JPS6179567A - Wheel truing device - Google Patents

Abstract

PURPOSE:To prevent coarseness on a machined surface from occurring as well as to make a span of service life in a grinding wheel ever so longer, by outputting a truing signal at a short interval immediately after wheel changing but afterward, at a long interval respectively, while controlling a driving device, and performing a wheel truing job. CONSTITUTION:A control unit 30 distributes each command pulse to drive units 40, 41 and 42 and controls infeed and traverse motion of a dressing wheel 14 and a truing wheel 3. A program to be stored in a memory 32 makes truing intervals from the first wheel truing to the second, the third and the fourth larger in consecutive order but afterward, it is set to identical large intervals, while an operation processor 30 reads out the contents of a work ground number counter 34 in regular sequence on the basis of the program stored in the memory 32, thereby controlling each of motors 15, 5 and 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a so-called grindstone correction device for truing and dressing the surface of a grindstone G.

[Prior Art] In general, CBlN (cubic boron nitride) grinding wheels have li!
! Because of its high quality, it has a long life and is suitable for mass production processing.

When such a whetstone reaches the end of its lifespan and is replaced with a new one, the new whetstone is not a perfect circle, resulting in sharp edges when rotated. For this reason, in order to remove this imperfection, truing and dressing (both are collectively referred to as correction) are performed using a large cutting tool. In this case, due to the large depth of cut, abrasive grains that are poorly held on the surface of the grindstone may fall off, or a large rack may be formed on the surface of the abrasive grains and bond (binder).

To explain this point with reference to the drawings, as shown in Fig. 8, the abrasive grains 21 are bonded by a vitrified bond 22, and since the cutting depth is large in the first correction, there are many bonds. Since the abrasive grains 21a on the surface are gouged out, they are likely to fall off, and deep scratches (cracks) 21b occur in the bond and the abrasive grains.

If a workpiece is ground using a grindstone in such a state, the abrasive grains may fall off during the grinding process, resulting in an early reduction in the surface roughness of the workpiece.

To prevent this, frequent corrections must be made, which quickly wears out the expensive grinding wheel and shortens its lifespan.

On the other hand, in the second and subsequent grindstone corrections, it is not necessary to remove the sharpness, and the cutting depth is small, so as shown in FIG.

[Problems to be Solved by the Invention] As described above, there is a large difference in cut color between the correction immediately after the grindstone is replaced and the one made after the second time, and there is a corresponding difference in the state of the grindstone surface. As shown in FIG. 7, the correction interval was always kept at a constant value n.

Therefore, when the grindstone is free from cracks, etc., the curve will be as shown in Figure 7, and the surface roughness S of the workpiece ground using this grindstone will be constant 1+I! Although it is within St, if a grinding wheel with cracks etc. is used for grinding at a correction interval of n, the surface scratch S will exceed the constant value S1 (curve mB in Figure 7), and the grindstone will be used as is. Doing so will encourage the abrasive grains to fall off and crack, and the surface roughness will worsen until it exceeds the allowable value.
It becomes impossible to restore the surface roughness S to within the allowable value, and grinding wheel runout occurs, making it impossible to perform normal grinding. In order to perform normal grinding, it is necessary to make many corrections m, which takes a lot of time and causes a lot of wear and tear on the grindstone.

Means for Solving the ε Problem] The present invention has been made to solve such conventional problems, and its main structure will be explained with reference to the conceptual diagram of FIG. 1. A linear pressure tool 201 corrects the surface of the grindstone in order to recover the grinding wheel, a drive device 202 provides feed to the correction tool 201, and a correction signal is output at a short correction interval immediately after the grindstone is replaced, and then immediately after the grindstone is replaced. A correction signal output device 203 that outputs a correction signal at a correction interval longer than , and the linear pressure signal output device 203
When a correction signal is output from the drive device 202,
II ml i to correct the grinding wheel by controlling
Here, the concept of the correction tool includes a truing wheel and a dressing wheel.

As shown in FIG. 2, the correction signal output device 203 sets a workpiece machining number setting wave that sets the number of workpieces to be machined to a small number immediately after the grindstone is replaced, and sets the number of workpieces to be machined to a large number after that. 203A, and a total of 1 to count the number of workpieces to be machined! It consists of a device 203B and a comparison device 203C that determines whether the number of workpieces machined counted by the counting device f1203B has reached the value set by the workpiece machining water film setting device 203A.

The correction timing detection device 203 includes a surface accuracy detection device RA2030 that detects the surface accuracy of the workpiece as shown in FIG. 3, and a surface accuracy detected by the surface accuracy detection device 203D that reaches a preset surface accuracy. A comparison device 203E is configured to determine whether or not the above-mentioned error has occurred, and a signal is sent from the comparison device 203E to the above-mentioned correction control device 204.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 4 is an overall view showing an embodiment of the present invention. In the figure, reference numeral 1 indicates a grinding wheel head, and the grinding wheel head 1 has CBN [
A grindstone 12 including a stone 2a is rotatably provided, and a truing wheel 3 that can come into contact with the surface of the CBN calm stone 2a is provided. The truing vehicle 3 has a support base 4
It is disposed on the grindstone head 1 via a motor 3A, and is rotationally driven by a motor 3A, and cuts in the direction of the grindstone 2a are made by another motor 5 via a gear 6.7 and a screw shaft 8. Further, the truing wheel 3 uses the traverse motor 9 as a drive source to perform traverse movement via the gears 1 and 12 (grinding wheel 2
(in the axial direction, that is, in the direction perpendicular to the plane of the paper).

On the other hand, above the grinding wheel 2, a dressing wheel 14 is rotatably provided via a support stand 13. The dressing wheel 14 is rotationally driven by a motor 14A,
The fine gap between the dressing wheel 14 and the surface of the grinding wheel 2a is adjusted by the motor 15 using the gears 16 and 17 and the screw shaft 1.
8. The grinding wheel 2 and the dressing wheel 14 are rotated in mutually different directions while maintaining the minute gap,
There is play in the minute gap! Dressing is performed by feeding lIt abrasive grains (this point is well known,
This is shown in detail in the Japanese Patent Publication No. 58-20753 filed by Ganto Toyama.

In FIG. 4, reference numeral 30 distributes command pulses to drive units 40, 41 and 42 that drive the motors 15, 5 and 9, respectively, to drive the dressing wheel 14 and the truing wheel 3.
A control device for controlling the cutting feed and traverse operation is shown, and includes an arithmetic processing device 31, a memory 32 . It is composed of a data input device 33.

The memory 32 stores a program for modifying the grinding wheel 2. As this program,
For example, as shown in Figure 6, the first correction interval from the first grinding wheel correction to the second grinding wheel correction is set to N1, which has a smaller number of pieces processed, and the second correction interval is from the second grinding wheel correction to the third grinding wheel correction. Set the interval to NZ greater than N1, 3
The third correction interval from the first correction to the fourth correction is set to N3, which is larger than NZ, and all subsequent corrections are set to N3. The contents of the workpiece processing counter 34 are sequentially read out to control the motors 15, 5.9.

[Function] To explain the function of this device based on the flowchart of FIG. 5, first, when the grinding wheel 2 in use reaches the end of its life, it is replaced with a new one. Press the correction command push button (flash). In response to this command, the arithmetic processing unit starts processing operations, and first the interval counter IC and the number counter WC.
Initialize the contents of II O11 (step 100), and then output a grinding wheel correction command (step 1).
01) According to this command, a pulse signal is outputted to the motor 15.5.9 via the drive units 40.4 and 42, and the grinding wheel is refined by the truing wheel 3 and the dressing wheel 14 as described above.

When the grindstone correction is completed, the process proceeds to step 102, where "'1'° is added to the content of the interval counter IC, and then it is determined whether the content of the interval counter IC is 11111, and the content is "1'°. When it is determined that the number of pieces to be processed N+ is set at the first sampling interval, the number N+ is read (steps 103 and 104).
.

Thereafter, the grinding process of the workpiece W by the grinding wheel 2 is counted by the machined number counter 34, and at the same time the machined number N reaches the set processing tree TI&N+, a grinding wheel correction command is output (steps 105, 106, 107).
>The second grindstone correction is carried out in the same manner as above.

After the second grinding wheel correction is performed, step 10 is performed again.
2,103.108, the number N2 of workpieces to be machined at the second regular interval is read (step 10).
9), after that, each time the workpiece W is ground, the number of grinding operations N
is repeated once at a time (110), and when the counted value reaches the set number of workpieces to be machined NZ, the third grinding wheel correction is performed in the same manner as the second time, and then the process proceeds to step 102. return.

Next, the 1c schedules 7102, 103. N is counted one by one (
Same 113. ), when the counted value reaches the set number of workpieces to be machined N3, the fourth grindstone correction is performed in the same manner as the third time, and the process returns to step 102.

After that, the correction interval is stopped at N
Every time three pieces are ground, the grindstone tz correction is repeated in the same manner as described above.

Here, in the first grinding wheel correction, the grinding wheel 2 is corrected with a large depth of cut in order to remove runout, so the surface of the grinding wheel is roughened, and the workpiece W is being ground with this grinding wheel 2. Then, the surface roughness S of the workpiece W decreases quickly. However, since the number N1 of workpieces processed during this first correction interval is set to be as small as, for example, 100 pieces, the second grindstone correction is performed earlier. Therefore, the surface roughness S of the workpiece W is not ground to a level greater than the allowable value SI.

Further, in the second and subsequent grindstone corrections, the depth of cut is small, so that the surface of the grindstone 2 is corrected to a state with fewer cracks. For this reason, even when the workpiece W is ground by the grinding wheel 2, the surface roughness S of the workpiece W does not drop as sharply as it did after the first grinding wheel correction, and the second. Number of workpieces processed in the third and subsequent intervals N2. N3 is, for example, 3oO
The number is set at 500 books. Therefore, the number of times the grindstone needs to be corrected can be reduced accordingly, and the life of the grindstone can be extended.

In addition, when repairing the grindstone using resinoid bond,
Normally, truing is performed first and then dressing is performed, and both are paired, but if the bond 22 (Figs. 8 and 9) is a vitrified bond, the workpiece is ground Sometimes the bond on the surface of the grinding wheel is scraped away to achieve the same effect as dressing, so normally only truing is used for correction.

[Modified Example] In the above embodiment, when setting the correction interval before grinding wheel correction, the number of workpieces to be machined is predetermined as Nτ, NZ, and N3, but the method is not limited to this method, and for example, Using a surface accuracy detection device that outputs the surface roughness of the workpiece after grinding as an electrical signal, the grinding wheel is corrected when the surface roughness reaches a set value based on the signal from the surface accuracy detection device. Good too. In this case, the setting (direct) is to set the surface roughness corresponding to Nl, N2, and N3 mentioned above in three stages.In addition, 1 correct time is set based on both the number of workpieces to be machined and the surface accuracy of the workpiece. You can do it like this.

g Effect of the invention 1 As described above, in the present invention, since the correction interval immediately after the grindstone is replaced is set to be larger than the correction interval from the second time onwards, cracks etc. occur due to the first correction of the grindstone. However, since the second grinding wheel correction is carried out early, the roughness of the machined surface of the workpiece will not become poor, and by setting the correction interval longer after the second time, it will be possible to prevent the number of grinding wheel corrections from increasing more than necessary. First, it has the effect of improving the life of the grindstone.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the concept of the present invention, FIGS. 2 and 3 are explanatory diagrams showing embodiments of the present invention, FIG. 4 is an overall diagram showing an embodiment of the present invention, and FIG. 4 is a flowchart that does not show the operation of FIG. 4, FIG. 6 is a graph showing the relationship between machining water rllN and surface roughness S of a workpiece machined using the grindstone modified according to the present invention, and FIG. The figure is a graph similar to Fig. 6 and shows the conventional one, Fig. 8 is an enlarged sectional view of the surface of the grinding wheel immediately after the first correction, and Fig. 9 is after the second correction; FIG. 2 is an enlarged sectional view of the surface of the grindstone immediately after turning positive by 1 Te. 2... Grinding wheel 3... Truing wheel 4.
... Dressing car patent applicant Toyota Machinery Co., Ltd. agent Patent attorney Sadamuki Okawa Patent attorney Jodo Fujitani Patent attorney Akio Maruyama Figure 6 Figure 7 Figure 8 Figure 9

Claims (3)

[Claims] (1) A correction tool that corrects the surface of the grindstone in order to restore the surface accuracy of the grindstone, a drive device that provides feed to the correction tool, and a correction signal that is output at short correction intervals immediately after the grindstone is replaced, and then is a correction signal output device that outputs a correction signal at a longer correction interval than immediately after the grindstone is replaced;
When a correction signal is output from the correction signal output device,
A grindstone correction device comprising: a correction control device that controls the drive device to correct the grindstone. (2) The correction signal output device includes a workpiece machining number setting device that sets a smaller number of workpieces to be machined immediately after the grindstone is replaced and a larger number of workpieces to be machined thereafter; The patent claim comprises a counting device that counts the number of workpieces, and a comparison device that determines that the number of workpieces machined counted by the counting device has reached the value set by the number of workpieces machined setting device. Range 1
Grinding wheel correction device as described in section. (3) The correction signal output device includes a surface accuracy detection device that detects the surface accuracy of the workpiece, and a comparison device that determines whether the surface accuracy detected by the surface accuracy detection device has reached a preset surface accuracy. A grindstone correction device according to claim 1, which comprises a device.