JPH069785B2 - Grinding control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a grinding control device, and in particular, when dressing a grindstone after grinding a predetermined number of workpieces (hereinafter referred to as “workpieces”), The present invention relates to a grinding control device capable of controlling the optimum number.

[Prior art]

Conventionally, for example, when grinding the inner surface of a work, while rotating the grindstone, it is axially fed to be inserted into the work, and then the work is fed in the direction perpendicular to the axis to sequentially perform black skin grinding, rough grinding, Finish grinding is applied and spark-out is performed at the end. And in this grinding process,
The grindstone is one that is damaged by grindstone damage due to clogging and wear accompanying grinding, and the sharpness is reduced.To recover the sharpness of this grindstone, conventionally, every time a predetermined number of workpieces are ground, That is, the whetstone is dressed by the dressing device every predetermined number of skips. The number of skips is obtained by experimentally determining the number of workpieces when the grinding stone is clogged, the amount of wear, etc. reaches a certain limit amount, and the number of skips is set. The number of skips is set differently for different types of work, for example, different sizes, materials, or heat treatments in the previous process, but the same number of works is used. Even if the same number of workpieces are ground by the same number, the grindstone damage varies. Therefore, the conventional grinding control device sets a small number of skips in consideration of this variation. Therefore, in the conventional grinding control device set to such a small number of skips,
If the actual whetstone damage is small, it means that dressing was done more often than necessary, and the life of the whetstone will be reduced accordingly.However, if the number of skips above is increased, the sharpness of the whetstone cannot be recovered. However, there arises a problem that the grinding accuracy is lowered. Further, Japanese Patent Publication No. 55-45344 discloses a grinding control device which integrates the number of inspected objects to be inspected and generates a dress signal to perform dressing when it reaches a predetermined value. Even if it is the same type of work, there are variations in stock removal and even if the same grinding is performed, the wear state of the grindstone will not be uniform.Therefore, in the above method, dressing must be performed at the optimum timing. It is inferior in grinding accuracy and grindstone life.

[Object of the Invention]

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a grinding control device capable of extending the life of a grindstone without reducing grinding accuracy by optimizing the number of skips.

[Structure and Action of Invention]

The inventors of the present invention have earnestly studied the cause of variation in the amount of damage to the grindstone even if the grindstone is formed by grinding the same number of works of the same number in the dressing, and found the following points.
That is, (a) Generally, the workpiece has a variation in its unmachined diameter,
Therefore, the machining allowance, which is the difference between the unmachined diameter and the finished diameter, causes variations in the so-called machining allowances. However, the larger the machining allowance, the greater the amount of grinding per workpiece, so the grinding stone is increased accordingly. The damage amount of will increase as the allowance increases.

(b) Therefore, in order to achieve the above object, the stock removals for each work are sequentially accumulated, and the number of works when the accumulated stock removal value reaches the dressing limit stock allowance determined in advance by experiment is dressed as the number of skips. do it.

Therefore, the present invention, in a grinding control device for performing dressing,
As shown in the functional block diagram of FIG. 1, a grinding device 1 that grinds a workpiece and grinds a grindstone;
Dress timing control means 61 for controlling the dress timing by the device 1, a work sensor 62 for obtaining a work allowance after the last dress, and an allowance accumulating means 63.
And a dress signal creating means 64 for giving a dress signal to the dress timing control means 61.

In the present invention having the above configuration, the work sensor 62 and the stock removal accumulating means 63 sequentially integrate the stock removal allowances, and when the integrated stock removal value reaches a predetermined value, the dress signal creating means 6
A dressing signal is input from 4 to the dressing timing control means 61, whereby the number of skips is reduced in the case of a work with a large stock removal, that is, dressing is performed earlier, the sharpness of the grindstone is sufficiently restored, and conversely the stock removal is performed. In the case of a small work, the number of skips increases, that is, dressing is not performed more frequently than necessary, and the life of the grindstone is extended.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

2 and 3 show a grinding control apparatus according to an embodiment of the present invention. In FIG. 2 showing the overall configuration, 1 is a grinding apparatus for grinding the inner surface of a work W and dressing the grindstone 6. This is the grindstone drive 7, the work drive 1
4, and a grindstone dressing device 15.

The grindstone table 2 of the grindstone driving device 7 is placed on the upper surface of the bed 1a so as to be slidable in the left-right direction in the figure, and a female screw box (not shown) fixed to the lower surface of the grindstone table 2 is for moving the grindstone table. A ball screw 3 is screwed together, and a grindstone feed motor 4 whose output shaft is connected to the ball screw 3 is fixed to the bed 1a. A wheel head motor 5 is mounted on the grindstone table 2, and a grindstone 6 is connected to an output shaft of the motor 5.

The work table 8 of the work driving device 14 is the bed 1
A work table moving ball screw 9 is screwed into a female screw box (not shown) fixedly mounted on the lower surface of the work table 8 on the upper surface of a so as to be slidable in the vertical direction in the figure. The cutting feed motor 10 to which the output shaft is connected is fixed to the bed 1a. A headstock 11 for chucking the work W is mounted on the work table 8, and the headstock 11 and the drive motor 12 mounted in the vicinity of the headstock 11 drive belt 13
Are connected by.

The grindstone dressing device 15 is of a swing type mounted on the work table 8, and a dressing tool 15b is attached to the swing arm 15a.

Reference numeral 20 denotes a machine (M / C) control device, which receives a cutting speed and a cutting amount signal from the pulse encoder 28 and performs feedback control so that the cutting speed and the cutting amount of the grinding device 1 become set values. In addition, the dressing signal and the dressing amount of the grindstone 6 are controlled by receiving the dressing signal from the dressing signal generating device 50.

In FIG. 3 showing the block configuration of the M / C control device 20 and the like, 21 is a notch for setting each feed speed according to the type of work such as semi-rapid feed, black skin feed, rough feed, finish feed and dress feed. The speed setting unit 22 is a cutting amount setting unit that sets the semi-rapid feed amount, the black skin grinding amount, the rough grinding amount, the finishing grinding amount, and the dress amount to a size according to the type of work, and these setting values, For example, the dress amount is N
The amount of dress that can recover the sharpness of the grindstone that has been individually ground is obtained in advance by an experiment, and this value is set. Reference numerals 23 and 24 respectively denote a cutting speed setting value and a cutting amount selecting section for selecting the cutting speed setting value and the cutting amount setting value in accordance with the selection signal E from the selection signal creating section 25. Sequence control unit 26
It is created according to the sequence signal F from. Again 27
Is a drive control signal creation unit, which sets the setting values selected by the cutting speed selection unit 23 and the cutting amount selection unit 24 as targets, and the rotation speed and the rotation amount of the cutting feed motor 10. The current value from the pulse encoder 28 to be detected is compared, and a drive control signal C for feedback control so that they match each other is created and output. A driver 29 outputs a drive signal D according to the drive control signal C.

Reference numeral 30 denotes a gap eliminator that detects that the grindstone 6 has come into contact with the surface to be processed of the work W from the change in the electric power of the wheel head motor 5. This is an unmachined inner diameter Ds of the work W.
It is a work sensor for detecting.

Reference numeral 40 denotes a stock removal accumulating device that obtains stock removal B'of the work W and sequentially integrates the stock removal B ', which is composed of a stock removal calculation unit 41 and a stock removal integration unit 42. The machining allowance calculation unit 41 receives a cutting position signal from the pulse encoder 28 and a contact detection signal from the gap eliminator 30 between the grindstone 6 and the workpiece W, and when grinding starts at the cutting position at the time of the detection. The machining allowance B ′ of each work W is calculated from the unmachined inner diameter Ds of the above and the preset finish inner diameter Df by the following equation (1).

B ′ = (Df−Ds) / 2 (1) Further, the stock removal accumulating unit 42 sequentially integrates the stock removal B ′. The integrated value is reset by the dress signal.

Reference numeral 50 is a dress signal creation device, which is composed of a reference allowance setting unit 51 and a dress signal creation unit 52. The reference allowance setting unit 51 sets a dress allowance S, which is a product of the average allowance Sm and the set skip count N, and the allowance S causes a predetermined whetstone damage when N pieces of the average allowance Sm are ground. It is shown that it occurs, and is obtained in advance by an experiment for each work type. Further, the dress signal creation unit 52 compares the stock removal allowance value B with the dress allowance S, and gives a dress signal H to the sequence control unit 26 when B ≧ S + Sm. here,
When the dress signal is created using an in-process gauge and a gauge such as the gap eliminator used in the present embodiment, in which the machining allowance is detected after the start of processing, as described above, B ≧ S + Sm Judgment is made, but if the machining allowance can be detected before the start of machining as in precage, it is judged by B ≧ S.

Next, the function and effect will be described.

In the apparatus of this embodiment, the cutting speed / cutting amount setting units 21 and 22.
Various cutting speeds and cutting amounts, and the standard allowance setting section 5
The average machining allowance Sm, the set skip number N, and the dress-to-dress reference machining allowance S are set in 1. And headstock 11
When the workpiece W is loaded on the device and the apparatus is started, the sequence signal F is input from the sequence control unit 26 to the selection signal creation unit 25, and the selection signal E is input from the creation unit 25 to the cutting speed selection unit 23 and the cutting Is input to the quantity selection unit 24,
In the selection unit, the set quasi-rapid feed speed and the set quasi-rapid feed amount, which are target values, are selected, and both target values are compared with the current value input from the pulse encoder 28 in the drive control signal creation unit 27, and the difference between them is determined. A corresponding drive control signal C is input to the driver 29, and a drive signal corresponding to the control signal C is input to the cutting feed motor 10, whereby the work W is fed in the direction perpendicular to the axis, and the cutting at this time is also performed. The speed and the depth of cut are fed back to the drive control signal creation unit 27 via the pulse encoder 28. Work W in this way
Is controlled to a predetermined feed rate and feed amount.

When the surface to be processed of the workpiece W comes into contact with the grindstone 6 in the semi-rapid feed, the target value and the current value match, and this matching signal G is input to the selection signal creating unit 25, and from the creating unit 25. A signal E for selecting the black skin feed speed and the black skin grinding amount is input to each of the selection sections 23 and 24, whereby the black skin cutting speed and the set black skin grinding amount are set as the target values to perform the black skin grinding. When the target value and the current value match in this black skin grinding, and the black skin grinding is completed, rough grinding, finish grinding, etc. are performed in sequence in the same manner as above with a predetermined set cutting speed and cutting depth. Then, the next work W is ground.

When the workpiece W contacts the grindstone 6 in the semi-rapid feed, the gap eliminator 30 detects the contact between the workpiece W and the wheel head motor 5 at the time of this contact, and the detection signal is input to the stock removal computing unit 41. , Here, the stock removal B ′ of the work W is calculated. This allowance B '
In the stock removal accumulating unit 42, the stock removal of the previous work W is sequentially accumulated. The machining allowance integrated value B thus obtained is input to the dress signal creating unit 52 and compared with the dressing reference dressing S added with the average machining allowance Sm in the creating unit 52, and when B ≧ S + Sm, the dress signal H is created,
It is input to the sequence control unit 26. Then, the dressing signal H causes the selection signal E to become a dressing signal for selecting the dressing speed and the dressing amount, whereby the dressing tool 15b of the dressing device 15 is dress-fed to the grindstone 6 and the dressing of the grindstone 6 is performed. Will be done. In this case, in the conventional grinding control device, the dressing timing is set by the number of skips N uniformly determined according to the work type, but in the present embodiment, if the stock removal allowance value B reaches the reference stock removal S + Sm, Dressing is performed, and thus the number of skips is corrected according to the stock removal.

As described above, in the present embodiment, the stock removal of the work W is integrated, and the dressing is performed with the number of skips corresponding to the integrated stock removal value and thus the grindstone damage amount. Therefore, when the work with a large stock continues, the above setting is performed. With the number of skips smaller than the number of skips N, that is, dressing is performed earlier before the damage of the grindstone becomes too large, the sharpness of the grindstone 6 can be easily recovered, and the grinding accuracy can be maintained. On the contrary, when a work with a small stock removal continues, dressing is performed with the number of skips larger than N, that is, dressing is not performed more frequently than necessary, so that the life of the grindstone can be extended.

Although the gap eliminator 30 has been described as an example of the work sensor in the above embodiment, the work sensor may be, for example, a pre-cage that measures the inner diameter of the work W before loading, or an in-process gauge that measures after loading. Further, although the case where the inner surface of the work is ground has been described in the above embodiment, the present invention can of course be applied to the outer surface grinding.

[Effects of the Invention] As described above, according to the grinding control device of the present invention, the machining allowances of the work are integrated, and when the integrated value reaches a predetermined value, dressing is performed, so that the dressing timing is optimized. Therefore, it is possible to extend the life of the grindstone while maintaining the grinding accuracy.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention, FIG. 2 is an overall configuration diagram of a grinding control device according to an embodiment of the present invention, and FIG. 3 is a block configuration diagram thereof. DESCRIPTION OF SYMBOLS 1 ... Grinding device, 20 ... M / C control device (dress timing control means), 30 ... Gap eliminator (work sensor), 40 ... Stock accumulating device, 50 ... Dress signal generation device, 61 ... Dress timing control device, 62 ... Work sensor, 63 ... Stock accumulating means, 64 ... Dress signal creating means.

Claims (1)

[Claims] 1. A grinding device for grinding a workpiece to dress a grindstone, a dress timing control means for controlling a dressing timing of the grindstone by the grinding device, and an inner diameter or an outer diameter of the workpiece. A workpiece sensor, a machining allowance accumulating means for sequentially accumulating machining allowances, which are machining allowances of a workpiece from the detection output of the work sensor, and a dress signal when the machining allowance integrated value from the machining allowance accumulating means reaches a predetermined value. A grinding control device comprising: a dress signal creating means for giving the dress timing control means.