JPH0453666B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to a grinding device that grinds a workpiece while intermittently measuring the dimensions of the workpiece with a rotating and reciprocating grindstone. be.

(Prior art) As shown in FIG. 1, this type of device rotates a grinding wheel 1 via a grinding wheel shaft 3 by a motor, and also reciprocates in the axial direction of the grinding wheel shaft 3 to move a workpiece M relative to the grinding wheel 1. relatively feed the workpiece M.
It is used for grinding.

The above-mentioned grinding equipment generally performs grinding through three processes: rough grinding, finish grinding, and spark-out, and the cutting speed is controlled by the cutting feed device that controls the cutting feed of the workpiece M relative to the grinding wheel 1. It can be controlled in three stages.

For example, to obtain the grinding amount curve l shown in Fig. 2, in the first step, grinding is performed at a high rough cutting speed in line with the rough cutting characteristic a until the cutting speed switching point _G2 , and in the second step, Grind to cutting speed switching point _G1 at a slightly slow finishing cutting speed in accordance with finishing cutting characteristic b, and in the final third stage, cut to size using only the restoring force of the deflection accumulated in the grinding wheel spindle 3. Cutting speed switching point along the cutting characteristic c
It is designed to grind to G ₀ and spark out. At this time, in the first stage rough grinding process, the workpiece M strongly presses the grindstone 1 in the radial direction due to high-speed cutting, and a deflection d occurs in the grindstone shaft 3. This deflection d causes the grinding surface Ma of the workpiece M to be inclined in the second-stage finish grinding process. Therefore, when grinding to cutting speed switching point G ₂ and switching from rough cutting speed to finishing cutting speed, the cutting feed amount is reduced corresponding to the above deflection d, and the above deflection d is removed. It's summery. That is, a pre-retraction amount S corresponding to the deflection d is set, and after the cut pre-retraction is performed, the cutting speed is switched to the finishing cutting speed.

By the way, to switch the cutting speed, the dimensions of the workpiece M are measured intermittently with a measuring device, for example, at intervals of T as shown in _FIG . ₁ , the switch is made when the dimension of the workpiece M corresponding to G ₀ or more is reached. Therefore, each cutting speed switching point G ₂ , G ₁ ,
G ₀ may be reached and passed during the next measurement, and the predetermined cutting feed amount, in other words, the grinding amount may be exceeded. That is, when retreating from a rough cut to a pre-cut, the timing is delayed, and the deflection d of the grindstone shaft 3 increases accordingly. Therefore, when the cut back is retreated by the above-mentioned cut back retreat amount S, a slight deflection d remains in the grinding wheel shaft 3 even after the cut back is retreated, and the grinding surface of the workpiece M is
Induces a slope of Ma. Moreover, if the above-mentioned back-back amount is made too large, a state will occur where the grindstone 1 is separated from the workpiece M at the initial stage of the finishing cut and the workpiece M is not ground, resulting in a decrease in grinding efficiency.

(Object of the invention) This invention was made in view of the above circumstances,
It is an object of the present invention to provide a grinding device which can ensure appropriate machining accuracy regardless of a delay in the timing of cutting back and retreat at the time of switching the cutting speed, and can also improve the efficiency of grinding.

(Structure of the Invention) According to the present invention, the measurement value from a measuring device that intermittently measures the dimensions of the workpiece is the set value from the cutting speed setting device that sets the dimensions of the workpiece corresponding to the cutting speed switching point. When the cut is exceeded, the cut feed device is controlled by adjusting the cutting retreat amount according to the exceeded amount.

That is, the present invention provides a grinding process in which, when the dimensions of a workpiece being machined with a rotating and reciprocating grindstone are intermittently measured and the cutting speed is switched to a predetermined cutting speed, the cutting speed is retreated prior to switching the cutting speed. The device includes a cutting feed device that controls the cutting feed of the workpiece relative to the grinding wheel so that the cutting position, cutting speed, and cutting back retreat amount are set in advance, and a cutting feed device that controls the cutting feed relative to the grindstone so that the cutting feed is controlled to a preset cutting position, cutting speed, and cutting retreat amount. a switching point setter that sets the dimensions of the workpiece corresponding to the switching point of the cutting speed;
A measuring device that intermittently measures the dimensions of a workpiece; a comparator that compares the measurement signal of the measuring device with the setting signal of the switching point setting device and generates a switching signal when the measurement signal reaches the setting signal or higher; Calculating the excess amount by which the measured measurement signal of the measuring device exceeds the setting signal of the switching point setter when the comparator generates the switching signal, and calculating the amount of increase in the amount of cutting advance retreat corresponding to this calculation result, It is equipped with a cut-back retreat amount adjustment device that sends the calculation result as a cut-back retreat amount control signal to the cut feed device, and the cut feed device receives the switching from the cut-back retreat amount adjustment device when the comparator generates the switching signal. A predetermined depth of cut retreat amount is adjusted by adding the depth of cut retreat amount control signal, and then the cutting speed is switched and controlled.

(Example) An example of the present invention will be described below with reference to the drawings.

FIG. 3 shows an example of a grinding device according to the present invention. In the figure, 1 is a grindstone for grinding a workpiece M, and 2 is a grindstone that is connected to the grindstone 1 through a grindstone shaft 3.
4 is a support stand for the wheel head 2, which is rotatably driven by a motor;
It is set to reciprocate in the axial direction of the grindstone shaft 3 (direction of arrow X). Reference numeral 5 denotes a measuring device for intermittently measuring the machining dimensions of the workpiece M, and is provided with a driven rod 7 driven by a driving rod 6 fixed to the support base 4. 8 is a return spring.

9 is a cutting feed device that feeds the workpiece M relative to the grindstone 1; 10a to 10c are cutting speed settings that set the rapid feed, rough cutting, and finishing cutting speeds to the cutting feed device 9, respectively; A feed motor 11 drives a block 12 comprising the measuring device 5, the workpiece M, etc. 13 is whetstone 1
This is a position setting device for setting the cutting start position P of the workpiece M, each cutting speed switching point G ₂ , G ₁ , G ₀ , cutting advance retreat amount S, etc.

Reference numerals 14a to 14c are switching point setters for respectively setting cutting speed switching points G ₂ , G ₁ , and G ₀ for switching the cutting feed speed of the cutting feed device 9, and 15 is a comparator. This comparator 15 compares the measurement signal from the measuring device 5 and the setting signal from the switching point setters 14a to 14c, and when the measurement signal exceeds the setting signal, a switching signal is sent to the cutting feed device via the sequence circuit 16. It is set to be sent on 9th. Reference numeral 17 denotes a backup/retreat amount adjustment device, which includes, for example, an arithmetic circuit 18 that calculates the excess of the measured value from the measuring device 5 over the set value in synchronization with the transmission of the switching signal from the comparator 15, and this arithmetic circuit. 18, and a pre-retraction amount calculator 19 which calculates an increase in the amount of pre-cut retraction based on the calculation result from step 18 and controls the cut feed device 9.

Next, the operation of the above configuration will be explained.

The position setting device 13 determines the cutting start position P of the workpiece M relative to the grindstone 1 by the cutting feed device 9;
After each cutting speed switching point G ₂ , G ₁ , G ₀ , cutting advance retreat amount, etc. are set, the workpiece M
Grinding of the workpiece M is started, and along with this grinding, the inner diameter of the workpiece M is intermittently measured by the measuring device 5. That is, in conjunction with the reciprocating movement of the grindstone 1 with respect to the workpiece M, the measuring device 5 moves forward and backward toward the workpiece M side. The rough depth of cut, finish depth of cut, and spark-out characteristics a, b, and c shown in Fig. 2 are
What is done accordingly is as described above.
In order to simplify the explanation, a case will be described below in which the rough cutting speed is shifted to the finishing cutting speed.

The measurement signal Gs from the measuring device 5 is input to the comparator 15. In this case, if the measurement signal Gs becomes larger than the setting signal G ₂ a preset in the switching point setter 14a for the switching point G ₂ from rough depth of cut feed to finish depth of cut feed, the above A switching signal Cs is sent from the comparator 15 to the cutting feed device 9 via the sequence circuit 16, while
It is also applied to the arithmetic circuit 18 at 7. When the arithmetic circuit 18 receives the switching signal Cs, it calculates the amount by which the measured value corresponding to the measurement signal Gs from the measuring device 5 exceeds the set value, and records the output signal Gg corresponding to this excess. It is sent to the retreat amount calculator 19. The back-and-back amount calculator 19 receives the output signal Gg, calculates a back-and-back amount corresponding to the excess amount, and controls the cutting feed device 9 with a control signal Ge based on this result.

For example, in FIG. 2, if the switching signal Cs is sent from the comparator 15 at a measurement point G ₂ s where the cutting feed of the workpiece M has passed a predetermined switching point G ₂ , the setting of the measurement value at that point If the excess amount over the value, that is, the excess amount of the cutting feed amount of the workpiece M is g, the position setting device 13 is set in the cutting feed device 9 so that the back-back amount S increases by an amount corresponding to the excess amount g. It is adjusted by adding the above excess amount g to the preset position setting value, in other words, the cutting advance retreat amount S. Therefore, even if the timing at which the rough cut is completed and the shift to back-back is delayed from the predetermined switching point _G2 as described above, the appropriate back-back amount will be set regardless of this, so the next The deflection of the grinding wheel shaft 3 does not increase during the finishing cut, and the precision of the machined surface of the workpiece M is maintained at a good level.
Of course, work M
Since the problem of the grindstone 1 separating during cutting does not occur, efficient grinding can be continued. In addition, although the above explanation takes as an example the transition from the rough cutting to the finishing cutting, it can also be applied to other switching points such as _G1 .

(Effects of the Invention) As described above, the present invention detects an excess of the cutting feed rate from a predetermined switching point, and increases the predetermined back-and-back amount in accordance with the excess. Even if the back-and-back timing is delayed from the point in time, appropriate back-and-back is performed to compensate for the delay, and as a result, a highly accurate ground surface is formed, and high efficiency of the grinding process can be ensured. .

[Brief explanation of drawings]

Fig. 1 is a partially cutaway side view showing the state in which grinding is being performed, Fig. 2 is a diagram showing the relationship between time and cutting feed amount in grinding, and Fig. 3 is a diagram showing the grinding process according to the present invention. FIG. 2 is a block diagram showing an example of a processing device. 1... Grinding wheel, 3... Grinding wheel shaft, 5... Measuring instrument, 9
... Cutting feed device, 10a-10c... Cutting speed setting device, 14a-14c... Switching point setting device, 15
... Comparator, 17... Backward retreat amount adjustment device, M...
…work.

Claims (1)

[Scope of Claims] 1. Grinding in which, when the dimensions of a workpiece being machined with a rotating and reciprocating grindstone are intermittently measured and the cutting speed is switched to a predetermined cutting speed, the cutting back is retreated prior to switching the cutting speed. In the processing device, a cutting feed device that controls the relative cutting feed of the workpiece with respect to the grindstone to a preset cutting position, cutting speed, and cutting back retreat amount; Comparison of the switching point setting device that sets the workpiece dimensions corresponding to the cutting speed switching point, the measuring device that measures the workpiece dimensions intermittently, and the measurement signal of the measuring device and the setting signal of the switching point setting device. A comparator that generates a switching signal when the measurement signal reaches a setting signal or higher, and a comparator that calculates the excess amount by which the measurement signal of the measuring device exceeds the setting signal of the switching point setter when the comparator generates a switching signal. and a cutting retraction amount adjustment device that calculates an increase in the cutting retraction amount corresponding to the calculation result and sends this calculation result to the cutting retraction amount control signal as a cutting retraction amount control signal, When the comparator generates a switching signal, the feed device adds the cut-back retreat amount control signal from the cut-back retreat amount adjustment device to adjust the preset cutting cut-back retreat amount, and then switches the cutting speed. A grinding device characterized in that it is controlled.