RU2734368C1 - Ultrasonic circular face-mill cutter - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metalworking, particularly, to tooth-processing tools, and is intended for vibrating ultrasonic cutting of evolvent high-precision gears and wheels, mainly medium and large modulus. Circular face-mill cutter includes body (1) with seats along the head body circumference and cutters (4). Circular face-mill cutter comprises located in each seat an acoustic system, which is piezoelectric transducer (2) connected to concentrator (3), made in form of waveguide, upper part of which on opposite side from converter is cutter (4) made integral with concentrator (3) or detachable, wherein cutters are made alternating on right-and-left and left-hand, wherein each converter is equipped with collector current collector (5) for connection to ultrasonic generator (6), length of each concentrator is from 1/4 λ up to 1/2 λ, where λ is ultrasonic vibration wave length.

EFFECT: increased accuracy and purity of gears and wheels processing.

4 cl, 6 dwg

Description

The invention relates to metalworking, namely to gear-working tools and is intended for vibration ultrasonic cutting of involute high-precision gears and wheels, mainly medium-modulus and large-modulus.

Cutting the teeth of wheels, gears is one of the most laborious processes in the creation of machines for widespread use. For the processing of teeth, 50-60% of the labor intensity of machining is spent. Machining includes gear hobbing, gear shaping, and finishing. Requirements for the quality and accuracy of processing the teeth of wheels and gears are growing, which leads to the development of new methods and devices.

A device for finishing turning and finishing the surfaces of parts with ultrasound is known, in which the end face of the emitter is made in the form of a working tip, and the device is equipped with a cutter for fine turning and a thrust rod designed to damp harmful vibrations arising during the processing of parts, while the cutter for finishing turning is located in front of the ultrasound emitter in the direction of their movement along the processed surface and fixed in the tide on the housing of the acoustic system, and the thrust bar, at the end of which, on the side of the processed surface, a replaceable contact element is fixed, is located behind the ultrasound emitter and fixed in the tide intended for fastening the acoustic system to the machine (see RF patent No. 2238839 according to class MPK B24B39 / 00, publ. 27.10.2004).

However, the device assumes a separate fastening of the acoustic system to the machine tool and is not intended for involute high-precision large-modulus and medium-modulus gears and wheels.

There is also known a device for ultrasonic processing of fine-modular gear wheels (see the abstract of the thesis for the degree of Doctor of Technical Sciences Agapov SI "Scientific substantiation and implementation of ultrasonic technologies in the production of precision fine-modular wheels" // http: // www1. vstu.ru/nauka/ dissertatsionnye-sovety / avtoreferat / 2015 / agapov-sergei-ivanovich.html). The device contains an acoustic system and a cutting tool fixed in the machine. The device ensures the interaction of the cutting edge of the tool with the workpiece under the conditions of ultrasonic action on the workpiece.

However, the device, like the previous analogue, assumes a separate fastening of the acoustic system to the machine and does not provide for the use of large-modulus and medium-modulus gears and wheels for processing.

Closest to the claimed one is a gear-cutting head (see RF patent No. 2217271 according to class IPC B23F21 / 00, publ. 27.11.2003), containing a body with round cutters installed in it by means of tool holders, each of which has a mechanism for adjusting the angle of inclination of the main cutting edges and a radial adjustment mechanism for determining the position of the cutting edges of circular cutters, having a wedge stop with an outer surface in the form of a truncated cone, installed coaxially with the body and made in the form of a sleeve.

However, the quality (precision and cleanliness) and cutting performance are low.

The technical problem lies in the development of the design of a gear-cutting head, which ensures the processing of medium-modulus and large-modulus gears and gears with simultaneous exposure to ultrasound.

The technical result consists in increasing the accuracy and cleanliness of processing by providing vibration cutting, as well as in increasing the productivity of the process by eliminating roughing and finishing.

The technical problem and the claimed result are achieved by the fact that the gear-cutting head, including a housing with seats around the circumference of the head body and cutters, according to the invention, contains an acoustic system located in each seat, which is a piezoelectric transducer connected to a concentrator made in the form of a waveguide , the upper part of which, on the side opposite to the transducer, is a cutter of resonance length, made integral with the concentrator or removable, and the cutters are made alternating to the right and left-handed, while each transducer is connected using a collector current collector to the ultrasonic generator, the length of each concentrator is from 1 / 4λ to 1 / 2λ, where λ is the wavelength of ultrasonic vibrations.

The cutter can be made removable in the form of a corner or in the form of a fork, one part of which performs the function of a right-hand cutting element, and the other - a left-hand cutting one, while the cutting elements are shifted relative to each other.

The cutter can be made in the form of a cutter waveguide segment divided by one or several slots into resonant working parts, shifted relative to each other along the radius of the circle, limited by the nominal diameter of the gear head and the module of the processed wheel (gears), some of which serve as right cutting cutters, and the following behind them - left-handed.

The invention is illustrated by drawings, where it is presented:

- in Fig. 1 is a schematic view of a gear cutting head, top view;

- in Fig. 2 is a cross-sectional view of a gear-cutting head;

- in Fig. 3, 4, 5, 6 - variants of acoustic systems with different shapes of incisors;

Positions in the drawings indicate:

1 - head body;

2 - piezoelectric transducer of the acoustic system (ultrasonic oscillatory system);

3 - speaker system concentrators;

4 - cutter;

5 - collector current collector;

6 - ultrasonic (US) generator;

7 - the bolt of fastening the gear-cutting head in the machine spindle;

8 –adjusting screw for precise setting of the position of the speaker system;

9 - bracket;

10 - emphasis;

11 - wedges.

Each acoustic system consists of an ultrasonic piezoelectric transducer 2 and a concentrator - a waveguide 3. The gear head contains a housing 1 with seats, in which piezoelectric transducers 2 of acoustic systems are rigidly fixed around the circumference in a precisely adjusted position using screws 8 and brackets 9. Concentrators of 3 acoustic systems protrude above the surface of the case at a distance from 1 / 4λ to 1 / 2λ, where λ is the wavelength of ultrasonic vibrations. The transducers 2 are connected to the ultrasonic generator 6 through the collector current collector 5, fixed on the back of the head strictly axisymmetrically to the case,

The upper part of the concentrator 3 (waveguide) is a cutter 4, which can be made integral with the concentrator or removable. The cutters are made left-handed and right-handed and are installed alternately in the body. The shift of the cutters relative to each other in opposite directions from the nominal diameter is ensured by means of stops 10 and wedges 11.

In the first case, the cutter 4 can be solid or with grooves dividing it into two or more parts. This improves the cutting ability of the head and stabilizes the cutting conditions. FIG. 3 shows a concentrator, the cutting part of which is made in the form of a knife with a groove made along the axis, dividing it into two working parts (two cutters), one of which plays the role of a right-hand cutter, and the other - a left-hand cutter.

FIG. 4 shows a hub, the cutting part of which includes three knife cutters formed by two slots.

If the cutter is removable, it can be angular or fork-shaped (Figs. 5, 6). The detachable part is rigidly attached to the hub using a stud bolt. This design allows to reduce the labor intensity in the manufacture of cutters, as well as improve maintenance.

The cutters, as well as their parts (Figs. 3, 4, 6), are displaced relative to each other by a distance determined by the design features of the gears or wheels being cut.

The gear head works as follows.

The ultrasonic gear-cutting head is fixed in the machine spindle with bolt 7. On the other spindle, the workpiece (gears, wheels) is fixed. According to the program, the controller turns on the ultrasonic generator 6, the actuators of the spindles with a set rotation speed and depth of cutters. There is a joint action of mechanical forces and pulsed ultrasonic forces of cutting the cutting edge of the cutter into the workpiece.

An ultrasonic gear cutting head is designed for cutting gear teeth or wheels with an average modulus S _b ~ 2-2.5 mm with a nominal diameter d _{n of the} heads from 160 mm to 250 mm. As the nominal diameter increases, the number of cutters increases. Depending on the magnitude of the module, the ultrasonic systems are selected with different powers from 70 W to 500 W, which can operate at a resonant operating frequency f _r 22 kHz, 38 kHz, 44 kHz and provide an amplitude of ultrasonic vibrations of 5-19 μm.

It is known that in the case of a separate attachment of the acoustic system to the machine, when cutting medium-modulus gears, ultrasonic devices with increased generated powers are required, which requires significant design changes, an increase in size and high costs.

In the claimed invention, this problem is solved. With an increase in the nominal diameter, the number of cutters increases, and the recommended linear-angular dimensions increase. This makes it possible to expand the technical and technological solutions for the development of various applied ultrasonic devices. It becomes possible to increase the acoustic power for each individual piezoelectric transducer of the acoustic system, to increase the resonant dimensions of the waveguide concentrators, to provide the required amplitude of ultrasonic vibrations at the end part of the concentrator-cutter. Consequently, the technical and technological possibilities of using standard gear cutting heads with a nominal diameter of more than 250 mm (315 mm, 400 mm, 500 mm) are expanding.

Example

A gear-cutting head with a nominal diameter of 160 mm and with six ultrasonic acoustic systems has the following parameters: operating resonance frequency 38 kHz, acoustic power ~ 100 W, ultrasonic amplitude 7 μm, cutting angle 10 °, penetration depth 0.1 mm, revolutions per minute 50, generator output power 1.0 kW, excitation voltage 200 V. Waveguide material - cutters: steel R6M5 GOST 19265-73.

A gear with a diameter of 240 mm made of steel 40X, with a module of 2.5 mm, with a tooth rim width of 18 mm, a helix angle of 35 °, a feed time of 17.6 seconds per tooth, was carried out on a universal gear cutting machine of the 5A27C4 type.

The proposed solution allows you to change the nature of the process of cutting teeth. With standard technology, the cutting process is forceful. The cutting layers are inhibited, the cutting force increases, and due to this, the chips stick to the cutting edge of the cutter. This leads to wear of the cutter and a decrease in the cleanliness of the tooth surfaces.

When cutting with an ultrasonic head, cutting conditions change, cutting forces are significantly reduced, the type of chips changes - it becomes more elongated. Due to high cutting speeds (~ 0.8 m / s), at every moment of interaction of the cutter with the workpiece, there is an instant plunge in and an instant exit of the cutting edge of the cutters. As a result, friction and interaction forces are reduced, and thermal loads on the cutters are reduced.

Due to the short-term pulse nature of the cutting mode, the surface is smoothed and the processing cleanliness is increased. There is no need for roughing, there is no need to use additional equipment and technological finishing. The tool life is increased, the possibility of ultrasonic cutting is provided in the technology of gear cutting of medium and large modulus wheels on standard equipment. At the same time, it is possible to perform double-sided fine cutting of teeth by the vibration rolling method.

Claims (4)

1. A gear-cutting head, including a housing with seats around the circumference of the head body and cutters, characterized in that it contains an acoustic system located in each seat, which is a piezoelectric transducer connected to a concentrator made in the form of a waveguide, the upper part of which is opposite from the side transducer is a cutter made integral with the concentrator or removable, and the cutters are made alternating for right- and left-handed, while each transducer is equipped with a collector current collector for connection to an ultrasonic generator, the length of each concentrator is from 1 / 4λ to 1 / 2λ, where λ is the wavelength of ultrasonic vibrations. 2. Gear head according to claim 1, characterized in that the cutter is removable in the form of a corner. 3. Gear head according to claim 1, characterized in that the cutter is removable in the form of a fork, one part of which performs the function of a right-hand cutting element, and the second - a left-hand cutting element, while the cutting elements are shifted relative to each other. 4. Gear head according to claim 1, characterized in that the cutter is made in the form of a knife waveguide segment, divided by one or more slots into resonant working parts, shifted relative to each other along the radius of the circle, limited by the nominal diameter of the gear head and the module of the processed wheel or gear, one of the working parts parts perform the functions of right-cutting incisors, and those following them - left-cutting.

Images