JPH04785B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention provides a numerically controlled grinding machine, more specifically, a grinding wheel head guided so as to be movable in a direction perpendicular to the spindle axis, which is parallel to the spindle axis. A grinding wheel having a cylindrical grinding surface and a shoulder grinding surface perpendicular thereto is mounted on a shaft, and the position of the cylindrical grinding surface in a first axis direction perpendicular to the main shaft axis and the shoulder grinding surface are has first and second current position registers that respectively store positions in a second axis direction parallel to the spindle axis of the grinding wheel head and workpiece table based on the contents of the first and second current position registers. This invention relates to a numerically controlled grinding machine that controls relative movement between the machine and the machine.

<Prior art> In numerically controlled grinding machines, the position of the grinding surface of the grinding wheel changes gradually as the grinding wheel is corrected, so the position of the grinding surface of the grinding wheel, rather than the position of the grinding head, is accurately detected and the position of the grinding surface of the grinding wheel is adjusted between the grinding head and the workpiece. It is necessary to control the relative movement between the object and the table.

For this reason, conventionally, a correction tool is placed on the workpiece table, and the position of the tip of the correction tool is measured in advance as a reference position.
Every time the grinding wheel correction is completed, the data of the reference position is set in the current position register with the grinding surface of the grinding wheel facing the correction tool, and thereby the contents of the current position register are adjusted to the reality of the grinding surface of the grinding wheel. It was designed to represent the position of

<Problems to be Solved by the Invention> However, in such conventional devices, if a power outage occurs during processing and the contents of the current position register that stores the position of the grinding surface of the grinding wheel are lost, the position of the grinding surface of the grinding wheel is lost. In such a case, it is necessary to manually correct the grinding wheel and reset the current position register using the correction tool as a position reference, which has the disadvantage of poor workability. .

<Means for Solving the Problems> FIG. 1 is an overall configuration diagram for clearly demonstrating the present invention. The cylindrical grinding surface Ga and the shoulder grinding surface Gb of the grinding wheel G between the reference point Pg provided on the grinding wheel head 1 and the reference position provided on the workpiece table 2 in the home position return state are perpendicular to the spindle axis Os. storage means 3 for storing distances in a first axis direction and a second axis direction parallel to the main axis Os; and first and second axes of the cylindrical part ground surface Ga and shoulder ground surface Gb with respect to the reference point Pg; Displacement amount storage means 4 for storing the amount of misalignment in the direction
and correcting the amount of deviation between the cylindrical grinding surface Ga and the shoulder grinding surface stored in the deviation amount storage means in accordance with the amount of positional change between the cylindrical grinding surface Ga and the shoulder grinding surface Gb due to the grindstone correction. a deviation amount correction means 5, an original position return means 7 for returning the grindstone head 1 and the workpiece table 2 to their original positions, and the storage means when the original position return is performed by the original position return means 7. The positional data of the grinding wheel head 1 and the workpiece table 2 stored in 3 is corrected by the amount of deviation between the cylindrical part grinding surface Ga and the shoulder part grinding surface Gb stored in the deviation amount storage means 4, and the first, Second current position register
It is equipped with a setting means 6 for setting RX and RZ.

<Operation> The deviation amount storage means 4 stores the reference point Pg of the grindstone head 1.
The first of the cylindrical part ground surface Ga and the shoulder part ground surface Gb
The deviation amounts Wx and Wz in the axis and second axis directions are stored, and the deviation correction means 5 changes the position of the cylindrical grinding surface Ga and the shoulder grinding surface Gb based on the grindstone correction every time the grindstone is corrected. The data of the deviation amounts Wx and Wz stored in the deviation amount storage means 4 is corrected according to the amount.

When the home position return means 7 returns to the home position, the setting means 6 is activated, and the original position data of the grindstone head 1 and workpiece table 2 stored in the storage means 3 is stored in the deviation amount storage means 4. amount of deviation
Correct it using the data of Wx and Wz and set it in the first and second current position registers RX and RZ. As a result, the contents of the current position registers RX and RZ are the cylindrical grinding surface Ga whose position has changed due to the grindstone correction,
The positions of the cylindrical part grinding surface Ga and the shoulder part grinding surface Gb can be accurately detected even after the grindstone is corrected.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. In FIG. 2, reference numeral 10 indicates a bed of a numerically controlled grinding machine, and a workpiece table 13 on which a headstock 11 and a tailstock 12 are installed is placed on the bed 10. A workpiece W is supported between the headstock 11 and the tailstock 12, and is rotationally driven by the rotation of a main shaft 15 connected to a main shaft drive motor (not shown). The workpiece table 13 is connected to a servo motor 16 via a feed screw mechanism (not shown), and is adapted to be moved in the Z-axis direction parallel to the main spindle axis Os. Note that 14 is a Z-axis origin detector that detects that the workpiece table 13 is located at its original position.

On the other hand, behind the bed 10, a grindstone stand 17 is provided.
is mounted so that it can advance and retreat in the X-axis direction perpendicular to the axis of the workpiece W, and this grindstone head 17 is driven by a servo motor 18.
The feed is controlled via an unillustrated feed screw connected to. The grinding wheel head 17 has an angular grinding wheel G having a cylindrical grinding surface Ga parallel to the spindle axis Os and a shoulder grinding surface Gb perpendicular to the cylindrical grinding surface Ga. The grindstone shaft 19 is rotatably supported via a grindstone shaft 19 that is obliquely supported, and is rotationally driven by a grindstone drive motor (not shown). Incidentally, an X-axis origin detector 21 is installed at the rear end of the bed 10 to detect that the grindstone head 17 has been retreated to its original position.

Further, a correction tool DT made of diamond or the like is attached to the side surface of the tailstock 12 on the side of the grindstone 17 via a bracket 22.
The grinding wheel G is corrected using the DT, and the side surface of the headstock 11 on the side of the grinding wheel G is provided with a first reference surface Sa parallel to the spindle axis Os and a second reference surface Sa perpendicular to this. A reference member S having a reference surface Sb is attached.

FIG. 3 shows a control circuit for controlling the grinding machine configured as described above, in which 40 indicates the servo motor 1.
Drive circuits 41 and 42 that drive 6 and 18, respectively.
This numerical control device 40 controls the machining of the workpiece W and the correction of the grinding wheel G by distributing pulses to the arithmetic processing device 45, the memory M, and the interface 4 connected to the arithmetic processing device 45.
6,47. The interface 46 includes a data writing device 50, a command switch RCS to MSZ for instructing the start of machining, etc.
The origin detectors 14 and 21 are connected, and the output of the interface 47 is connected to the drive circuits 41 and 42.

The memory M stores the grinding surface Ga of the cylindrical part of the grinding wheel G,
In addition to the current position registers RX and RZ that store the positions Xc and Zc of the shoulder grinding surface Gb in the X and Z axis directions, a machining data area MDA, an NC program area NCPA, and a control data area CDA are provided. In the machining data area MDA, data such as the index position of the workpiece table 13, the finished dimensions of the machined surface, and the completed rough grinding dimensions are written by the data writing device 50.

On the other hand, the NC program for the workpiece grinding cycle and the NC program for grinding wheel correction are written in the NC program area NCPA using the data writing device 50, and in the control data area CDA,
Data indicating the positional relationship between the whetstone head 17 and the reference member S when the whetstone head 17 is moved to its original position is stored.

That is, as shown in FIG.
The intersection point between the center axis Og of The separation distance Mx in the X-axis direction between the grindstone reference point Pg and the first reference surface Sa of the reference member S in the state where the wheelhead is located at the position, and the grindstone reference point Pg and the second reference surface Sb
A separation distance Mz in the Z-axis direction between the two is stored. In addition, this control data area CDA contains
The distance Lx in the X-axis direction from the spindle axis Os to the first reference surface Sa of the reference member S, the amount of deviation Wx in the X-axis direction of the cylindrical grinding surface Ga with respect to the grinding head reference point Pg, and the Z-axis direction of the shoulder grinding surface Gb The amount of deviation Wz is stored. Note that the deviation amounts Wx and Wz of the cylindrical part grinding surface Ga and the shoulder part grinding surface Gb are automatically measured and stored when the grindstone is replaced.

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.

Operation when returning to home position When restarting operation after an emergency stop or at the start of operation every morning, the command switch RCS is pressed and the processing unit 45 returns the grinding wheel G to its home position.
command.

As a result, the arithmetic processing unit 45 executes the program shown in FIG. 6, and the origin detectors 21 and 14 of each axis are activated in order to position the grindstone head 17 and workpiece table 13 at the original positions shown in FIG. 60, 61 to distribute pulses on the X and Z axes until the and,
Thereafter, the following calculations (1) and (2) are performed, and the calculation results Xo and Zo are set in the X-axis and Z-axis current position registers RX and RZ (62).

Xo = Mx + Lx - Wx ... (1) Zo = Mz - wz ... (2) From this, the contents of the current position register RX are as follows: Grinding of the cylindrical part from the spindle axis 0s with the grinding wheel G returned to the original position It accurately represents the amount of retreat in the X-axis direction to the surface Ga, that is, the position in the X-axis direction, and the contents of the current position register RZ are based on the workpiece table 13.
It accurately represents the Z-axis direction position of the shoulder ground surface Gb with reference to the second reference surface Sb of the reference member S in the state in which the reference member S has been returned to its original position.

After this, when the grindstone head 17 and workpiece table 13 are moved based on the numerical control program, the contents of RX and RZ are updated according to the amount of movement, and the contents of RX and RZ are Ga, current position of shoulder grinding surface Gb in X-axis and Z-axis directions
Accurately represents Xc and Zc.

Operations during machining and grindstone correction When a machining command is given to the processing unit 45 by pressing the machining start switch GSS, the processing unit 45 selects an NC program for machining the workpiece from the NC program area NCPA, and Numerical control processing shown in FIG. 7 is performed. If the read program data is a movement command for the X-axis or Z-axis, the programmed end point data
Incremental movement amount by subtracting the current positions Xc, Zc of the cylindrical part ground surface Ga and shoulder ground surface Gb stored in the current position registers RX, RZ from Xe, Ze.
Xi and Zi are calculated 77, 81, and pulse distribution is performed based on these 78, 82.

Further, when the grindstone correction start switch DSS is pressed, 45 selects an NC program for grindstone correction from the NC program area NCPA, and performs the numerical control process shown in FIG. 7 on this program.

As shown in Fig. 5, the program for grinding wheel correction is as follows: After positioning the grinding wheel G at a position where the correction tool DT cuts into the cylindrical grinding surface Ga by a distance r, the correction tool DT moves the grinding wheel G The workpiece table 13 is moved to a position facing the top of the shoulder, and then the correction tool DT is relatively retreated along the shoulder grinding surface Gb. Therefore, the shoulder ground surface Gb
The depth of cut of the correction tool DT in is set to r·tanθ, where θ is the angle between the plane where the top of the grinding wheel G is located and the X-axis.

At the end of the program for commanding such a grindstone correction operation, a G code G07 for position correction command is programmed. When the data of this G07 is read out, the 45 reads out the data of the cutting depth r of the correction tool DT on the cylindrical part grinding surface Ga that is programmed following G07.
Distribute a number of negative correction pulses to the X axis according to 8
6. During the distribution of this correction pulse, the current position register
The contents of RX do not change, and only the grinding wheel G is advanced by the depth of cut r. This causes the current position stored in the current position register RX to
The position of the cylindrical part ground surface Ga represented by Xc matches the position of the actual cylindrical part ground surface Ga. Following this, r・tanθ is added to the current position Zc stored in the current position register RZ, and the current position register RZ
The position of the cylindrical part grinding surface Ga represented by the current position Zc stored in is made to match the position of the actual shoulder part grinding surface Gb.

Then, following this, the control data area
Data of deviation amount stored in CDA Wx, Wz
A process is performed to reduce the depth of cut r and r·tanθ on the cylindrical part ground surface Ga and the shoulder part ground surface Gb from 88.

In this way, the grinding surface of the cylindrical part can be improved by adjusting the grinding wheel.
If the positions of Ga and shoulder grinding surface Gb change and the deviation amounts Wx and Wz of cylindrical grinding surface Ga and shoulder grinding surface Gb with respect to the grinding wheel head reference point Pg change, the deviation will change according to the amount of change. The stored values of the quantities are corrected, and the deviation amounts Wx and Wz in the control data area CDA are matched with the actual deviation amounts after the grindstone correction. Therefore, after the grinding wheel has been corrected many times, by returning to the original position, the corrected deviation amount Wx,
Based on Wz, the X-axis coordinate values Xo and Z represent the positions of the cylindrical part grinding surface Ga and the shoulder part grinding surface Gb in the original position state.
The axis coordinate value Zo is calculated, so even if the positions of the cylindrical part grinding surface Ga and the shoulder part grinding surface Gb change due to grinding wheel correction, the cylindrical part grinding surface Ga and the shoulder part grinding surface
Gb position can be detected accurately.

In addition, due to power outage or machine stoppage at the end of the day's work, the current position registers RX, RZ
Even if the contents disappear, just by performing the above-mentioned return to original position operation, the current position register RX will be updated according to the actual positions of the cylindrical grinding surface Ga and the shoulder grinding surface Gb whose positions have changed due to the grindstone correction. , RZ are initialized, and the contents of the current position registers RX and RZ can be made to match the actual position of the grinding surface, resulting in good workability.In addition, in the above example, the grinding wheel G was of an angular shape. , the present invention is the eighth grinding wheel G.
The present invention can also be applied to a numerically controlled grinding machine using a cylindrical grindstone having the shape shown in the figure.

In this case, since there is no fixed relationship between the depths of cut r1 and r2 on the cylindrical grinding surface Ga and the shoulder grinding surface Gb, program the data for the depths of cut r1 and r2 following the G07 code. , the deviation amount data Wx, Wz may be corrected based on the data of r1, r2.

<Effects of the Invention> As described above, in the invention, the amount of deviation between the cylindrical grinding surface and the shoulder grinding surface with respect to the reference point of the grinding wheel head is memorized, and the deviation amount of the grinding surface of the cylindrical portion and the shoulder grinding surface is stored based on the positional change of each grinding surface when the grinding wheel is corrected. The data of the amount of deviation is corrected, and when returning to the original position, the current position register is set based on the corrected deviation amount data and the position data of the grinding wheel head and workpiece table in the original position state. Even if the current position data of the cylindrical grinding surface and shoulder grinding surface is lost due to a power outage, etc., the positions of the cylindrical grinding surface and shoulder grinding surface can be accurately calculated by returning the grindstone head to its original position. . Therefore, even if the current position data is lost, there is no need to manually correct the grindstone and reset the contents of the current position register, which has the advantage of very good work efficiency.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram for clearly demonstrating the present invention.
2 to 8 show embodiments of the present invention,
Fig. 2 is a schematic plan view of the numerically controlled grinding machine, Fig. 3 is a block diagram of the control circuit that controls the grinding machine shown in Fig. 2, and Fig. 4 shows the grinding wheel G and reference member S in the state of returning to their original positions. FIG. 5 is a diagram showing the positional relationship between the grinding wheel G and the correction tool DT at the time of grinding wheel correction, and FIGS. 6 and 7 show the operation of the arithmetic processing unit 45 in FIG. 3. Flowchart, No. 8
The figure is a partial view of a cylindrical grinding wheel to which the present invention can be applied. 13... Workpiece table, 17... Grindstone stand, 1
6, 18... Servo motor, 40... Numerical control device, 41, 42... Drive circuit, 45... Arithmetic processing unit, DT... Correction tool, G... Grinding wheel, Ga...
Cylindrical part ground surface, Gb...Shoulder part ground surface, Wx, Wz...
...Amount of deviation.

Claims (1)

[Claims] 1. A grinding wheel having a cylindrical grinding surface parallel to the spindle axis and a shoulder grinding surface perpendicular thereto is mounted on a grindstone head guided so as to be movable in a direction perpendicular to the spindle axis, and first and second current position registers each storing a position of the cylindrical part grinding surface in a first axial direction perpendicular to the main shaft axis and a position of the shoulder part grinding surface in a second axial direction parallel to the main shaft axis; In a numerically controlled grinding machine, the relative movement between the grinding wheel head and the workpiece table is controlled based on the contents of the first and second current position registers. storage means for storing distances in the first and second axial directions between a reference point provided on the table and a reference position provided on the workpiece table; A deviation amount storage means for storing the amount of deviation of the surfaces in the first and second axial directions; and a deviation amount storage means for storing the amount of deviation in the positions of the cylindrical part grinding surface and the shoulder part grinding surface in accordance with the amount of positional change of the cylindrical part grinding surface and the shoulder part grinding surface due to grindstone correction. a deviation amount correction means for correcting the deviation amount between the cylindrical part grinding surface and the shoulder part grinding surface, an original position return means for returning the grindstone head and the workpiece table to their original positions, and the original position return means The position data of the grindstone head and workpiece table stored in the storage means when the return to the original position was performed is calculated by the amount of deviation between the cylindrical part ground surface and the shoulder ground surface stored in the deviation amount storage means. A numerically controlled grinding machine characterized by comprising a setting means for setting the corrected current position in the first and second current position registers.