KR20220165384A - Arbor type hybrid spindle capable of ultrasonic vibration cutting and electric discharge machining - Google Patents

Abstract

The present invention relates to an arbor type hybrid spindle capable of ultrasonic vibration cutting and electric discharge machining, which applies ultrasonic vibration cutting and electrical discharge machining of an elliptical trajectory to general milling, thereby capable of increasing processing efficiency. The present invention includes: a fixed frame; an arbor type housing; an ultrasonic vibration cutting unit; and an electric discharge machining unit.

Description

Avatar Type Hybrid Spindle with Ultrasonic Vibration Cutting and Electrical Discharge Machining

The present invention relates to an ARBOR TYPE hybrid spindle capable of ultrasonic vibration cutting and electrical discharge machining of an elliptical trajectory.

In general, electrical discharge machining refers to processing by intermittently conducting electric discharge between a processing electrode and a workpiece. More precise machining is possible by such electric discharge machining.

Recently, a technique of electrical discharge machining by rotating a machining tool by a spindle as a machining electrode has been used.

For reference, a spindle is one of parts used in machine tools such as lathes, milling machines, and drilling machines, and refers to a rotating shaft whose shaft end is used to mount a workpiece or a cutting tool.

These spindle electric discharge machining devices have recently been widely used because more precise hole digging, cutting, and grinding are possible.

However, recently, ultra-precision machining of hundreds of μm is required, and it is difficult to perform such ultra-precision machining with conventional spindle electrical discharge machining apparatuses.

Republic of Korea Patent Publication No. 10-1998-021683 (published date: 1998.06.25.)

The present invention has been made to solve the above-described problems, and ultrasonic vibration cutting and electric discharge machining are applied to general milling machining to increase machining efficiency by applying ultrasonic vibration cutting and electric discharge machining of an elliptical trajectory. Provides an avatar type hybrid spindle capable of ultrasonic vibration cutting and electric discharge machining But it has a purpose.

The avatar type hybrid spindle capable of ultrasonic vibration cutting and electrical discharge machining according to the present invention for realizing the above object is detachably coupled to a machine tool, and is provided with a coupling hole on the same axis as the drive shaft of the machine tool fixed frame; A avatar housing having one side coupled to the drive shaft, the other side rotatably coupled in the coupling hole, and having a collet for tool coupling at the other end; an ultrasonic vibration cutting unit provided in the avatar housing and processing the workpiece by generating ultrasonic vibration so that the tool intermittently contacts the workpiece; and a discharge machining unit which is provided at a connection portion between the fixed frame and the avatar housing and processes the workpiece by using discharge between the tool and the workpiece.

In this case, the avatar housing includes a first body (BT40 arbor), one side of which is coupled to the drive shaft, and a coupling shaft of a predetermined length and diameter protrudes from the other central axis line; And an insertion hole is provided on one side so as to be coupled to the coupling shaft of the first body, and after being coupled to the coupling shaft, it is integrally fixed with the first body through a fastening member, and an accommodation space for coupling the ultrasonic transformer therein. It may include a; second body provided.

In addition, on the other side of the second body, a plurality of helical grooves are formed on the outer circumferential surface based on the central axis so that ultrasonic vibration generated along the central axis of the avatar housing through the ultrasonic vibration cutting unit can form an elliptical trajectory. A conical horn formed at a predetermined angle spaced apart; may include a combined one.

In addition, the ultrasonic transformer may include a preload bolt whose end is screwed to the central axis of the conical horn, and a rear mass member and an insulating inner ring having a predetermined length are sequentially fitted to the outer circumferential surface; a plurality of copper plate conductors fitted to the outer circumferential surface of the insulating inner ring, and a plurality of piezoelectric elements fitted to the outer circumferential surface of the insulating inner ring to be disposed between the copper plate conductors; and an insulating washer ring fitted to the outer circumferential surface of the insulating inner ring with the copper plate conductor and the piezoelectric element assembly interposed therebetween to protect the piezoelectric element from the discharge signal of the discharge processing unit.

In addition, the conical horn includes a flange portion protruding with a predetermined diameter on one outer circumferential surface so that the other side of the second body can be fastened and fixed via a fastening member; and a plurality of set-screw fastening parts provided to be spaced apart at a predetermined angle from the outer circumferential surface of the flange part so as to adjust the mass balance during rotation of the avatar housing.

In addition, the ultrasonic vibration cutting unit is provided with a receiving coil wound around the outer circumferential surface of one side of the second body and a transmission coil wound around the outer circumferential surface of the annular bracket of the fixing frame so as to be disposed on the outer circumferential surface of the receiving coil. It may include; a rotary transformer that changes the value of the voltage or current supplied to the cutting unit.

In addition, the electrical discharge machining unit, an insulating ring coupled and fixed to the outer circumferential surface of the other side of the second body; a copper ring coupled and fixed to an outer circumferential surface of the insulating ring; and a carbon brush that is elastically supported on the fixing bracket via a spring so as to be elastically in contact with the outer circumferential surface of the copper ring, and transmits an electrical signal for electrical discharge machining.

The present invention having the configuration as described above has the advantage of improving processing efficiency compared to general milling processing methods by enabling ultrasonic vibration cutting and electric discharge machining of an elliptical trajectory.

In particular, machining with ultrasonic vibration of an elliptical trajectory increases the cutting speed compared to general machining and can make intermittent contact between the tool and the workpiece. Accordingly, the cutting force and the cutting temperature can be reduced, and the surface quality of the workpiece can be increased.

In addition, as the contact time between the cutting tool and the workpiece decreases, tool life can be increased.

In addition, the heat source generated by the electric discharge machining through the electric discharge machining unit can directly machine the workpiece, and the workpiece can be softened through this processing heat. That is, by processing the softened workpiece, it is possible to increase the machining efficiency compared to the general workpiece.

In addition, as the damaged layer formed during electrical discharge machining is removed, the processing quality of the workpiece can be improved.

1 is a perspective view of an avatar type hybrid spindle capable of ultrasonic vibration cutting and electrical discharge machining according to the present invention;
Figure 2 is a cross-sectional side view showing the internal configuration of the avatar type hybrid spindle capable of ultrasonic vibration cutting and electrical discharge machining according to the present invention;
3 is an exploded perspective view of the avatar housing according to the present invention;
Figure 4 is a side cross-sectional view of Figure 3;
5 is a side view of an ultrasonic transformer according to the present invention;
Figure 6 is an exploded perspective view of Figure 5;
Figure 7 is a cross-sectional side view of Figure 5;
8 is a view showing the driving principle of the ultrasonic transformer according to the present invention and the polarity combination of the piezoelectric element.

Hereinafter, the configuration and operation of specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Here, in adding reference numerals to the components of each drawing, it should be noted that the same components are marked with the same numerals as much as possible, even if they are displayed on different drawings.

1 is a perspective view of an avatar type hybrid spindle capable of ultrasonic vibration cutting and electrical discharge machining according to the present invention, and FIG. 2 is a side cross-sectional view showing the internal configuration of the avatar type hybrid spindle capable of ultrasonic vibration cutting and electrical discharge machining according to the present invention. .

1 and 2, the avatar type hybrid spindle 1 capable of ultrasonic vibration cutting and electric discharge machining according to a preferred embodiment of the present invention includes a fixed frame 100, an avatar type housing 200, ultrasonic vibration The cutting part 300 and the electric discharge machining part 400 may be included.

The detailed description of the configuration of the present invention is as follows.

First, the fixed frame 100 constitutes the main frame of the avatar type hybrid spindle 1, and this fixed frame 100 can be detachably coupled to the machine tool.

In this case, an annular bracket 110 having a coupling hole 111 on the same axis as a driving shaft (not shown) of the machine tool may be coupled to the fixing frame 100 .

One side of the avatar housing 200 is coupled to the drive shaft of the machine tool, and the other side may be rotatably coupled into the coupling hole 111 of the fixing frame 100 . In addition, a collet 201 for tool coupling may be provided at the other end of the avatar housing 200 to process a workpiece (not shown).

3 and 4, the avatar housing 200 has one side coupled to the drive shaft and a first body in which a coupling shaft 211 having a predetermined length and diameter protrudes on the central axis of the other side ( 210) (BT40 arbor), and an insertion hole 221 is provided on one side so as to be coupled to the coupling shaft 211, and after being coupled to the coupling shaft 211, the first through a fastening member (not shown) It may include a second body 220 integrally fixed with the body 210 . And the other side of the second body 220 may be coupled to the conical horn 230 (see FIG. 2).

That is, as the first body 210 and the second body 220 are made of a coupling structure of the coupling shaft 211 and the insertion hole 221 on the same axis, the rotation of the avatar type hybrid spindle 1 occurs. Possible run-out errors can be prevented.

In addition, inside the second body 220 of the avatar housing 200, an accommodation space ( S) may be provided.

Referring to FIG. 5, the ultrasonic vibration cutting unit 300 is provided in the inner accommodation space S of the avatar housing 200, so that the tool coupled to the collet 201 intermittently contacts the workpiece by ultrasonic waves. Vibration can be generated to process the workpiece.

In this case, the outer circumferential surface of the conical horn 230 has a helical groove based on the central axis so that ultrasonic vibration generated along the central axis of the avatar housing 200 through the ultrasonic vibration cutting unit 300 can form an elliptical trajectory. (231) A plurality of them may be formed to be spaced apart at a predetermined angle.

Preferably, the helical grooves 231 may have a depth of 1 mm, a width of 10 mm, a number of 8, an inclination angle of 20°, and a pitch of 60 mm.

In this case, the inclination angle is the inclination value of both sides symmetrical from the center line of the conical horn 230, and the pitch is the distance between the center lines of the helical grooves 231. The resonance frequency of the two-axis Langevan ultrasonic transformer 310 was determined through simulation of dynamic characteristics, and the final selected frequency was about 39 kHz.

6 and 7, the ultrasonic transformer 310 has an end screwed to the central axis of the conical horn 230 and has a rear mass member 313 on the outer circumferential surface and an insulating inner ring of a predetermined length ( 315) are sequentially fitted into the preload bolt 311, the plurality of copper plate conductors 317 fitted to the outer circumferential surface of the insulating inner ring 315, and the insulating inner ring disposed between the copper plate conductors 317. A plurality (preferably two) of piezoelectric elements 318 fitted to the outer circumferential surface of the ring 315 may be included.

In this case, the ultrasonic transformer 310 is fitted and coupled to the outer circumferential surface of the insulating inner ring 315 with the copper plate conductor 317 and the piezoelectric element 318 assembly interposed therebetween, and receives piezoelectric power from a discharge signal from the discharge processing unit 400 to be described later. An insulation washer 319 protecting the element 318 may be provided (see FIG. 7).

Referring to FIG. 8 , the ultrasonic vibration cutting unit 300 configured as described above simultaneously vibrates in the longitudinal direction (axial direction) and the torsion direction. Longitudinal vibration occurs when an alternating current electrical signal (ultrasonic wave of about 39 kHz) is applied to the copper plate conductor 317. The key principle is the combination of the shape (circle) and polarity of the piezoelectric element 318. In the case of vibration in the torsional direction, it occurs in the helical groove 231 of the conical horn 230 when an alternating current electric signal (ultrasonic wave of about 39 kHz) is applied. As a result, the ultrasonic transformer 310 can simultaneously generate longitudinal and torsional vibrations at about 39 kHz ultrasonic waves.

Referring back to FIG. 2, on one side of the second body 220, there is a rotary transformer 320 that changes the value of voltage or current supplied to the ultrasonic transformer 310 for the operation of the ultrasonic vibration cutting unit 300. may be provided.

Specifically, the rotary transformer 320 includes a receiving coil 321 in which a copper coil is wound around an outer circumferential surface of one side of the second body 220, and a fixed frame 100 spaced apart from the outer circumferential surface of the receiving coil 321. It may include a transmission coil 323 formed by winding a copper coil around the annular bracket 110 of the.

At this time, the second body 220 and the annular bracket 110 may be made of ferrite steel. Ferrite steel can improve the effect of the magnetic flux principle, and can increase the amount of induced electromotive force generated. As a result, the amount of induced current flowing from the transmitting coil 323 to the receiving coil 321 can be increased.

That is, the rotary transformer 320 is driven by the magnetic flux principle, and has a structure in which current generated in the transmitting coil 323 is induced to the receiving coil 321 to supply power. The rotary transformer 320 of this structure is a non-contact power supply method, and can be used semi-permanently because there is no contact between coils. will do

Referring back to FIG. 6, the conical horn 230 is a flange portion 233 protruding with a predetermined diameter on one outer circumferential surface so that it can be fastened and fixed to the other side of the second body 220 through a fastening member (not shown). ) may be provided. In addition, a plurality of set screw fastening parts 235 may be provided on the outer circumferential surface of the flange part 233 at a predetermined angle so as to adjust the mass balance when the avatar housing 200 rotates.

In addition, on one surface of the flange portion 233 of the conical horn 230 coupled to the second body 220, a slot 234 having a predetermined diameter and thickness to reduce run-out error during rotation of the spindle 1 ) may be provided (see FIGS. 2 and 5). In this case, the slot 234 may be formed with a diameter corresponding to the inner diameter of the accommodation space (S) so that it can be fitted into the accommodation space (S) of the second body 220.

Referring back to FIG. 2, the electric discharge machining unit 400 is provided at the connection portion of the fixed frame 100 and the avatar housing 200, and this electric discharge machining unit 400 uses electric discharge between the copper electrode and the workpiece. You can process the workpiece by doing so.

Specifically, the electric discharge processing unit 400 includes an insulating ring 410 coupled and fixed to the outer circumferential surface of the other side of the second body 220, and a copper ring 420 coupled and fixed to the outer circumferential surface of the insulating ring 410, An electrical signal for electrical discharge machining is installed in the fixing frame 100 to be elastically supported via a spring 431 so that the outer circumferential surface of the copper ring 420 rotates integrally with the second body can be elastically pressed and contacted. It may include a carbon brush 430 that transfers to the copper ring 420.

In this case, the carbon brush 430 may use a graphite material. Graphite can facilitate contact with the copper ring 420 by serving as a solid lubricant.

In addition, the R value of the curved portion where the copper ring 420 and the carbon brush 430 come into contact may be the same. Accordingly, even when rotating at high speed, the carbon brush 430 can maintain contact with the copper ring 420 by the spring 431 .

In addition, a handle H may be provided on one side of the carbon brush 430 . Accordingly, assembly and disassembly of the spindle 1 may be facilitated.

In addition, the insulating ring 410 may prevent the applied electrical signal from leaking into the avatar housing 200 .

In addition, plastic bolts may be used to couple the insulating ring 410 and the copper ring 420 . Accordingly, it is possible to block the electrical signal of the copper ring 420 from being counted as a volt.

The present invention having the configuration as described above can configure the ultrasonic vibration cutting unit 300 and the electric discharge machining unit 400 in one avatar type hybrid spindle 1, and through this avatar type hybrid spindle 1, the elliptical trajectory Processing efficiency can be increased by applying ultrasonic vibration cutting and electrical discharge machining to general milling.

In particular, machining with ultrasonic vibration of an elliptical trajectory increases the cutting speed compared to general machining and can make intermittent contact between the tool and the workpiece. Accordingly, the cutting force and the cutting temperature can be reduced, and the surface quality of the workpiece can be increased.

In addition, as the contact time between the cutting tool and the workpiece decreases, tool life can be increased.

In addition, the heat source generated by the electric discharge machining through the electric discharge machining unit can directly machine the workpiece, and the workpiece can be softened through this processing heat. That is, by processing the softened workpiece, it is possible to increase the machining efficiency compared to the general workpiece.

In addition, as the damaged layer formed during electrical discharge machining is removed, the processing quality of the workpiece can be improved.

In the above, the present invention has been shown and described with specific specific examples, but the present invention is not limited to the above-described embodiments, and various changes and modifications are possible without departing from the technical spirit of the present invention.

1: avatar type hybrid spindle 100: fixed frame
110: annular bracket 111: coupling hole
200: avatar housing 201: collet
210: first body (BT40 arbor) 211: coupling shaft
220: second body 221: insertion hole
230: cone horn 231: helical groove
233: flange portion 234: slot
235: set screw fastening part 300: ultrasonic vibration cutting part
310: ultrasonic transformer 311: preload bolt
313: rear mass member 315: insulation inner ring
317: copper plate conductor 318: piezoelectric element
319: insulation washer 320: rotary transformer
321: receiving coil 323: transmitting coil
400: electric discharge machining part 410: insulation ring
420: copper ring 430: carbon brush
431: spring

Claims (7)

A fixed frame detachably coupled to the machine tool and provided with a coupling hole on the same axis as the drive shaft of the machine tool;
A avatar housing having one side coupled to the drive shaft, the other side rotatably coupled in the coupling hole, and having a collet for tool coupling at the other end;
an ultrasonic vibration cutting unit provided in the avatar housing and processing the workpiece by generating ultrasonic vibration so that the tool intermittently contacts the workpiece; and
Avatar type hybrid spindle capable of ultrasonic vibration cutting and electrical discharge machining including; provided at the connection part of the fixed frame and the avatar type housing and processing the workpiece by using the discharge between the tool and the workpiece.
According to claim 1,
The avatar housing,
a first body having one side coupled to the drive shaft and a coupling shaft having a predetermined length and diameter protruding on the central axis of the other side; and
An insertion hole is provided on one side so as to be coupled to the coupling shaft of the first body, and after being coupled to the coupling shaft, it is integrally fixed with the first body through a fastening member, and there is an accommodation space for coupling the ultrasonic transformer therein. An avatar type hybrid spindle capable of ultrasonic vibration cutting and electrical discharge machining including a second body provided.
According to claim 2,
On the other side of the second body,
A conical horn in which a plurality of helical grooves are formed at a predetermined angle on the outer circumferential surface based on the central axis so that the ultrasonic vibration generated along the central axis of the avatar housing can form an elliptical trajectory through the ultrasonic vibration cutting unit; An avatar type hybrid spindle capable of ultrasonic vibration cutting and electric discharge machining including combined ones.
According to claim 3,
The ultrasonic transformer,
A preload bolt whose end is screwed to the central axis of the conical horn and into which a rear mass member and an insulating inner ring of a predetermined length are sequentially fitted to the outer circumferential surface;
a plurality of copper plate conductors fitted to the outer circumferential surface of the insulating inner ring, and a plurality of piezoelectric elements fitted to the outer circumferential surface of the insulating inner ring to be disposed between the copper plate conductors; and
An arbor capable of ultrasonic vibration cutting and electric discharge machining including an insulating washer ring fitted to the outer circumferential surface of the insulating inner ring with the copper plate conductor and the piezoelectric element assembly interposed therebetween to protect the piezoelectric element from the discharge signal of the electric discharge machining unit. type hybrid spindle.
According to claim 3,
The conical horn,
A flange portion protruding with a predetermined diameter on an outer circumferential surface of one side so that the other side of the second body can be fastened and fixed via a fastening member; and
Avatar type hybrid spindle capable of ultrasonic vibration cutting and electrical discharge machining further comprising; a plurality of set screw fastening parts provided at a predetermined angle on the outer circumferential surface of the flange portion so as to adjust the mass balance during rotation of the avatar type housing.
According to claim 2,
The ultrasonic vibration cutting part,
A receiving coil wound around the outer circumferential surface of one side of the second body and a transmission coil wound around the outer circumferential surface of the annular bracket of the fixing frame are provided so as to be disposed on the outer circumferential surface of the receiving coil, and the voltage or A rotary transformer that changes the value of current; Avatar type hybrid spindle capable of ultrasonic vibration cutting and electrical discharge machining including.
According to claim 2,
The electric discharge machining part,
an insulating ring coupled and fixed to the outer circumferential surface of the other side of the second body;
a copper ring coupled and fixed to an outer circumferential surface of the insulating ring; and
Ultrasonic vibration cutting and electrical discharge machining including a carbon brush that is elastically supported by means of a spring in the fixing bracket so that it can be elastically pressed into contact with the outer circumferential surface of the copper ring and transmits an electrical signal for electrical discharge machining. This avatar is available as a hybrid spindle.

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