JPH0569655B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) This invention relates to a balance detection device that detects and displays the rotational balance of a machine tool such as a grinder.

(Prior art) Conventionally, when adjusting the rotational balance of the grinding wheel of a grinding machine, the grinding wheel was attached to one shaft, and that shaft was
Place the whetstone on a horizontal bar and observe the direction and speed in which the whetstone naturally rolls from a stationary state, estimate the unbalanced position and amount of the whetstone, and perform correction work to balance the whetstone accordingly. It was on. However, this method is inefficient as it relies on skill.
Moreover, since it does not take into account the unbalance of the grinding wheel support shaft of the grinding machine, there is a problem that even though the unbalance of the grinding wheel has been corrected, when the grinding wheel is attached to the support shaft and rotated, an unbalance will occur. It was hot.

(Problems to be Solved by the Invention) This invention was made to solve the above-mentioned conventional problems, and detects unbalance when a rotating workpiece such as a grindstone is attached to a support shaft and rotated. , it lies in resisting the balance detection device of the machine tool, which can accurately display it.

Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention provides a workpiece comprising a support shaft rotated by a motor, and a rotating workpiece such as a grindstone mounted on the support shaft. In the machine, an origin detection sensor detects the rotational direction origin of the support shaft, a vibration detection means detects the amplitude of vibration of the machine tool, and the support shaft is detected based on the detection results of the origin detection sensor and the vibration detection means. a filter circuit that detects amplitude data for each rotation period during steady rotation of the filter, and divides the amplitude data for each rotation period detected by the filter circuit into data for each of a plurality of index positions with respect to the origin. At the same time, the average data of the amplitude corresponding to each index position is calculated based on the added data for the set rotation speed for each index position, and the maximum or minimum average data is selected from among the average data at each index position. a control means for outputting a comparison result between the selected average data of the lever and a predetermined reference value as a control signal; and a maximum or minimum amplitude and an index position corresponding to the amplitude based on the control signal from the control means. The gist is that a display means for displaying the information is provided.

(Operation) That is, the filter circuit detects amplitude data for each rotation period during steady rotation of the support shaft. Then, the control means divides this amplitude data into data for each index position, further adds the data for the set number of revolutions, and then calculates the average data of the amplitude for each index position. Then, the maximum or minimum average data is selected from among the average data obtained for each index position, the selected average data is compared with a predetermined reference value, and the comparison result is Output as a control signal. Then, according to this control signal, the maximum or minimum amplitude and the indexed position corresponding to the amplitude are 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 table 2 for holding a work W is provided on a frame 1 of a 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 face 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 serving as vibration detection means is attached to the column 1a at the top of the frame 1. Further, as shown in FIG. 2, 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 photocoupler 9 is provided on the frame 1 outside the base end of the support shaft 4. A detection sensor 8 is provided to output 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.
Further, the acceleration pickup 5 has a magnet (not shown), and is attracted to a part of the frame 1 by the magnet. Therefore, acceleration pick-up 5
The mounting position can be changed freely.

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

As shown in FIG. 3, the front surface of the display 10 is a display section 12, and a support shaft 4
A total of 36 index position indicators 13 are arranged in a ring shape at every 10 degrees of rotation angle corresponding to each index position. Each indexing position display body 13 includes a red light emitting diode and a green light emitting diode. Further, an origin indicator 14 having a built-in light emitting diode is arranged to correspond to an index position indicator 13 for the angular position at which the origin detection sensor 8 generates a signal. A runout amount display unit 15 is provided within the ring of the indexing position display body 13, and displays a runout amount of the support shaft 4, that is, the amplitude of vibration during steady rotation of the support shaft 4. A maximum shake amount mode indicator 16b and a minimum shake amount mode indicator 16a are provided within the ring, and a hold indicator 17 indicating a display hold state is also provided. These display bodies 16a, 16b, and 17 each have a built-in light emitting diode.

Note that the maximum runout amount refers to the runout amount at the indexing position where the amplitude is maximum on the positive side when the runout amounts (amplitudes) obtained for each indexing position are compared with each other. The amount also refers to the amount of shake at the index position where the amplitude is maximum on the negative side when the amounts of shake (amplitude) for each index position are compared with each other.

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.

Figure 4 shows a block diagram of the balance detection device in this embodiment, and shows the central processing unit (hereinafter referred to as
CPU) 20 has an input/output port (hereinafter referred to as I/
(referred to as O) 21 and an oscillator 25 are connected, and these constitute a control means 41. I/O
21 includes, as an input device, a piezoelectric acceleration pickup 5 for detecting vibrations of the machine base via a filter circuit 24, the origin detection sensor 8, a hold switch 19, a mold changeover switch 18, and an index position indicator as an output device. 13, origin indicator 14,
Shake amount display section 15, maximum shake amount mode display 16
b, a minimum shake amount mode indicator 16a and a hold indicator 17 are connected. The CPU 20 also includes a read-only memory (hereinafter referred to as ROM) 22 and a random access memory (hereinafter referred to as RAM).
23 is connected, the ROM 22 stores programs, and the RAM 23 is provided with a data area for storing data. The oscillator 25 is provided to measure the number of oscillations generated by one rotation of the support shaft 4.

The filter circuit 24 shown in FIG.
and a circuit that detects vibrations of the support shaft 4. A voltage generated by the charge of the piezoelectric acceleration pickup 5 is amplified as an acceleration signal SG1 by a charge amplification circuit 32, and the charge amplification circuit 33 can adjust the degree of voltage amplification, that is, the vibration sensitivity. At this time, resistance R1
Sensitivity can be adjusted with . And a low-pass filter (L.
PF) 34 and a high-pass filter (HPF) 35 attenuate the acceleration signal SG1, the attenuated acceleration signal SG1 is compensated by a voltage amplification circuit 36, and a bandpass filter (BPF) 37 converts the rotation of the support shaft 4 into an acceleration signal SG1. can be synchronized. At this time,
Synchronization is adjusted using resistor R2. Then, the integration circuit 38 converts the acceleration signal SG1 into the speed signal SG2, the voltage amplification circuit 39 adjusts the output impedance, and the analog signal is converted into a digital signal.
When the speed signal SG2 is converted into a digital signal by the D converter 40 and the signal SG2 is inputted to the CPU 20 of the control means 41 via the I/021,
The CPU 20 is designed to drive the motor 6.

Although not shown, a remote control device is provided so that it can be operated at hand, and this device is equipped with a hold switch similar to the hold switch 19, a vibration sensitivity adjuster R1, and a synchronization adjuster R2.

The operation of the balance detecting device configured as above will be explained according to the flowchart of FIG. 6.
The program of this flowchart proceeds under the control of the CPU 20.

Now, with the rotating grindstone 3 attached to the support shaft 4, the motor 6 is started to rotate the support shaft 4 and the rotating grindstone 3. When the power switch 11 is turned on in this state, initial settings are made in step S1.
In step S2, it is determined whether the support shaft 4 has reached steady rotation. At this time, the determination is made by measuring the pulse interval of the origin detection pulses oscillated by the current point detection sensor 8 based on the number of oscillation pulses of the oscillator 25, and storing the data in the RAM 23 for a specified number of rotations (in this embodiment, 2 rotations). The data is stored in the pulse interval area, and the CPU 20 compares the data within the next specified number of revolutions (in this embodiment, one revolution), and if they are approximately the same number of oscillation pulses, 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 oscillated, and at the same time as the oscillation, the process proceeds to step S4.

In steps S4 to S7, while the support shaft 4 makes one rotation, as much runout amount (amplitude) data D as can be processed by the A/D converter 40 is stored in the RAM 23, and at the same time as the support shaft 4 completes one rotation, step S8
Proceed to.

In this step S8, the detected runout amount data D is divided into runout amount data Dn for every 10 degrees based on the total number of runout amount data D, and in step S9, the runout amount data Dn divided for every 10 degrees are divided for each index position. The sum of the data for each indexed position is calculated, and the averaged data Sn is calculated from the number of data. In step S10, the data Sn averaged for each indexed position is stored in the RAM2.
Store in 3. Then, in step S11, it is determined whether or not the set number of rotations (4 rotations in this embodiment) has been repeated. If the number of rotations has been repeated, the process advances to the next step S12, and if not, the process returns to step S3 and repeats steps S3 to S3 until the set number of rotations is reached. Repeat S11.

In step S12, the average data Sn at each indexed position is read from the RAM 23, the average data Sn for the set number of revolutions is added for each determined position, and the average data Yn is calculated for each indexed position from the set number of revolutions. In step S13, the average data Yn is stored in the RAM 23.

After step S14, the mode changeover switch 18
is the maximum, and steps S14 to S16 are processed within the specified number of rotations of the grindstone 3 (three rotations in this embodiment). In this step S14, the maximum runout amount and its respective index positions (hereinafter referred to as angles) are selected by comparing the average data Yn, and the step
In S15, maximum shake angle correction and maximum shake amount conversion are performed. This maximum shake angle correction is to make it easier to confirm the maximum shake angle on the display unit 12. For example, when the maximum shake amount value is 1, the shake angle where the corresponding shake amount value is 0.8. This means that the maximum deflection angle is allowed and included up to the range of . Therefore, in this case, the deflection angle included in the range where the deflection amount is 0.8 or more is treated as the maximum deflection angle, and the maximum deflection angle is displayed on the display unit 12 by the plurality of index position indicators 13. The maximum deflection angle is easier to visually recognize than when using a single indexing position indicator 13. Further, the maximum shake amount conversion means converting the shake amount into an amount that can be displayed on the shake amount display 15.

In step S16, it is determined whether or not the maximum runout amount obtained in step S14 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; if it is not greater than or equal to the reference value, that is, the balance of the rotating grindstone It is determined that the condition has been removed, and the process proceeds to step S19.
"Good" is displayed on the shake amount display 15 as a signal indicating the completion of balancing.

In step S17, the maximum deflection amount and deflection angle obtained in step S15 are displayed on the display section 12, and in step S18, when the hold switch 19 is turned on, the display state is maintained and a hold display indicating the maintained state is displayed. 17 is turned on. When the hold switch 19 is off, the process returns to step S3 and the maximum shake amount mode display operation is repeated again.

Although the steps after step S14 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 S14 to S17 are performed.

Next, the display state of the display 10 will be explained. At the same time as the power switch 11 is turned on, "-----" is displayed on each digit of the run-out amount display 15 until the rotation speed becomes stable, and at the same time as the support shaft 4 passes the origin, the origin display 14 lights up. Light up. This origin indicator 14
appears to keep on because the lighting interval is narrow.
Then, as the rotation of the support shaft 4 stabilizes, the runout amount indicator 15 is
The amount of runout is illuminated, and the index position indicator 13 is displayed.
turns on the light emitting diode at the minimum or maximum deflection angle position. At this time, mode selector switch 1
8, either the minimum or maximum display is lit. When the rotating grindstone 3 is balanced, "good" is displayed on the runout amount display 15.

As described above, in this balance detection device, the maximum unbalance position where the amount of runout is the largest or the minimum unbalance position where the amount of runout is the smallest and the distribution of the unbalance are
Since it can be accurately recognized by the display 13 together with the support shaft 4 while attached to the support shaft 4 without removing it from the vehicle, no skill is required.

In addition, in the process of calculating the maximum or minimum unbalance position and its unbalance amount, the filter circuit 2
Divide the runout amount data D detected in step 4 into data Sn for each index position, add them for each index position by the set number of rotations, and then divide by this set number of rotations to obtain the data for each index position. The maximum unbalanced position, etc. is determined by calculating the average data Yn, selecting the maximum of the average data Yn for each index position, and comparing the selected maximum average data Yn with the reference value. is calculated, it is possible to accurately and stably detect the unbalance position and the unbalance amount.

Note that the present invention is not limited to the above-mentioned embodiments, and may include changing the detectors to ones different from those in the above-mentioned embodiments, arranging the display bodies in a straight line,
Further, changes can be made without departing from the spirit of the invention, such as arranging them radially and simultaneously displaying the amount of runout and its indexed position in analog form.

Effects of the Invention As detailed above, according to the present invention, when a rotary workpiece such as a rotary grindstone is attached to a support shaft, the maximum or minimum unbalance position and the amount of unbalance can be determined for the rotary workpiece and the support shaft. This has excellent effects in that it can be easily and accurately recognized, and unbalance correction work can be performed easily and quickly.

[Brief explanation of the drawing]

Figure 1 is a schematic side view of the balance detection device installed on the grinding machine, Figure 2 is a partial sectional view of the support shaft, Figure 3 is a front view of the display, and Figure 4 is a block diagram of the control means. , FIG. 5 is a filter circuit diagram, and FIG. 6 is a flowchart showing the display function of the balance detection device. 4 is a support shaft, 5 is a piezoelectric acceleration pickup,
8 is an origin detection sensor, 10 is a display, 20 is a central processing unit, and 24 is a filter circuit.

Claims (1)

[Claims] 1. A support shaft 4 rotated by a motor 6,
In a machine tool having a rotary workpiece such as a grindstone 3 mounted on the support shaft 4, an origin detection sensor 8 detects the origin of the rotational direction of the support shaft 4, and a vibration detection sensor 8 detects the amplitude of vibration of the machine tool. means 5; a filtering circuit 24 for detecting amplitude data D for each rotation period during steady rotation of the support shaft 4 based on the detection results of the origin detection sensor 8 and the vibration detection means 5; and the filtering circuit 24. Divide the amplitude data D for each rotation period detected by into data Sn for each of a plurality of index positions based on the origin, and
Calculate the average amplitude data Yn corresponding to each index position based on the added data Sn for the set number of rotations for each index position, and calculate the maximum or minimum average data Yn from among the average data Yn at each index position. a control means 41 that selects and outputs the comparison result between the selected average data Yn and a predetermined reference value as a control signal; and a maximum or minimum amplitude and its amplitude based on the control signal from the control means 41. A balance detection device for a machine tool, comprising: display means 10 for displaying an indexed position corresponding to .