

The invention relates to metalworking, to mechanical engineering technology, in particular to the designs of metal-cutting tools, and can be used in the design and manufacture of mills, for example, for processing the profile of the rolling surface of wheelsets of railway vehicles.

Known adaptive milling cutter containing a housing, in the radial grooves of which are placed with fixed cutting plates made of hard alloy cutters that interact with the damping element [1].

The disadvantages of the known milling cutter are the limited technological capabilities, since the milling cutter does not allow machining surfaces of complex shape, which are obtained on CNC machines or using a copier, as well as the complexity of the design, assembly and adjustment - all this makes the milling process expensive and inefficient.

Known prefabricated mill containing a housing with cutters, damping elements made in the form of thin-walled bushings, and an intermediate disk [2].

The disadvantages of the known milling cutter are the limited technological capabilities, since the milling cutter is intended only for machining planes and does not allow machining bodies of revolution and surfaces of complex shape that are obtained on CNC machines or using a copier, as well as the complexity of the design, assembly and adjustment - all this The milling process is expensive and inefficient.

The objective of the invention is the expansion of technological capabilities for processing bodies of revolution and surfaces of complex shape using CNC machines, copiers, etc., as well as simplifying the design, assembly and tuning, improving productivity, processing quality and tool life by ensuring a smooth cutting process and converting the kinetic energy of the impact into the potential energy of the bending of the elastic plate.

The problem is solved with the help of the proposed adaptive milling cutter containing a housing, in the radial grooves of which are placed cutters interacting with the damping element fixed to them by hard alloy cutting plates, the radial grooves of the housing being trapezoidal in shape, the groove surfaces are lined with bronze porous self-lubricating plates that perform the functions of sliding bearings, while the plates, except for one side, are made plane-parallel and fixed to the housing It is important that the said side plate is movable in the form of a wedge and is designed to regulate the gap between it and the cutter with a screw screwed into a threaded hole, the axis of which passes along the plane of contact of the side plate in the form of a wedge with a body and half is drilled into the plate, and the other half - in the case, while the thread is cut only in the case half of the hole, the cutting inserts are made round, and their fastening to the cutters - mechanical.

In addition, the cutters are made in a trapezoidal shape, in the reciprocal form of the radial grooves of the housing, installed in them along a sliding fit and held in the housing from one end by a cover, and from the other by a washer-shaped corrugated spring and a second cover, while the covers are attached to the housing by screws.

In this case, the milling cutter is designed for surface treatment of rolling wheelsets of railway vehicles.

The essence of the design of the cutter is illustrated by drawings.

Figure 1 shows the proposed mill, a view from the spring-loaded end; figure 2 - a view of figure 1, rotated; figure 3 is a section bB in figure 1; figure 4 is a cross-section bb in figure 1; figure 5 is a diagram of the acting forces; figure 6 - washer-shaped corrugated spring, front view; Fig.7 - washer-shaped corrugated spring, end view.

The adaptive milling cutter comprises a housing 1 with cutters 2 with mechanical fastening of hard alloy cutting round plates 3 and a damping element 4. The housing 1 has radial trapezoidal grooves 5 extending to the axis of rotation, the surfaces of which are lined with bronze porous self-lubricating plates 6, 7 and 8, which perform function of plain bearings.

Plane-parallel plates 6 and 7 are fixed (by known methods, for example, glued or with screws) on the housing motionless. The side plate 8 is made in the form of a wedge with an angle α, is movable and serves to regulate the gaps between the cutters 2 and the plates 6, 7 and 8.

Clearance adjustment is carried out using a screw 9 screwed into a threaded hole, the axis of which passes along the plane of contact of the wedge-shaped plate 8 with the body 1 at an angle α to the axis of rotation and half drilled in the plate 8, and the other half in the body 1, while the thread is cut only in the body half of the hole. Half of the drilled hole in the plate 8 is blind, the threaded half of the hole in the housing 1 is through. When adjusting the screw 9 abuts against the end face of the blind hole of the plate 8 and makes it move in the longitudinal direction.

Cutters 2 are made of a trapezoidal shape, the reciprocal form of the grooves 5, made in the housing. The cutters 2 are installed in the housing I on the plates 6, 7 and 8 along a sliding fit and are held in it by covers 10 and 11.

From one end, the cover 10 is directly attached to the housing 1 by screws 12, and from the other end, the cover 11 through the washer-shaped corrugated spring 4 is also attached to the housing 1 by screws 12. In this case, the protrusions of the corrugations of the spring 4 must contact the cutters 2.

The proposed prefabricated cutter allows self-adaptation to heterogeneity of the processed material, to fluctuations in the allowance and other thermomechanical damage and to reduce impact loads on the teeth of the tool during processing, which will increase the durability of the cutting elements.

An additional degree of freedom allows the tooth under the action of the cutting force P _{x to} move along the guide plates in the axial direction, in contact with the elastic element and overcoming its resistance. After coming out of contact with the workpiece, the elastic element returns the tooth to its original position. In order to improve the reliability of the design, one side guide plate is made wedge-shaped and movable, which allows you to select and adjust the technological gaps.

The mill shown in figures 1-7, is intended for processing the profile of the surface of the rolling wheelsets of railway vehicles. However, this design can be effectively used for milling any surfaces of various workpieces.

For machining, when restoring the profile of the rolling surface of railway wheelsets, a different cutting tool is used, for which replaceable plates of different shape and composition are used for the cutting part. The main obstacle to the effective use of the tool is the thermomechanical damage to the wheel rim that occurs during operation [3].

The preload of the elastic element 4 is provided by screws 12.

When the cutter rotates at a constant speed, at the time of cutting the tooth into the part at a place of increased hardness, the axial displacement of the cutting tooth occurs due to the bending of the elastic spring corrugation and a decrease in the width of the chip removed. This ensures a smooth embedding process and the transition of the kinetic energy of the impact into the potential energy of the bending of the elastic spring.

After the tooth comes out of contact with the workpiece, the previously deformed elastic element comes to its original state, returning the tooth to its original position.

Due to the presence of elastic tooth supports and its axial displacement due to the bending of the elastic corrugated spring, a smoothly intermittent entry and exit of the cutter teeth from contact with thermomechanical damage to the processed surface is ensured.

The rolling surface of the wheelset of the railway transport with thermomechanical damages was processed, the diameter of the wheel blank was 1009 mm, the diameter of the finished parts after processing was 995 mm, the processing was carried out in one pass, so the milling depth was 7 mm. Induction annealing was carried out before mechanical treatment of the rolling surface; the average hardness in the rolling circle after heat treatment was 289 HB. The wheel is made of grade 2 steel in accordance with GOST 10791-89 steel chemical composition: C - 0.60%; Mn - 0.78%; Si - 0.31%; P - 0.03%; S - 0.03%; the rest is iron. Machining modes: rotation speed of the wheel blank - V _s = 5 m / min (n _s = 1.6 min ^-1 ); cutter rotation speed - V _and = 342 m / min (n _and = 320 min ^-1 ); feed per revolution - S _o = 2.7 mm / rev. The mill of the proposed design had the number of teeth z = 10; outer diameter - 340 mm; cup plates RPUX2710MO of T14K8 hard alloy. Processing was carried out on a modernized wheel-turning lathe machine mod. KZh 1836 (manufactured at Kramatorsk KZTS).

Tests established that, with the same performance, the resistance of the proposed tool increased by 2.1 ... 2.5 times.

Sources of information

1 A.S. 806293 USSR, MKI 5 V 23 C 5/06. 1981 - prototype.

2 A.S. 1569105 USSR, MKI 5 V 23 C 5/06. Team cutter. V.I. Petrov and others. Application No. 4340167 / 31-08, head. 12/07/88, publ. 06/07 90. Bull. No. 21.

3 Bogdanov A.F. et al. Restoring the profile of the surface of rolling wheelsets: Textbook / A.F. Bogdanov, I.A. Ivanov, M. Sitage. - SPb .: PGUPS, 2000, p. 44.

Claims (3)

1. Adaptable milling cutter containing a housing, in the radial grooves of which are placed with hard alloy cutting plates mounted on them, cutters interacting with a damping element, characterized in that the radial grooves of the housing are trapezoidal, the groove surfaces are lined with bronze porous self-lubricating plates that perform the functions bearings, while the plates, except for one side, are made plane-parallel and fixed to the housing motionless, and the said side plate in It is made movable in the form of a wedge and is designed to regulate the gap between it and the cutter with a screw screwed into a threaded hole, the axis of which passes along the plane of contact of the side plate in the form of a wedge with a body and half is drilled in the plate, and the other half is drilled in the body, this thread is cut only in the body half of the hole, the cutting inserts are made round, and their fastening to the cutters - mechanical. 2. The milling cutter according to claim 1, characterized in that the cutters are trapezoidal, in the reciprocal form of the radial grooves of the housing, mounted in a sliding fit and held in the housing from one end by a cover, and from the other by a washer-shaped corrugated spring and a second cover, This cover is attached to the housing with screws. 3. The mill according to claim 1 or 2, characterized in that it is intended for surface treatment of the rolling wheelset of railway vehicles.

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