JP4539557B2 - Method and apparatus for controlling sizing of machine tool - Google Patents

Description

The present invention relates to a sizing grinding control method and apparatus for a machine tool capable of simultaneously and independently machining different machining locations of a workpiece with tools respectively provided on a plurality of tool stands .

  A twin head crankpin grinding method that can grind crankpins having different crankshafts simultaneously and independently by two grindstone heads is already known from Japanese Patent Application Laid-Open No. 54-71495. The crankpin part of the crankshaft is pivoted around the journal part of the crankshaft, so when machining while directly measuring the machining part, use a follow-up type sizing device described later, and each machining part A method of controlling the feed of the corresponding grinding wheel base on the basis of a signal generated from the sizing device every time a predetermined dimension is reached is adopted.

  In the above-described twin head crankpin grinding machine, since the processing by each grinding wheel base is performed independently, the grinding processing by each grinding wheel base may not proceed simultaneously depending on the state of the workpiece, the state of the grinding wheel, and the like. Therefore, even if one side is sparked out, that is, the cut is zero, the work piece is resisted by the grindstone of the other grindstone table, and the work piece is in a bent state. This will affect the finishing accuracy and roundness of the crankpin. Moreover, if the other grindstone base is maintained in the spark-out state until the other has completed the spark-out, it will be overcut.

Accordingly, an object of the present invention is to provide high-precision machining, particularly finishing accuracy, in a machine tool that can simultaneously and independently machine different machining locations of a workpiece with tools respectively provided on a plurality of tool stands . A sizing processing control method capable of improving the roundness and an apparatus therefor.

In order to solve the above-described problem, the structural feature of the invention described in claim 1 is that a workpiece having a plurality of different machining locations is rotatably supported, and a plurality of tool platforms including tools are provided for each tool. Are indexed at positions facing each machining location, and each tool base is independently moved back and forth so that each tool processes each of the different machining locations, and a plurality of sizing devices are provided for each tool. A machining control method for a machine tool that measures the dimensions of each machining location to be machined and controls the advance and retreat movement of each tool base by the dimensions of each machining location measured by each sizing device . The first tool table corresponding to the machining location detected by the first sizing device that has been processed by one of the tools and has reached the target dimension is retracted by a predetermined amount and processed by the second tool. Reaching the target dimension Second the sizing was the second the tool stand and the corresponding detected machining spot by the device by a predetermined amount backward, first and second of said tool after the first, second the tool stand is retracted a predetermined amount It is to process the next process by moving the stage forward simultaneously.

The structural feature of the invention described in claim 2 is that, in claim 1, the current process is a pre-process of a final process, and the next process is the final process.

The structural feature of the invention described in claim 3 is that a workpiece having at least two machining points is supported so as to be rotationally driven, and each grindstone is aligned and opposed to each machining point on two grindstone tables provided with a grindstone. Each machining location indexed at each position, each grinding wheel table is moved back and forth independently so that each tool grinds each different machining location, and two sizing devices are provided to grind each grinding stone. This is a twin-head grinding machine sizing control method that controls the advance and retreat movement of each grinding wheel base according to the dimensions of each machining location measured by each sizing device, and the final spark-out grinding process in step before performing, by a predetermined amount retracting the first said wheel head corresponding to the detected machining spot that reaches the first of the target dimension is grinding by the grinding wheel by a first of the measuring device, the The second abrasive The second said wheel head, which has been reached in the grinding target dimension corresponds with machining spot detected by the second of the measuring device by a predetermined amount retracted by the first, second the wheel head is Tokoro After the fixed amount of retreat, the first and second grinding wheel heads are simultaneously advanced to perform grinding in the final spark-out grinding process.

The structural features of the invention according to claim 4 are: a workpiece support device that rotatably supports a workpiece having a plurality of different machining locations; a plurality of tool tables provided with tools; and A table that is slidably mounted in the front-rear direction and in which each tool is indexed in the longitudinal direction at a position facing and aligned with each machining location, and a plurality of sizing devices that measure the dimensions of each machining location machined by each tool And each tool base is independently moved back and forth so that each tool processes the different processing points, and each tool is measured according to the size of each processing point measured by each sizing device. A machine tool control device for controlling advancing and retreating of a table, wherein the first sizing device detects that it has been processed by the first tool and has reached a target dimension in a step before the final step. Pair with location First the tool post by a predetermined amount retracted, the second of the tool stand that has reached the processed target dimension by a second of the tool corresponding to the machining spot, which is detected by the second of the measuring device for And a control device that performs the final process by simultaneously moving the first and second tool tables forward after the first and second tool tables have moved back by a predetermined amount.

In the invention according to claim 1 configured as described above, the respective tool stands are moved back and forth independently so that the respective tools respectively process different processing portions of the workpiece. The first tool table corresponding to the machining location detected by the first sizing device is processed by the first tool in the current process and detected to have reached the target dimension by a predetermined amount, and processed by the second tool. The second tool base corresponding to the machining location detected by the second sizing device to reach the target dimension is retracted by a predetermined amount, and after the first and second tool bases have retracted by a predetermined amount , The second tool rest is advanced simultaneously to perform the next process. As a result, different machining locations of the same workpiece can be simultaneously and independently machined by independent back and forth movements of a plurality of tool stands, and the machining resistance applied to the workpiece in the next process becomes uniform. There is no risk of adversely affecting the circularity and the like, and high-precision machining can be performed.

In the invention according to claim 2 configured as described above, it corresponds to the machining position detected by the first sizing device that the target dimension has been processed by the first tool in the previous process of the final process. The first tool base is retracted by a predetermined amount, and the second tool base corresponding to the machining location detected by the second sizing device is processed by the second tool and has reached the target dimension by a predetermined amount. is, first, the first after the second tool post is retracted a predetermined amount, since advanced second tool post to simultaneously perform processing in the final step, high first, the finish dimension of the second machining position It can be processed with high accuracy.

In the invention according to claim 3 configured as described above, the first and second grindstone bases are independently moved back and forth so that each grindstone grinds different machining points of the workpiece. The first grindstone table corresponding to the machining location detected by the first sizing device that has been ground by the first grindstone and reached the target dimension in the previous process of the final spark-out grinding process is retracted by a predetermined amount. The second grindstone table corresponding to the machining location detected by the second sizing device after being ground by the second grindstone and having reached the target dimension is retracted by a predetermined amount, and the first and second grindstone tables After the predetermined amount of retraction, the first and second grinding wheel heads are simultaneously advanced to perform the grinding process in the final spark-out grinding process. As a result, different machining points of the same workpiece can be simultaneously and independently ground by independent back and forth movements of the first and second grinding wheel platforms, and the workpiece is applied to the workpiece in the final spark-out grinding process. Since the grinding resistance becomes uniform, there is no possibility of adversely affecting the roundness and the like, and the finishing dimensions of the first and second machining locations can be ground with high accuracy.

In the invention which concerns on Claim 4 comprised as mentioned above, each tool stand is independently moved back and forth so that each tool may each process the process location from which a workpiece differs. The first tool table corresponding to the machining location detected by the first sizing device that has been processed by the first tool and reached the target dimension in the previous process of the final process is retracted by a predetermined amount, and the second tool After the second tool rest corresponding to the machining position detected by the second sizing device is processed by the second sizing device and is moved back by a predetermined amount, after the first and second tool stands are moved back by a predetermined amount. The first and second tool rests are simultaneously advanced to perform the final process. As a result, different machining points of the same workpiece can be simultaneously and independently machined by independent back-and-forth movements of the first and second tool stands, and the machining resistance applied to the workpiece in the final process is uniform. Therefore, there is no possibility of adversely affecting the roundness and the like, and high-precision machining can be performed.

  An embodiment in which the machine tool sizing control method of the present invention is applied to a twin head crankpin grinding machine will be described below with reference to FIGS.

  As shown in FIG. 1, the twin head crankpin grinding machine is provided with grinding wheel bases 8 and 9 which are two right and left machining heads so as to be slidable in the left and right directions and the front and rear directions. A headstock 18 and a tailstock 17 that support a crankshaft W, which is a workpiece, are installed at positions parallel to the axis. That is, on the bed 1, a right Z-axis table 6 for placing the right grindstone table 8 on the Z-axis guide rail 2 in the longitudinal left-right direction (Z-axis direction) is slidably provided by the feed screw 3. In the same row, a left Z-axis table 7 on which the left grindstone base 9 is placed in the left-right direction (Z-axis direction) on the bed 1 is slidably provided by a feed screw 4. In each of the left and right Z-axis tables 6 and 7, grindstone tables 8 and 9 provided with grindstones 14 and 15 are rotatably driven in a longitudinal direction (X-axis direction) orthogonal to the longitudinal left-right direction (Z-axis direction). The feed screws 12 and 13 are slidably provided.

  A headstock 18 and a tailstock 17 are installed in the front longitudinal direction of the left and right grindstone heads 8 and 9, and a crankshaft W, which is a workpiece, is supported by a pair of centers therebetween. The spindle stock 18 is provided with a servo motor 18M for driving the rotation of the crankshaft so that the shaft end of the crankshaft W can be gripped and rotated by a chuck or the like. It is configured to support the W core.

  Each feed screw is provided with a servo motor with an encoder, and is controlled by a control device described later. That is, a servo motor 60 with an encoder 70 is provided at the end of the feed screw 3 for moving the right Z-axis table 6 on which the right grindstone table 8 is placed in the longitudinal left-right direction (Z-axis direction). The feed screw 4 for the axis table 7 is provided with a servo motor 68 with an encoder 72. On the left and right Z-axis tables 6 and 7, servo motors 44 with encoders 50 and 52 are attached to end portions of feed screws 12 and 13 for sliding in the front-rear direction (X-axis direction) of the grinding wheel bases 8 and 9, respectively. 48 is provided. The grindstones 8 and 9 are supported so that the grindstones 14 and 15 are rotationally driven. Of course, a driving motor for driving the grindstone is built in the grindstone tables 8 and 9.

  The schematic configuration of the twin head crankpin grinding machine according to the embodiment of the present invention is as described above. The crankshaft W as a workpiece is supported between the headstock 18 and the tailstock 17, and the left and right Z axes The tables 6 and 7 are indexed by the servo motors 60 and 68 at the positions where the grindstones 14 and 15 are aligned and opposed to the processing positions of the crankshaft W, in FIG. 1, the crankpins CP (A) and CP (C). Next, the spindle drive servomotor 18M with the encoder 18E of the headstock 18 is rotated to control and rotate the crankshaft W. At that time, the crankshaft W is rotated about the axis of the bearing portion, that is, the center of the journal CP (e), so that the crank pins CP (a) to CP (c) which are machining points are centered on the journal CP (e). Will make a revolving turning motion. The X-axis direction feed screws 12 and 13 on the left and right tables 6 and 7 are moved forward and backward by the servo motors 44 and 48, respectively. At that time, since the crankpins CP (A) and (C) which are the machining locations are revolving and rotating, the grindstones 8 and 9 are moved back and forth in synchronization with the rotation of the spindle servomotor 18M by the control means. 14 and 15 are used for grinding. In accordance with the grinding operation, the servo motors 44 and 48 of the grinding wheel bases 8 and 9 give a cutting forward motion, and operate to gradually finish to the final finished dimensions.

  Further, in the twin head crankpin grinding machine of the embodiment of the present invention, a sizing device 20 is placed on the upper surface of each grindstone base 8 and 9 as shown in FIG. 2 in order to control the finishing dimension. Yes. This sizing device 20 is a well-known following type sizing device (for example, manufactured by Marposs, Italy) of a type that measures the dimensions of a processing part by following the crank pin that revolves and turns continuously. This will be described with reference to FIG.

  A support member 21 of the sizing device 20 is placed on the upper surface of the grindstone table 9, and a second arm 23 is pivotally supported at the tip of a first arm 22 that is pivotally supported by the support member 21 and extends forward of the grindstone 15. A measuring rod 28 for measuring is fixed to the tip of the second arm 23 at a right angle. The measuring rod 28 is composed of a V block 25 fixed to the tip thereof and in contact with the outer periphery of a crank pin CP (c) as a machining location, and a probe 27 provided at the center thereof so as to be able to advance and retract. The forward / backward movement is electrically detected and output as an electrical signal.

  A guide member 26 is fixed to the tip of the V block 25, and serves as a guide for engaging the V block 25 of the measuring rod 28 with the crankpin CP (c). The sizing device 20 is provided with an operating device for moving the measuring rod 28 to a rest position (two-dot chain line position) and a measurement position (solid line position).

  A hydraulic cylinder 31 is provided on the upper surface of the grindstone base 9, and the operation piece 30 mounted perpendicularly and offset to the rear end of the first arm 22 is pressed by the piston 32 of the cylinder 31 to thereby provide the first. The arm 22 is rotated upward and maintained at a rest position indicated by a two-dot chain line in FIG. At this time, since the second arm 23 is only pivotally supported at the tip of the first arm 22, the position cannot be maintained. Therefore, the third arm 24 is fixed below the tip of the first arm 22. The position of the second arm 23 is maintained at the rest position by the support protrusion 29 at the tip of the arm 24. When the measuring rod 28 is gradually lowered by returning the piston 32 of the hydraulic cylinder 31 from the rest position of the two-dot chain line and comes to the position of the crankpin CP (c), the guide member 26 is first moved to the crankpin CP (c). The crank pin CP (c) is engaged with the V block 25 along the guide member 26, and at this time, the second arm 23 is free to move away from the support protrusion 29 of the third arm 24. It can be turned. That is, the V block 25 is always engaged as the crankpin CP (c) revolves along a locus indicated by a one-dot chain line.

  Next, a control device for a twin head crankpin grinder according to an embodiment of the present invention will be described. As shown in FIG. 3, the present control system includes a numerical controller device 78. The numerical controller 78 includes a right grinding wheel control CPU 80, a left grinding wheel control CPU 90, a ROMI 09, and a RAM 111 that are connected to each other via a bus 88. It is configured to be connectable to.

  An X-axis servo motor control circuit 84 and a Z-axis servo motor control circuit 86 are connected to the right grinding wheel control CPU 80 via an interface 82. A right X-axis servo motor 44 is connected to the X-axis servo motor control circuit 84, and the encoder 50 is arranged on the right X-axis servo motor 44 as described above. A motor control circuit 84 is connected. The Z-axis servo motor control circuit 86 is connected to the right Z-axis servo motor 60, and the right Z-axis servo motor is provided with the encoder 70 described above. The encoder 70 is connected to the Z-axis servo motor control circuit 86. It is connected to the.

  Further, an X-axis servo motor control circuit 94, a Z-axis servo motor control circuit 96, and a main-axis servo motor control circuit 98 are connected to the left grindstone control CPU 90 via an interface 92. A left X-axis servo motor 48 is connected to the X-axis servo motor control circuit 94, and an engoer 52 is disposed in the left X-axis servo motor 48, and the encoder 52 includes an X-axis servo motor control circuit 94. It is connected to the. The Z-axis servo motor control circuit 96 is connected to the left Z-axis servo motor 68, and the left Z-axis servo motor is provided with an encoder 72. The encoder 72 is connected to the Z-axis servo motor control circuit 96. ing.

  The spindle servo motor control circuit 98 is provided with a spindle servo motor 18M. The spindle servo motor 18M is provided with an encoder 18E. The encoder 18E is connected to the spindle servo motor control circuit 98. . Further, an input / output device 107 having a CRT 103 and a numeric keypad 105 is connected to the bus 88 via an interface 101. The ROM 109 stores system control programs and the like, and the RAM 111 stores processing programs and the like. In addition to the numerical control device 78, a sequence controller 112 is connected to the bus 88 via an interface 113, and the left and right sizing devices 20L and 20R provided on both the left and right grinding wheel platforms include A-D converters. It is connected via the interface 114.

  Next, a specific control method that is a feature of the present invention will be described with reference to the flowchart of FIG. 4 showing the control steps. First, indexing is performed in order to align the left and right grinding wheel bases 8 and 9 with the crank pins CP (A) and CP (C) at the machining locations in accordance with a signal of machining start 120 (121). Next, both the grinding wheel bases 8 and 9 are fast-forwarded and advanced (122), and the grinding wheel bases 8 and 9 are coarsely fed from the stage where the grinding stones 14 and 15 come into contact with the processed portions of the crank pins CP (A) and CP (C). Advancement (123) is made, and the advancement of the grindstone table 20 is stopped once after a certain amount of grinding, and the sizing device 20 is inserted into the respective crank pins CP (A) and CP (C) (124). Then, fine grinding feed forward (125) is performed to perform fine grinding.

  In precision grinding, the dimension value is measured by the sizing device 20, and when one of the crank pins (for example, CP (a)) reaches the target dimension for finishing the precise grinding, that is, the sizing from either one of the sizing devices 20 is performed. When a signal is output (126), the corresponding grindstone base 8 is retracted (127) by a predetermined amount of 0.1 mm to 0.5 mm, and the grindstone 14 is separated from the crankpin CP (A). In the meantime, the other grinding wheel base 9 continues to perform precision grinding, and when the other crank pin CP (c) reaches the target dimension for finishing fine grinding (128), that is, from the other sizing device 20. When the fixed-size signal is output, the corresponding grindstone base 9 is also retracted (129) by a predetermined amount of 0.1 mm to 0.5 mm, and the grindstone 15 is separated from the crankpin CP (c).

  At the same time, both the grindstone heads 8 and 9 are advanced (130) by the retracted amount (0.1 mm to 0.5 mm), and at the same time, the spark-out (131) is performed, and the crank pins CP (A) and CP (C) After the grinding process is finished and the left and right grinding wheel platforms 8 and 9 are retracted by a certain amount (132), the sizing device is returned to the rest position (133), and the grinding wheel platforms 8 and 9 are retracted (134). Further, in step (135), when grinding of the next crank pins CP (B) and CP (D) remains (NO), the process returns to the first step again, and both wheel heads are connected to the crank pins. The grinding wheel bases 8 and 9 are indexed to positions to be aligned with CP (B) and CP (D) (121), the same grinding cycle is executed, and when grinding of all the crank pins is completed, both grinding wheel bases are restored to the original positions. Return to position (136) and all grinding cycles are completed (137).

  The above grinding cycle is shown in FIG. 5. The upper line shows the amount of cut by the left and right grinding wheel bases 8 and 9, and the lower line shows the diameter change of the crank pins CP (A) and CP (C). . Note that the upper line in FIG. 5 only shows the cutting amount of the grinding wheel head, and as described above, the grinding wheel bases 8 and 9 move back and forth in the X-axis direction in synchronization with the turning motion of the crank pin CP. However, a desired cutting amount is given and grinding is performed.

  From the stage (a) where the grindstone comes into contact with the machining portion from the rapid feed forward, the coarse grinding feed forward is performed for about 8 revolutions of the crank pin CP, and the advance of the grindstone base 20 is stopped and fixed once from the stage (b) after a fixed amount of grinding. The sizing device 20 is inserted (b to c), and then the dimension measurement is performed by the sizing device 20 while the crankpin is ground for about 5 rotations in the fine grinding feed forward. When the precision grinding finish target dimension is reached first, the grindstone base 8 corresponding to the crankpin CP (A) is retracted by a predetermined amount (0.1 mm to 0.5 mm) at (d1) (e1), The crankpin CP (c) is continuously subjected to precise grinding, and when the precision grinding finish target size is reached (d2), the grindstone base 9 corresponding to the crankpin CP (c) is also set to a predetermined amount (0.1 mm). Retreat (e2). Note that the lengths between d1-e1-f1-g1 and d2-d2-f1-g1 in FIG. 5 are enlarged for easy understanding.

  And if it confirms that both whetstone bases 8 and 9 retreated, both these whetstone bases 8 and 9 shall be advanced simultaneously (f1-g1, f2-g2) by the retreated amount (0.1 mm-0.5 mm). Then, both the grindstones 14 and 15 simultaneously perform the spark-out for about one or two rotations of the workpiece, finish the grinding of the crankpins CP (i) and CP (c) (h1, h2), and retract the grindstone tables 8 and 9 .

  In the case of the present invention, different crankpins CP (A) and CP (C) are simultaneously ground by the two left and right grinding wheel bases 8 and 9 that are individually controlled, and the processing progress is different. Become. Therefore, the diameter dimension of each crankpin CP (A) and CP (C) follows a locus as shown by the lower line in FIG. The crank pins CP (A) and CP (C), which are the workpieces W, have a diameter before grinding of Db and a finished diameter of Df.

  The first rough grinding and then the fine grinding are performed, but the grinding work by the two grinding wheel bases 8 and 9 is not exactly the same, so there is a difference in the difference Δd1 and Δd2 between the dimension at the end of the rough grinding and the finishing dimension Df. Out. Therefore, if fixed-size grinding is performed during precision grinding, it will be understood that there is a difference in the time required to reach the target dimension (Df + Δd3) for completion of precision grinding.

  At this time, the grinding wheel base 8 that has reached the target dimension for finishing fine grinding first is continued, and the next process is sparked out, that is, the cutting amount of the grinding wheel base 8 is made zero to eliminate the resistance from the grinding wheel 14 to the workpiece. Even if the finishing process for the deflection of the workpiece is performed, the workpiece W is still bent because the other grinding wheel base 9 is still incised during the fine grinding process. Therefore, the deflection of the workpiece W returns, that is, the spark-out performed in anticipation of springback is almost ineffective, and the spark-out cannot be performed as expected, and the finishing accuracy of the crankpin CP (A) Roundness will deteriorate.

  Therefore, as a feature of the present invention, the grindstone table 8 that has reached the fine grinding end target dimension first is retracted by a predetermined amount at one end, and waits until the other reaches the fine grinding end target dimension. At this time, the grindstone table 8 is not moving forward but moving back and forth in the X-axis direction according to the rotation of the workpiece. When the measurement dimension of the other crank pin CP (c) reaches the precision grinding target dimension, the corresponding grinding wheel base 9 is also retracted by a predetermined amount, so that the resistance applied to the workpiece W is eliminated and the workpiece is bent. Exclude.

  Thereafter, both the grinding wheel heads 8 and 9 are moved forward by the retracted amount, so that the workpiece W is simultaneously subjected to a spark-out for one to two revolutions, that is, grinding is performed by Δd3 corresponding to the deflection of the workpiece. (Δd3 in FIG. 5 is enlarged for easy understanding, and is actually a very small amount.) Therefore, since the load applied to the crankshaft W by the two grinding wheel bases is not biased at the time of sparking out, accuracy is improved. It is possible to perform a high final finishing process.

  Next, a second embodiment of the sizing processing control method according to the present invention will be described with reference to FIG. The outline is the same as in FIG. 4. First, indexing is performed in order to align the left and right grinding wheel bases with the crank pins CP (A) and CP (C), which are the machining locations, according to the signal of machining start (140) ( 141). Next, both the wheel heads 8 and 9 are fast-forwarded (142), and when the wheels come into contact with the processed parts of the respective crank pins, both wheel heads are moved forward to coarse grinding (143). The dimensioning device 20 is inserted into the crankpin portion (144). Then, the fine grinding is performed in the fine grinding feed forward (145) while measuring the dimensions. When one of the measured dimensions of the left and right crankpins CP (A) and CP (C) reaches the precision grinding target size first (146), the corresponding grinding wheel base 8 is retracted by a predetermined amount (147), The other crankpin CP (c), which is continuously performing the fine grinding, is kept waiting until the fine grinding finish target dimension is reached.

  Then, when the measured value of the other crank pin CP (c) reaches the precise grinding end target dimension (148), the grinding wheel base 9 which has been cut back by a predetermined amount with the cutting amount of the corresponding grinding wheel base 9 set to zero. 8 is advanced by the retreated amount (149), and both the grinding wheel heads perform a spark-out (150) for one or two rotations of the workpiece. At this time, while one of the grinding wheel bases 8 moves forward to a position where the sparking is performed, the other grinding wheel base 9 has a cut amount of zero, that is, is in a spark-out state, so there is a slight difference between the left and right spark-out times. However, there is no influence because the amount of retreat is very small. In addition, when the cutting amount of the final step, that is, the cutting amount of the fine grinding process is small (for example, φ2 μm / rev), since the load applied to the workpiece is small, the amount of bending is small, that is, the amount returned by springback is small Therefore, even if the spark-out time is somewhat longer, there is no particular effect on the processing accuracy and roundness.

  Subsequent operation steps (151) to (156) are the same as steps (132) to (137) in FIG. As a result, the time for retreating the grindstone can be shortened, so that the cycle time can be shortened.

  Next, a third embodiment of the sizing processing control method according to the present invention will be described with reference to FIG. Since the outline is the same as FIG. 4 and FIG. 6, only different points will be described. Steps (160) to (166) are the same as steps (120) to (126) in FIG.

When one of the left and right grinding wheel bases 8 and 9 first reaches the precision grinding target dimension in step (166), the left and right grinding wheel bases 8 and 9 are temporarily retracted by a predetermined amount (0.1 mm to 0.5 mm) ( 167). Then, only the grindstone table 9 on the side that has not yet reached the precise grinding target dimension is cut again and advanced (168), and when the precise grinding end target dimension is reached (169), it is retracted by a predetermined amount again (170), The grindstone bases 8 and 9 are simultaneously moved forward (171) by a predetermined amount, and the left and right grindstones 14 and 15 simultaneously spark out the crank pins CP (i) and CP (c) (172).

  The following steps (173) to (178) are the same as steps (132) to (136) in FIG. In the embodiment of FIGS. 4 and 5, when the grindstone table 8 on the side that has previously reached the precision grinding target dimension is retracted, the resistance applied to the workpiece W changes and the amount of deflection of the workpiece W changes. Therefore, a change in the bending during the fine grinding process in the other grinding wheel table 9 may affect the machining accuracy. However, according to the third embodiment shown in FIG. Since the left and right grindstone heads are simultaneously retracted and the remaining grinding is performed again when the diameter reaches a fixed size, more accurate grinding can be performed.

  Next, a fourth embodiment of the sizing processing control method according to the present invention will be described with reference to FIG. The outline is the same as that in FIG. 4, and sizing control is also performed in rough grinding. First, indexing is performed in order to align the left and right grinding wheel bases 8 and 9 with the crank pins CP (A) and CP (C), which are the machining locations, in accordance with a signal of machining start (180) (181). Next, both the grinding wheel bases 8 and 9 are fast-forwarded and moved forward (182), and the grinding wheels 14 and 15 come into contact with the processed portions of the respective crank pins CP (A) and CP (C) to process the black skin on the workpiece surface. Then, the sizing device 20 is inserted into the crankpins CP (A) and CP (C) (183). Then, while performing the dimension measurement, both grinding wheel heads are moved forward in rough grinding (184), and either one of the measured dimensions of the left and right crank pins CP (A) and CP (C) is set to the target dimension for finishing rough grinding first. When it reaches (185), the corresponding grindstone table 8 is retracted by a predetermined amount (186), and waits until the other crankpin CP (c) reaches the rough grinding end target dimension.

  When the measured value of the other crank pin CP (c) reaches the rough grinding end target dimension (187), the one grindstone table 8 that has been retracted by a predetermined amount is advanced (188), and the left and right grindstone tables 8, Then, 9 is finely fed, and the crankpins CP (A) and CP (C) are finely ground (189). Hereinafter, steps (190) to (201) are the same as those in the first embodiment of FIG. Therefore, even when the total machining allowance is small, there is no influence of bending, and more accurate grinding can be performed.

  (Other Embodiments) Although the above embodiment is applied to a twin head crankpin grinding machine, the machining control method of the present invention is not limited to the crankpin grinding, and two or more of the same workpiece are used. Can be applied to any part that can be processed at the same time, such as simultaneous processing of crank pins and journals, cylindrical grinders capable of plunge cutting, cam grinders, pin mirrors and cam mirrors using cutter tools It is.

The top view of the twin head crankpin grinder of this invention. The side view showing the sizing apparatus in the twin head crankpin grinding machine of this invention. The block diagram which shows the fixed-size process control apparatus of the twin head crankpin grinding machine of this invention. The control flowchart of the sizing process control of the twin head crankpin grinding machine of this invention. FIG. 3 is a cycle diagram of sizing processing control of the twin head crankpin grinding machine of the present invention. The control flowchart of the sizing processing control method in 2nd Embodiment. The control flowchart of the sizing processing control method in 3rd Embodiment. The control flowchart of the sizing processing control method in 4th Embodiment.

Explanation of symbols

1: Bed 8: Right grinding wheel base 9: Left grinding wheel base 14: Right grinding wheel 15: Left grinding wheel 17: Tailstock 18: Spindle base 22: Sizing device 25: V block 28: Measuring rod 27: Probe 78: Numerical control apparatus

Claims (4)

A workpiece having a plurality of different machining locations is rotatably supported, and a plurality of tool stands provided with tools are indexed to positions where each tool is aligned and opposed to each machining location, and each tool has the different machining locations. Each tool base is moved back and forth independently so as to process each, and a plurality of sizing devices are provided to measure the dimensions of each machining site processed by each tool, and each machining measured by each sizing device A machining control method for a machine tool that controls the forward / backward movement of each tool table according to the size of a part,
In the current step, the first tool table corresponding to the machining location detected by the first sizing device to be processed by the first tool and having reached the target dimension is retracted by a predetermined amount, and the second The second tool table corresponding to the machining location detected by the second sizing device that has been processed by the tool and reached the target dimension is retracted by a predetermined amount, and the first and second tool tables are A sizing process control method for a machine tool , wherein the first and second tool rests are simultaneously advanced after a predetermined amount of retreat to perform the next process.   2. The sizing process control method for a machine tool according to claim 1, wherein the current process is a pre-process of a final process, and the next process is the final process. A workpiece having at least two machining points is supported so as to be rotationally driven, and two whetstone bases equipped with a grindstone are indexed to positions where each grindstone is aligned and opposed to each machining point, and each tool has the different machining points. Each grindstone stand is moved back and forth independently so as to grind each, and two sizing devices are provided to measure the dimensions of each machining point ground by each grindstone and measured by each sizing device. This is a twin-head grinding machine sizing control method that controls the forward and backward movement of each grinding wheel head according to the dimensions of each machining point, and is ground by the first grinding wheel in the previous process of performing the final spark-out grinding process. this it has reached the target size of the first of said wheel head and the corresponding machining spot detected by the first of the measuring device by a predetermined amount backward, reaches the target size is grinding by a second of said grinding wheel There is a second of said wheel head a predetermined amount backward corresponding to the machining spot, which is detected by the second of the sizing device, the first after the first, second the wheel head is retracted a predetermined amount, the second A method for controlling sizing of a twin head grinder, wherein the grinding wheel head is advanced simultaneously to perform grinding in the final spark-out grinding process. A workpiece support device that rotatably supports a workpiece having a plurality of different machining locations, a plurality of tool tables provided with tools, and the tool table slidably mounted in the front-rear direction. In a sizing control device of a machine tool comprising a table indexed in the longitudinal direction at a position facing and aligned with a machining location, and a plurality of sizing devices that measure the dimensions of each machining location machined by each tool,
Each tool table is independently moved back and forth so that each tool processes each of the different machining locations, and the forward / backward movement of each tool platform is controlled by the dimensions of each machining location measured by each sizing device. A control device for a machine tool , wherein a first portion corresponding to a machining location detected by the first sizing device that has been processed by the first tool and has reached a target dimension in a step preceding the final step . The tool base is retracted by a predetermined amount, and the second tool base corresponding to the machining location detected by the second sizing device is processed by the second tool and has reached the target dimension by a predetermined amount. And a control device for processing the final process by simultaneously advancing the first and second tool stands after the first and second tool stands are retracted by a predetermined amount. Sizing processing control device.

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