JPS59129665A - Feeding device for cut of grinder - Google Patents

Abstract

PURPOSE:To prevent the feeding of excess grinding and improve the reliability of the grinder by a method wherein the upper limit of the output signal of an adding and subtracting circuit, which is outputted in accordance with a difference between a set speed and an actual working speed, is limited by a limiter circuit and a grindstone is separated from a work when the driving power of the grindstone has exceeded a predetermined upper limit. CONSTITUTION:Upon feeding of idle grinding, the actual working speed is not increased even if a work table is fed and a deviation from the set speed is increased, however, the upper limit of the signal S6, holding the deviation, is limited by the limiter circuit 22 to restrict the upper limit of the feeding speed of the table and the grindstone or the work will never be damaged. When the table is retracted by the increase of a grinding force, the output signal S12 of a comparating circuit 32 is inputted into an automatic grindstone dressing device and the dressing of the grindstone subsequent to the retraction of the work is effected automatically, then, the grinding work is re-started automatically by the signal S6 of a speed setting and switching circuit 23.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutting feed device for a grinding machine that grinds a workpiece by bringing a grindstone into contact with the workpiece.

For example, in a grinding machine such as an internal grinder, the workpiece and the grinding wheel are brought into contact with the grinding part of the workpiece by moving the workpiece and the grinding wheel with a sheath. Then, relative movement (feed of cut) in the same direction is continued to grind a predetermined amount of the workpiece.The speed of this feed of cut determines the machining speed, that is, the amount of part to be ground per unit time. However, it is generally desirable to keep this machining speed constant throughout the grinding process in order to make the surface roughness of the workpiece uniform. Speed cutting method,
■Two constant speed cutting methods are well known.

The constant speed cutting method (2) uses a cutting feed motor etc. to set the cutting feed speed to a constant value, which simplifies the equipment configuration, but it causes deflection of the grinding wheel shaft system and workpiece support system, making it difficult to clean. There is a drawback that even if the cutting feed rate is constant, the machining speed is not necessarily constant. Furthermore, if the grindstone becomes worn or clogged and its sharpness decreases, it also has the disadvantage that the machining speed decreases. This latter drawback is also recognized in the constant speed cutting method (2).

For example, as shown in Japanese Patent Publication No. 57-22704, the dimensions of the grinding part of the workpiece during grinding are continuously measured and the rate of change is calculated to determine the actual machining speed. A cut feed device for a grinding machine has also been proposed in which the cut feed system is opened to the open side so as to match the set machining direction. By performing the above control, the machining speed can be kept constant regardless of the deflection of the grinding wheel shaft system or workpiece support system, or the deterioration of the sharpness of the grinding wheel.

However, in the cutting feed device that performs the above-described control, the cutting feed rate is gradually increased as the grindstone's roughness decreases, so there is a risk that the grinding force will increase to an extremely dangerous level.

Also, during dry grinding, even though feed is being performed in the cutting feed direction (empty ωF cutting feed), the other cutting depth does not change.
If the grinding feed speed becomes abnormally high, the grinding wheel may violently collide with the workpiece, causing accidents such as the grinding wheel falling off the wheel head or causing injury to the workpiece. This can be prevented by starting the above control at the same time as the start of grinding, but in order to do so,
Contact between grindstone and workpiece? Since detection means and the like are required for detection, the components 11 to 11 of the grinding machine become tedious.

The present invention has been made in view of the above-mentioned circumstances, and is intended to prevent the above-mentioned 11F cutting force from increasing excessively, and to synchronize the start of machining speed control and the start of grinding using a multiple device. The purpose of this is to provide a 115-type re-infeeding device Lj on the machining speed control side, which can prevent an excessively high dry grinding feed rate even if it is not provided.

The cutting feed device of the grinding machine of the present invention includes a processing speed setting device that sets the cutting feed speed of the cutting feed motor that moves the workpiece and the grinding wheel relative to each other, and a processing speed setting device that continuously adjusts the dimensions of the grinding part of the workpiece during grinding. an in-process gauge that measures, a machining speed detection circuit that detects the actual machining speed by inputting the workpiece size signal measured by this in-process gauge, and a machining speed detection circuit that detects the set speed of the 1nn continuous speed setting device and the machining speed detection circuit. Compare the actual machining speed and output signal according to the difference? The addition/subtraction circuit that occurs and this addition/subtraction dance. times j. a limiter circuit that limits the limit of the output signal of @ to prevent the empty ωF cutting feed speed from becoming excessive; a backward vehicle seat setting device that sets the backward speed of the cutting feed motor; and this backward speed. A speed setting switching circuit receives the output signal of the setting device and the output/signal of the limiter circuit and selectively outputs these signals, and the speed of the cutting feed motor is changed to the open side 1 according to the output of this speed setting switching circuit. The cutting feed motor control circuit, the grinding wheel which increases as the cutting quality of the Ishido grinding wheel decreases, the power setting device that sets the upper limit of the drive power of the drive morph, and the power detection circuit that detects the power of the grinding wheel drive motor. 1 heat and this power detection 1
When the detection value of the circuit becomes larger than the setting value of the front power setting device, the speed setting switching circuit is switched and the output of the reverse speed setting device is set. It is equipped with a comparison circuit that outputs the output from the gate circuit.

Since the device with the above configuration is not designed to set the starting point of cutting feed rate control to the open side 1, if it is activated, cutting feed rate control will be performed on the page, and during dry grinding, as mentioned above, the cutting feed rate will be controlled. (υf cutting feed speed is increased. However, if the above limiter circuit is provided to limit the output signal of the adjustment circuit,
After that, the feed rate during double grinding does not increase, and an excessive increase in the edge speed during dry grinding can be prevented. In addition, when the drive power of the grinding wheel drive motor exceeds a predetermined upper limit value, the output signal of the retreat/gradation setting device is input to the cutting feed motor control circuit, so that the cutting feed motor changes in the cutting feed direction. The grinding wheel and the workpiece are separated by being driven in the opposite backward direction.

Therefore, (grinding force decreases due to decrease in cutting quality of σF grinding wheel)
It cannot be raised to the hidden limit. Preferably, when the grindstone and workpiece are separated in this way, the pressure of the grindstone is automatically lowered (refitted or reshaped), and when the grindstone % correction is completed, the speed setting switching circuit is switched to Q. Then, feed the cut again.

Embodiments of the present invention will now be explained in detail with reference to the drawings.

Fig. 1 shows a grinding machine equipped with a tied infeed slotting device according to one embodiment of the present invention, and Fig. 2 shows the configuration of the open side 1j'l (of the incision feeding device). The grindstone table 1 shown in FIG. It is designed to move forward and backward in the direction indicated by the arrow.A wheel head 3 that is rotatably driven by a grinding wheel drive motor 2 is mounted on the grindstone table 1, and the wheel head 3 has a substantially circular shape. A columnar sharpening stone 4 is attached.

A bed 5 is fixed at a position facing the whetstone table 1, and a work table 6 is mounted on the bed 5 so as to be movable in the three directions indicated by arrows (1) in the figure, that is, in a direction perpendicular to the moving direction of the whetstone table 1 (11i1). is supported. A workpiece 7 to be subjected to grinding is fixed to this worktable 6. Note that in a grinding machine that grinds the workpiece 70F@+ff1i, the workpiece 7 is also normally rotated.

A nut 9 is fixed to a block 8 integrally connected to the work table 6, and a lead screw 11 rotated by a cutting feed motor 10 supported by the bed 5 is screwed into the nut 9.

Further, an in-process gauge 12 for measuring the dimensions of the grinding portion of the work 7 is attached to the work table 6.

This in-process gauge 12 is, for example, (υ
f The sub-portion of grinding consists of a differential transformer with a movable iron core connected to a measuring head that is lightly pressurized, or air is discharged from a nozzle toward the grinding section of the workpiece 7, and the distance from the nozzle to the grinding section is A so-called air micrometer that detects the distance from the nozzle to the secondary part by utilizing the change in air discharge resistance depending on the change in the air discharge resistance is used to continuously measure the dimensions of the ground part while the workpiece 7 is being ground. It is something that can be used.

When performing the grinding process, the grinding wheel 4 is first rotated, and the grinding wheel table 1 is sent to the work table 6 side until the circumferential surface of the grinding wheel 4 touches the grinding portion of the work 7 by 1#. Also, the cutting feed motor lO is activated and the lead screw 1
1 is rotated, and the work table 6 is rotated by the screwing of the nut 9.
In this case, the grinding surface of the workpiece 7 approaches the grinding wheel 4 (direction, that is, the direction of cutting feed). After the workpiece 7 comes into contact with the grinding wheel 4, the worktable 6 continues to move in the above direction in rows 1.11, and the grinding surface of the workpiece 7 is ω [grinding feed]. Feed of work table 6 after contact with grindstone 4 (
Cutting feed) Only the uf cutting key according to V is ground. While this grinding process is being performed, the dimensions of the grinding portion of the workpiece 7 are continuously measured by the in-process gauge 12.

As shown in Hajime, the work table 6 is fed by cutting after dry grinding, and the work table 6 is moved until the grinding process is completed. Be turned to the slave side. Hereinafter, with reference to FIG. 2 showing the structure of the leg restraint part,
I will explain.

The workpiece size reduction signal S1 outputted by the in-process gauge 12 which measures the dimensions of the grinding portion 26 of the workpiece 7 is continuously input to the differentiator circuit 28.

(Dan'7j・Circuit 28 is this workpiece size (G No. 11
Find the rate of change by attacking. In other words, the differentiating circuit 28 functions as an applied IC degree detection circuit for determining the actual machining speed;

The signal S2 indicating the above change>e+ is amplified by the detection signal amplifier 29, and is converted into an actual machining speed signal S3 by adding/subtracting:
It is input to the comparator 21a of the bath 21.

At the same time, the comparator 21a receives a set speed signal corresponding to the optimum depth of cut 1% li determined from the surface roughness of the workpiece 7, the rotation speed of the grinding wheel 4, etc. Processing to form,
The set speed signal S should also be input to the 44 degree setting device 20. ratio! The tzu 42.1a compares the second set speed signal S4 and the sixth recorded actual machining speed signal, and inputs the first comparison signal to the error amplifier 21t). The error amplifier 21b has these, 8ψ constant speed 1ro No. S4 and actual processing..., 7 of the degree S3.
8 (direction and size) ``i+g'' output [word S6 is emitted, and the output signal is connected to the limiter circuit 22 and speed change setting 1
The cutting feed motor control circuit 24 is manually powered through the four circuits 23 (both of which will be described in detail later).

The cutting feed motor control circuit 24 outputs a motor control signal S7 according to the input output signal S6 of the error amplifier 21b.
Output. This motor i same 11 III signal S7 controls the rotation of the cutting feed motor 10 so that the deviation between the machining speed signal S3 and the set speed signal S4 becomes zero.
It's something to groan about.

In other words, if the actual machining speed exceeds the set speed, the cutting feed motor 10 is controlled to lower the actual machining speed, that is, to reduce the rotational km, and on the contrary, the actual machining moisture is set. When the speed is below, the cutting feed motor 10 is controlled to increase the actual machining speed, that is, to increase the rotational speed. Moreover, the cutting feed motor 10
The rotational speed control 11i should be set larger as the deviation between the large machining speed tW and the set speed becomes larger.

By 3t, the actual machining speed converges to the set rate, and even if disturbances such as deflection of the shaft system of the grinding wheel 4 or the support system of the workpiece 7, or even a decrease in the cutting quality of the grinding wheel 4, the actual machining speed will remain constant. The speed is always maintained at the set speed, and the surface roughness of the workpiece 7 becomes uniform. For example, if the motor 10 is a pulse motor, this is controlled by the number of pulses, or if it is a DC motor, it is controlled by the point angle.

When the machining speed is constant as described above, the cutting feed rate of the work table 6 is gradually increased by jC as the cutting quality of the grinding wheel 4 decreases, and the pressing force (grinding force) between the II grinding wheel 4 and the workpiece 7 is increased. However, in this device, the grinding force is prevented from increasing abnormally to the extent that it adversely affects the grinding wheel 4, its shaft system, or the workpiece 7 and its support system. ing. This point will be explained below.

In addition to the previously described signal S6, a reverse hardness 1 word S8 is input from the reverse speed d regulator 33 to the speed setting switching circuit 23 described above. Grinding 1i1 ('f5 The paddy driving power of the driving motor 2 is detected by the pill force detection circuit 30, and the power signal S output by the power detection circuit 3
IO is input to comparator i[j2G 32. This comparison circuit 32 has a set power signal 3 formed by the power setting device 31.
n is input, the comparison circuit 32 compares the power signal S+o and the set power signal Sn, and outputs a signal SI2 when the actual power exceeds the set power. This signal 81
2 is input to the speed setting switching circuit 23, and the speed setting switching circuit 23 is switched to output the backward speed signal S8. Therefore, the above-mentioned backward speed signal S8 is inputted to the cut feed motor control circuit 24, and the cut feed motor control circuit 24 rotates the cut feed motor 10 in the direction opposite to the direction of the cut feed. Motor control signal S7
is output fb. Thereby, the work table 6 is moved back so as to separate the work 7 from the grinding wheel 4 as well.

The reason why the driving power of the grinding wheel drive motor 2 increases as described above is because the sharpness of the grinding wheel 1 decreases and the grinding force increases. Therefore, if this driving power exceeds the predetermined power, By interrupting the grinding process, it is possible to prevent the grinding force from increasing excessively. Of course, the set power is set to the driving power of the grinding wheel drive motor 2 when the grinding wheel 4 is worn to the point where the grinding wheel needs to be repaired.

When the work table 6 is retreated due to the increase in grinding force as described above, an alarm or display may be used to notify the operator of this fact and have the operator make appropriate adjustments to the grinding wheel. The output signal 81 of the comparator circuit 32
2 is input into a known automatic grindstone correction device, and it is preferable that the grindstone correction is performed automatically after the workpiece 7 is retreated. The degree d, y constant switching circuit 23,
It is also possible to switch the signal S6 back to output 4-5 to restart the grinding process automatically.

Next, regarding the action of the limiter circuit 22, ii! a Ming J
-ru. As already explained, the rotational speed of the cutting feed motor 10 is controlled according to the deviation between the actual machining speed and the set speed (carried by the signal S6) because of the constant control side 1. Therefore, during idle grinding feeding, the actual machining speed and speed do not increase even if the work table 6 is fed, so the above deviation is large, and the output/1 stage number S6 is increased by 1 positive due to the control responsiveness. By increasing the number of corners by one corner according to theory 21b, the feed rate (empty grinding feed rate) of the work table 6 is gradually increased, and if this continues, the feed consistency of the work table 6 will be abnormally increased. Since the upper limit value of the signal S6 that handles the above deviation is limited by the limiter 22, the speed of the work table 6 exceeds the speed corresponding to the second limit of the signal S6. That's complete. I wonder if the grinding wheel 4 or the workpiece 7 will be able to smell the world.

In the embodiment described above (/?C), the cutting feed is performed by moving the work table 6, but the workpiece is not moved in the grinding machine. In some cases, the cutting feed is performed by moving the grinding wheel, and in such a case, the motor for moving the grinding wheel may be controlled in the same manner as the cutting feed motor 10 in the above embodiment.

As explained in detail above, the cutting feed device for a grinding machine of the present invention can keep the machining speed constant to even out the surface roughness of the workpiece, and can also prevent an excessive increase in dry grinding feed without using a complicated device. It also reliably prevents abnormal increases in grinding force, and has the effect of greatly increasing the reliability and safety of the grinding machine.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a block diagram showing the structure of the opening section J of the above embodiment. 2. Grinding wheel drive motor 4. Grinding wheel 6.
・Work table 7... Work table 9...
10...Feed of cut required 11...
Lead screw 12... In-process game 220... Machining speed setting device 21... Addition IE,
jjl-Circuit 22...Limit circuit 2
3... Speed] Sho setting switching circuit 24... Cutting feed motor control +11M1 circuit 26... Grinding section 28...
・Differentiator circuit 30...Power detection circuit 31...Power setting device 32...Comparison circuit 33...
・Rear speed setting device SL...Ward law signal S3...Actual machining speed signal S4 ・Setting speed signal &...Output signal of working U reduction/stop circuit S7...
Motor control quotient 1 signal S8... Retreat! *Degree signal 1 (1...Power signal 811...
... Setting 73b Force signal 812 ... Comparison circuit output signal Shin 1 Figure

Claims (1)

[Claims] A machining rate setting device that sets the cutting feed speed of the cutting feed motor that moves the workpiece and the grinding wheel relative to each other, and a grinding jMI
An in-process gauge that continuously measures the dimensions of the grinding part of the workpiece being machined; a machining speed detection circuit that receives the workpiece dimension signal measured by the in-process gauge as input and detects the actual machining speed; and the υ Loe speed setting device. There is an addition/subtraction circuit that compares the set speed and the actual machining speed detected by the machining speed detection circuit and generates an output signal according to the difference between them, and an adder/subtraction circuit that limits the upper limit of the output 1 of this adder/subtraction circuit to adjust the dry grinding feed rate. A limiter circuit to prevent excessive cutting, a backward speed setting for setting the backward speed of the cutting feed motor, an output signal from this backward speed setting device, and an output 4h from the IJ limiter circuit.
a speed setting switching circuit that manually selects and outputs the number 1^; a cutting feed motor control circuit that controls the speed of the cutting feed motor according to the output of the speed setting switching circuit;
A power setting device that sets the upper limit of the driving power of the grinding wheel drive motor that increases due to a decrease in the sharpness of the grinding wheel, a power detection circuit that detects the power of the grinding wheel drive motor, and a detection value of this power detection circuit. A cutting feed device for a grinding machine, comprising a comparator circuit that switches the speed setting switching circuit to output an output signal of the backward speed setting device from the switching circuit when the speed setting switching circuit becomes larger than the set value of the power setting device.