JPS61142057A - Machine tool vibration detecting device - Google Patents

Abstract

PURPOSE:To easily change the position of a detector to a detecting place in accordance with a unit of machine by installing a magnet on a vibration detector and installing said detector to a part of a machine tool by the adsorbing action of said magnet. CONSTITUTION:An accelerator pickup 5 is adsorbed to a place suited to detecting the vibration of a grinding wheel 3, e.g., on the upper part of a column 1a, by means of a magnet 26. And, a motor 6 is driven with the grinding wheel 3 being installed on a supporting shaft 4. A wave filtering circuit 24 selects the vibration of a rotary machining body, i.e., the grinding wheel 3, from various vibrations detected by the acceleration pickup 5, and the vibration of the rotary machining body 3 is converted into an oscillation quantity by a controlling means 20 and indicated by an indicating means 10.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a vibration detection device for a machine tool.

(Prior Art) Conventionally, when detecting vibrations of a rotating workpiece in a machine tool, a pickup device has been attached around the rotating part of the machine.

(Problems to be Solved by the Invention) As described above, in the past, the mounting position of the pickup device was limited and was often subject to space and wiring constraints.

An object of the present invention is to enable detection of vibrations of a rotary workpiece or the like at a convenient position on a machine stand.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a method in which a magnet is attached to a detector, and the detector is attached to a part of a machine tool by the attraction action of the magnet. I configured it.

(Function) The detector is attracted by a magnet to a location where it is easy to detect the imaging of the machine base, and detects the vibration. Then, a filter circuit selects the vibration of the rotary workpiece from the detected various vibrations,
The vibration of the rotary workpiece is converted into a photographic amount by a control means. Therefore, the amount of vibration detected by the detector is displayed by the display means.

(Example) Hereinafter, an example in which the present invention is embodied in a surface grinder will be described based on the drawings.

As shown in FIG. 1, a piezoelectric acceleration pickup 5 is used as a detector of the vibration detection device, and an iron plate 27 is attached to the bottom of the acceleration pickup 5.
A magnet 26 is adhered to the outer surface of 7. Then, the acceleration pickup 5 is attracted to a part of the frame 1 by the magnet 26, as will be described later.

As shown in FIG. 2, a table 2 for holding a workpiece W is provided on a frame 1 of the grinding machine. A support shaft 4 shown in FIG. 2 is rotatably mounted on the table 2, and a grindstone 3 is fixed to the tip thereof so as to oppose the workpiece W on the table 2 from above. A motor 6 for driving the support shaft 4 is arranged behind the support shaft 4.

A piezoelectric acceleration pickup 5 is mounted on the column 1a at the top of the frame 1. is attached. Further, as shown in FIG. 3, a detection piece 7 is provided protruding from the outer periphery of the base end of the support shaft 4, and an origin consisting of a photosensor 9 is provided on the frame 1 outside the base end of the support shaft 4. A detection sensor 8 is provided and outputs an origin detection signal each time the detection piece 7 passes through this portion.

Note that the frame 1 includes all parts except the part rotated by the motor 6.

A display 10 is fixed on the outside of the column 1a, and a power switch 11 is provided on the side of the display 10 for turning on and off the balance detection device of this embodiment.
is provided.

As shown in FIG. 4, the front surface of the display device 1o is a display section 12, and the display section 12 has a total of 36 pieces at each rotation angle of 10 degrees, corresponding to each index position of the support shaft 4. The index position indicators 13 are arranged in a ring shape. The position indicator 13 has a built-in red light emitting diode.

Further, an origin indicator 14 having a built-in light emitting diode is arranged so as to correspond to the index position indicator 13 of the angular position from which the origin detection sensor 8 outputs a signal. A runout amount display section 15 is provided within the ring of the indexing position display body 13, and a runout amount display section 15 that numerically displays the runout of the grinding wheel 3 based on the blinking of seven liquid crystal segments for one character is provided. Inside the ring 13 is a maximum swing mode display 16a,
A minimum shake m mode display body 16b is provided, and a hold display body 17 is provided that does not indicate the display bold state (
is being pulled. These display bodies 16a, 16b, and 17 each have a built-in light emitting diode.

Further, on both sides of the upper part of the display section 12, a mode changeover switch 18 for selecting the maximum shake amount display mode or the minimum shake amount display mode, and a hold switch 19 for holding the display are arranged.

FIG. 5 shows a block diagram of the balance detection device in this embodiment, and the central processing unit (hereinafter referred to as CPU)
An input/output port (hereinafter referred to as I10) 21 is connected to 20. The input/output port 21 includes a piezoelectric acceleration pickup 5 that detects vibrations of the machine base via a filtering circuit 24 as an input device, the origin detection sensor 8, a hold switch 19, a mode changeover switch 18, and an output device as an output device. ' A position indicator 13, an origin indicator 14, a shake amount indicator 15, a maximum shake amount mode indicator 16a1, a minimum shake amount mode indicator 16b, and a hold indicator 17 are connected. In addition, the CPU 20 has read-only memory (
(hereinafter referred to as ROM) 22 and random access memory (hereinafter referred to as ROM) 22 and random access memory (hereinafter referred to as ROM)
23 (hereinafter referred to as RAM) is connected, ROM 22 stores programs, and RAM 23 is provided with a data area for storing data.

The filter circuit 24 includes a charge amplification circuit 28 that converts the charge of the acceleration pickup 5 into an acceleration signal SG1, two voltage amplification circuits that adjust vibration sensitivity with a variable resistor R1, and a variable resistor R2 that synchronizes with the vibration of the grindstone. A bandpass filter (B, P.

F) 30, an integration circuit 31 that converts the acceleration signal SG1 into a speed signal SG2, and a voltage amplification circuit 32 that adjusts the amplification factor of the speed signal SG2 are connected in this order. The speed signal SG2 output from the filter circuit 24 is converted into a digital signal by the A/D converter 33.

Now, the operation of the balance display device having the vibration detector configured as described above will be explained according to the flowchart shown in FIG. The program in this flowchart proceeds under the control of the CPU 20.

First, the acceleration pickup 5 is attracted by the magnet 26 to a location suitable for detecting vibrations of the rotary grindstone 3.

For example, in this embodiment, the acceleration pickup 5 is attracted to the upper part of the column 1a.

Then, with the rotating grindstone 3 attached to the support shaft 4, the motor 6 is driven to rotate the support shaft 4 and the rotating grindstone 3. When the power switch 11 is turned on in this state, step S
1, initial settings are made, and in step S2, it is determined whether or not the grindstone 3 has reached steady rotation. At this time, the determination is made by measuring the pulse interval of the origin detection pulse output from the origin detection sensor 8, storing the data in the RAM 23 for the specified number of rotations, and comparing each data within the next specified number of rotations. If they have substantially the same pulse interval, the process moves to the next step S3. If the pulse interval data do not match, the count is restarted from the beginning. In step S3, the process waits for the origin signal from the origin detection sensor 8 to be output, and at the same time as the origin signal is output, the process proceeds to step S4.

In steps 84 to S7, while the grindstone 3 rotates once,
/The amount of runout data D that can be processed by the D converter 33
is stored in the RAM 23, and the process proceeds to step S8 at the same time as the completion of one rotation of the grindstone 3.

In this step S8, the detected shake amount data D is converted into shake amount data [)n for every 10 degrees by the total number of shake amount data D.
In step S9, the runout data □n divided into every 10 degrees is used as data for each index position, and the sum for each index position is calculated, and averaged data 3n is calculated from the number of data. . Step S10
Then, the averaged data 3n for each index position is
is stored in RAM'23. Then, step S11
Then, it is determined whether or not the set number of revolutions has been repeated. If it has been repeated, the process proceeds to the next step 812, and if not, the process returns to step S2 and continues in step 8 until the set number of revolutions is reached.
Repeat steps 2 to S11.

In step 812, the average data 3n at each indexed position is read from the RAM 23, the average data Sn for the set number of rotations is added for each indexed position, and the average data Yn is calculated for each indexed position from the set number of rotations. In step 813, the average data Yn is stored in RAM2.
Store in 3.

From step S14 onwards, the mode switching switch 18 is at its maximum setting, and steps 814 to 816 are when the grinding wheel 3
Processed within the specified rotation speed. In this step 814, the maximum runout amount and its respective indexed positions (hereinafter referred to as angles) are selected by comparing the average data Yn, and in step S15, the maximum runout range angular position setting means that an allowable range is set for the maximum runout amount. , refers to selecting an angle with a runout amount that is within the allowable range. Also, what is the maximum runout amount conversion?
This is to convert the amount of shake into an amount that can be displayed on the amount of shake display 15.

In step 816, it is determined whether or not the maximum runout amount obtained in step 514 is greater than or equal to a reference value. If it is greater than or equal to the reference value, the process proceeds to step S17; When it is determined that the balance has been achieved, the process proceeds to step 819, where 'good' is displayed on the run-out sum display 15 as a signal that the balance has been completed.

In step 817, the maximum runout amount and the maximum runout range angular position obtained in step 815 are displayed on the display unit 12, and in step 818, when the hold switch 19 is turned on, the display state is maintained and the maintenance state is indicated. The hold display 17 is turned on. When the hold switch 19 is off, the process returns to step S2 and the maximum shake amount mode display operation is repeated again.

Although the steps after step 814 have been described assuming the case where the amount of shake is the maximum, even when the amount of shake is the minimum, the amount of shake is displayed in the same manner as when it is the maximum. At this time, the mode changeover switch 18 is in the minimum mode. That is, in the case of the minimum mode, the minimum shake amount and its angle are selected and the processes corresponding to steps 814 to 817 are performed.

Next, the display state of the display 10 will be explained. power switch 1
1 is turned on, II II is displayed on each digit of the runout amount display unit 15 until the rotational speed becomes stable, and the origin display 14 is displayed blinking as the support shaft 4 passes the origin position. Then, as the rotation of the grindstone 3 stabilizes, the runout amount is illuminated on the runout amount display section 15 at each prescribed rotational speed, and the index position indicator 13 lights up the light emitting diode at the minimum or maximum runout angle position. At this point, the mode selector switch 18 lights up the display for either the minimum or maximum mode. Then, when the rotating grindstone 3 is balanced, 'good' is displayed on the runout amount display section 15.

Since the acceleration pickup can be relocated to a location on the machine base where it is easy to detect or to a location where it is easy to install, vibration can be detected at a convenient location without being subject to space or wiring constraints.

Effects of the Invention As detailed above, the present invention has the advantage that the detector can be relocated to a detection location depending on the machine.

[Brief explanation of drawings]

Figure 1 is a perspective view of the vibration detector, Figure 2 is a side view of the vibration detector attached to the grinding machine, Figure 3 is a partial sectional view of the support shaft,
FIG. 4 is a front view of the display, FIG. 5 is a block diagram of the control means, FIG. 6 is a block diagram of the high wave circuit, and FIG. 7 is a flowchart showing the display operation. 3 is a rotary workpiece, 5 is a detector, 10 is a display means, 20 is a control means, and 24 is a filter circuit.

Claims (1)

[Claims] 1. A detector (5) capable of detecting vibrations of a machine tool, and a filter circuit connected to the detector (5) to extract vibrations of a specific frequency from among various vibrations. (24) and a rotating machine tool body (3) based on the specific vibration.
a control means (20) for calculating the runout amount of the rotary workpiece (3), and a display means (10) for displaying the runout amount of the rotary workpiece (3) by the action of the control means (20); Attach the magnet (26) and
A vibration detection device for a machine tool in which a detector (5) is attached to a part of the machine tool by the adsorption action of (26).