JP2002239900A - Grinding wheel driving method, dressing method and grinder used in the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dressing method for a grinding wheel for maintaining sharpness by reducing the frequency of dressing while maintaining good sharpness of the grinding wheel, performing dressing work at an accurate timing and maintaining further more sharpness of the grinding wheel. SOLUTION: Vibration generated during grinding a work W with the grinding wheel 26 being normally rotated is detected by a vibration detector 34. When the amplitude of the vibration gets to 0.10-0.25 μm, grinding work is stopped. Then, grinding work for the work W is performed by the grinding wheel 26 reversely rotated and the normal rotation and reverse rotation of the grinding wheel 26 are repeated at least once, and when the amplitude of the vibration detected by the vibration detector 34 gets to 0.60-0.70 μm, the grinding work is stopped and dressing work of the grinding wheel 26 is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving method and a dressing method for a grindstone and a grinder used therefor.

[0002]

2. Description of the Related Art Generally, in a surface grinder, a cylindrical grinder, or the like, dressing work of a grindstone surface is periodically performed to maintain sharpness of the grindstone. In other words, the abrasive grains on the surface of the grindstone with the rotation during work grinding gradually wear the cutting blade portion on the front side in the rotation direction, and the sharpness as a grindstone decreases,
Conventionally, dressing work on the whetstone surface has been indispensable. On the other hand, since the dressing operation is performed while the grinding operation is interrupted, it is desirable that the number of times of dressing is as small as possible from the viewpoint of avoiding a decrease in the efficiency of the grinding operation. Therefore, conventionally, as described in Japanese Utility Model Application Laid-Open No. 2-104962, a technique has been proposed in which the rotational driving direction of the grindstone in the grinding work process is switched between normal and reverse at predetermined time intervals or arbitrarily according to the operator's judgment. ing. That is, if the rotational driving direction of the grindstone is limited to one direction, frequent dressing work is required. However, if the rotational driving direction of the grindstone is switched between forward and reverse, the rotational direction front (forward direction) and rear side (forward direction) Since both cutting edges (in the opposite direction) can be used for workpiece grinding, the number of dressings can be reduced as compared with the conventional case.

[0003]

However, the reduction in sharpness of the grindstone differs depending on the material of the workpiece to be ground and the content of the grinding operation. For this reason, when the direction of rotation of the grinding wheel is switched at predetermined time intervals, the degree of wear at the cutting edge portion is large due to grinding of a work having high hardness, and the next work is performed with the grinding wheel having sharply reduced sharpness. Sometimes they were ground. In addition, when the switching timing of the grinding wheel rotation direction is left to the judgment of the operator, the switching timing of the rotation direction of the grinding wheel may be delayed or lost in some cases because it depends on the subjectivity of the operator. There was also.

Further, even if the direction of rotation of the grindstone is switched between normal and reverse, when the grindstone is used for a long period of time, it is necessary to perform a dressing operation. However, the timing at which such dressing work is performed is conventionally left to the discretion of each worker, and it has been difficult to perform the dressing work at an accurate timing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a grinding wheel capable of maintaining the sharpness of the grinding wheel, reducing the number of dressings and maintaining the efficiency of the grinding operation. And a grinding machine used therefor.

Another object of the present invention is to provide a method of dressing a grindstone capable of performing dressing work at an appropriate timing and maintaining the sharpness of the grindstone more appropriately, and a grinder used therefor. .

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 detects a vibration generated during grinding of a workpiece by a normally rotating grindstone by a vibration detector, and detects the vibration. When the amplitude of the workpiece reaches a first set value that is set in advance according to the grinding accuracy of the workpiece grinding surface, the grinding operation is stopped, and then the grinding wheel is rotated in reverse to perform the workpiece grinding operation. .

According to a second aspect of the present invention, in the first aspect, the first set value is set to 0.10 to 0.25 μm. The invention according to claim 3 is
The gist of the present invention is that the work of grinding the work by the reverse rotation of the grindstone is automatically performed by a signal from the control device.

According to a fourth aspect of the present invention, in the first aspect, the amplitude of the vibration detected by the vibration detector after the normal rotation and the reverse rotation of the grinding wheel is repeated at least once is equal to the first rotation.
The gist is that the grinding operation is stopped when a second set value larger than the set value is reached, and the dressing operation of the grindstone is performed.

A fifth aspect of the present invention is characterized in that, in the fourth aspect, the second set value is set to 0.60 to 0.70 μm. The invention according to claim 6 is
The gist of the present invention is that the work of grinding the work by the reverse rotation of the grindstone and the work of dressing the grindstone are automatically performed by a signal from the control device.

According to a seventh aspect of the present invention, there is provided a grinding wheel mounted on a spindle, driving means for rotating the grinding wheel together with the spindle, reversing means for reversing the direction of rotation of the grinding wheel, the grinding wheel and the spindle. A vibration detector for detecting vibration generated during grinding of a workpiece by a normally rotating grindstone, and a vibration detected by the vibration detector. When the amplitude reaches a first set value, and a switching means for switching the reverse rotation means to an operable state after the notification means is operated. .

An eighth aspect of the present invention is characterized in that, in the seventh aspect, a first adjusting means for adjusting the first set value of the amplitude is provided. The invention according to claim 9 is the invention according to claim 7
In the above, the grinding operation of the work is performed by rotating the grindstone in the reverse direction, and after repeating the normal rotation and the reverse rotation of the grindstone one or more times, the amplitude of the vibration detected by the vibration detector is equal to the first amplitude.
When a second set value that is larger than the set value is reached, a notifying unit that notifies the second set value, and a dressing unit that stops the grinding operation and performs a dressing operation of the grindstone after the notifying device is operated. The gist is that

According to a tenth aspect of the present invention, in the ninth aspect, there is provided a first adjusting unit and a second adjusting unit for adjusting the first set value and the second set value of the amplitude, respectively.

According to an eleventh aspect of the present invention, when a grinding resistance generated during grinding of a workpiece by a normally rotating grindstone is detected by a resistance detector, and the grinding resistance reaches a preset reverse rotation set value. After the grinding operation is stopped, the work is ground by rotating the grindstone in the reverse direction.

According to a twelfth aspect of the present invention, in the eleventh aspect, the set value for reverse rotation is set in a plurality of stages, and each set value is set such that a difference in grinding resistance falls within a range of ± 5 N / mm. The gist is that

According to a thirteenth aspect of the present invention, in the eleventh or twelfth aspect, the work of grinding the workpiece by the reverse rotation of the grindstone is automatically performed by a signal from the control device.

According to a fourteenth aspect of the present invention, in the eleventh aspect, the grinding resistance detected by the resistance detector reaches the set value for dressing after the normal rotation and the reverse rotation of the grinding wheel are repeated at least once. The point is that the grinding operation is stopped and the dressing operation of the grindstone is performed.

According to a fifteenth aspect of the present invention, in the fourteenth aspect, the set value for dressing is set to a resistance value of 80 to 100% of a maximum grinding resistance value suppressed by forward / reverse rotation of the grindstone. Is the gist.

According to a sixteenth aspect of the present invention, in the fourteenth or fifteenth aspect, the work of grinding the workpiece by the reverse rotation of the grindstone and the dressing work of the grindstone are automatically performed by a signal from the control device. I do.

The invention according to claim 17 is characterized in that a grinding wheel mounted on a spindle, a driving means for rotating the grinding wheel together with the spindle, a reversing means for reversing the direction of rotation of the grinding stone, In a grinding machine provided with anti-loosening means for preventing loosening of a connection point with a resistance detector for detecting a grinding resistance generated during grinding of a workpiece by a normally rotating grindstone, the resistance was detected by the resistance detector. When the grinding resistance reaches the set value for the reverse rotation, a notifying means for notifying the same, and a switching means for stopping the grinding operation and switching the reverse rotation means to an operable state after the notifying means is operated. The gist is that

According to an eighteenth aspect of the present invention, in the seventeenth aspect, there is provided a first adjusting means for adjusting a reverse rotation set value of the grinding resistance. According to a nineteenth aspect of the present invention, in the seventeenth aspect, the workpiece is ground by rotating the grindstone in the reverse direction, and after the normal rotation and the reverse rotation of the grindstone are repeated one or more times, the resistance is detected by the resistance detector. When the grinding resistance reaches the set value for dressing, there is provided a notifying means for notifying the setting value, and a dressing means for stopping the grinding operation and performing a dressing operation of the grindstone after the notifying means is operated. Is the gist.

According to a twentieth aspect of the present invention, in the nineteenth aspect, there is provided a first adjusting means and a second adjusting means for respectively adjusting a plurality of reverse rotation set values and dressing set values of the grinding resistance. And

According to a twenty-first aspect of the present invention, a temperature of a grinding portion generated during grinding of a workpiece by a normally rotating grindstone is detected by a temperature detector, and the temperature of the grinding portion determines the grinding accuracy of the ground surface of the workpiece. The gist of the present invention is to stop the grinding operation when the first set value set in advance is reached, and then perform the grinding operation on the workpiece by rotating the grindstone in the reverse direction.

According to a twenty-second aspect of the present invention, in the twenty-first aspect, the work of grinding the workpiece by the reverse rotation of the grindstone is automatically performed by a signal from the control device. According to a twenty-third aspect of the present invention,
After repeating the normal rotation and reverse rotation of the whetstone one or more times,
When the temperature of the grinding section detected by the temperature detector reaches a second set value which is larger than the first set value, the grinding operation is stopped and the dressing operation of the grindstone is performed.

According to a twenty-fourth aspect of the present invention, in the twenty-second or twenty-third aspect, the work grinding and the dressing of the work by the reverse rotation of the grindstone are automatically performed by a signal from the control device. I do.

According to a twenty-fifth aspect of the present invention, there is provided a grinding wheel mounted on a spindle, driving means for rotating the grinding wheel together with the spindle, reversing means for reversing the rotating direction of the grinding stone, A grinding machine provided with a loosening prevention means for preventing loosening of a connection portion with a temperature detector for detecting a temperature of a grinding portion generated during grinding of a work by a normally rotating grindstone, and detected by the temperature detector When the temperature of the ground portion reaches the first set value, a notifying means for notifying the first set value, and a switching means for switching the reversing means to an operable state after the notifying means is operated. Is the gist.

According to a twenty-sixth aspect of the present invention, in the twenty-fifth aspect, there is provided a first adjusting means for adjusting a first set value of the temperature of the grinding portion. The invention according to claim 27 is the method according to claim 25 or 26, wherein the work is ground by rotating the grindstone in the reverse direction, and the temperature is detected by the temperature detector after repeating the normal rotation and the reverse rotation of the grindstone one or more times. When the temperature of the grinding unit to be reached reaches a second set value larger than the first set value, a notifying unit for notifying the same, and after the notifying unit is operated, the grinding operation is stopped, and the grinding wheel is stopped. And a dressing means for performing the above dressing operation.

According to a twenty-eighth aspect of the present invention, in the twenty-seventh aspect, there is provided a first adjusting means and a second adjusting means for adjusting the first set value and the second set value of the temperature of the grinding portion, respectively. And

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of a surface grinder embodying the present invention will be described below with reference to FIGS.

As shown in FIG. 1, a saddle 8 is provided on the upper surface of the bed 7 so as to be movable back and forth (in a direction parallel to the paper). A table 10 is movably supported by a pair of guide rails 9 provided so as to extend leftward and rightward (in a direction perpendicular to the paper surface) with respect to the upper surface of the saddle 8, and a work W is held on the table 10. The work W is moved back and forth and left and right with respect to the bed 7 with the back and forth movement of the saddle 8 and the left and right movement of the table 10.

A column 12 is erected on the upper surface of the bed 7, and an elevating saddle 13 is provided on the column 12, as shown in FIG. 2, so that the elevating mechanism (not shown) moves up and down. As shown in FIG. 1, a spindle head 14 is provided on the elevating saddle 13 so as to be directed in the front-rear direction.

As shown in FIG. 3, a spindle 15 is rotatably supported in the spindle head 14 by a bearing 16, and an annular seal ring 17 is attached to a tip end of the spindle head 14 by a plurality of bolts 18. . A male thread 15a is formed at the tip of the spindle 15 protruding from the spindle head 14, and the seal ring 17 is formed on the male thread 15a.
A female thread 19a of the seal nut 19 located inside is screwed together, and a labyrinth seal 20 is formed by the outer periphery of the seal nut 19 and the inner periphery of the seal ring 17.

A slit 21 is formed in the seal nut 19, and a tightening bolt 22 is screwed into the seal nut 19 from the front so as to narrow the slit 21.
For this reason, the female screw portion 19a of the seal nut 19 applies a tightening force to the male screw portion 15a of the main shaft 15 in the opposite directions before and after the slit 21, so that the seal nut 19
To prevent loosening when rotational force is applied to the motor.

A tapered portion 15b is formed at the tip of the male screw portion 15a of the main shaft 15, and a grindstone flange 23 is fitted on the tapered portion 15b. Same whetstone flange 2
3 is provided with a plurality of bolts 24 on the holding plate 2.
5, a grindstone 26 is sandwiched and fixed between the holding plate 25 and the grindstone flange 23.

A male screw portion 15c is formed at the tip of the tapered portion 15b of the main shaft 15, and a female screw portion 27a of a grindstone mounting nut 27 is screwed to the male screw portion 15c to prevent the grindstone flange 23 from being detached forward. are doing. A slot 28 is formed on the grindstone mounting nut 27, and the slot 28
A tightening bolt 29 is screwed into the grindstone mounting nut 27 from the front so as to narrow the diameter. For this reason, similarly to the seal nut 19, the female screw portion 27 a of the grindstone mounting nut 27 applies a tightening force to the male screw portion 15 c of the main shaft 15 in a direction opposite to each other before and after the slit 28, and a rotational force is applied to the grindstone mounting nut 27. Prevents loosening when acting. The slot 28 of the grinding wheel mounting nut 27 and the tightening bolt 29 constitute a locking device.

As shown in FIG. 1, a motor 31 as a driving means is mounted on the back side of the elevating saddle 13, and when the main shaft 15 is driven to rotate by the motor 31, the grindstone 26 at its tip is rotated. It has become. The motor 31 is connected to a three-phase AC power supply 33 via an inverter 32 as a reverse rotation means. The motor 31 rotates forward or backward by the current control of the inverter 32, and the rotating direction of the grindstone 26 is also changed. In addition,
A converter for converting AC into DC may be connected between the three-phase AC power supply 33 and the inverter 32 to rotate the DC motor forward and backward.

As shown in FIG. 3, a vibration detector 34 is housed on the inner peripheral surface of the tip end portion of the spindle head 14 so as to be located between the head 16 and the bearing 16. The vibration detector 34 detects the vibration generated on the grindstone 26 during the grinding of the work W and transmits the vibration to the control device 35. As the vibration detector 34, for example, an electric vibrometer is used.
Specifically, there is a piezoelectric acceleration pickup that generates an electromotive force proportional to an external force, and converts the amplitude of vibration into an electric signal and outputs the electric signal.

As shown in FIG. 2, coolant nozzles 36 are provided on both left and right sides of the grindstone cover 30, respectively, and the tips of both coolant nozzles 36 are bent so as to face the lower side of the grindstone 26, respectively. Both coolant nozzles 3
Numeral 6 is connected to a coolant tank (not shown) via a pipe 37. During grinding, the coolant is selectively supplied from the tank to one of the coolant nozzles 36 and directed from the supplied coolant nozzle 36 toward the grindstone 26. Coolant is injected. The grindstone cover 30 is provided with a cover 38 for preventing the coolant from being scattered during the grinding as shown by a chain line in FIG.

A molding dresser 42 and a dressing dresser 43 are mounted on the upper surface of the table 10 via a support table 41. As shown in FIG. 4, the forming dresser 42 and the dressing dresser 43 are supported so as to be integrally rotatable on the same axis, and are driven by a motor 44 serving as a rotation driving means also connected coaxially. Both dressers 42, 43
Is a disk-shaped rotary dresser for dressing the grindstone 26, and the rotation directions of the dressers 42 and 43 are opposite to the rotation direction of the grindstone 26 as shown in FIG. The dressers 42 and 43 are rotated at a rotation speed different from the rotation speed of the grindstone 26, and the size may be either.
The forming dresser 42 includes diamond abrasive grains having a hardness higher than that of the grindstone 26, and the dressing dresser 43 is formed of a raw stainless steel before quenching. As shown in FIG.
Reference numeral 6 includes abrasive grains 45 and bonds 46. The stainless steel material forming the dressing dresser 43 is a whetstone 26.
Is softer than the abrasive grains 45, harder than the bond 46, and has stickiness.

Next, a control device 35 for controlling various operations of the grinding machine configured as described above will be described. FIG.
As shown in (1), the control device 35 includes a CPU (Central Processing Unit) 51 for analyzing and calculating various data, an operation input unit 52, a ROM (Read Only Memory) 53 and an R
An AM (Random Access Memory) 54 and the like are provided. R
The OM 53 stores program data for centrally managing the various operations of the grinding machine, the driving method of the grinding wheel 26 based on the vibration detection, and the entire dressing method.
54 is used as a work area.

The control device 35 includes a detection circuit 55 for taking in data output from the vibration detector 34 and an A / D
It has a converter 56. The charge output generated in the vibration detector 34 with the rotation of the grindstone 26 is supplied to the detection circuit 55. The detection circuit 55 is configured by an amplifier, a band-pass filter, an integrator, and the like, converts the output of the vibration detector 34 into a speed signal, and converts only the band corresponding to the rotation frequency of the grindstone 26 from the obtained speed signal. Extract and generate an output signal corresponding to the amplitude of the vibration. When the output signal of the detection circuit 55 is A
Digital / analog conversion is performed through the / D converter 56 to generate data indicating the amplitude. Data indicating the amplitude is supplied to the CPU 51. Note that an output signal corresponding to the amplitude of the vibration may be generated from the obtained speed signal.

The CPU 51 of the control device 35 is connected to a display device 62 and a mechanism control unit 63 by an interface 61. The display device 62 is, for example, a CRT (Cathod).
e Ray Tube) or liquid crystal. And C
A predetermined image is displayed on the screen of the CRT based on the display information from the PU 51. The mechanism control unit 63 includes a CPU 5
A control signal for controlling each mechanism including the aforementioned motors 31 and 44 is generated in accordance with the control information from 1. The control signal generated in the mechanism control unit 63 is supplied to each unit.

The CPU 5 connected to each unit as described above
1 is appropriately R based on input information from the operation input unit 52.
Data is read from the OM 53 and the RAM 54, and data is written to the RAM 54 to execute each process described later.

In the first embodiment, a first adjusting means for inputting and setting a first set value of the vibration amplitude for switching the rotation direction of the grindstone 26 to an arbitrary value by the CPU 51 and the operation input unit 52 is constituted. ing. Also, the CPU 51
And the operation input unit 52 constitute a second adjusting unit for inputting and setting a second set value of the amplitude of vibration for dressing the grindstone 26 to an arbitrary numerical value.

Next, a case where the work W is ground by the surface grinder configured as described above will be described. First, prior to the grinding operation, by operating the keyboard of the operation input unit 52, the first amplitude of the vibration is determined based on the required grinding accuracy of the ground surface of the workpiece W to be ground.
The set value is 0.10 to 0.25 μm, and the second set value is 0.
It is set to 60 to 0.70 μm. This setting operation is performed by displaying a set value input image on a CRT screen of the display device 62. In this setting, for example, the processing accuracy of the ground surface required for the work differs depending on the material of the work and the purpose of use. For this reason, the appropriate relationship between the workpiece material and the required processing accuracy and the specific numerical values of the first and second set values corresponding thereto is recorded in advance in a recording unit (for example, the RAM 54) as a data list. . Then, the first and second set values suitable for the work to be processed may be selected and set from the data list.

Next, when a switch for starting grinding of the operation input section 52 is operated, an operation signal is output from the control device 35 to the inverter 32, and the grinding wheel 26 is specified (forward rotation).
Rotated in the direction. Further, the table 10 is reciprocated along a moving path that is predetermined according to the shape of the work W in response to a signal from the control device 35. The grindstone 26 is also lowered to a position suitable for the height position of the work W. Further, coolant is sprayed from a coolant nozzle 36 on a side corresponding to the rotation direction of the grindstone 26, and the work W is ground by the grindstone 26.

On the other hand, in synchronization with the start of the grinding operation, the vibration detector 34 starts the operation of detecting the vibration of the grindstone 26, and the amplitude data of the detected vibration is output to the control device 35.
Then, the work time for grinding the work W becomes long, and the grinding stone 26
Is worn, the amplitude of the vibration falls within a preset first set value of “0.10 to 0.25 μm”. Then, the control device 35 notifies that the amplitude of the vibration is within the set range by the screen of the display device 62, an alarm buzzer, a notification lamp, or the like. In synchronization with this, a signal for stopping the grinding operation is output from the control device 35, the table 10 and the grindstone 26 are returned to the original positions shown in FIG. 1, the rotation of the motor 31 and the injection of the coolant nozzle 36 are stopped. , The work of grinding the work W is temporarily suspended.

Thereafter, an operation signal is sent from the control device 35 to the inverter 32, and the inverter 32
The switching signal of the rotation direction is output to the
Is reversed, and the work of grinding the work W is performed again in the same manner as the above-described grinding work. This motor 31
During the grinding operation by the reverse rotation of the coolant, the coolant is injected from the other coolant nozzle 36.

As described above, the grindstone 26 has been rotated in both the forward and reverse directions. A normal surface grinder cannot change the rotation direction of the grindstone 26 determined at the time of design. However, in the surface grinding machine of the first embodiment, the slit 2 formed on the grinding wheel mounting nut 27 is not used.
The nut 8 is tightened by the tightening bolt 29 to prevent the whetstone mounting nut 27 from loosening. For this reason,
Regardless of whether the grindstone 26 is rotated in the forward or reverse direction,
Can be continued without separating from the main shaft 15. Further, since the sealing nut 19 is also provided with the same anti-loosening measures, the sealing function is not loosened due to the impact when the grindstone 26 rotates in the reverse direction and the sealing function is not impaired.

When the rotation direction of the grindstone 26 is reversed as described above, the sharpness of the grindstone 26 is restored to a state almost immediately after dressing. Explaining the reason, as shown in FIG. 6, the cutting edges G1 and G2 are formed on the individual abrasive grains 45 of the grindstone 26 after the dressing at the positions on both sides in the rotation direction of the grindstone 26, respectively. Fig. 6
In the case of the normal rotation as shown in (1), only one cutting edge G1 of each abrasive grain 45 is used. Further, when the grindstone 26 is reversed as shown in FIG. 7, the other unused cutting edge G2 can grind the work W.

Therefore, the time required for dressing can be extended by reversing the rotation of the grindstone 26 at least once. When the grinding operation time of the work W is increased by performing the forward / reverse rotation of the grindstone 26 a plurality of times, the cutting edges G1 and G2 wear together as shown in FIG. 8, and the entire shape of the grindstone 26 becomes elliptical, It may be polygonal. As a result, the sharpness of the grindstone 26 decreases, and the grindstone 2
The amplitude of the vibration of No. 6 increases. Then, the vibration detector 34
When the amplitude of the vibration detected by the control unit 35 reaches a range of the second set value “0.60 to 0.70 μm” set in advance, the control device 35 determines that the amplitude of the vibration is within the set range. The notification is made by a screen of the display device 62, an alarm buzzer, a notification lamp, or the like. In synchronization with this, a signal for stopping the grinding operation is output, and
, The grinding operation of the workpiece W is stopped. Thereafter, the dressing of the grindstone 26 is performed manually or automatically, and the overall shape is corrected as follows.

The saddle 8 and the table 10 are moved to the left in FIG. 2 by a signal from the control device 35, and the forming dresser 42 is stopped at a position corresponding to the grinding wheel 26 up and down as shown in FIG. Next, the grindstone 26 is
To rotate counterclockwise to form the dresser 42
Is rotated clockwise by the motor 44. Further, the elevating saddle 13 is moved downward to move the grindstone 26 to a position where the grindstone 26 comes into contact with the forming dresser 42 as shown in FIG. 8, and the outer peripheral surface of the forming dresser 42 and the outer peripheral surface of the grindstone 26 are brought into sliding contact with each other. Let it.

In FIG. 8, the forming dresser 42 and the grindstone 26 rotate in opposite directions with a predetermined speed difference. Further, since the forming dresser 42 is made of a material harder than the grindstone 26, both the abrasive grains 45 and the bond 46 are ground by the forming dresser 42. Molding dresser 4
The outer peripheral surface of the grindstone 26 after being ground by 2 is dressed to a smooth surface. As shown in FIG. 4, when the thickness of the grindstone 26 is larger than the thickness of the forming dresser 42, if the forming dresser 42 is moved back and forth along the axial direction, the entire outer peripheral surface of the grindstone 26 is dressed throughout. Is done.

When the dressing by the forming dresser 42 is completed, the grindstone 26 is moved upward and the forming dresser 4
Then, the table 10 is moved forward to dispose the dressing dresser 43 below the grindstone 26.
Then, as in the case of using the molding dresser 42, the grinding stone 26
Is lowered toward the dressing dresser 43, and the grindstone 26 is pressed against the dressing dresser 43 to bring the outer peripheral surfaces of the two into sliding contact with each other. Also, a speed difference is generated between the two. Then, since the dressing dresser 43 is formed of a material that is softer than the abrasive grains 45 and harder than the bond 46, the outer peripheral surface of the grindstone 26 is ground by the outer peripheral surface of the dressing dresser 43. At this time, the outer peripheral surface of the abrasive grains 45 remains protruding without being ground, and only the outer peripheral surface of the bond 46 is cut off. In this manner, dressing is performed by grinding only the bond 46 and protruding the abrasive grains 45 to perform dressing, whereby the sharpness of the grindstone 26 is further improved. The dressing dresser 43 is also similar to the molded dresser 42,
By moving the grinding wheel 26 back and forth along the axial direction, the entire outer peripheral surface of the grindstone 26 can be sharpened.

After the dressing by the dressing dresser 43, since the sharpness of the grindstone 26 is very good, the work of grinding the workpiece W by the grindstone 26 can be continued again.

According to the grinding machine of the first embodiment, the following features can be obtained. (1) Vibration generated during the grinding of the work by the grindstone 26 rotating forward is detected by the vibration detector 34, and when the amplitude of the vibration reaches the first set value “0.10 to 0.25 μm”, the grinding is performed. After the operation was stopped, the work was ground by rotating the grindstone in the reverse direction. For this reason, the number of dressings can be reduced while maintaining the sharpness of the grindstone 26 satisfactorily, and the efficiency of the grinding operation can be favorably maintained.

When the amplitude of the vibration is equal to the first set value "0.1
If the grindstone 26 is reversed before it reaches "0 to 0.25 [mu] m", the number of reversals increases and the efficiency of the grinding operation decreases. Conversely, if the grindstone 26 is reversed after exceeding the first set value, the number of reversals decreases, but the sharpness of the grindstone 26 is impaired,
Grinding work cannot be performed properly. As a specific example, when the amplitude of the vibration is 0.03 μm or less, for example, equal to or less than the first set value (0.10 μm), the grinding length that can clear the desired grinding accuracy of the work W is 291 to 388 m. It has been confirmed by experiments that the grinding length is reduced to 97 m when it reaches 0.15 μm included in the first set value.

(2) Since the work of grinding the work by the reverse rotation of the grindstone 26 is automatically performed by the operation signal from the control device 35, the efficiency of the grinding work can be improved.

(3) When the amplitude of the vibration detected by the vibration detector reaches the second set value “0.60 to 0.70 μm” after the normal rotation and the reverse rotation of the grindstone 26 are repeated at least once. Then, the grinding operation was stopped and the grindstone 26 was dressed. For this reason, the dressing operation can be performed at an appropriate timing, and the sharpness of the grindstone 26 can be maintained more favorably.

The amplitude of the vibration described above is equal to the second set value “0.6”.
If the dressing work of the grindstone 26 is performed before reaching “0 to 0.70 μm”, the number of the work increases and the efficiency of the grinding work decreases. Conversely, after exceeding the second set value,
When the wheel 6 is reversed, the number of dressing operations is reduced, but the sharpness of the grindstone 26 is impaired, and the grinding operation cannot be performed properly.

(4) The first and second set values of the amplitude can be adjusted by the operation input unit 52. For this reason,
The cycle timing between the work processing by the forward and reverse rotation of the whetstone and the dressing work of the whetstone can be optimized according to the required processing accuracy of the work W, and the grinding wheel can be used effectively to achieve the accuracy of the grinding surface of the work. Can be improved.

(5) Since the dressing work of the grindstone 26 is automatically performed by a signal from the control device 35, the efficiency of the dressing work can be improved. (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

The description of the same components as those of the first embodiment will be omitted, and different components will be described. In the second embodiment, attention is paid to the fact that the grinding resistance in the normal direction changes due to a change in the shape of the abrasive grains 45 when the abrasive grains 45 are in contact with the surface of the workpiece W and performing the grinding operation. . That is, as shown in FIG. 9, when the abrasive grains 45 are sharp as shown by the solid line, the grinding resistance is small, and as shown by the two-dot chain line, when the leading side in the rotation direction of the grinding wheel 26 is worn, the grinding resistance is increased. Therefore, when this grinding resistance is detected and the value becomes a preset reverse rotation set value, the grinding wheel 26
The grinding performance is enhanced by reversing the above.

Since the above-mentioned change in the grinding resistance can be grasped as a change in the rotational torque acting on the grindstone 26 during the grinding operation, the current proportional to the rotational torque supplied to the motor 31 as shown in FIG. The value is measured by an ammeter 65 as a grinding resistance detector. Then, the detected current value is converted into a grinding resistance value by the detection
The input is made to U51. (See FIG. 5) FIG. 11A shows the relationship between the grinding time and the grinding resistance (N / mm; Newton-millimeter) when the metal bond diamond grindstone 26 is used, and FIG. The same relationship when used is shown. The two-dot chain lines in FIGS. 11A and 11B show the grinding resistance curves when the grinding wheel 26 is not reversed, and the solid line indicates that the grinding force reverses every time the grinding resistance reaches a plurality of preset reverse rotation setting values. 4 shows a grinding resistance curve in the case of performing.

The set value for reverse rotation described above is set to many times in FIG. 11 (a). Specifically, the first reverse rotation set value R1a (3.0 N / mm), the second reverse rotation set value R
1b (3.5 N / mm), set value R1c for third reverse rotation
(5.5 N / mm), the fourth reverse rotation set value R1d (5.6
N / mm), set value R1e for fifth reverse rotation (6.5 N / m
m), sixth reverse rotation set value R1f (6.5 N / mm), seventh reverse rotation set value R1g (7.0 N / mm), eighth reverse rotation set value R1h (8.0 N / mm), ninth Set value R for reverse rotation
1i (7.5 N / mm), set value R1j for tenth reverse rotation
(7.7 N / mm), the eleventh reverse rotation set value R1k (9.
0N / mm), the twelfth reverse rotation set value R11 (9.1 N /
mm), the set value R1m for thirteenth reverse rotation (8.5 N / m
m) and the fourteenth reverse rotation set value R1n (8.4 N / mm).

In FIG. 11B, the first reverse rotation set value R1
a (4.9 N / mm), the second reverse rotation set value R1b (7.
5N / mm), the third reverse rotation set value R1c (10.5N /
mm).

As described above, the plurality of set values for reverse rotation are ± 5.
They are set with a difference of N / mm. As is clear from the graph of FIG. 11, it can be seen that the grinding resistance is suppressed by repeating the reverse rotation of the grindstone 26, and the work of grinding the work W is properly performed.

In FIG. 11A, the maximum grinding resistance suppressed by the forward and reverse rotation of the grindstone 26 is 10.5 N / mm, and in FIG. 11B, it is 15.0 N / mm. A grinding resistance value of 80 to 100% of the maximum grinding resistance value is recorded in the RAM 54 of the control device 35 as the dressing set value R2.

A plurality of set values R1a to R1 for grinding force for reverse rotation
1n can be independently adjusted by the CPU 51 and the operation input unit 52 as first adjusting means. The dressing set value R2 of the grinding resistance can also be adjusted independently by the CPU 51 and the operation input unit 52 as the second adjusting means.

In the second embodiment, the ammeter 65
Is the set value for dressing R2
Is reached, it is displayed on the display device 62 as the notification means. After the display device 62 is operated, the grinding operation is stopped manually or automatically, and the dressing operation of the grindstone 26 is performed by the dressing means 42, 43, 44 using the control device 35 manually or automatically.

In the second embodiment, the following effects can be expected in addition to the effects common to the effects of the first embodiment described above. (6) The grinding resistance generated during the grinding of the workpiece by the rotating grindstone 26 is detected by the ammeter 65, and when the value reaches the set value for reverse rotation, the grinding operation is stopped. Thereafter, the grindstone 26 is reversed. Dressing work is performed when the set value for dressing is reached. For this reason, the reverse rotation and the dressing operation of the grindstone can be performed at an appropriate timing, and the sharpness of the grindstone 26 can be favorably maintained. (Third Embodiment) A third embodiment in which the present invention is embodied in a surface grinder.
An embodiment will be described with reference to FIGS. The description of the same configuration as in the first embodiment will be omitted, and different configurations will be described.

In the third embodiment, as shown in FIG. 12, a temperature detector 70 is attached to the lower part of the spindle head 14, and the temperature of the grindstone 26 during the grinding of the workpiece W is detected by the detector 70. . The temperature data detected by the temperature detector 70 is input to the detection circuit 55 of the control device 35. Then, when the work of grinding the work W with the grindstone 26 is performed for a long time and the grindstone 26 is worn, the grinding resistance increases and the temperature of the grindstone 26 increases due to frictional heat. When the detected value of the temperature of the grindstone reaches a first set value set in advance, the detected value is displayed on the display device 62 as a notification unit. Thereafter, the work of grinding the work W is stopped manually or automatically, and the reverse rotation of the grindstone 26 is performed manually or automatically using the control device 35.

When the forward and reverse rotation of the grindstone is repeated a plurality of times and the wear of the grindstone progresses and the temperature of the grindstone reaches the second set value, the dressing operation of the grindstone 26 is performed manually or automatically using the controller 35. Will be

The temperature of the grindstone 26 changes as shown in FIG. 13 as the grinding operation time of the work W increases. Since the temperature distribution curve differs depending on the state of the grinding surface of the grindstone 26 and the type of the work W to be ground and the type of the grindstone,
The temperature at which the reverse rotation of the grindstone and the dressing operation are required is measured in advance by the combination of the work W and the grindstone 26. Then, based on the measurement data, a first set value for the reverse rotation of the grindstone and a second set value for the dressing of the grindstone are determined, and a set value suitable for the grinding condition is selected and set from the data. Enter a new value and set it.

In the third embodiment, the following effects can be expected in addition to the effects common to the effects of the first embodiment described above. (7) The temperature generated during the grinding of the workpiece by the rotating grindstone 26 is detected by the temperature detector 70, and when the value reaches the first set value, the grinding operation is stopped. Thereafter, the grindstone 26 is reversed. When the second set value is reached, a dressing operation is performed. For this reason, the grinding wheel reverse rotation and dressing work are performed at an appropriate timing,
Satisfactorily can be maintained.

The above embodiments may be modified as follows. -As shown in FIG. 14, the type of the grindstone 26 and the work W
The shape of the grinding resistance takes various forms depending on the material, and all are different. Based on this grinding resistance curve, the reverse rotation set value R1
a to R1n and the dressing set value R2 may be recorded in a recording medium in advance, and data suitable for the grinding conditions may be selected from the data, and the workpiece W may be ground based on the data.

As shown in FIG. 15, grinding resistance detectors 66 and 67 using piezoelectric elements may be installed on the upper surface of the table 10 so as to contact the left and right end surfaces of the work W. The grinding resistance detectors 66 and 67 electrically detect the pressure at the contact portion with the end face of the work W as an element proportional to the grinding resistance.

Although not shown, the reverse rotation set values R1a to
R1n may be only one set value R1. The amplitude of the vibration is 0.01 μm as the vibration detector 34
For example, a spectrum analyzer (FF
T) may be used. Also, a plurality of piezoelectric acceleration pickups that are in contact with the outer peripheral surface of the spindle 15 with respect to the inner peripheral surface of the spindle head 14 are arranged at equal intervals, and a balance vector (commercially available) that detects vibration using the pressure received by these pickups. Name: Nagase Integrex Co., Ltd., see JP-A-61-189423).

The main shaft 15 and the grindstone flange 23 may be keyed so as not to rotate, and this flange may be fixed with a usual grindstone mounting bolt.・ Vibration amplitude is in the setting range (0.10 to 0.25 μm)
Is notified, the operator operates the switch on the operation panel to rotate the grindstone 26 in the reverse direction, and
May be performed. The first set value has no range, for example, 0.10 μm or 0.1 μm.
It may be 25 μm.

The amplitude of the vibration is within the set range (0.60 to
After notification of the change to 0.70 μm), the worker may operate the switch on the operation panel to perform the dressing work of the grindstone 26. Further, the second set value may be set to, for example, 0.60 μm or 0.70 μm without a range.

The dressing operation of the grindstone 26 may be performed when the amplitude or the grinding resistance reaches the set value for dressing without the reversal of the grindstone 26. The dressing operation may be performed after removing the grindstone 26 from the main shaft 15 and moving to a separately installed dressing device.

Other than the surface grinder, the present invention may be embodied as, for example, a cylindrical grinder, an NC grinder, a high reciprocating forming grinder, or the like. Technical ideas other than the claims grasped from the embodiment will be described below.

(Technical Thought 1) A grinding machine according to claim 7, wherein the work of grinding the workpiece by the reverse rotation of the grindstone is automatically performed by a signal from a control device.
This grinding machine can improve the work efficiency of grinding the work.

(Technical Thought 2) The grinding machine according to claim 9, wherein the dressing operation of the grinding stone by the dressing means (42, 43, 44) is automatically performed by a signal from the control device.

This grinding machine can improve the efficiency of dressing work of a grindstone. (Technical idea 3) In claim 7, the first set value is selected and set from a data list of vibration amplitudes recorded in advance according to the material of the work and the required processing accuracy of the ground surface. Grinding machine that is configured to.

This grinding machine can easily set the first set value. (Technical idea 4) In claim 9, the first set value and the second set value are selected from a data list of vibration amplitudes recorded in advance according to the material of the work and the required processing accuracy of the ground surface. Grinding machine that is configured to be set.

This grinding machine can easily set the first and second set values.

[0088]

As described above in detail, the inventions according to claims 1 to 28 can reduce the number of dressings and maintain the efficiency of the grinding operation satisfactorily while maintaining the sharpness of the grindstone.

According to the fourth, ninth and twenty-third aspects of the present invention, in addition to the effects of the above-mentioned aspects, the dressing operation can be performed at an appropriate timing, and the sharpness of the grindstone can be maintained more favorably.

[Brief description of the drawings]

FIG. 1 is a right side view showing a first embodiment of a surface grinder embodying the present invention.

FIG. 2 is a partial front view of the grinding machine.

FIG. 3 is an enlarged vertical sectional view of a tip end portion of the spindle head.

FIG. 4 is a perspective view showing a dressing device.

FIG. 5 is a block circuit diagram of a control device of the surface grinding machine.

FIG. 6 is an explanatory view showing the progress of wear of abrasive grains of a grindstone.

FIG. 7 is an explanatory view showing the progress of wear of abrasive grains of a grindstone.

FIG. 8 is an explanatory view showing a dressing state of a grindstone.

FIG. 9 is an enlarged partial cross-sectional view showing abrasive grains of a grindstone.

FIG. 10 is a block circuit diagram of a control device for a surface grinding machine according to a second embodiment.

FIGS. 11A and 11B are graphs showing a relationship between grinding time and grinding resistance in the second embodiment.

FIG. 12 is a right side view of a grinding machine according to a third embodiment.

FIG. 13 is a gram showing the relationship between grinding time and grinding wheel temperature.

FIG. 14 is a graph showing the relationship between grinding time and grinding resistance in another example.

FIG. 15 is a front view showing another example of the grinding resistance detecting means in another example.

[Explanation of symbols]

26: Grinding stone, 27: Grinding stone mounting nut constituting locking means, 28: Slotting constituting locking means, 29 ...
Fastening bolts constituting the locking means, 31 motors as driving means, 32 inverters constituting reversing means,
34 a vibration detector, 35 a control device constituting a switching means, 42 a molded dresser constituting a dressing means,
43 a dresser constituting the dressing means, 44 a motor constituting the dressing means, 51 a CPU constituting the first adjusting means and the second adjusting means, 52 an operation input constituting the first adjusting means and the second adjusting means Reference numeral 62 denotes a display device as a notification means, 65 denotes an ammeter as a grinding resistance detector, and 70 denotes a temperature detector.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // B24B 5/00 B24B 5/00 Z 7/00 7/00 Z

Claims (28)

[Claims] A vibration generated during grinding of a work by a normally rotating grindstone is detected by a vibration detector, and the amplitude of the vibration is set to a first set value set in advance according to the grinding accuracy of the ground surface of the work. A method for driving a grinding wheel in a grinding machine, comprising: after the grinding operation is stopped, rotating the grinding wheel in a reverse direction to perform the grinding operation on the workpiece. 2. The method according to claim 1, wherein the first set value is set to 0.10 to 0.25 μm. 3. The method of driving a grindstone in a grinding machine according to claim 1, wherein the work of grinding the workpiece by reverse rotation of the grindstone is automatically performed by a signal from a control device. 4. The method according to claim 1, wherein the amplitude of the vibration detected by the vibration detector is larger than the first set value after the normal rotation and the reverse rotation of the grindstone are repeated at least once.
A method of dressing a grindstone in a grinder that stops the grinding work when the set value is reached and performs the work of dressing the grindstone. 5. The method according to claim 4, wherein the second set value is set to 0.60 to 0.70 μm. 6. The method of dressing a grindstone in a grinding machine according to claim 4, wherein the work of grinding the work by the reverse rotation of the grindstone and the work of dressing the grindstone are automatically performed by a signal from a control device. 7. A grindstone (26) mounted on a spindle (15).
Driving means (31) for rotationally driving the grindstone together with the spindle.
Reversing means (32) for reversing the direction of rotation of the whetstone
And a vibration detecting means for detecting vibration generated during grinding of the workpiece by the normally rotating grindstone in a grinding machine provided with a loosening prevention means (27, 28, 29) for preventing the connection portion between the grindstone and the spindle. A detector (34), and a notification unit (6) for notifying when the amplitude of the vibration detected by the vibration detector (34) reaches the first set value.
2) and a switching machine (35) for switching the reversing means (32) to an operable state after the notification means is operated. 8. The grinding machine according to claim 7, further comprising first adjusting means (51, 52) for adjusting the first set value of the amplitude. 9. The method according to claim 7, wherein the amplitude of the vibration detected by the vibration detector is changed after the grinding operation of the work is performed by rotating the grindstone in the reverse direction, and the normal rotation and the reverse rotation of the grindstone are repeated at least once. When the second set value that is larger than the first set value is reached, a notifying unit (62) for notifying the second set value, and after the notifying unit is operated, the grinding operation is stopped and the dressing operation of the grindstone is performed. A grinding machine equipped with a dressing means (42, 43, 44) for performing the dressing. 10. A grinding machine according to claim 9, further comprising a first adjusting means and a second adjusting means (51, 52) for adjusting the first set value and the second set value of the amplitude, respectively. 11. A resistance detector detects a grinding resistance generated during grinding of a workpiece by a normally rotating grindstone, and sets the grinding resistance to a preset reverse rotation set value (R1a to R1).
a method of driving a grinding wheel in a grinding machine, wherein, when n) is reached, after the grinding operation is stopped, the grinding wheel is rotated in the reverse direction to perform the grinding operation on the workpiece. 12. The method according to claim 11, wherein the set values for the reverse rotation are provided in a plurality of stages, and each set value has a difference in grinding resistance of ± 5N.
/ Method for driving a grinding wheel in a grinding machine set to fall within the range of / mm. 13. The method of driving a grinding wheel in a grinding machine according to claim 11, wherein the work of grinding the workpiece by the reverse rotation of the grinding wheel is automatically performed by a signal from a control device. 14. The dressing set value (R2) according to claim 11, wherein after the normal rotation and the reverse rotation of the grindstone are repeated at least once, the grinding resistance detected by the resistance detector is set.
The method of dressing a grindstone in a grinder that stops the grinding work when it reaches the point and performs the dressing work of the grindstone. 15. The grinding wheel according to claim 14, wherein the set value for dressing is set to a resistance value of 80 to 100% of a maximum grinding resistance value (R2) suppressed by forward / reverse rotation of the grinding wheel. Dressing method. 16. The method of dressing a grindstone in a grinding machine according to claim 14, wherein the work of grinding the work by the reverse rotation of the grindstone and the work of dressing the grindstone are automatically performed by a signal from a control device. 17. A grinding wheel (2) mounted on a spindle (15).
6) and a driving means (31) for rotating and driving the grindstone together with the main shaft.
Reversing means (32) for reversing the rotation direction of the whetstone
And a grinding machine provided with anti-loosening means (27, 28, 29) for preventing the connection between the grinding wheel and the spindle from detecting the grinding resistance generated during grinding of the workpiece by the normally rotating grinding wheel. A resistance detector (65), and an informing means (6) for notifying when the grinding resistance detected by the resistance detector (65) reaches the reverse rotation set value.
2) and a switching device (35) for switching the reversing device (32) to an operable state after the notification device is activated. 18. A grinding machine according to claim 17, further comprising a first adjusting means (51, 52) for adjusting a set value for reversing the grinding resistance. 19. A grinding machine according to claim 17, wherein the grinding wheel is rotated in the reverse direction to perform a grinding operation on the workpiece, and after the normal rotation and the reverse rotation of the grinding wheel are repeated at least once, the grinding resistance detected by the resistance detector is dressed. A notification means (62) for notifying when the set value has been reached, and a dressing means (42, 43, 44) for stopping the grinding operation and for performing a dressing operation of the grindstone after the notification means is operated. ) And a grinder equipped with. 20. A grinding machine according to claim 19, further comprising a first adjusting means and a second adjusting means (51, 52) for adjusting a plurality of reverse rotation set values and dressing set values of the grinding resistance. 21. A temperature detector detects a temperature of a grinding portion generated during grinding of a workpiece by a normally rotating grindstone, and the temperature of the grinding portion is set in advance according to a grinding accuracy of a grinding surface of the workpiece. A method for driving a grindstone in a grinder, wherein when a set value is reached, the grinding work is stopped, and then the grindstone is rotated in the reverse direction to perform the work for grinding the work. 22. The method of driving a grinding wheel in a grinding machine according to claim 21, wherein the work of grinding the workpiece by the reverse rotation of the grinding wheel is automatically performed by a signal from a control device. 23. The second set value according to claim 21, wherein the temperature of the grinding portion detected by a temperature detector after the forward rotation and the reverse rotation of the grindstone is repeated at least once is larger than the first set value. A method of dressing a grindstone in a grinder in which the grinding work is stopped and the grindstone is dressed when the temperature reaches a predetermined value. 24. A method of dressing a grindstone in a grinder according to claim 22 or 23, wherein the work of grinding the work by the reverse rotation of the grindstone and the work of dressing the grindstone are automatically performed by a signal from a control device. 25. A grinding wheel (2) mounted on a spindle (15).
6) and a driving means (31) for rotating and driving the grindstone together with the main shaft.
Reversing means (32) for reversing the direction of rotation of the whetstone
And a grinder provided with anti-loosening means (27, 28, 29) for preventing the connection between the grindstone and the spindle from being loosened. A temperature detector (70) for detecting, a notifying means (62) for notifying when the temperature of the grinding section detected by the temperature detector (70) reaches a first set value, and the notifying means. A switching means (35) for switching the reversing means (32) to an operable state after being operated. 26. A grinding machine according to claim 25, further comprising first adjusting means (51, 52) for adjusting a first set value of the temperature of the grinding section. 27. The method according to claim 25, wherein the grinding wheel is rotated in the reverse direction to grind the work, and after the normal rotation and the reverse rotation of the grinding wheel are repeated once or more, the temperature detector (7) is turned on.
0) when the temperature of the grinding section detected reaches the second set value which is larger than the first set value, a notifying means (62) for notifying the second set value; A grinding machine provided with dressing means (42, 43, 44) for performing a dressing operation of a grindstone by stopping the operation. 28. The grinding machine according to claim 27, further comprising first adjusting means and second adjusting means (51, 52) for adjusting the first set value and the second set value of the temperature of the grinding unit, respectively.