JP6994838B2 - Machine tool controls and machine tools - Google Patents

Description

The present invention relates to a machine tool control device and a machine tool.

When turning a workpiece with a tool, so-called flow-shaped continuous chips are generated and discharged to the surroundings. When this continuous chip wraps around the work or tool, it causes damage to the work or tool. Therefore, for example, Patent Document 1 discloses a method of vibration cutting processing in which a work is reciprocated (oscillated) with respect to a tool and can be discharged in a state of chips in which chips are divided.

Jitsukaisho 48-98779 Gazette

However, in the method described in Patent Document 1, it is disclosed that the center line of the swing angle by the cutting tool coincides with the perpendicular line with respect to the cutting feed direction drawn from the center of rotation to the work. In order to improve the machining accuracy of the work and the tool life, it is desired to make it easier for cutting oil to enter between the work and the cutting tool.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a machine tool control device and a machine tool that facilitates the entry of cutting oil in vibration cutting.

First, the present invention relates to the relative rotation of the work and the cutting tool, the relative movement of the work and the cutting tool in the cutting feed direction of the work, and the predetermined position as the center of rotation. A control device for a machine tool that vibrates and cuts the work by a control means that controls forward and backward movement of the cutting tool with respect to the work in the cutting feed direction of the work. The vertical line drawn from the center of rotation to the work in the cutting feed direction is located on the most forward position side of the swing range of the cutting tool with respect to the center line that bisects the swing range of the cutting tool. It has a swing adjusting means for swinging the cutting tool by setting the swing adjusting means, and the swing adjusting means makes the vertical line move forward and backward in the angle of the swing range of the cutting tool. It is characterized in that it is sometimes set so that it is on the most forward position side of the swing range of the cutting tool with respect to the center line by half the angle at the time of non-cutting, which is the period during which the work and the cutting tool are not in contact with each other. And.

Secondly, the present invention relates to the relative rotation of the work and the cutting tool, the relative movement of the work and the cutting tool in the cutting feed direction of the work, and the predetermined position as the center of rotation. A control device for a machine tool that vibrates and cuts the work by a control means that controls forward and backward movement of the cutting tool with respect to the work in the cutting feed direction of the work. The vertical line drawn from the center of rotation to the work in the cutting feed direction is located on the most forward position side of the swing range of the cutting tool with respect to the center line that bisects the swing range of the cutting tool. It has a swing adjusting means for swinging the cutting tool by setting the swing adjusting means, and the swing adjusting means makes the vertical line move forward and backward in the angle of the swing range of the cutting tool. It is characterized in that it is sometimes set so as to be the center of the angle at the time of cutting, which is the period during which the work and the cutting tool are in contact with each other .

Thirdly, it is a machine tool provided with a control device for any of the above machine tools .

The present invention can obtain the following effects.
(1) The vertical line drawn from the center of rotation to the work in the cutting feed direction is shifted closer to the most advanced position of the cutting tool than the center line of the swing angle of the cutting tool. The gap between the and can be increased. Since this gap can be used to promote the entry of cutting oil, it is possible to improve the machining accuracy of the work and the tool life.
Furthermore, the vertical line drawn from the center of rotation to the work in the cutting feed direction is shifted to the most forward position from the center line of the swing angle by half the angle of the swing range of the cutting tool when not cutting. For example, it is possible to reduce the gap between the cutting tool and the work when the cutting tool moves forward, and increase the gap between the cutting tool and the work when the cutting tool moves backward. As a result, it is possible to further improve the machining accuracy of the work and the tool life.

(2) The vertical line drawn from the center of rotation to the work in the cutting feed direction is shifted closer to the most advanced position of the cutting tool than the center line of the swing angle of the cutting tool. The gap between the and can be increased. Since this gap can be used to promote the entry of cutting oil, it is possible to improve the machining accuracy of the work and the tool life.
Furthermore, if the vertical line drawn from the center of rotation to the work in the cutting feed direction is set to be the center of the angle at the time of cutting among the angles of the swing range of the cutting tool, it will be connected to the work when the cutting tool is advanced. While reducing the gap, it is possible to increase the gap with the work when the cutting tool is retracted. As a result, it is possible to further improve the machining accuracy of the work and the tool life.

(3) It is possible to provide a machine tool capable of improving the machining accuracy of the work and improving the tool life.

It is a figure which shows the outline of the machine tool according to one Example of this invention. It is a schematic diagram which shows the relationship between a cutting tool and a work. It is a figure explaining the reciprocating movement and the position of a cutting tool. It is a figure which shows the relationship of the cutting edge path at each rotation of the nth rotation, the n + 1th rotation, and the n + 2nd rotation of the spindle. It is a block diagram of a control device. It is a figure which shows the relationship between the cutting edge path of a cutting tool, and the swing range. It is a figure explaining the calculation of a cutting width and a non-cutting width. It is a figure explaining the calculation of the forward position angle and the backward position angle.

Hereinafter, the control device and the machine tool of the machine tool of the present invention will be described with reference to the drawings. As shown in FIG. 1, the machine tool 100 includes a spindle 110, a cutting tool 130 such as a cutting tool for vibrating a work W (hereinafter referred to as machining), and a control device 180.
A chuck 120 is provided at the tip of the spindle 110, and the work W is held by the spindle 110 via the chuck 120. The spindle 110 is rotatably supported by the spindle 110A, and is rotated by the power of a spindle motor (for example, a built-in motor) provided between the spindle 110A and the spindle 110, for example.

The cutting tool 130 is mounted on the cutting tool base 130A.
The bed of the machine tool 100 is provided with a Z-axis direction feed mechanism 160, an X-axis direction feed mechanism 150, and a B-axis rotation mechanism 170.
The Z-axis direction feed mechanism 160 includes a base 161 integrated with the bed and a Z-axis direction guide rail that slidably supports the Z-axis direction feed table. When the Z-axis direction feed table moves along the Z-axis direction (corresponding to the rotation axis direction of the work W) by driving a linear servomotor (both not shown), the cutting tool base 130A moves in the Z-axis direction. Moving.

The X-axis direction feed mechanism 150 is mounted on the bed of the machine tool 100 via, for example, the Z-axis direction feed mechanism 160, and includes an X-axis direction guide rail that slidably supports the X-axis direction feed table. When the X-axis direction feed table moves along the X-axis direction orthogonal to the Z-axis direction shown by driving a linear servomotor (both not shown), the cutting tool table 130A moves in the X-axis direction.

The B-axis rotation mechanism 170 is mounted on the bed of the machine tool 100 via, for example, the Z-axis direction feed mechanism 160 and the X-axis direction feed mechanism 150, and includes a base that rotatably supports the B-axis rotation table. ing. When the B-axis rotation table swings around a predetermined rotation center (for example, shown by B in FIG. 2) by the forward / reverse drive of a linear servomotor (both not shown), the cutting tool table 130A becomes an XZ plane. It repeats forward and backward along the cutting feed direction (for example, the Z-axis direction).

The Y-axis direction feed mechanism may be provided in the machine tool 100. The Y-axis direction is a direction orthogonal to the Z-axis direction and the X-axis direction shown in the figure. The Y-axis direction feed mechanism also has a Y-axis direction feed table that can be driven by a linear servomotor. When the Y-axis direction feed mechanism is mounted on the bed of the machine tool 100 via the Z-axis direction feed mechanism 160 and the X-axis direction feed mechanism 150, and the cutting tool base 130A is mounted on the Y-axis direction feed table, the cutting tool 130 is Z. It can be moved not only in the axial direction and the X-axis direction but also in the Y-axis direction. The Z-axis direction feed mechanism 160 and the X-axis direction feed mechanism 150 may be mounted on the bed of the machine tool 100 via the Y-axis direction feed mechanism.

The rotation of the spindle 110 and the movement of the B-axis rotation mechanism 170, the Z-axis direction feed mechanism 160, the X-axis direction feed mechanism 150, the Y-axis direction feed mechanism (hereinafter referred to as the B-axis rotation mechanism 170, etc.) It is controlled by the control device 180. The control device 180 drives the spindle motor to rotate the work W with respect to the cutting tool 130 in the direction of the arrow in FIG. 2, and drives the Z-axis direction feed mechanism 160 to move the cutting tool 130 with respect to the work W in FIG. The cutting tool 130 is moved in the positive direction of the Z-axis and drives the B-axis rotation mechanism 170 to swing the cutting tool 130 in the positive and negative directions of the Z-axis of FIG. 2 with respect to the work W.

Although it has been described that the cutting tool base 130A can be moved, the present invention is not limited to this example. The headstock 110A may be movable in the negative direction of the Z axis of FIG. 2, or the headstock 110A may be movable in the X, Y, and Z axis directions. Alternatively, both the headstock 110A and the cutting tool base 130A may be movable.
Although the example in which the linear servomotor is used for the B-axis rotation mechanism 170 or the like has been described, a known ball screw and servomotor may be used.

FIG. 2 shows, for example, a case where the work W rotates with respect to the cutting tool 130, the cutting feed direction is parallel to the Z-axis direction, and the work W advances in the positive direction, and the cutting tool 130 moves with respect to the work W on the Z-axis. An example of moving in a direction and swinging in the Z-axis direction with respect to the center of rotation B is shown.
The control device 180 moves the cutting tool 130 in the positive direction of the Z axis by a predetermined forward amount (forward movement), and then moves the cutting tool 130 in the negative direction of the Z axis by a predetermined backward amount (the control device 180). (Recover). As a result, as shown in FIG. 3, the cutting tool 130 can be fed to the work W by the difference (advancement amount) between the forward amount and the backward amount.

Specifically, the work W is rotated in a predetermined direction by the spindle motor. On the other hand, the cutting tool 130 is fed in the positive direction of the Z axis by the Z-axis direction feed mechanism 160, and is forwarded in the positive direction of the Z axis and returned in the negative direction of the Z axis by the B-axis rotation mechanism 170. This is repeated, and the feed amount is the sum of the amount of progress for one rotation of the work W, that is, the amount of progress during the change from 0 ° to 360 ° of the spindle phase.

As a result, the peripheral surface of the work W is machined into a sinusoidal curve by the cutting tool 130. FIG. 4 shows an example in which the number of times the cutting tool 130 reciprocates (also referred to as the number of vibrations D per rotation) while the work W makes one rotation is 3.5 (times / r).
The peripheral surface shape of the work W at the n (n is an integer of 1 or more) rotation of the spindle 110 machined by the cutting tool 130 (shown by the solid line in FIG. 4) and the circumference of the work W at the n + 1th rotation of the spindle 110. The surface shape (shown by the broken line in FIG. 4) has the phase of vibration inverted and is deviated in the main axis phase direction (horizontal axis direction of the graph of FIG. 4). Specifically, since the waveforms of each sinusoidal curve are reversed, the lowest point of the valley of the peripheral surface shape of the work W shown by the broken line in FIG. 4 (the highest point of the mountain in the cutting tool 130) in the same spindle phase. Is opposed to the position of the highest point (the lowest point of the valley in the cutting tool 130) of the peripheral surface shape of the work W shown by the solid line in FIG.

As a result, the cutting edge locus of the cutting tool 130 overlaps the machined portion at the time of the reciprocating movement this time and the machined portion at the time of the next reciprocating movement. Since the peripheral surface shape of the work W at the nth rotation of the spindle 110 is included, the cutting tool 130 causes an idle swing operation without machining the work W. During this air swing operation, the chips generated from the work W are divided into chips. In this way, the machine tool 100 processes the outer shape of the work W while generating chips.

The number of vibrations D per rotation can be, for example, 1.1 or 1.25 (times / r), or can be set to a value smaller than 1 (times / r). When the vibration frequency D is set to a value smaller than 1 (times / r), for example, 0.5, the spindle 110 makes two rotations while the spindle 110 makes one reciprocation in the Z-axis direction.

As shown in FIG. 5, the control device 180 has a control unit 181 and an input unit 182, and a storage unit 183, which are connected via a bus.
The control unit 181 includes a motor control unit 190 that is composed of a CPU or the like and controls the operation of each motor, and a vibration adjustment unit 191 that sets the feed of the Z-axis direction feed mechanism 160 and the swing of the B-axis rotation mechanism 170. Be prepared. The control unit 181 corresponds to the control means of the present invention, and the vibration adjustment unit 191 corresponds to the swing adjustment means of the present invention.

The control unit 181 loads various programs and data stored in, for example, the ROM of the storage unit 183 into the RAM, and executes the various programs to execute the machine tool 100 via the motor control unit 190 and the vibration adjustment unit 191. You can control the operation of.
The reciprocating motion of the cutting tool 130 is executed at a vibration frequency f based on a predetermined command cycle T. The vibration frequency f is determined from the vibration frequency D and the rotation speed R of the spindle 110.

The control unit 181 can obtain a predetermined vibration waveform based on, for example, the input value of the input unit 182 or the machining program. More specifically, the number of times the cutting tool 130 reciprocates (vibration number D per rotation) during one rotation of the work W, which is shown in FIG. 6, will be described with reference to an example of 1.5 (times / r). The cutting tool 130 operates like a pendulum between the most advanced position E and the last retracted position G with respect to the rotation center B while being fed in the Z-axis direction. Since the cutting tool 130 reciprocates back and forth along the Z-axis direction by moving forward (from G to E) and backward (from E to G), the machining area of the nth rotation of the spindle 110 (work W) (FIG. 6). (Indicated by a solid line), a machining region at the n + 1st rotation (shown by a broken line in FIG. 6), and a machining region at the n + 2nd rotation (shown by a dotted chain line in FIG. 6) are obtained.

In the Z-axis direction, the distance between the most forward position E and the last retracted position G is the amplitude Q * F of the vibration waveform, Q is the amplitude feed ratio (dimensionless number), and F is the feed amount (mm / r). ).
The period in which the work W and the cutting tool 130 are in contact with each other when the cutting tool 130 is advanced and retracted is, for example, the n + 1th rotation machining area shown by the broken line in FIG. 6 and the n + 2 rotation shown by the alternate long and short dash line in FIG. It corresponds to the period that does not overlap with the machined area of the eye (during cutting of the work W (during cutting) ; indicated by the area 200). When the work W is cut, it corresponds to the spindle phases θ1 to θ3, and when the cutting tool 130 reaches the most advanced position E, it becomes the tool position Z2.

On the other hand, the period during which the work W and the cutting tool 130 are not in contact with each other when the cutting tool 130 is advanced and retracted is shown by, for example, the n + 1th rotation machining region shown by the broken line in FIG. 6 and the one-point chain line in FIG. It corresponds to the period in which the machining area of the n + 2nd rotation overlaps (when the cutting tool 130 is idle (when not cutting) ; indicated by the area 201). When the cutting tool 130 is idle, it corresponds to the spindle phases θ3 to θ5, and when the cutting tool 130 reaches the last retracted position G, it becomes the tool position Z4.

The vibration adjusting unit 191 has a swing range of the cutting tool 130 in order to improve the machining accuracy of the work W and the tool life based on the relationship between the cutting edge path of the cutting tool 130 and the swing range as described above. The amplitude center position C of the cutting tool 130 is set to a position different from the foot H of the perpendicular line with respect to the cutting feed direction drawn from the rotation center B of the cutting tool 130 to the work W.

Specifically, regarding the cutting edge path of the cutting tool 130 described with reference to FIG. 6, first, the intersection of the n + 2nd rotation machining region shown by the alternate long and short dash line in FIG. 6 and the n + 1th rotation machining region shown by the broken line in FIG. The main axis phases θ1, θ3, and θ5 are obtained.
Here, considering the magnitude of the feed amount F, the upward-sloping slope of the waveform can be ignored. Therefore, the waveform described with reference to FIG. It can be approximated to a waveform that travels in the horizontal direction without inclination as shown by (indicated by the broken line). Further, in order to facilitate the calculation, it is considered that the cutting tool 130 has reached the last retracted position G in the vibration waveform when the spindle phase is 0 °.

The machined region of the n + 2nd rotation shown by the alternate long and short dash line in FIG. 6 is used as the reference vibration waveform (shown by the waveform in FIG. 7). Focusing on the processing area of the n + 2nd rotation and the processing area of the vibration waveform of the n + 1th rotation (shown by the waveform one lap before in FIG. 7) shown by the broken line in FIG. Expressed on the right side, the intersection of the waveform and the waveform one lap before can be obtained from Equation 1.

The main axis phases θ1, θ3, and θ5 obtained from Equation 1 are the intersections of the waveform and the waveform one lap before.
The obtained spindle phases θ1 to θ3 correspond to the time of cutting the work W (region 200 in FIG. 6), and the tool position Z3 of the cutting tool 130 in the spindle phase θ1 (θ3) can be obtained. Then, the tool position Z2 of the cutting tool 130 at the most advanced position E can be obtained from the tool position Z3 and the waveform. As shown in FIG. 7, the distance from the tool position Z3 to Z2 is the width A'at the time of cutting, and corresponds to the angle at the time of cutting among the angles of the swing range of the cutting tool.

On the other hand, the obtained intersection points θ3 to θ5 correspond to the time when the cutting tool 130 is idle (region 201 in FIG. 6), and the tool position Z4 of the cutting tool 130 at the last retreat position G is obtained from the tool position Z3 and the waveform. be able to. As shown in FIG. 7, the distance from the tool positions Z3 to Z4 corresponds to the width A at the time of non-cutting. The sum of the non-cutting width A and the above-mentioned cutting width A'is the amplitude Q * F.

Subsequently, as shown in FIG. 8, the foot H of the perpendicular line drawn from the rotation center B to the work W in the cutting feed direction is used, and the angle formed by this straight line BH and the straight line BE drawn from the rotation center B to the most advanced position E. Let θf be (hereinafter referred to as a forward position angle) θf, and be an angle (hereinafter referred to as a backward position angle) θb formed by this straight line BH and a straight line BG drawn from the rotation center B to the last retracted position G.
In this case, the vibration adjusting unit 191 is set so that the receding position angle θb is larger than the advancing position angle θf.

In this way, the swing range (backward position angle θb) of the cutting tool 130 when retracting with respect to the straight line BH is wider than the swing range (forward position angle θf) of the cutting tool 130 when moving forward with respect to the straight line BH. When the cutting tool 130 is retracted (particularly from H to G in FIG. 8), the gap between the tool tip and the work can be increased. Since this gap can be used to promote the entry of cutting oil, it is possible to improve the machining accuracy of the work and the tool life.
Further, the swing range of the cutting tool 130 is not determined by the shape of the cam as in the prior art, and can be easily changed by inputting machining parameters or the like.

On the other hand, the setting content of the vibration adjusting unit 191 is that the center line (indicated by the straight line BC in FIG. 8) that bisects the pendulum angle of the cutting tool 130 is shifted to the rearmost retracted position G side from the straight line BH. It can be considered that it is set to the position. If the amplitude center position C of the swing range of the cutting tool 130 is shifted toward the last retracted position G, the gap between the tool tip and the work is increased when the cutting tool 130 is retracted (particularly from H to G in FIG. 8). Because it can be done.

Then, in order to maximize the machining accuracy of the work W, paying attention to the above-mentioned width A'at the time of cutting, the straight line BH may be set at a position where the width A'at the time of cutting is bisected. If the forward position angle θf is set so that the straight line BH passes through the midpoint of the width A'during cutting, the gap with the work W is reduced when the cutting tool 130 is advanced (especially from H to E in FIG. 8). This is because the gap between the cutting tool 130 and the work W when the cutting tool 130 is retracted (particularly from H to G in FIG. 8) can be increased.
In other words, the foot H of the perpendicular line drawn from the rotation center B to the work W with respect to the cutting feed direction is the angle of the center of the width A'at the time of cutting among the angles (θf + θb) of the swing range of the cutting tool. It means that it is set to be.

On the other hand, paying attention to the width A at the time of non-cutting, the foot H of the perpendicular line drawn from the rotation center B to the work W in the cutting feed direction is the cutting tool with respect to the amplitude center position C of the cutting tool 130. The cutting tool 130 is shifted by half the width A (that is, A / 2) in the direction opposite to the feeding direction (the positive direction of the Z axis) so that it is on the most forward position E side of the swing range. Just do it.
That is, the foot H of the perpendicular line drawn from the center of rotation B to the work W with respect to the cutting feed direction is bisected from the angle of the swing range of the cutting tool (θf + θb) than the center line that bisects the swing range of the cutting tool. , The width A at the time of non-cutting is set to be on the most forward position E side only by an angle that is halved.

Specifically, assuming that the length of the straight line BE (straight line BG) connecting the rotation center B and the most forward position E (last retracted position G) is L, the amplitude center position C is the straight line BH as shown in FIG. This means that the forward position angle θf is shifted toward the last retracted position G by A / 2, and the forward position angle θf can be obtained from the equation 2 and the backward position angle θb can be obtained from the equation 3. Since Q * F = A + A'as described above, the number 2 (Q * F / 2-A / 2) is half the width A'at the time of cutting (that is, A'/ 2). Equivalent to.

In this case, the gap Gf with the work W when the cutting tool 130 is advanced (particularly from H to E in FIG. 8) is the number 4, and the work W when the cutting tool 130 is retracted (particularly from H to G in FIG. 8). The gap Gb with and can be obtained from the equation 5.

More specifically, an example in which the length L of the straight line BE (straight line BG) is 50 (mm), the amplitude Q * F is 0.06 (mm), and the width A at the time of non-cutting is 0.015 (mm). To explain, when the amplitude center position C is on the straight line BH as in the prior art, the forward position angle θf is 0.034 (deg) and the backward position angle θb is −0.034 (deg). The gap between the cutting tool 130 and the work W was 0.009 (μm).

On the other hand, in the case of the present embodiment, the forward position angle θf is 0.017 (deg), and the gap Gf with the work W when the cutting tool 130 is forward is 0.002 (μm). It can be seen that the surface of W becomes more minute unevenness. Further, the retreat position angle θb is −0.052 (deg), and the gap Gb with the work W when the cutting tool 130 is retracted is 0.021 (μm), so that the entry of cutting oil can be further promoted. I understand.

100 ・ ・ ・ Machine tool 110 ・ ・ ・ Spindle 110A ・ ・ ・ Spindle 120 ・ ・ ・ Chuck 130 ・ ・ ・ Cutting tool 130A ・ ・ ・ Cutting tool base 150 ・ ・ ・ X-axis direction feed mechanism 151 ・ ・ ・ Base 160・ ・ ・ Z-axis direction feed mechanism 161 ・ ・ ・ Base 170 ・ ・ ・ B-axis rotation mechanism 180 ・ ・ ・ Control device 181 ・ ・ ・ Control unit 182 ・ ・ ・ Input unit 183 ・ ・ ・ Storage unit 190 ・ ・ ・Motor control unit 191 ・ ・ ・ Vibration adjustment unit

Claims (3)

The relative rotation of the work and the cutting tool, the relative movement of the work and the cutting tool in the cutting feed direction of the work, and the rotation center of the predetermined position in the cutting feed direction of the work. A control device for a machine tool that vibrates and cuts the work by a control means for controlling the forward and backward swings of the cutting tool with respect to the work.
The control means sets the perpendicular line drawn from the center of rotation to the work in the cutting feed direction to the most forward position of the swing range of the cutting tool with respect to the center line that bisects the swing range of the cutting tool. It has a swing adjusting means that swings the cutting tool by setting it to the side.
The swing adjusting means sets the vertical line during non-cutting, which is a period during which the work and the cutting tool are not in contact with each other when the cutting tool is advanced and retracted within the angle of the swing range of the cutting tool. A machine tool control device that is set so that only half the angle of the cutting tool is on the most forward position side of the swing range of the cutting tool with respect to the center line . The relative rotation of the work and the cutting tool, the relative movement of the work and the cutting tool in the cutting feed direction of the work, and the rotation center of the predetermined position in the cutting feed direction of the work. A control device for a machine tool that vibrates and cuts the work by a control means for controlling the forward and backward swings of the cutting tool with respect to the work.
The control means sets the perpendicular line drawn from the center of rotation to the work in the cutting feed direction to the most forward position of the swing range of the cutting tool with respect to the center line that bisects the swing range of the cutting tool. It has a swing adjusting means that swings the cutting tool by setting it to the side.
The swing adjusting means is used for cutting the vertical line during cutting, which is a period during which the work and the cutting tool are in contact with each other when the cutting tool is advanced and retracted within the angle of the swing range of the cutting tool. A machine tool control device that is set to be the center of the angle . A machine tool provided with the control device for the machine tool according to claim 1 or 2 .

Images