Machine tool of high-frequency vibration

A machine tool of high-frequency vibration is provided. A main shaft structure of the machine tool comprises a rotating shaft, the end of which is provided with a tool holder chuck for fixing a tool holder; the upper portion of which is provided with a rotating coil portion; the main shaft structure is correspondingly provided with a stationary coil portion; and the tool holder is provided with a high-frequency vibration module. By non-contact coils, an external electric power/signal can be transmitted into the high-frequency vibration module to avoid a wear phenomenon in a contact-rotating electrode. Because the inductive coil is arranged outside of the tool holder, the manufacturing cost of the tool holder is reduced, and the convenience of changing the tool holder is increased. Moreover, the machining stability and efficiency of the tool holder are improved by a control method of sensing/feedback signals with wireless transmission.

FIELD OF THE INVENTION

The present invention relates to a machine tool of high-frequency vibration, and more particularly to a machine tool and a control method of sensing/feedback signals thereof which installs an inductive coil in a main shaft and transmits electric power/signal into a high-frequency vibration tool holder by contact type electrodes.

BACKGROUND OF THE INVENTION

High-frequency vibration cutting is a new type machining technology, and by adding a high-frequency vibration into a common cutting tool, an interrupted contact is generated between a cutting tool and a workpiece, and it fundamentally changes the conventional cutting method. This change can solve the problems existing in the conventional cutting technologies, for example the vibration and the heat accumulation during a cutting process or the unstable machining quality, so that the cutting effect is improved.

In a conventional high-frequency vibration technology, a high-frequency vibration device is disposed inside a tool holder, which is removably mounted on a machining center. Generally, the machining center having high-frequency vibration has two methods to supply electric power, a contact type and a non-contact type. Because electrodes of the contact type are more easily worn out, the non-contact type electricity supply is more frequently adopted in the new type of high-frequency vibration machining center.

In the conventional technology of a non-contact type electricity supply, inductive coils are adopted, wherein a stationary coil is disposed in a machining center, and a rotating coil is disposed inside a tool holder, so that it can avoid an electrode wear phenomenon of a contact type rotating electrodes. However, since the inductive coils are installed inside the tool holder, the manufacturing cost of the tool holder is increased and the convenience of changing the tool holder is decreased.

Hence, it is necessary to provide an improved machine tool of high-frequency vibration and a control method of sensing/feedback signals thereof to solve the problems existing in the conventional technologies.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a machine tool of high-frequency vibration, which installs an inductive coil in a main shaft and transmit electric power/signal into a high-frequency vibration tool holder by contact type electrodes. Therefore, it can avoid a wear phenomenon in a contact-rotating electrode, such as a slip ring. Additionally, because the inductive coil is arranged outside the tool holder, the manufacturing cost of the tool holder is reduced and the convenience of changing the tool holder is increased.

For achieving above-mentioned object, the present invention provides a machine tool of high-frequency vibration, which comprises a main shaft structure and a high-frequency vibration tool holder, wherein the main shaft structure includes:

a main body fixed on a working side of the machine tool;

a rotating shaft rotatably disposed inside of the main body;

a tool holder chuck coaxially disposed under the rotating shaft, wherein the tool holder chuck has a pair of position keys coaxially arranged with each other, and inner side surfaces of the position keys are provided with at least one pair of first electrodes;

a stationary coil portion including a stationary ring and at least one primary coil, which are both hollow shaped and are coaxially stacked and fixed on an upper portion of the rotating shaft, wherein the stationary ring is fixed on the main body, so that the stationary coil portion is fixed relative to the main body; and a pair of external electric wires are electrically connected to the stationary ring; and

a rotating coil portion including a rotating ring and at least one secondary coil, which are both hollow shaped and are coaxially stacked and fixed on an upper portion of the rotating shaft, wherein the secondary coil corresponds to the primary coil of the stationary coil portion; the rotating ring is fixed on the rotating shaft, so that the rotating coil portion is rotated with the rotating shaft, and the rotating coil portion is electrically connected to the at least one pair of first electrodes of the inner side surfaces of the position keys by at least one pair of inner electric wires;

wherein the high-frequency vibration tool holder comprises:

a holder shank portion disposed on an upper end of the tool holder, and configured for clamping and fixing with the tool holder chuck of the main shaft structure, wherein the holder shank portion includes a pair of end keyways corresponding to the pair of position keys of the tool holder chuck; and outer sides of the end keyways are provided with at least one pair of second electrodes corresponding and contacting to the at least one pair of first electrodes of the tool holder chuck;

a receiving portion disposed on the middle portion of the tool holder, wherein a high-frequency vibration module is disposed inside the receiving portion, and is electrically connected to the at least one pair of second electrodes; and

a tool chuck disposed on the lower portion of the tool holder, and configured for clamping and downwardly fixing a cutting tool;

wherein the machine tool further comprises an automatic machining control module and a high-frequency control module; the automatic machining control module controls and rotates the rotating shaft, so as to cause the cutting tool under the tool holder to rotate so as to process a cutting operation; the high-frequency control module controls an electric power/signal to pass through the at least one pair of external electric wires to the stationary ring of the stationary coil portion, then the electric power/signal is transmitted to the at least one primary coil, and the at least one secondary coil of the rotating coil portion is induced to generate an electric power/signal, then the electric power/signal passes through the rotating ring, and passes through the at least one pair of inner electric wires to be transmitted to the at least one pair of first electrodes of the tool holder chuck, then the electric power/signal is transmitted to the at least one pair of second electrodes of the holder shank portion, and finally the electric power/signal is transmitted to the high-frequency vibration module to provide the cutting tool with a high-frequency vibration.

In one of the embodiments of the present invention, the pair of first electrodes are contact type spring electrodes; and the pair of second electrodes include conducting sheets in an inner ring thereof and insulating sheets in a periphery thereof.

In one of the embodiments of the present invention, the high-frequency vibration module is selected from a group of a piezoelectric actuator, a voice coil actuator, and a magnetic actuator.

In one of the embodiments of the present invention, the number of the primary coils is two and that of the secondary coils is correspondingly two, wherein one set of the primary coil and the secondary coil is configured for transmitting electric power and carrier wave signals, and the other set of the primary coil and the secondary coil is only configured for transmitting carrier wave signals.

In one of the embodiments of the present invention, the machine tool further comprises a wireless signal receiving module and a computer module; and the high-frequency vibration tool holder further comprises a sensing module and a wireless signal transmitting module; the sensing module is configured to transmit at least one sensing data to the wireless signal receiving module by the wireless signal transmitting module, and after the sensing data is analyzed and computed by the computer module, the computer module transmits the analyzed result to be a control command outputting to the automatic machining control module and the high-frequency control module.

In one of the embodiments of the present invention, the sensing module includes a strain gauge, and the sensing data includes an internal stress data of the high-frequency vibration tool holder sensed by the strain gauge.

In one of the embodiments of the present invention, the sensing module includes a thermometer, and the sensing data includes a temperature data of the high-frequency vibration tool holder sensed by the thermometer.

For achieving above-mentioned object, the present invention provides a control method of sensing/feedback signals of a machine tool of high-frequency vibration, which comprises following steps of:

(a) providing a machine tool and a high-frequency vibration tool holder, wherein the machine tool is provided with an automatic machining control module, a high-frequency control module, a wireless signal receiving module, and a computer module; and the high-frequency vibration tool holder is provided with a high-frequency vibration module, a sensing module, and a wireless signal transmitting module;

(b) using the automatic machining control module to control a rotating power and a feed quantity of the high-frequency vibration tool holder of the machine tool to process a work piece; and using the high-frequency control module to control the high-frequency vibration tool holder to generates a high-frequency vibration;

(c) using the sensing module to transmit at least one sensing data to the wireless signal receiving module by the wireless signal transmitting module, and analyzing and computing the sensing data by the computer module;

(d) using the computer module to transmit an analyzed result of the sensing data to be a control command outputting to the automatic machining control module and the high-frequency control module; and

(e) using the automatic machining control module to adjust the rotating power and the feed quantity of the high-frequency vibration tool holder, and adjusting the vibration frequency of the high-frequency vibration tool holder by the high-frequency control module.

In one of the embodiments of the present invention, the sensing module includes a strain gauge, and the sensing data includes an internal stress data of the high-frequency vibration tool holder sensed by the strain gauge.

In one of the embodiments of the present invention, the sensing module includes a thermometer, and the sensing data includes a temperature data of the high-frequency vibration tool holder sensed by the thermometer.

As described above, by using the machine tool of high-frequency vibration and the control method of sensing/feedback signals thereof, it not only can lower the manufacturing cost of the tool holder and increase the convenience of changing the tool holder, but can also improve the machining stability and efficiency of the high-frequency vibration tool holder.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The foregoing objects, features, and advantages adopted by the present invention can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings. Furthermore, the directional terms described in the present invention, such as upper, lower, front, rear, left, right, inner, outer, side, etc., are only directions with reference to the accompanying drawings, so that the used directional terms are used to describe and understand the present invention, but the present invention is not limited thereto. In the drawings, units with similar structures use the same numerals.

A machine tool of the present invention can be a machine tool which needs a function of high-frequency vibration, and the structure and the principle of the machine tool with the function of high-frequency vibration is described below.

Refer now toFIGS. 1 to 3,FIG. 1is an assembling schematic view of a machine tool of high-frequency vibration according to a preferred embodiment of the present invention;FIG. 2is a structural schematic view of a main shaft structure of the machine tool according to a preferred embodiment of the present invention; andFIG. 3is a schematic view of a high-frequency vibration tool holder according to a preferred embodiment of the present invention. A machine tool1with high-frequency vibration according to the present invention comprises: a main shaft structure100and a high-frequency vibration tool holder200. The main shaft structure100includes a main body110, a rotating shaft120, and a tool holder chuck130. The main body110is fixed on a working side of the machine tool1; the rotating shaft120is rotatably disposed inside of the main body110; and the tool holder chuck130is coaxially disposed under the rotating shaft120, wherein the tool holder chuck130has a pair of position keys131, and inner side surfaces of the position keys131are provided with at least one pair of first electrodes132.

Furthermore, the main shaft structure100further comprises a stationary coil portion140and a rotating coil portion150. The stationary coil portion140includes a stationary ring141and at least one primary coil142, which are both hollow shaped and are coaxially stacked and fixed on an upper portion of the rotating shaft120. The stationary ring141is fixed on the main body110, so that the stationary coil portion140is fixed relative to the main body110, and a pair of external electric wires143is electrically connected to the stationary ring141. Additionally, the rotating coil portion150includes a rotating ring151and at least one secondary coil152, which are both hollow shaped and are coaxially stacked and fixed on an upper portion of the rotating shaft120. The secondary coil152corresponds to the primary coil142of the stationary coil portion140. The rotating ring151is fixed on the rotating shaft120, so that the rotating coil portion150is able to be rotated with the rotating shaft120, and the rotating coil portion150is electrically connected to the at least one pair of first electrodes132of the inner side surfaces of the position keys131by at least one pair of inner electric wires153.

As shown inFIGS. 1 to 3, the high-frequency vibration tool holder200comprises a holder shank portion210, a receiving portion220, and a tool chuck230. The holder shank portion210is disposed on an upper end of the tool holder200, and is configured for clamping and fixing with the tool holder chuck130of the main shaft structure100. The holder shank portion210includes a pair of end keyways211corresponding to the pair of position keys131of the tool holder chuck130. Outer sides of the end keyways211are provided with at least one pair of second electrodes212corresponding and contacting to the at least one pair of first electrodes132of the tool holder chuck130. The receiving portion220is disposed on the middle portion of the tool holder200. A high-frequency vibration module240is disposed inside the receiving portion220, and is electrically connected to the at least one pair of second electrodes212. Additionally, the tool chuck230is disposed on the lower portion of the tool holder200, and is configured for clamping and downwardly fixing a cutting tool300.

Refer now toFIG. 4, which is a schematic view of a control method of the machine tool of high-frequency vibration according to a preferred embodiment of the present invention. The machine tool1further comprises an automatic machining control module160and a high-frequency control module170. The automatic machining control module160controls and rotates the rotating shaft120, so as to cause the cutting tool300under the tool holder200to rotate so as to process a cutting operation. The high-frequency control module170controls an electric power/signal to pass through the at least one pair of external electric wires143to the stationary ring141of the stationary coil portion140, then the electric power/signal is transmitted to the at least one primary coil142, and the at least one secondary coil152of the rotating coil portion150is induced to generate an electric power/signal, then the electric power/signal passes through the rotating ring151, and then passes through the at least one pair of inner electric wires153to be transmitted to the at least one pair of first electrodes132of the tool holder chuck130, then the electric power/signal is transmitted to the at least one pair of second electrodes212of the holder shank portion210, and finally the electric power/signal is transmitted to the high-frequency vibration module240to provide the cutting tool300with a high-frequency vibration.

As described above, in the present invention, because the rotating ring151is disposed on the rotating shaft120, and the electric power/signal is transmitted into the high-frequency vibration tool holder200by the contact type first electrodes132and second electrodes212, so that it can avoid an electrode wear phenomenon of a contact type rotating electrodes, and because the rotating ring151is disposed outside of the tool holder200, the manufacturing cost of the tool holder is reduced and the convenience of changing the tool holder is increased.

Furthermore, preferably, the pair of first electrodes132can be contact type spring electrodes, and the pair of second electrodes212includes conducting sheets in the inner ground and insulating sheets in the periphery thereof.

Preferably, the pair of the first electrodes132includes a positive electrode and a negative electrode, and the pair of the second electrodes212correspondingly includes a positive electrode and a negative electrode.

Preferably, the high-frequency vibration module240can be selected from a group of a piezoelectric actuator, a voice coil actuator, and a magnetic actuator.

In another possible embodiment of the present invention, the number of the primary coils142is two (or more than two) and that of the secondary coils152is correspondingly two (or more than two), wherein one set of the primary coil142and the secondary coil152are configured for transmitting electric power and carrier wave signals, and the other set of the primary coil142and the secondary coil152are only configured for transmitting carrier wave signals.

Refer now toFIG. 4again.FIG. 4shows a control method of sensing/feedback signals of the above-mentioned machine tool of high-frequency vibration:

Firstly, providing a machine tool1and a high-frequency vibration tool holder200, wherein the machine tool1is provided with an automatic machining control module160, a high-frequency control module170, a wireless signal receiving module180and a computer module190; and the high-frequency vibration tool holder200is provided with a high-frequency vibration module240, a sensing module250, and a wireless signal transmitting module260.

Next, the automatic machining control module160controls a rotating power and a feed quantity of the high-frequency vibration tool holder200of the machine tool1to process a work piece; and the high-frequency control module170controls the high-frequency vibration tool holder200to generates a high-frequency vibration.

Next, the sensing module250transmits at least one sensing data to the wireless signal receiving module180by the wireless signal transmitting module260, and the sensing data is analyzed and computed by the computer module190.

Next, the computer module190transmits an analyzed result of the sensing data to be a control command outputting to the automatic machining control module160and/or the high-frequency control module170.

Finally, the automatic machining control module160adjusts the rotating power and the feed quantity of the high-frequency vibration tool holder200, and the high-frequency control module170adjusts the vibration frequency of the high-frequency vibration tool holder200, so that the machining stability and efficiency of the high-frequency vibration tool holder200is improved.

As described above, the machine tool of high-frequency vibration of the present invention further comprises a wireless signal receiving module180and a computer module190; and the high-frequency vibration tool holder200further comprises a sensing module250and a wireless signal transmitting module260. Therefore, the sensing module250is configured to transmit at least one sensing data to the wireless signal receiving module180by the wireless signal transmitting module260, and after the sensing data is analyzed and computed by the computer module190, the computer module190transmits the analyzed result to be a control command outputting to the automatic machining control module160and the high-frequency control module170, so as to improve the machining stability and efficiency of the high-frequency vibration tool holder200.

Furthermore, preferably, the sensing module250can include a strain gauge, and the sensing data includes an internal stress data of the high-frequency vibration tool holder200sensed by the strain gauge.

Preferably, the sensing module250can include a thermometer, and the sensing data includes a temperature data of the high-frequency vibration tool holder200sensed by the thermometer.

Preferably, the sensing data can be increased by a signal amplifier (not shown).

Selectively, the high-frequency vibration tool holder200can also use the above-mentioned non-contact type electric power/signal transmitting method to transmit the data of the high-frequency vibration into the computer module190, so as to control the high-frequency control module170adjusting the vibration frequency of the high-frequency vibration module240. Since this is a known technology, which may possibly be used in the present invention, it is not descripted herein.

In the present invention, by the control method of sensing/feedback signals with wireless transmission, the sensed data, such as the frequency of the high-frequency vibration, the internal stress of the tool holder200and/or the temperature of the tool holder200, is transmitted into the computer module190for combination analysis, so as to control the automatic machining control module160and/or the high-frequency control module170.

As shown inFIG. 5A, the sensing module250can include at least one strain gauge251, which is installed in any direction inside of the high-frequency vibration tool holder200, and is used to sense a variation of the internal stress, namely manufacturing loading, of the tool holder200in the direction in which the strain gauge251is installed. That is, by the sensed data, the computer module190can analyze a change of the manufacturing loading of the tool holder200in the direction.

For example, by an ideal condition or a former record of the manufacturing loading of the strain gauge, a standard curve S0of manufacturing loading is established, and a default range, a maximum value MAX and a minimum MIN, is also established. As shown inFIG. 5B, after the feedback data is analyzed by the computer module190, if the present manufacturing loading S1is bigger than the maximum value MAX, the computer module190will issue a command to the automatic machining control module160to lower the rotating power and the feed quantity of the high-frequency vibration tool holder200, so as to reduce the manufacturing loading in the direction. Next, as shown inFIG. 5C, now the feedback data shows that the present manufacturing loading S1is back to the default range, so that the machining stability of the high-frequency vibration tool holder200is improved.

Oppositely, if the present manufacturing loading S1is smaller than the minimum value MIN, the computer module190will issue a command to the automatic machining control module160to increase the rotating power and the feed quantity of the high-frequency vibration tool holder200, so as to improve the machining efficiency of the high-frequency vibration tool holder200.

Certainly, the high-frequency vibration tool holder200can select to install a plurality of the strain gauges251in many wanted directions, so as to sense loading situations in the many directions or an axial direction of high-frequency vibration tool holder200, or to estimate the consuming situation of the tool holder200. Therefore, the automatic machining control module160is commanded to adjust the rotating power and the feed quantity of the high-frequency vibration tool holder200.

According to the above-mentioned design, non-contact coils transmitting electric power/signal avoids a wear phenomenon of electrodes. Additionally, because the inductive coil is arranged outside of the tool holder, the manufacturing cost of the tool holder is reduced and the convenience of changing the tool holder is increased. Moreover, the machining stability and efficiency of the high-frequency vibration tool holder is improved by a control method of sensing/feedback signals with wireless transmission.

The present invention has been described with preferred embodiments thereof and it is understood that many changes and modifications to the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.