Numerical controller and machine tool
阅读说明:本技术 数值控制装置和机床 (Numerical controller and machine tool ) 是由 渡边俊大 于 2020-03-12 设计创作,主要内容包括:本发明提供一种数值控制装置和机床,数值控制装置能够抑制使多个驱动轴的速度周期性地变化的机床的振动。本公开的一个方式所涉及的数值控制装置基于加工程序来控制直线驱动的至少2个摆动驱动轴,使得互不相同的对象物分别以固定的周期规则性地进行速度变化,该数值控制装置控制所述至少2个摆动驱动轴,使得所述至少2个摆动驱动轴的周期性变化分量的相位差保持固定。(The invention provides a numerical controller and a machine tool, the numerical controller can restrain vibration of the machine tool which enables speeds of a plurality of driving shafts to change periodically. A numerical controller according to one aspect of the present disclosure controls at least 2 swing drive shafts that are linearly driven based on a machining program so that objects different from each other regularly change speed at a fixed period, and controls the at least 2 swing drive shafts so that a phase difference of a periodically changing component of the at least 2 swing drive shafts is kept constant.)
1. A numerical controller controls at least 2 swing drive shafts driven linearly based on a machining program so that different objects regularly change in speed at a fixed period,
the numerical control device controls the at least 2 oscillating drive shafts such that the phase difference of the periodically changing components of the at least 2 oscillating drive shafts remains fixed.
2. The numerical controller according to claim 1, comprising:
a swing condition acquisition unit that acquires the amplitude and frequency of the periodically varying component of the at least 2 swing drive shafts from the machining program;
a phase difference setting unit that sets a phase difference of the periodically changing components of the at least 2 swing drive shafts;
a swing phase setting section that assigns different phases to the at least 2 swing drive axes so that the at least 2 swing drive axes obtain the phase difference set by the phase difference setting section; and
and a command generation unit that generates a command signal for operating the at least 2 swing drive shafts at the phase assigned by the swing phase setting unit.
3. The numerical control apparatus according to claim 2,
the swing phase setting unit calculates the phase of at least 1 of the other swing drive shafts by adding the phase difference set by the phase difference setting unit to the phase of the specific swing drive shaft.
4. A numerical control apparatus according to claim 3,
the command generation unit includes a reference phase acquisition unit that acquires a phase to be a reference based on a value of a command signal for the specific swing drive axis or a value of a feedback signal from the swing drive axis.
5. The numerical control apparatus according to claim 4,
the reference phase acquisition unit calculates the current phase of the specific oscillating drive shaft based on the value of the command signal for the specific oscillating drive shaft or the value of the feedback signal from the specific oscillating drive shaft, and the amplitude and frequency of the periodically varying component acquired by the oscillation condition acquisition unit.
6. Numerical control apparatus according to any one of claims 2 to 5,
the command generation unit includes:
a reference value calculation unit that calculates a reference value corresponding to a fixed speed obtained by removing a periodically varying change amount from a speed of the swing drive shaft based on the machining program;
a deviation calculation unit that calculates a deviation from the reference value that varies periodically with the amplitude and frequency of the periodically varying component acquired by the oscillation condition acquisition unit and the phase assigned by the oscillation phase setting unit; and
a target value calculation unit that calculates a target value of the swing drive shaft by adding the reference value and the deviation.
7. The numerical control apparatus according to any one of claims 1 to 6,
the numerical controller maintains phase differences of the 2 swing drive shafts for driving the object in directions parallel to each other at substantially a half cycle.
8. The numerical control apparatus according to claim 7,
the amplitude of the periodically varying components of the 2 oscillating drive shafts are approximately equal.
9. A machine tool is provided with:
the numerical control apparatus according to any one of claims 1 to 8; and
at least 2 oscillating drive shafts controlled by the numerical control device.
Technical Field
The present invention relates to a numerical controller and a machine tool.
Background
A machine tool such as a lathe is used, which includes a spindle for relatively rotating a cutting tool with respect to a workpiece to be machined, and a feed shaft for relatively moving the cutting tool with respect to the workpiece in a direction parallel to a rotation axis of the spindle, and cuts the workpiece with the cutting tool by cooperating the spindle and the feed shaft. The main spindle, feed shaft, and other drive shafts in such machine tools are often controlled by a numerical controller.
In a machine tool such as a lathe, since a cutting edge of a cutting tool continuously cuts off a material of a surface of a workpiece, the cut-off material becomes a slender chip (chip) depending on a material of the workpiece, and may be entangled and attached to the cutting tool to hinder machining of the workpiece. In contrast, as described in patent document 1, for example, the following technique is known: the numerical controller is used to perform the oscillating cutting in which the cutting tool is reciprocated relative to the workpiece by regularly changing the speed of the cutting tool at a fixed cycle. In the oscillating cutting, the cutting tool is moved back and forth to periodically separate the cutting tool from the workpiece, and thus the chips are cut at a constant length.
In order to efficiently perform machining, a machine tool is known, which can simultaneously drive a plurality of workpieces and a plurality of tools corresponding to the respective workpieces, such as a parallel double-spindle lathe described in patent document 2.
Disclosure of Invention
Problems to be solved by the invention
When the swing cutting described in patent document 1 is applied to a machine tool having independent drive axes such as a parallel double-spindle lathe described in patent document 2, the swings of the drive axes of reciprocating motions of a plurality of tools and the like are overlapped, and the entire machine tool may vibrate in accordance with the swing cycle of the drive axes. As a result, there is a possibility that an abnormal load is generated in the machine tool, the loss of the tool is increased, or the machining accuracy is lowered.
Accordingly, an object of the present disclosure is to provide a numerical controller and a machine tool, the numerical controller being capable of suppressing vibration of the machine tool that periodically changes the speeds of a plurality of drive axes.
Means for solving the problems
A numerical controller according to one aspect of the present disclosure controls at least 2 swing drive shafts that are linearly driven based on a machining program so that objects different from each other regularly change speed at a fixed period, wherein the numerical controller controls the at least 2 swing drive shafts so that a phase difference of a periodically changing component of the at least 2 swing drive shafts is kept constant.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present disclosure, it is possible to provide a numerical controller capable of suppressing vibration of a machine tool in which speeds of a plurality of drive axes periodically change.
Drawings
Fig. 1 is a schematic diagram illustrating a structure of a machine tool according to a first embodiment of the present disclosure.
Fig. 2 is a block diagram showing the configuration of a numerical controller of the machine tool of fig. 1.
Fig. 3 is a block diagram showing a configuration of a numerical controller according to a second embodiment of the present disclosure.
Fig. 4 is a block diagram showing a configuration of a numerical controller according to a third embodiment of the present disclosure.
Fig. 5 is a schematic diagram showing a configuration of a modified example of the machine tool according to the present disclosure.
Fig. 6 is a schematic diagram showing the configuration of another modification of the machine tool according to the present disclosure.
Fig. 7 is a schematic diagram showing a configuration of a further modification of the machine tool according to the present disclosure.
Description of the reference numerals
100: a machine tool; 1.1 a, 1 b: a numerical control device; az1, Az 2: a swing drive shaft; w1, W2: a workpiece; t1, T2: a cutting tool (object); 10: a program analysis unit; 21. 22: a first swing condition acquisition unit; 30: a phase difference setting unit; 40. 40 a: a reference phase acquisition unit; 50. 50 b: a swing phase setting unit; 61. 62, 61b, 62 b: an instruction generation unit; 71. 72: a reference value calculation unit; 81. 82, 81b, 82 b: a deviation calculation unit; 91. 92: a target value calculation unit.
Detailed Description
An embodiment of a machine tool according to an embodiment of the present disclosure will be described below with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of a
The
More specifically, the
The numerical controller 1 controls the main shafts Ac1, Ac2, the swing drive shafts Az1, Az2, and the cutting shafts Ax1, Ax 2. The numerical controller 1 controls the 2 swing drive shafts Az1 and Az2 so that the speed of different objects (cutting tools T1 and T2) is regularly changed at a fixed cycle. The numerical controller 1 is characterized in that it controls the 2 swing drive shafts Az1, Az2 so that the phase difference of the periodically changing components of the 2 swing drive shafts Az1, Az2 for driving the cutting tools T1, T2 in the directions parallel to each other is kept constant (approximately half cycle). Therefore, the frequency of the speed change of the first swing drive shaft Az1 and the frequency of the speed change of the second swing drive shaft Az2 are controlled to be equal values.
As a specific configuration, the numerical controller 1 may be configured to include: a
The numerical controller 1 can be realized by reading an appropriate program into a computer device having a CPU, a memory, and the like. The respective components of the numerical controller 1 may be functionally classified, that is, may not be clearly classified in terms of physical configuration and structure of a program for realizing the numerical controller 1.
The
The first weaving
The phase
The reference
The swing
The first
Specifically, the first
The reference
The
The
As described above, in the
Since the numerical controller 1 includes the oscillation
In the numerical controller 1, the swing
In the numerical controller 1 according to the present embodiment, the reference
Further, the numerical controller 1 controls the 2 swing drive shafts Az1, Az2 so that the phase difference of the periodically changing components of the 2 swing drive shafts Az1, Az2 for driving the cutting tools T1, T2 in the directions parallel to each other is maintained at substantially half a cycle, and therefore, it is possible to reliably prevent the forces acting on the 2 swing drive shafts Az1, Az2 from overlapping and increasing. In this case, it is preferable that the amplitudes of the periodic variation components of the 2 swing drive shafts Az1 and Az2 are substantially equal to each other so that 2 workpieces can be processed equally. The phrase "substantially equal in amplitude" means that the ratio of the larger amplitude to the smaller amplitude is preferably 1.5 or less, more preferably 1.2 or less, and still more preferably 1.1 or less.
Next, a
The numerical controller 1a may include: a program analysis unit 10 that analyzes the machining program; a wobble condition acquisition unit that acquires the amplitude and frequency of the periodic variation component of the 2 wobble drive shafts Az1, Az2 (a first wobble condition acquisition unit 21 that acquires the amplitude and frequency of the periodic variation component of the first wobble drive shaft Az1, and a second wobble condition acquisition unit 22 that acquires the amplitude and frequency of the periodic variation component of the second wobble drive shaft Az 2) from the machining program analyzed by the program analysis unit 10; a phase difference setting unit 30 that sets the phase difference of the periodically changing components of the 2 swing drive axes Az1, Az 2; a reference phase acquisition unit 40a that acquires the phase of the first swing drive shaft Az1 that becomes a reference; a swing phase setting unit 50 that assigns different phases to the first swing drive shaft Az1 and the second swing drive shaft Az2 so that the phase difference set by the phase difference setting unit 30 is obtained for the swing drive shafts Az1 and Az 2; and a command generating unit that generates command signals for operating the swing drive shafts Az1 and Az2 at the phases assigned by the swing phase setting unit 50 (the first command generating unit 61 that generates a command signal for operating the first swing drive shaft Az1, and the second command generating unit 62 that generates a command signal for operating the second swing drive shaft Az 2).
The
The reference
In the
A numerical controller 1b according to a third embodiment of the present disclosure will be further described. Fig. 4 is a block diagram showing a configuration of a numerical controller 1b that can be used in place of the numerical controller 1 of fig. 2 in the
The numerical controller 1b can be configured to include: a program analysis unit 10 that analyzes the machining program; a wobble condition acquisition unit that acquires the amplitude and frequency of the periodic variation component of the 2 wobble drive shafts Az1, Az2 (a first wobble condition acquisition unit 21 that acquires the amplitude and frequency of the periodic variation component of the first wobble drive shaft Az1, and a second wobble condition acquisition unit 22 that acquires the amplitude and frequency of the periodic variation component of the second wobble drive shaft Az 2) from the machining program analyzed by the program analysis unit 10; a phase difference setting unit 30 that sets the phase difference of the periodically changing components of the 2 swing drive axes Az1, Az 2; a swing phase setting unit 50b that assigns different phases to the first swing drive shaft Az1 and the second swing drive shaft Az2 so that the phase difference set by the phase difference setting unit 30 can be obtained; and a command generating unit that generates command signals for operating the swing drive shafts Az1 and Az2 at the phases assigned by the swing phase setting unit 50b (the first command generating unit 61b that generates a command signal for operating the first swing drive shaft Az1, and the second command generating unit 62b that generates a command signal for operating the second swing drive shaft Az 2).
The wobble phase setting unit 50b supplies the first
The first command generating unit 61b includes: a reference
The first deviation calculation unit 81b can calculate the deviation Δ 1 as, for example, h1 · sin (360 ° · f · t + Φ 1). In this case, the second deviation calculation unit 82b can calculate the deviation Δ 2 as, for example, h2 · sin (360 °. f · t + Φ 2). In this way, by calculating the target values of the first swing drive axis Az1 and the second swing drive axis Az2 as a function of time by the first
Although the embodiments of the numerical controller and the machine tool according to the present disclosure have been described above, the numerical controller and the machine tool according to the present disclosure are not limited to the above-described embodiments. The effects described in the present embodiment are merely the best effects produced by the present disclosure, and the effects produced by the numerical controller and the machine tool according to the present disclosure are not limited to the effects described in the present embodiment.
The numerical controller according to the present disclosure may control 3 or more swing drive shafts such that the phase difference of the periodically changing component of the 3 or more swing drive shafts remains constant. As an example, in the case where 3 cutting tools that perform the same cutting are driven by 3 swing drive shafts, respectively, the numerical controller according to the present disclosure may control the 3 swing drive shafts such that the phases of the periodically changing components of the respective swing drive shafts are maintained in a state of being different from each other by 120 °. This also prevents the forces acting on the 3 oscillating drive shafts from overlapping each other and causing large vibrations. In this case, the phase of 1 of the 3 swing drive shafts may be used as a reference, and the phase of the other 2 swing drive shafts may be controlled so that the phase difference with respect to the reference phase is a fixed angle. That is, a plurality of slave drive shafts may be subordinate to 1 master drive shaft.
The machine tool according to the present disclosure may be a lathe including 2 swing drive shafts Az1 and Az2 for driving 2 tools T1 and T2 for simultaneously machining different portions of a single workpiece W as shown in fig. 5, or may be a multi-spindle machining center including 2 swing drive shafts Az1 and Az2 for relatively moving a plurality of workpieces W1 and W2 and a plurality of rotary tools T1 and T2 as shown in fig. 6. The machine tool according to the present disclosure may be a multi-axis grinding apparatus (not shown) that periodically changes the speed of different grinding materials (tools) or grinding objects (workpieces), or may be a multi-axis electric discharge machining apparatus (not shown) that changes the distances between a plurality of workpieces and electrodes. Therefore, the numerical controller according to the present disclosure can be applied to control of such various machine tools.
The numerical controller and the machine tool according to the present disclosure are used not only to suppress vibration generated by contact between a tool and a workpiece, but also to suppress vibration that may be generated in the apparatus due to an inertial force of an object driven by an oscillating drive shaft. That is, the numerical controller according to the disclosure may control the phases and amplitudes of the swing drive shafts so as to cancel out the inertial forces of the tool, the workpiece, and the like driven by the plurality of swing drive shafts and the base, the chuck, and the like for holding the tool, the workpiece, and the like. In addition, in this case, the driven swing drive shaft may include a drive shaft that is not necessary for machining in the machine tool. As the drive shaft which is not necessary for the machining, for example, a drive shaft for driving a chuck, a base, or the like of an unretained workpiece or a tool can be used.
As an example, the machine tool shown in fig. 7 includes: a first swing drive shaft Az1 that drives a first cutting tool T1 for turning a first workpiece W1; a second swing drive shaft Az2 that drives a second cutting tool T2 for turning the second workpiece W2 in the same phase in a direction parallel to the first swing drive shaft Az 1; and a third swing drive shaft Az3 that drives, for example, the milling head F or the like in a phase different by a half cycle in a direction parallel to the first swing drive shaft Az1 and the second swing drive shaft Az2 in order to cancel out vibrations of the first swing drive shaft Az1 and the second swing drive shaft Az 2.
The numerical controller according to the present disclosure may set a plurality of groups each including a plurality of swing drive shafts, and may keep the phase difference of the swing drive shafts in each group constant. At this time, the period of the speed change may be different between the groups.
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