RU2234398C1 - Device for ultrasonic threading of inner threads - Google Patents

Abstract

FIELD: cutting metals.

SUBSTANCE: device has a spindle unit with a passage for receiving a bent screw tap and mechanism for feeding blanks, which is mounted coaxially to it. The mechanism of feeding blanks is made of a slide-wave-guide provided with an ultrasonic transformer at one end and pusher at the opposite end. The pusher is a transformer of the velocity of ultrasonic oscillations.

EFFECT: enhanced quality of thread.

1 dwg, 1 tbl

Description

The invention relates to the processing of metals by cutting, and in particular to devices for cutting and rolling of internal threads in nuts with taps, and can be used in mechanical engineering.

Known devices for cutting threads by ultrasound, made in the form of a waveguide, in the axial hole of which is located the shank of the tap, connected by a fastener and provided with a collar pressed against the end of the waveguide for acoustic contact between them.

A device for cutting internal threads by means of ultrasound by AS No. 394171, IPC B 23 G 1/16, publ. 08/22/1973, bull. No. 34, in which the shank of the tap is attached to the waveguide of the acoustic system of the ultrasonic transducer.

A common drawback of all the above devices is the impossibility of their use in automatic mode due to the use of straight-shank taps attached to the waveguide of the speaker system. Ultrasonic vibrations in known devices are superimposed on the tap. At the same time, in the process of threading, the cutting force changes as the tap deepens into the hole, and at the outlet of the tap cone from the through hole and when it is turned out, in accordance with this, the amplitude of the tap oscillations must be changed accordingly to obtain a threaded surface and tool life. . To comply with this condition, an additional adjusting device for the amplitude of the oscillations of the tap is required.

The closest in technical essence to the proposed solution is a nut-cutting machine according to A.S. No. 1419835, IPC B 23 G 1/16, publ. 08/30/08. bull. No. 32, in which the curved tap is placed in the spindle unit, the workpiece feed mechanism is made in the form of a pusher, in which the sleeve is mounted with the possibility of axial movement.

In the known device, a mechanism is used to center the workpiece relative to the sleeve, which is placed in the sleeve and is made in the form of a heel with an axial inner cone. The heel rotates with the tap during the cutting process, which inevitably leads, like any rotating part, to gradual wear, clogging with grease and chips. The chips generated during the cutting process are removed from the cutting zone through the external axial grooves (grooves) on the solid body of the heel and through the axial pusher window, thereby removing the chips. The thread cutting mechanism does not fundamentally differ from traditional classical schemes and therefore the quality of the thread, the resistance of the tap and the performance are not changed.

An object of the invention is to improve the quality of the cut thread, increase productivity and durability of taps.

This object is achieved in that in a device for cutting internal threads, including a spindle unit with a curved tap located in it, the workpiece feed mechanism mounted coaxially with the tap is made in the form of a waveguide slider equipped with an ultrasonic transducer at one end and a pusher at the opposite, in this case, the pusher is an element of the transformer of speed of ultrasonic vibrations.

The drawing shows a General view of the described device.

The device comprises a spindle 1 with a channel in which a curved tap 2 is placed, a feeder 3, which provides the supply of blanks-nuts 4 in the cutting zone. The tap is centered relative to the spindle channel using the nuts put on it. A slider-waveguide 5 is installed coaxially with the tap, at one end of which an ultrasonic transducer 6 is fixed, and at the other end there is a pusher 7 made in the form of a hollow cylinder with through axial holes for chip removal.

The slider serves as a waveguide of the acoustic system, and the pusher acts as a transformer of ultrasonic vibration velocity. The length of the slider with the pusher is selected so that at the free end of the pusher is the antinode of the standing wave of ultrasonic vibrations excited by an ultrasonic (acoustoelectric) transducer. This mode of operation of the acoustic system allows you to excite vibrations of the workpiece-nut of the required amplitude and clamping force at the resonant frequency.

The device operates as follows.

The workpiece-nut 4 from the feeder 3 enters the cutting zone. Next, the pusher 7, making a reciprocating motion, compresses the workpiece to the rotating tap 2 and pushes it onto the intake part of the tap. The threading process occurs due to the passage of the workpiece-nut through a rotating tap, then into the basket with the finished nuts. Cutting fluid is supplied to the cutting zone.

During operation of the device, the pusher excites ultrasonic vibrations in the workpiece-nut from the transducer 6 through the waveguide slider 5. In this case, due to the vibration of the workpiece-nut, the torque acting on the tap is reduced, jamming and breakage of the tap are eliminated, and cutting and lubrication and cooling conditions are improved the edges of the tap, the chips are crushed and the conditions for their evacuation from the cutting zone are improved, the cutting edges of the tap are cleared of adhering chips, and the workpiece-nut is self-centered.

It is known that work when cutting metal is spent mainly on the plastic deformation of the sheared layer and on external friction on the working faces of the tool. Ultrasonic vibrations imparted to the cutting tool or the workpiece-nut have a significant impact on both components of the cutting work: the alternating stresses created by them accelerate the movement and formation of dislocations, providing the occurrence of plastic deformation at lower stresses, and cyclic movements of the contact surfaces cause a periodic rotation of the friction force vectors on the working edges of the tool, significantly reducing chip resistance and facilitating the chip process education.

A workpiece-nut vibrating with ultrasonic frequency is pushed onto the intake part of the tap and vibrations of the workpiece-nut help center it relative to the axis of the tap.

The pusher also causes cavitation of the cutting fluid (coolant) and cleaning the surface of the tap of the cavitating coolant from adhering chips.

Example

On the model MN-62 nut-cutting machine, a slider-pusher with an ultrasonic transducer was installed on one stream.

Nuts M10.6N according to GOST 5915-70 were made from steel 10 according to TU 14-178-387-2000 with MR-7U cutting fluid according to OST 38.01.445-88 with M10 taps according to GOST 6951-71 (manufactured in Vladivostok )

The test results are summarized in table.

As a result of industrial tests, it was determined that the message of ultrasonic vibrations to the workpiece-nut through the slider-pusher leads to a 3.9-fold increase in the resistance of taps and an increase in the productivity of a nut-cutting machine to 36.7% with an improvement in thread quality to 5N.

Claims (1)

A device for cutting internal threads using ultrasound, comprising a spindle assembly with a channel designed to accommodate a bent tap, and a workpiece feed mechanism installed coaxially with it, characterized in that the workpiece feed mechanism is made in the form of a waveguide slider equipped with an ultrasonic transducer at one end and the pusher on the opposite, while the pusher acts as a transformer for the speed of ultrasonic vibrations.