JP2013000808A - Vibration suppressing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration suppressing device that easily and reliably changes a rotational speed into stable rotary speed in changing the rotational speed manually, and reduces a burden on a worker.SOLUTION: On the display screen 12a of a display device 12, an acceleration instruction part 31a and a deceleration instruction part 31b comprising a plurality of indicators 32, 32, ..., are provided so as to display the manipulation direction and the manipulated variable of a dial 14 in changing the rotational speed into the stable rotational speed. Accordingly, the worker easily recognizes the manipulation direction and the manipulated variable of a dial 14 by visually recognizing the display. Thus, the load on the worker is reduced, the rotational speed is reliably changed into the stable rotational speed in a short period of time, and improvement of worked surface precision, breakage prevention of a tool, or the like can be expected.

Description

  The present invention relates to a vibration suppressing device for suppressing chatter vibration generated during machining in a machine tool that performs machining while rotating a tool or a workpiece.

  Conventionally, for example, there is a machine tool that supports a tool on a rotating shaft, moves the tool and / or the workpiece relative to each other while feeding the workpiece, and processes the workpiece with the rotating tool. In the machine tool, a so-called “chatter vibration” occurs during machining due to excessive cutting depth during machining, and there are problems such as deterioration of finishing accuracy of the machined surface and sudden wear and chipping of the tool. Arise.

Therefore, the present applicant has devised a vibration suppression device for suppressing such “chatter vibration” as disclosed in, for example, Patent Document 1. In the vibration suppression device disclosed in Patent Document 1, when the vibration in the frequency domain exceeds a predetermined threshold, it is determined that chatter vibration has occurred, and a stable rotation speed capable of suppressing the chatter vibration is calculated. At the same time, the rotational speed of the rotary shaft is automatically changed to a stable rotational speed.
On the other hand, instead of automatically changing the rotation speed of the rotating shaft, for example, as disclosed in Non-Patent Document 1, candidates for the stable rotation speed against the generated chatter vibration are displayed on the screen, A method has been devised in which one of the stable rotational speeds is selected by the operator and the rotational speed of the rotary shaft is manually changed to a stable rotational speed. As a means for the operator to manually change the rotation speed, the present applicant has devised an override dial as disclosed in Patent Document 2, for example.

JP 2008-290188 A JP 2011-67887 A

Improvement of machining efficiency using “machining navigation”: Industrial Research Co., Ltd. “Machine and Tools” January 2010-pages 73-77

However, in the case of a vibration suppression device that automatically changes the rotation speed, the rotation speed of the rotary shaft is changed at an unexpected timing, and how the rotation speed is changed when viewed by an operator. Since it is not possible to immediately determine whether or not, it may be desired to manually change the rotation speed.
On the other hand, when changing the rotation speed manually, when changing the rotation speed to the stable rotation speed displayed on the screen, for example, operate the override dial in any direction (increase / decrease of the rotation speed). You have to judge what you have to do. Then, when considering the deterioration of the machined surface accuracy due to the occurrence of chatter vibration or the risk of tool breakage, the above determination must be made in as short a time as possible. Therefore, there is a risk of burden on the worker.

  Therefore, the present invention has been made in view of the above problems, and when manually changing the rotational speed, it can be easily and reliably changed to a stable rotational speed, thereby reducing the burden on the operator. An object of the present invention is to provide a vibration suppression device that can be used.

In order to achieve the above object, the invention according to claim 1 of the present invention inputs a command value for the rotational speed of the rotary shaft in a machine tool having a rotary shaft for rotating a tool or a workpiece. Command means, an operator operable by the operator, and adjusting means for adjusting the rotation speed by changing the ratio for increasing or decreasing the command value; and the rotation speed of the rotary shaft from the command value and the ratio A rotation speed setting means for setting, a rotation shaft control device for rotating the rotation shaft at the set rotation speed, and a stable vibration capable of suppressing the chatter vibration when detecting chatter vibration generated when the rotation shaft is rotated. A vibration suppression device including a calculation device for calculating a rotation speed, wherein a display device for displaying the stable rotation speed is provided, and the rotation speed is changed to the stable rotation speed in the display device. At this time, an operation direction display unit for displaying in which direction the speed adjustment or deceleration should be performed on the adjusting means and an operation amount display unit for displaying how much the ratio should be changed are provided. It is characterized by that.
According to a second aspect of the present invention, in the first aspect of the invention, in the operation direction display section and the operation amount display section, a plurality of arrow-shaped indicators arranged in two predetermined directions are lit or blinked. The operation direction is indicated by the direction of the indicator that is lit or blinking, and the operation amount is indicated by the number of the indicator that is lit or blinking.

  According to the present invention, on the display device that displays the stable rotational speed, when changing the rotational speed to the stable rotational speed, the operation direction display that displays whether the adjustment means should be operated in the speed increasing or deceleration direction. And an operation amount display unit for displaying how much the ratio for increasing / decreasing the command value should be changed. Therefore, the operator can easily grasp the operation direction and the operation amount of the adjusting means by visually recognizing those displays. In particular, in a machine tool equipped with an adjusting means, the amount of operation of the adjusting means for changing to a stable rotational speed differs depending on the command value even if the rotational speed when chatter vibration occurs is the same. Become. However, according to the vibration suppression device of the present invention, since the operation amount of the adjustment means is also displayed, the operator can grasp the operation amount of the adjustment means very easily. Therefore, the burden on the operator can be reduced, the rotation speed can be reliably changed to a stable rotation speed in a short time, and improvement of the machining surface accuracy and prevention of tool breakage can be expected. it can.

It is block block explanatory drawing of a vibration suppression apparatus. It is explanatory drawing which showed the rotating shaft housing from the side. It is explanatory drawing which showed the rotating shaft housing from the axial direction. It is explanatory drawing which showed the display screen of the display apparatus. It is explanatory drawing which showed the override dial. It is explanatory drawing which showed the override switch.

  Hereinafter, a vibration suppression device according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram showing a block configuration of the vibration suppressing device 10. FIG. 2 is an explanatory view showing the rotary shaft housing 1 to be subjected to vibration suppression from the side, and FIG. 3 is an explanatory view showing the rotary shaft housing 1 from the axial direction.
The vibration suppressing device 10 is for suppressing “chatter vibration” generated in the rotating shaft 3 provided in the rotating shaft housing 1 so as to be rotatable around the C axis. "Vibration vibration" by analyzing vibration sensors 2a to 2c for detecting vibration acceleration in the time domain (meaning vibration acceleration on the time axis), which is a characteristic value, and detection values by the vibration sensors 2a to 2c. And a control device 5 that controls the rotational speed of the rotary shaft 3 based on the determination result.

  The vibration sensors 2a to 2c are attached to the rotary shaft housing 1 as shown in FIGS. 2 and 3, and one vibration sensor detects vibration acceleration in the time domain in a direction perpendicular to the other vibration sensors. (For example, the vibration sensors 2a to 2c are attached so as to detect vibration acceleration in the time domain in the X-axis, Y-axis, and Z-axis directions orthogonal to each other).

  On the other hand, the control device 5 detects the occurrence of “chatter vibration” based on the vibration acceleration in the time domain detected from the vibration sensors 2a to 2c, and detects the occurrence of “chatter vibration”. A calculation device 11 for calculating a stable rotation speed for suppressing the rotation, a display device 12 for displaying the calculated stable rotation speed, and a command for instructing the rotation speed of the rotary shaft 3 at the start of machining, for example. Means 13, an override dial (hereinafter simply referred to as a dial) 14 that is an adjusting means for adjusting the rotation speed by changing the ratio of increasing / decreasing the command value, command value from command means 13 and input from dial 14 The rotational speed setting device 15 that sets the rotational speed of the rotary shaft 3 from the input value that has been input, and the operation of the rotary shaft 3 are controlled and set by the rotational speed setting device 15. And a rotary shaft control apparatus 16 for changing the rotational speed of the rotary shaft 3 to the rotational speed.

  In the vibration suppressing device 10, the occurrence of “chatter vibration” is detected by a known method as disclosed in Patent Document 1, and a stable rotational speed capable of suppressing the generated “chatter vibration” is calculated by the arithmetic unit 11. In the calculation. Then, the calculated stable rotation speed is displayed on the display device 12. Thereafter, when the operator operates the dial 14, the rotation speed setting device 15 sets a new rotation speed corresponding to the operation amount, and the rotation axis is set to the rotation speed newly set by the rotation axis control device 16. 3 is changed to suppress “chatter vibration”.

Here, the configuration of the dial 14 which is a main part of the present invention and the display control in the display device 12 will be described with reference to FIGS. 4 is an explanatory view showing the display screen 12a of the display device 12, and FIG. 5 is an explanatory view showing the dial 14. As shown in FIG.
As shown in FIG. 4, the dial 14 has an adjustment knob 21 that can be rotated, and has built-in detection means (not shown) that detects the rotation angle of the adjustment knob 21. Is rotated by an angle corresponding to, the rotational speed is changed by 10% (that is, a rotational speed obtained by multiplying the current rotational speed by 0.9 or 1.1 is newly set in the rotational speed setting device 15). Is possible). When the adjustment knob 21 is rotated to the right, the rotation speed increases, and when the adjustment knob 21 is rotated to the left, the rotation speed decreases.

  On the other hand, the display device 12 includes a display screen 12a. The display screen 12a displays the current rotation speed, the stable rotation speed calculated by the calculation device 11, the operation direction and the operation amount of the dial 14 in the manner shown in FIG. To display. Among these, the display unit 31 indicating the operation direction and the operation amount of the dial 14 is configured by three arrow-shaped indicators 32, 32,. The direction of the indicators 32, 32... Is associated with the operation direction of the dial 14, and the right indicator 32, 32... Group is a speed increasing instruction unit 31a for instructing an increase in rotational speed, and a left pointing indicator 32. , 32... Constitute a deceleration instructing section 31 b that instructs to decelerate the rotational speed. And when changing to a stable rotational speed, when it is necessary to increase the speed, the indicators 32, 32,... Of the speed increasing instruction section 31a are turned on. The indicators 32, 32,. The number of indicators 32 to be lit is set according to the operation amount of the dial 14, and the number of indicators 32 to be lit is increased by one for each scale. Therefore, for example, when it is necessary to increase the speed by 10%, only one indicator 32 of the speed increasing instruction unit 31a is turned on. The indicators 32, 32,... In addition, even when it is necessary to increase or decrease the speed by 40% or more, all the three indicators 32, 32,.

ここで、上記式（１）におけるＳは現在の回転速度、Ｓ_ｃｏｍは加工プログラムで定められた回転速度の指令値（指令手段１３により指令される指令値）、Ｓ_ｏｐｔは安定回転速度、ｋはダイヤル１４における変更ピッチ（本実施形態では１０％であるため０．１となる）である。 The operation amount N (number of scales) of the dial 14 can be obtained by the following equation (1).

In the above equation (1), S is the current rotational speed, S _com is the rotational speed command value (command value commanded by the command means 13) determined by the machining program, S _opt is the stable rotational speed, k Is the change pitch in the dial 14 (in this embodiment, it is 0.1 because it is 10%).

As an example for changing the rotation speed to the stable rotation speed using the display device 12 and the dial 14 as described above, for example, the rotation speed when “chatter vibration” occurs is 1500 min ⁻¹ . Consider a case where the stable rotational speed calculated in the arithmetic unit 11 is 1850 min ⁻¹ .
First, assuming that the adjustment knob 21 of the dial 14 is 100% at the time of occurrence of “chatter vibration”, the command value by the command means 13 is also 1500 min ⁻¹ . At this time, in order to change the rotational speed to the stable rotational speed, it is necessary to increase the rotational speed by 20%. Therefore, in this case, the two indicators 32 and 32 are turned on in the speed increase instruction unit 31a. Therefore, the operator may rotate the dial 14 in the two-scale speed-up direction according to the display.
On the other hand, if the adjustment knob 21 of the dial 14 is 120% when “chatter vibration” occurs, the command value by the command means 13 is 1250 min ⁻¹ . At this time, in order to change to the rotation speed closest to the stable rotation speed, it is necessary to increase the rotation speed by 30%. Therefore, in this case, the three indicators 32, 32,... Are turned on in the speed increase instruction unit 31a. Therefore, the operator may rotate the dial 14 in the direction of three-scale speed increase according to the display. The display device 12 includes a control device (not shown), and the control device performs the above-described control (calculation relating to which indicator 32 should be lit and how much).

  According to the vibration suppressing apparatus 10 as described above, the speed increasing instruction section 31a and the speed reducing instruction section 31b including a plurality of indicators 32, 32... Are provided on the display screen 12a of the display apparatus 12, and the rotation speed is stably rotated. The operation direction and operation amount of the dial 14 when changing to the speed are displayed. Therefore, the operator can easily grasp the operation direction and the operation amount of the dial 14 by visually recognizing these displays. In particular, in a machine tool equipped with a dial 14, even if the current rotational speed is the same as described above, the amount of operation of the dial 14 for changing to a stable rotational speed is different due to a difference in command value. . However, since the vibration suppression device 10 also displays the operation amount of the dial 14, the operator can grasp the operation amount of the dial 14 very easily. Therefore, the burden on the operator can be reduced, the rotation speed can be reliably changed to a stable rotation speed in a short time, and improvement of the machining surface accuracy and prevention of tool breakage can be expected. it can.

  Note that the configuration related to the vibration suppression device of the present invention is not limited to the mode of the above-described embodiment. Of course, the configuration related to detection of “chatter vibration”, the display mode in the display device, the configuration of the adjusting means, and the like. Can be appropriately changed as necessary without departing from the spirit of the present invention.

  For example, override switches 41a and 41b as shown in FIG. 6 can be employed as the adjusting means. The override switch 41a increases the rotation speed by 10% every time the push-in operation is performed, while the override switch 41b decreases the rotation speed by 10% every time the push-in operation is performed. Even if such override switches 41a and 41b are employed, the same effect can be obtained by displaying the number of operations (that is, the operation amount) on the display device 12.

Further, the acceleration display portion and the deceleration display portion are not limited to those of the above embodiment, and numerical values corresponding to the operation amounts such as “1”, “2”, and “3”, “acceleration” and “deceleration”. It may be configured to display a word indicating the operation direction such as “”.
Furthermore, the change pitch of the override dial 14 and the override switches 41a and 41b may be variable. In this case, information related to the changed pitch may be input to the display device 12 and display corresponding to the set changed pitch may be performed. Even if the information related to the change pitch is not input to the calculation device 12, for example, the reference change pitch is set to 10% and the display device 12 calculates and displays the change pitch. If the change pitch is changed, it is displayed on the operator side. The actual operation amount may be calculated from the operated operation amount. Even in such a configuration, since the operation amount at the reference change pitch is calculated and displayed on the display device 12, the operator only needs to perform calculation using the ratio, and the burden on the operator is greatly increased. There is nothing wrong.

Furthermore, when the change pitch is not variable as described above, the change pitch of the override dial 14 or the like is not limited to 10% of the above-described embodiment, for example, 1% or 5%. There is no problem. Furthermore, instead of lighting the indicator, the indicator may be blinked. In the above embodiment, the indicator is sequentially turned on one by one until 30%, and blinked when it is 40% or more. The aspect can also be changed as appropriate.
In addition, the present invention is not limited to a machining center that rotates a tool and can be used to suppress vibrations of a machine tool such as a lathe that rotates a workpiece.

  Rotating shaft housing, 2a, 2b, 2c, vibration sensor, 3, rotating shaft, 5 ... control device, 10 ... vibration suppression device, 11 ... arithmetic device, 12 ... display device, 12a ...・ Display screen, 13 ・ ・ Command means, 14 ・ ・ Override dial (adjustment means), 15 ・ ・ Rotation speed setting device (rotation speed setting means), 16 ・ ・ Rotation axis control device, 21 ・ ・ Adjustment knob, 31 ・· Display unit, 31a · · Speed increase instruction unit (operation direction display unit, operation amount display unit), 32b · · Deceleration instruction unit (operation direction display unit, operation amount display unit), 32 · · Indicators, 41a, 41b ·・ Override switch (adjustment means).

Claims (2)

In a machine tool having a rotary shaft for rotating a tool or a workpiece, command means for inputting a command value of the rotation speed of the rotary shaft, and a ratio that can be operated by an operator and increases or decreases the command value. Adjustment means for changing and adjusting the rotation speed, rotation speed setting means for setting the rotation speed of the rotation shaft from the command value and the ratio, and rotation for rotating the rotation shaft at the set rotation speed A vibration suppression device comprising: an axis control device; and a calculation device that calculates a stable rotation speed capable of suppressing chatter vibration when detecting chatter vibration generated when the rotating shaft is rotated,
While providing a display device for displaying the stable rotation speed,
On the display device, when changing the rotation speed to the stable rotation speed, an operation direction display section for displaying whether the adjustment means should be operated in either speed increasing or deceleration direction, and how much the ratio is changed A vibration suppression apparatus comprising an operation amount display unit that displays whether or not to perform the operation.   In the operation direction display unit and the operation amount display unit, a plurality of arrow-shaped indicators arranged in two predetermined directions can be lit or blinked, and the operation direction is lit depending on the direction of the lit or blinking indicator. Alternatively, the operation amount is displayed by the number of the blinking indicators, respectively.

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