JPH0540930Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial field of application) The present invention is designed to prevent overrun conditions when the feed device that feeds the workpiece to the grinding wheel in a grinding machine is fed more than a preset feed amount. This relates to improvements to safety devices to prevent this from occurring.

(Conventional technology) Conventionally, as a safety device for this type of grinding machine,
The cut feed table with the workpiece attached is fed by the cut feed motor, and when the cut feed table is fed by a predetermined amount or more, the limit switch set to the device protection limit feed position There is a known device that detects this and outputs a feed stop signal to the cut feed motor to prevent damage to the dresser or the like due to overrun of the cut feed table.

(Problem to be solved by the invention) However, in the conventional device described above, when the cutting feed table becomes overrun, the cutting feed is immediately stopped, so damage to the dresser etc. due to overrun can be effectively prevented. However, if the operator is away from the grinding machine for other work and does not notice that the grinding machine has stopped due to the cutting feed table stopping, the grinding machine may remain in a state where it has stopped grinding the workpiece. There is. Moreover,
The standard for replacing the grinding wheel begins only after the grinder has stopped, which cannot meet today's needs for reducing grinding machine stop time and workpiece machining process time in seconds or less, resulting in decreased productivity. There is a problem with doing so.

In addition, in the conventional type described above, the stroke of the cutting feed table is controlled by a limit switch, so the setting position of the limit switch must be reset every time the workpiece diameter changes, making the operation cumbersome. There was also the problem of poor work efficiency.

In addition, instead of a limit switch, it is possible to set the stroke of the cutting feed table by equipping the device with a numerically controlled stroke end function, but the cutting feed table can be adjusted for each different workpiece diameter. The setting value of the stroke end must be changed, and this cannot be an essential solution.

The present invention has been developed in view of the above points, and its purpose is to improve the control mode of the feed device in a grinding machine so that grinding can be carried out without causing an overrun state of the cutting feed table. Allowing an operator to leave the grinding machine for a predetermined period of time while the machine remains in operation;
To simplify the operation of a safety device of a grinding machine by automatically preventing an overrun state of a feeding device simply by setting a reference value for the limit of use of a grinding wheel.

(Means for Solving the Problems) In order to achieve the above object, the solution of the present invention has a feeding device that feeds the cutting of the workpiece to the grinding wheel in the grinding machine and corrects the grinding wheel using the dresser. The target is a safety device for a grinding machine that prevents an overrun condition due to cutting that exceeds the feed amount.

The feeding device then feeds the workpiece from the initial cutting feed start position where it starts cutting feed to the feed position where the diameter of the grinding wheel decreases due to correction of the grinding wheel by the dresser and reaches a reference value near the grinding limit. A grinding wheel usage standard setting device that sets a grinding wheel usage standard value corresponding to the feed amount when The detected feed amount value is compared with the grindstone usage standard value set by the grindstone usage standard setting device, and when the feed amount detection value exceeds the grindstone usage standard value, a grindstone replacement command signal is sent to prompt the replacement of the grindstone. It is provided with a first comparator that outputs the difference value between the two to a notification means such as a buzzer or a lamp, and also thereafter outputs the difference value between the two.

Furthermore, the feed amount when the feeder is fed from the feed position corresponding to the grinding wheel use standard value set by the grinding wheel use standard setting device to the device protection limit feed position that determines the overrun state of the feeder. A device protection limit setter that sets a corresponding device protection limit value compares the difference value output from the first comparator with the device protection limit value set by the device protection limit setter, and calculates the difference value. and a second comparator that outputs a cutting feed stop signal for forcibly stopping the cutting feeding to the feeding device when the feeding device reaches the device protection limit value.

(Function) With the above configuration, in the present invention, when grinding a workpiece by feeding the workpiece to the grindstone using the feeding device, the first comparator outputs the output from the position detector and the grindstone use reference setting device. Based on the signal, the feed amount detection value for the workpiece from the initial cut feed start position to the cut feed end position, and the grindstone usage reference value up to the reference value near the limit of reduction in the grindstone diameter due to the correction of the grindstone by the dresser. are compared,
When the detected feed amount value exceeds the grindstone usage standard value,
A grindstone replacement command signal is output from the first comparator to the notification means, and the difference value between the two is calculated by the first comparator, and the difference value signal is output to the second comparator. be done. Then, in the second comparator, based on the output signals from the first comparator and the device protection limit setter,
The above-mentioned difference value is compared with the device protection limit value corresponding to the feed amount of the feeding device from the feed position corresponding to the grinding wheel usage standard value to the device protection limit feed position, and when the difference value reaches the device protection limit value, It is determined that the feeder is in an overrun state, and the second comparator outputs a cutting feed stop signal to the feeder, forcing the feeder to stop. This prevents the feeding device from overrunning and ensures the safety of the device.

At this time, when the value detected by the feed amount of the feeder by the position detector reaches the standard value for use of the grinding wheel, the first comparator outputs a grinding wheel replacement command signal, giving advance notice of the request for grinding wheel replacement. , the feeder will not enter an overrun state until the difference value between the detected feed value from the initial cut feed start position to the cut feed end position for the above workpiece and the grindstone usage reference value reaches the device protection limit value. During this time, the workpiece is being ground. Therefore, the operator can leave the grinder while operating the grinder and continue grinding the workpiece for a predetermined period of time until this overrun state occurs; The user can perform other work at the same position, or perform preparation work for replacing the grinding wheel of the grinding machine.

In addition, the difference value between the two after the detected feed value exceeds the grinding wheel usage standard value is compared with the device protection limit value, which corresponds to the feed amount to the device protection limit feed position that determines the overrun state of the feed device. The stop of the feeding device is controlled depending on whether or not there is a match.
Just by setting the grindstone usage standard value, which varies depending on the diameter of the workpiece and grindstone, the device protection limit feed position will be automatically set according to the device protection limit value.
Even if the diameter of the workpiece, etc. changes, there is no need to reset the device protection limit feed position accordingly.
The safety of the grinding machine can be ensured with simple operation.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 schematically shows the overall configuration of a safety device for preventing an overrun of a feed device of a grinding machine A according to an embodiment of the present invention. In the figure, 1 is a bed, and on the bed 1 is a cutting feed table 5 equipped with a main shaft 4 that supports a cylindrical workpiece 3.
and a grindstone feeding table 9 equipped with a grinding device 8 having a grinding wheel 7 attached to the tip of a rotating shaft 6.

Further, the cut feed table 5 is attached to the bed 1 so as to be able to reciprocate in the cut direction (vertical direction in the figure) by a cut feed motor 10. On the other hand, the grindstone feed table 9 is mounted to the bed 1 so as to be able to reciprocate in a direction perpendicular to the cutting direction (in the left-right direction in the figure) by a drive motor (not shown).

Furthermore, a dresser 11 for modifying the surface of the grindstone 7 is attached to the center side (right side in the figure) of the cut feed table 5.
The surface of the grindstone 7 is modified in order to provide new cutting teeth when the grindstone 7 becomes clogged or the cutting teeth wear out. Further, on the outside of the table 5 (on the left side in the figure), the above-mentioned grindstone 7 of the cutting feed table 5 is provided.
A potentiometer 12 is attached as a position detector for detecting the cutting feed position of the workpiece 3 relative to the feed position.

The potentiometer 12 is connected to a feed control device 13 that controls the stroke of the cutting feed table 5. The feed control device 13
As shown in Fig. 2, the grindstone usage standard setter 1
4, a first comparator 15, a device protection limit setter 16, and a second comparator 17. The grindstone usage standard setter 14 is configured to reduce the diameter of the grindstone 7 by adjusting the grindstone 7 with the dresser 11 from the initial cut feed start position at which the cut feed table 5 starts cutting feed to the workpiece 3. A reference value for use of the grindstone is set in advance, which corresponds to the feed amount when the cutting feed is carried out to a feed position that is a reference value near the limit of grinding. As shown in Fig. 3, the above-mentioned grindstone usage standard value means that the grindstone 7, which has not been corrected even once, cuts from the position where the cutting feed starts for the first time to the cutting feed end position where it finishes grinding the workpiece 3. The feed amount A ₁ is added to the usage amount of the grinding wheel 7, which is the total amount when the grinding wheel 7, whose diameter is reduced by correcting the surface by a predetermined depth, reaches the limit where it cannot be corrected any further. This value is the sum of the amount of grindstone used _A2 . In other words, for example, when a grindstone with a diameter of 20mm is corrected 200 times by 10μ at each time,
The above grindstone usage amount A ₂ is A ₂ =10×10 ⁻³ ×200=2 mm.

Further, the first comparator 15 connects the potentiometer 1
The detected value of the feed amount of the workpiece 3 from the initial cutting feed start position to the cutting feed end position with respect to the grindstone 7 detected in step 2 is compared with the grindstone use standard value set by the grindstone use standard setting device 14. When the feed amount detection value reaches the grindstone usage reference value, a grindstone replacement command signal to prompt the replacement of the grindstone 7 is output to an alarm (notification means) such as a buzzer or lamp (not shown), and after that, both Output the difference value. Based on this difference value, when the cutting feed table 5 finishes grinding the workpiece 3, the amount of feed beyond the feed position corresponding to the grindstone usage reference value is determined.

The device protection limit setter 16 is a device that determines the overrun state of the cut feed table 5 further from the feed position corresponding to the grindstone use reference value set by the grindstone use standard setter 14. The device protection limit value (in Fig. 3
A ₃ ) is set in advance. As shown in FIG. 3, the device protection limit value A ₃ is defined as the feed until the tip of the dresser 11 is moved from a feed position near the correction limit of the grindstone 7 to a position near the surface of the rotating shaft 6. This is the tolerance value for the overrun state corresponding to the amount, and if this is exceeded, the dresser 1
1 increases the possibility that the dresser 11 will come into contact with the rotating shaft 6 when correcting the grindstone 7, resulting in an overrun state of the cutting feed table 5. Note that this device protection limit value _A3 is not necessarily limited to the feed amount until the tip of the dresser 11 is fed to a position where it interferes with the surface of the rotating shaft 6, but is not necessarily limited to the amount of feed until the tip of the dresser 11 is moved to a predetermined position on the near side of the interference position. It may be the feed amount until the feed is moved. Specifically, the device protection limit value A ₃ is, for example, a feed amount equivalent to the amount of 10 corrections of the grinding wheel 7 by the dresser 11, and the above-mentioned grinding wheel diameter is 20 mm.
In the case of the example of the grindstone, since the correction amount is 10 times each time, A ₃ = 10×10 ^-3 ×10 = 100μ.

Further, the second comparator 17 includes the first comparator 1
5 and the device protection limit value set by the device protection limit setter 16,
When the difference value reaches the device protection limit value, a cutting feed stop signal for forcibly stopping the cutting feed motor 10 is output. In other words, when the difference value reaches the device protection limit value _A3 , it means that the cutting feed table 5 is in an overrun state where the cutting feed is further advanced beyond the device protection limit feed position. The motor 10 is stopped to immediately stop the feed.

The first comparator 15 receives each output signal from the grindstone use standard setter 14 and the potentiometer 12, and detects the grindstone use reference value and the feed amount from the initial cut feed start position to the cut feed end position. A first comparison circuit 18 compares the magnitude with the value, and upon receiving the output signal from the first comparison circuit 18, both the above-mentioned values (grinding wheel usage reference value and feed amount detection value from the initial cutting feed start position) are used. and a difference value detection circuit 19 that calculates the difference value of and outputs a difference value signal to the second comparator 17. In addition, upon receiving the output signal from the first comparison circuit 18, when the detected feed amount from the initial cut feed start position to the cut feed end position reaches the grindstone usage reference value, a grindstone replacement command signal is sent to the alarm. A grindstone use reference output circuit 20 is provided for outputting.

Further, the second comparator 17 receives each output signal from the device protection limit setter 16 and the difference value detection circuit 19, and controls the feed from the feed position corresponding to the grinding wheel use reference value to the device protection limit feed position. A second comparison circuit 21 compares the magnitude of the device protection limit value, which is a quantity, with the difference value output from the difference value detection circuit 19; The device protection limit output circuit 22 outputs a feed stop signal to the cutting feed motor 10 when the cut feed motor 10 reaches the device protection limit value.

Next, to explain the operation of the above embodiment,
First, the workpiece 3 is set on the grinding machine A, and after inputting the grindstone usage reference value (A ₁ +A ₂ in FIG. 3) to the feed control device 13, the grindstone feed table 9 is sent toward the grinding workpiece 3 side. . When the grindstone feed table 9 reaches the initial cutting feed start position, the output voltage of the potentiometer 12 at that cutting feed start position is set to 0V. after that,
Every time the cutting feed table 5 is fed 1 mm into the cutting by the cutting feed motor 10, the potentiometer 12
The output voltage from increases by 1V. This results in
The feed amount of the cutting feed table 5 is detected according to the magnitude of the output voltage of the potentiometer 12.

Further, in the first comparison circuit 18, based on each output signal from the grindstone use standard setter 14 and the potentiometer 12, the above-mentioned grindstone use reference value is compared with the feed amount detection value from the initial cutting feed start position. When the feed amount detection value reaches the grindstone use reference value, a grindstone replacement command signal is output from the grindstone use reference output circuit 20 to the alarm, and thereafter, the difference value detection circuit 19 outputs the above two values (the grindstone use reference value). The difference value between the usage reference value and the feed amount detection value from the initial cutting feed start position is calculated, and the difference value signal is used as the second
It is output to the comparison circuit 21.

In the second comparison circuit 21, the difference value detection circuit 19 and the device protection limit setter 16
Based on the respective output signals from the difference value detection circuit 19, the difference value which is the output signal from the difference value detection circuit 19 and the device protection limit value A which is the feed amount from the feed position corresponding to the grinding wheel usage reference value to the device protection limit feed position are determined. ₃ is compared, and when the difference value reaches the equipment protection limit value A ₃ ,
The cutting feed motor 10 is connected to the device protection limit output circuit 22.
The cut feed stop signal is output, and the cut feed table 5 is activated by the device protection limit output circuit 22.
stroke is stopped.

Note that the cutting feed stop signal may be output when the difference value becomes larger than the device protection limit value.

Therefore, in the above embodiment, when the feed position of the cutting feed table 5 reaches a feed position near the grinding limit corresponding to the grindstone use reference value A ₁ +A ₂ , the grindstone use reference output circuit 20 instructs the operator to Although a replacement command is issued, for example, if the operator is away from the grinding machine and it takes some time to come to the grinding machine, the cutting feed table 5 continues to be fed during that time. Thereafter, when the feed position reaches the device protection limit feed position according to the device protection limit value _A3 , the table 5 automatically stops and its overrun is prevented.

In other words, even after the grindstone use reference output circuit 20 issues a command to replace the grindstone to the operator, the table 5 remains unchanged until the feed position of the cutting feed table 5 reaches the device protection limit feed position determined by the device protection limit value _A3 . Since the work 3 is ground without causing an overrun state of the table 5, the grinder A is operated to continue grinding the work 3 without causing an overrun state of the table 5. can move away from the grinding machine A, and in the meantime, the operator can perform other work far away from the grinding machine A, or perform preparation work for replacing the grindstone 7, which is the standard for use.

In this case, when the diameter of the workpiece 3 changes, the feed amount A ₁ shown in FIG. 3 changes accordingly, and even when the diameter of the grindstone 7 changes, the grindstone usage amount A ₂ changes accordingly.
In other words, the grindstone usage reference value A ₁ +A ₂ changes according to changes in the workpiece 3 and the grindstone diameter, but the device protection limit value A ₃ is a constant value. And in this example,
The difference value between the two when the feed amount detection value of the cutting feed table 5 detected by the potentiometer 12 exceeds the grindstone use standard value is the allowable value for the overrun state of the cutting feed table 5. When the difference value reaches the device protection limit value _A3 , the stroke feed of the cutting feed table ₅ is stopped. By simply setting the above-mentioned grindstone use reference value A ₁ + A ₂ according to the diameter of the workpiece 3 and grindstone 7 in advance, the device protection limit feed position corresponding to the device protection limit value A ₃ is automatically set as a slide.
Even if the diameter of the workpiece 3 differs, there is no need to reset the device protection limit feed position accordingly.
With the simple operation of setting the reference value for use of the grindstone, damage such as detachment of the diamond at the tip of the dresser 11 due to overrun of the cutting feed table 5 can be prevented, and work efficiency is significantly improved.

(Effects of the invention) As described above, according to the invention, in the safety device for preventing the overrun of the feeder of a grinding machine, the feeder cuts the workpiece from the initial cut feed start position to the cut feed end position. Comparing the amount of feed at the time of loading with a preset grindstone use reference value, and outputting a grindstone replacement command signal to the notification means to prompt the grindstone to be replaced when the feed amount exceeds the grindstone use reference value, After that, the feed amount when the feed device is further fed into the cut from the feed position corresponding to the above-mentioned grindstone usage standard value is compared with the device protection limit value that determines the overrun state of the feed device, and the feed amount is determined to be the device protection limit. By forcibly stopping the cutting feed of the feeder when the value is reached, the operator is notified that the grinding wheel is near its usable limit before the feeder overruns.
Even if the operator is away from the grinding machine, the
It is possible to safely operate the grinding machine and continue grinding the workpiece without causing an overrun state of the feed device, which improves productivity. By simply setting the changing grindstone usage reference value, the device protection limit feed position can be automatically set to slide based on the device protection limit value, eliminating the need for resetting the limit switch or changing the stroke end setting value of the table as in the past. Overruns of the feeder can be prevented with a simple operation of setting the standard value for use of the grinding wheel, and the safety of the grinding machine can be ensured with a simple operation, significantly improving work efficiency. do.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, with Fig. 1 showing the overall schematic configuration, Fig. 2 showing the feed control block diagram of the cutting feed table, and Fig. 3 showing the positional relationship between the workpiece and the grinding wheel. It is a diagram. A... Grinding machine, 5... Cut feed table, 12
... Potentiometer, 14 ... Grinding wheel use standard setter, 15 ... First comparator, 16 ... Device protection limit setter, 17 ... Second comparator.

Claims (1)

[Scope of Utility Model Registration Claim] A system that prevents the feeding device that feeds the workpiece to the grinding wheel in a grinding machine and corrects the grinding wheel using a dresser to prevent the feed device from feeding more than a preset feed amount and causing an overrun condition. This is a safety device for a grinding machine to prevent the above-mentioned grinding machine, and includes a position detector for detecting the cut feed position of the workpiece relative to the grindstone of the feeder, and an initial cut feed position for the feeder to start cutting feed to the workpiece. Grinding wheel use that sets a grinding wheel usage standard value corresponding to the feed amount when the grinding wheel diameter is reduced by correction of the grinding wheel by the dresser from the infeed feed start position to the feed position where the grinding wheel diameter becomes the reference value near the limit of grinding. The reference setting device, the detected value of the feed amount from the initial cut feed start position to the cut feed end position of the workpiece detected by the above position detector, and the grindstone use set by the above grindstone use standard setter. Compare with the reference value, and when the detected feed amount exceeds the grindstone use reference value, output a grindstone replacement command signal to the notification means to prompt the replacement of the grindstone, and also output the difference value between the two afterwards. a first comparator for determining the feed device; and a device protection limit setter that sets a device protection limit value corresponding to the feed amount when the difference value output from the first comparator is compared with the device protection limit value set by the device protection limit setter. and a second comparator that outputs a cut feed stop signal that forces the feed device to stop its cut feed when the difference value reaches the device protection limit value. A safety device for grinding machines.