JPS6238111B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a grinding wheel feeding device for a grinding machine.

In recent years, in order to simplify the feeding mechanism of the grindstone head,
In some grinding machines, a servo motor for grinding feed is used to perform correction feeding of the grinding wheel for dressing of the grinding wheel.
Since the position of the processed surface of the grinding wheel changes depending on the number of times of dressing, it is not possible to position the processed surface of the grinding wheel at a constant position even if the grinding wheel head is returned to its fixed original position.

Therefore, in such a grinding machine, if a power outage occurs during processing and the contents of the position register that stores the position of the grinding wheel surface are lost, the position of the grinding wheel surface will be completely unknown. If such a situation occurs, use the master workpiece to position the grinding wheel machining surface at a certain position from the center of the workpiece, and then position the distance data according to the outer diameter of the master workpiece. It was necessary to set it in the register, which was very troublesome.

In addition, in the past, the amount of movement of the grinding wheel when the grinding wheel moves forward from its fixed original position until the machining surface of the grinding wheel is located at the starting point a certain distance from the center of the workpiece is measured by the amount of movement of the grinding wheel. At the same time, the corrected feed amount of the grinding wheel head performed in conjunction with dressing is stored cumulatively.
If the position of the machined surface becomes unknown due to a power outage, etc., return the grinding wheel head to its original position, and then move the wheel head forward by the sum of the memorized movement amount and the cumulative value of the correction feed. The grinding wheel processing surface is positioned at the starting point, so that even if the position memory of the grinding wheel processing surface is lost due to a power outage, etc., the grinding wheel processing surface can be positioned at a fixed position from the center of the workpiece. However, even in this case, if there is a difference in dimension between the diameter of the newly installed grinding wheel and the diameter of the previously used grinding wheel when new, the grinding wheel head may be moved from its original position. Since the amount of movement until it is located at the starting origin changes, this amount of movement must be measured and reset again, which has the disadvantage of poor operability. In other words, since the amount of movement of the grinding wheel until it is located at the starting point cannot be directly measured, the movement of the grinding wheel from the state in which the grinding wheel is in contact with the surface of the master workpiece to the original position is performed by retracting the grinding wheel head to its original position. This is because, after detecting the amount of movement, the distance from the starting origin to the outer periphery of the master workpiece must be subtracted from this amount of movement.

In view of these conventional problems, the present invention is designed so that even if the diameter of the newly installed grinding wheel is different from the previous one, it is only necessary to set the diameter data of the newly installed grinding wheel. The following embodiments will be explained based on the drawings.

FIG. 1 shows the main body of the grinding machine, in which a workpiece W is held between a headstock 13 and a tailstock 15 placed on a bed 11 via a table 12, and connected to a spindle motor 16. It is adapted to be rotationally driven by the rotation of the main shaft 17.

In addition, a drive motor 2 is installed at the rear of the bed 11.
A grindstone stand 23 supporting a grinding wheel 22 rotated by the grinding wheel 1 is guided so as to be movable toward the workpiece W,
It is connected to the output shaft of the servo motor 24 via a feed screw (not shown). A position detector 25 is provided at the rear end of the bed 11 to detect when the grinding wheel 22 has been retreated to its fixed original position.

Reference numeral 26 denotes a dressing device whose base 27 is fixed to the side surface of the grinding wheel 22 mounting side of the grinding wheel head 23, and a ram guided by the base 27 so as to be movable in a direction orthogonal to the rotational axis of the grinding wheel 22. 2
A dressing roll 30 is rotatably supported at the tip of the grinding wheel 8 and rotated by a motor 31 about an axis parallel to the rotational axis of the grinding wheel 22 . The ram 28 is connected to a servo motor 32 fixed to the base 27 via a feed screw (not shown).
is connected to.

FIG. 2 shows a control circuit for controlling the grinding machine configured as described above, and in the same figure, reference numeral 40 indicates the servo motor 24,
This numerical control device 40 controls the machining of the workpiece W and the dressing of the grinding wheel 22 by distributing pulses to drive circuits 41 and 42 that drive the 32, respectively. Interface 4 connected to processing device 45
6,47. The interface 46 includes a data writing device 50, command switches GCS, DCS, etc. that command the start of machining, etc.
RCS, DRC, REW and manual pulse generator 51
and the position detector 25 are connected, and the output of the interface 47 is connected to the drive circuits 41 and 42.

The memory M also includes a core memory, a processing data area TDA into which data is written by the data writing device 50, and a control data area.
CDA is provided, and the internal machining data area TDA contains the position P0 at the start origin of the grinding wheel machining surface 22a and the forward end position in each process of rapid advance, rough grinding feed, and fine grinding feed. Data D0 to D3 representing P1 to P3 as distances from the workpiece axis are written prior to machining. Note that FIG. 3 is a diagram showing the positional relationship between the start origin P0 and the forward end positions P1 to P3 of each process.

On the other hand, the control data area CDA contains the cutting depth L1 during dressing, the retreat amount L2 after dressing is completed, the radius value R of the grinding wheel 22, and the grinding wheel head 23.
The distance S from the workpiece axis 0W to the grinding wheel axis 0G when the dressing roll 30 is located at the original position
Data representing the distance T from the grinding wheel axis 0G to the surface of the dressing roll 30 when the roller is located at the backward end is written when the machine is assembled.

In addition, the RAM area RA in the memory M includes a position register SPR for storing data SPD representing the position of the grinding wheel machining surface 22a, and a dressing roll 3.
A position register DPR is configured to store data DPD representing the position of 0.

Next, the operation of the numerically controlled grinding machine having the above configuration will be explained, focusing on the operation of the arithmetic processing unit 45.

(i) Home position return operation When the position memory of the grinding wheel machining surface 22a is lost due to a power outage, or when restarting operation after an emergency stop, the command switch RCS
is pressed to instruct the arithmetic processing unit 45 to return the grinding wheel 22 to its original position.

As a result, the arithmetic processing unit 45 executes the program shown in FIG. 4 to perform processing for returning to the original position. That is, first, in step (100), the arithmetic processing unit 45 sends pulses to the drive circuit 41 until the position detector 25 is activated, and returns the grinding wheel 22 to its original position. When this is completed, in step (101), the grinding wheel head 23 stored in the control data area CDA is
Subtract the data of the grinding wheel radius value R, which is also stored in the control data area CDA, from the data of the distance S from the workpiece axis 0W to the grinding wheel axis 0G when is located at the original position,
Position register SPR as position data SPD of 2a
Set to .

After this, at step (102), the position data D0 of the start origin stored in the machining data area TDA is subtracted from the position data SPD stored in the position register SPR to find the movement amount ΔX, and step (102) is reached. 103) and this movement amount △
The number of pulses corresponding to X is output to the drive circuit 41. As a result, the grinding wheel 22 is moved toward the workpiece W by an amount corresponding to △X, and the grinding wheel 22 is moved toward the workpiece W side by an amount corresponding to △
2a is correctly positioned at the starting origin P0. When this is completed, the process returns to the main routine (not shown) and pulse distribution is stopped. Note that while the grinding wheel 22 is moving, the grinding wheel 22
Each time the wheel moves a predetermined distance, the position data SPD of the position register SPR is increased or decreased by 1 depending on the direction of movement, so that the position data SPD correctly represents the position of the grinding wheel machining surface 22a with respect to the center of the workpiece. . Therefore, when the grinding wheel processing surface 22a is located at the starting point P0, the content of the position register SPR becomes the same value as the position data D0 of the starting point P0.

(ii) Machining operation When machining the workpiece W, the command switch
Press GCS. As a result, the arithmetic processing unit 4
5 controls workpiece machining based on the program shown in FIG.

First, in step (110), the arithmetic processing unit 45 determines whether or not all machining processes have been completed based on the status of process completion flags FG1 to FG4 set for each machining process, and determines whether or not all machining processes have been completed. If not, step (111) sets the flag FG.
The process to be performed in the next row is determined based on the states of FG1 to FG4, and the process moves to any of steps (112a) to (112d) depending on the process to be performed next. At the start of machining, all flags FG1 to FG4 are reset, and the process moves to step (112a) to perform rapid forward movement. As a result, the position data D1 of the fast forward end P1 is subtracted from the position data SPD stored in the position register SPR to calculate the movement amount ΔX, and step (113a)
The number of pulses corresponding to the amount of movement △X is distributed to the drive circuit 41 at a rapid feed speed, and
is fast forwarded forward. After this, the flag FG1 is set in step (114a), and the process returns to step 110. Thereafter, the same operation is repeated to perform rough grinding feed and fine grinding feed of the grinding wheel 22, and after this, the grinding wheel 22 is moved backward until the grinding wheel processing surface 22a is located at the starting point P0, and the operation is completed. .

(iii) Dressing operation When the command switch DCS connected to the interface 46 is pressed, the arithmetic processing unit 45 executes the program shown in FIG. 6 and performs processing for dressing.

First, in step (120), the number of pulses corresponding to L2-L1 is distributed to the drive circuit 42 at a rapid feed speed, and the dressing roll 30 is advanced to a position where it is in a zero cut state with respect to the grinding wheel processing surface 22a. After that, in step (121), a number of pulses corresponding to the depth of cut L1 are applied to the drive circuit 42.
The cutting speed is distributed to the dressing roll 3.
0 into the grinding wheel 22 by the cutting depth L1. Then, in step (122), the number of pulses corresponding to the retreat amount L2 is distributed to the drive circuit 42, and the dressing roll 30 is retreated by the retreat amount L2, and then, in step (123), the control data area is
The cutting depth L1 is subtracted from the grindstone diameter data R stored in the CDA, and this is written back to the original storage area to complete the operation.

Therefore, the data on the diameter of the grinding wheel stored in the control data area CDA is reduced by an amount corresponding to the depth of cut each time dressing is performed, and always represents the actual radius of the grinding wheel 22. Therefore, after performing the above-described origin return operation, the grinding wheel processed surface 22a is accurately positioned at the starting origin P0 regardless of the decrease in the diameter of the grinding wheel.

(iv) Operation when replacing the grinding wheel When replacing the grinding wheel, operate the command switch DRC before starting work. As a result, in step (130) in FIG. 7, the arithmetic processing unit 45 distributes pulses to the drive circuit 42 until the dressing roll 30 is located at the rearward end and an unillustrated position detector is activated. The dressing roll 30 is retreated to the retreat end. Then, in step (131), the position data T stored in the control data area is preset to the position register DPR that stores the position of the tip of the dressing roll 30.

After completing the replacement of the grinding wheel 22, the operator rotates the manual pulse generator 51. The rotation of this manual pulse generator 51 causes the interface 46 to
When a pulse is sent out, the arithmetic processing unit 45 executes the routine shown in FIG. and the position register at step (141).
Subtract 1 from the position data DPD of DPR.

As a result, the position data T set in the position register DPR is subtracted according to the amount of advance of the dressing roll 30, and the position data T set in the position register DPR is decreased according to the amount of advance of the dressing roll 30.
The content of is a value corresponding to the distance from the center of the grinding wheel 0G to the surface of the dressing roll 30.

Then, at the point where the dressing roll 30 comes into contact with the grinding wheel processing surface 22a, the rewriting command switch is activated.
Press REW. As a result, the arithmetic processing unit 45 transfers the contents DPD of the position register DPR to the area for storing the grinding wheel diameter data R in the control data area CDA at step (150) in FIG.
As mentioned above, the contents of the position register DPR represent the distance from the outer periphery of the dressing roll 30 to the center of the grinding wheel 22, and this operation is performed with the dressing roll 30 in contact with the replaced grinding wheel 22. If done, the replaced grinding wheel 22
The data according to the radius of the control data area
Stored in CDA.

Therefore, even after the grinding wheel 22 has been replaced, the grinding wheel processing surface 22a can be correctly positioned at the starting point by performing the above-described return to original position operation.

In the above embodiment, the present invention was applied to a grinding machine in which the grinding wheel was moved along a path perpendicular to the workpiece axis; It can also be applied to a grinding machine that moves along the In this case, the distance along the path from the intersection of the workpiece axis and the path to the grinding wheel axis is fixedly memorized, and when the grinding wheel is returned to its original position, the radius of the top of the grinding wheel is calculated from this fixedly memorized distance. The position of the grinding wheel machined surface can be calculated by subtracting the value, and the subsequent feed can be controlled using the position of this top as the position of the machined surface.

It goes without saying that the present invention can also be applied to a grinding machine in which the forward ends of rough grinding feed and fine grinding feed are controlled by signals from a sizing device.

As described above, in the present invention, the dressing roll position register memorizes the position of the tip of the dressing roll and changes the contents according to the movement of the dressing roll, and the dressing roll is fixed. a non-volatile first memory means for storing the distance from the grinding wheel axis to the tip of the dressing roll when the dressing roll is retreated to its original position; a first rewriting unit that rewrites the contents of the dressing roll position register to data stored in the first storage unit when the dressing roll position register is replaced with data stored in the first storage unit; Since it is equipped with a non-volatile second storage means that stores the contents of the single roll position register as the diameter of the grinding wheel, it has the effect of easily measuring the diameter of the grinding wheel without using a special measuring device. . Further, there is a non-volatile third storage means for fixedly storing the distance from the workpiece axis to the grinding wheel axis when the grinding wheel is retreated to the fixed original position, and the grinding wheel is stored in the second storage means each time dressing is performed. a second rewriting means for reducing the diameter of the wheel; a reversing control means for retracting the grinding wheel to the fixed original position in response to the original position return command; and a second rewriting means for reducing the diameter of the wheel; and setting means for subtracting the diameter data stored in the second storage means from the distance data stored in the third storage means and setting the result in the grinding wheel position register. Even if the memory of the position of the processed surface of the grinding wheel is lost, the position of the processed surface of the grinding wheel can be easily determined based on the diameter of the grinding wheel, resulting in improved workability.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a schematic plan view of the main body of the grinding machine, FIG. 2 is a block diagram of a control circuit that controls the grinding machine shown in FIG. 1, and FIG. A diagram showing an example of a grinding cycle for machining the workpiece W shown in the figure, and FIGS. 4 to 9 are flowcharts showing the operation of the arithmetic processing unit 45 in FIG. 2. 13... Headstock, 15... Tailstock, 16... Main spindle motor, 17... Main shaft, 22... Grinding wheel, 22
a... Grinding wheel processing surface, 23... Grinding wheel stand, 24...
Servo motor, 25... position detector, 26... dresser, 40... numerical control device, 45... arithmetic processing unit, M... memory, W... workpiece.

Claims (1)

[Claims] 1. It has a grinding wheel position register that stores data corresponding to the distance from the workpiece axis to the grinding wheel machining surface, and whose contents change according to the movement of the grinding wheel. Based on the contents of this grinding wheel position register, In a grinding wheel feeding device for a grinding machine that detects the position of the processed surface of the grinding wheel and controls the feed of the grinding wheel, the position of the tip of the dressing roll is memorized and the position of the dressing roll is controlled. a dressing roll position register whose contents change accordingly, and a non-volatile first register that stores the distance from the grinding wheel axis to the tip of the dressing roll when the dressing roll retreats to its fixed original position. a storage means; and a first book for rewriting the contents of the dressing roll position register with the data stored in the first storage means when the dressing roll is retreated to the fixed original position and the grinding wheel is replaced. a non-volatile second storage means for storing the contents of the dressing roll position register as the diameter of the grinding wheel at the time when the dressing roll contacts the grinding wheel after the grinding wheel is replaced; a non-volatile third storage means for fixedly storing the distance from the workpiece axis to the grinding wheel axis when the workpiece is retreated to its original position, and the diameter of the grinding wheel stored in the second storage means is decreased each time dressing is performed. a second rewriting means for rewriting the grinding wheel to the fixed original position in response to the home position return command; 1. A grinding wheel feeding device for a grinding machine, comprising: setting means for subtracting diameter data stored in a second storage means from distance data stored in a storage means and setting the result in a grinding wheel position register.