JP3836098B2 - Crank pin grinding method and grinding apparatus - Google Patents

Description

  The present invention relates to a method and apparatus for grinding a crankpin of a crankshaft.

A twin head crankpin grinding method that can grind crankpins at different portions of the crankshaft simultaneously and independently by two grinding wheel heads is already known from Japanese Patent Laid-Open No. 54-71495. The crank pin of the crankshaft, which is the machining part, pivots around the journal part of the crankshaft, so when machining while directly measuring the machining part, use the following sizing device, which will be described later, 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 the diameter reaches a predetermined dimension is adopted.
JP 54-71495 A

  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. As a result, the progress of the machining process varies between the grinding process by one of the grinding wheel platforms and the grinding process by the other grinding wheel platform. If grinding is performed with the progress of the machining process varied between the two grinding wheel platforms, the grinding resistance applied to the workpiece will be different and the workpiece will be bent. It will affect the roundness.

  Accordingly, an object of the present invention is to improve high-precision grinding, particularly finishing accuracy and roundness, in a grinding apparatus that simultaneously and independently grinds a plurality of crankpins of a crankshaft by at least two grinding wheel platforms. It is providing the grinding method and grinding apparatus which can be performed.

Therefore, in order to solve the above problems, at least a spindle head that rotates the crankshaft with the journal center as a rotation axis, and a grindstone that moves forward and backward independently from each other in a direction orthogonal to the rotation axis of the crankshaft. A method of simultaneously controlling each of two or more grindstone platforms and grinding a plurality of crankpins of the crankshaft at the same time, wherein the grinding of the process one stage before the final process has been completed. base of all of the wheel head grinding final step is suspended until the grinding of one step before the step of final step is completed, to initiate subsequent respective grinding of by that final step in the wheel head simultaneously Thus, the grinding process of the final process is completed at the same time, and then each grindstone table is retracted simultaneously .

Further, the crankpin grinding method of the present invention includes a headstock for rotationally driving the crankshaft with the journal center as a rotation axis, and a grinding wheel that moves forward and backward independently from each other in a direction perpendicular to the rotation axis of the crankshaft. Each of at least two or more grinding wheel bases is synchronously controlled, and includes at least a rough grinding process, a fine grinding process performed after the rough grinding process, and a final spark-out process performed after the fine grinding process. A method of simultaneously grinding a plurality of crankpins of the crankshaft according to the order of machining steps, wherein all the grinding wheel platforms perform a spark-out of the final grinding wheel table that has been previously ground in the precision grinding process. temporarily interrupted until the grinding of fine grinding step is completed, at the same time open spark-out subsequently that by the respective wheel head in the final step As spark-out of the last process is completed at the same time by, it is characterized in that to subsequently retract each wheel head of simultaneously.

  The present invention relates to a spindle head for rotationally driving a crankshaft around a journal center as a rotation axis, and at least two or more grinding wheel heads that move forward and backward independently from each other in a direction orthogonal to the rotation axis of the crankshaft and that have a grinding wheel In the case where a plurality of crankpins of the crankshaft are simultaneously ground by synchronously controlling each of the crankshafts, the grinding process in the final step of the grindstone table that has been finished in the grinding process of the step one step before the final step is performed. All the grinding wheel platforms were temporarily suspended until the grinding process of the process one stage before the final process was completed, and then the grinding process of the final process was simultaneously performed by each grinding wheel platform. Grinding resistance applied to each grinding point is almost uniform, and there is no risk of adverse effects on roundness, etc., and all crank pins are ground with high precision. It can be.

  Further, in the present invention, the crankpin of the crankshaft is determined by the order of at least the rough grinding process, the fine grinding process performed after the rough grinding process, and the final spark-out process performed after the fine grinding process. In the case of simultaneously grinding, the spark-out of the final process of the grinding wheel head that has finished the fine grinding process is temporarily suspended until all grinding wheel tables have finished the fine grinding process. In the final spark-out process, the grinding resistance applied to each grinding point of the workpiece becomes substantially uniform and there is no difference in the number of spark-outs. The finished dimensions of all crankpins can be ground with high accuracy without adversely affecting the above.

  An embodiment in which the crankpin grinding 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 grinding wheel bases 8 and 9, and a crankshaft W as 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, and is configured 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 known follow-up sizing device of a type that measures the dimensions of a machining location by following the crank pin that revolves and turns constantly, and will be described below 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 controller 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 AD 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 the signal is output (126), the grinding process by the corresponding grinding wheel base (in this embodiment, the grinding wheel base 8) is temporarily suspended (127). 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 grinding wheel base 9 also temporarily suspends the grinding process.

  Then, in order to perform the spark-out (131) at the same time, the grinding process by the grindstone tables 8, 9 which have been temporarily suspended is simultaneously started again (130). After finishing the grinding of the crankpins CP (A) and CP (C) and moving the left and right grinding wheel bases 8 and 9 back by a certain amount (132), the sizing device is returned to the rest position (133). 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) in which 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 from the stage (b) in which a fixed amount of grinding is performed. 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, grinding of the grinding wheel base 8 corresponding to the crankpin CP (A) is temporarily suspended (e1) and the other crankpin CP (C) is reached. Continues fine grinding, and when the fine grinding finish target dimension is reached (d2), the grinding wheel base 9 corresponding to the crankpin CP (c) also temporarily suspends grinding (e2). In this example, when temporarily interrupting the grinding process, when the spindle head and the grinding wheel base are synchronously controlled, the grinding wheel base is moved backward by a predetermined amount, and the grinding process is started again at the same time. Both wheel heads are simultaneously advanced by a predetermined amount. Also, the lengths between d1-e1-f1-g1 and d2-d2-f1-g1 in FIG. 5 are enlarged for easy understanding.

  Then, the grinding process by the grinding wheel bases 8 and 9 which have been temporarily suspended is started again at the same time, and the sparking is simultaneously performed by the grinding wheels 14 and 15 for about one to two rotations of the workpieces. ) Is finished (h1, h2), and the grinding wheel bases 8, 9 are moved backward.

  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 process 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, even if 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 set to zero, the other grinding wheel is used. Since the table 9 is still incised during the fine grinding, the workpiece W is bent due to the difference in grinding resistance. Therefore, the finishing accuracy and roundness of the crankpin CP (A) are deteriorated.

  Therefore, as a feature of the present invention, the grinding of the grinding wheel base 8 that has been finished in the precision grinding process is temporarily suspended until the other grinding wheel base 9 finishes the grinding work in the precision grinding process. Then, when the precise grinding process of the crankpin CP (c) by the other grindstone table 9 is completed, the corresponding grindstone table 9 also temporarily suspends the grinding process, eliminates the resistance applied to the workpiece W, and deflects the workpiece. Exclude.

  Thereafter, the grinding process by the two grinding wheel bases 8 and 9 is started again at the same time, and at the same time, the workpiece W is subjected to a spark-out for one to two revolutions, that is, the grinding process is performed for 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 a crankpin grinding 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 machining locations, according to a machining start (140) signal ( 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), and are fixed after a certain amount of grinding. The dimensioning device 20 is inserted into the crankpin portion (144). And fine grinding is performed by fine grinding feed advance (145), performing dimension measurement. When one of the measured dimensions of the left and right crankpins CP (A) and CP (C) reaches the target dimension for finishing precise grinding first (146), the corresponding grinding wheel base 8 temporarily suspends grinding (147). And wait until the other crankpin CP (c), which is continuously performing the fine grinding, reaches the fine grinding end target dimension.

  Then, when the measured value of the other crank pin CP (c) reaches the target size for finishing the precise grinding (148), the grinding wheel base 8 where the cutting amount of the corresponding grinding wheel base 9 is set to zero and the grinding process is temporarily interrupted. Grinding is started (149), and both the grinding wheel heads perform a spark-out (150) for one to two rotations of the workpiece. At this time, until one of the grinding wheel bases 8 starts grinding, the other grinding wheel base 9 has a cut amount of zero, that is, is in a spark-out state, so that there is a slight difference between the left and right spark-out times. There is no influence. 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 temporarily interrupting the grinding process can be shortened, so that the cycle time can be shortened.

  Next, a third embodiment of a crankpin grinding 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 platforms 8 and 9 reaches the precision grinding target dimension first in step (166), the grinding process by the left and right grinding wheel platforms 8 and 9 is temporarily suspended. Then, only the grinding wheel base 9 on the side that has not yet reached the precision grinding target dimension is ground again (168). When the precision grinding finish target dimension is reached (169), the grinding process is temporarily suspended again (170), Grinding is again started at the same time using the grinding wheel bases 8 and 9, and the crankpins CP (i) and CP (c) are simultaneously sparked out by the left and right grinding wheels 14 and 15 (172). In step 170, as described in the second embodiment, the grinding process of the grindstone table 9 may be continued without being temporarily interrupted, and the spark-out may be continuously performed.

  The following steps (173) to (178) are the same as steps (132) to (136) in FIG. In the embodiment shown in FIGS. 4 and 5, when the grinding process of the grindstone table 8 on the side that has reached the fine grinding target dimension is temporarily interrupted, the resistance applied to the workpiece W changes, and the deflection amount of the workpiece W changes. However, since the bending may change during the fine grinding process in the other grinding wheel base 9, the processing accuracy may be affected. However, according to the third embodiment shown in FIG. For example, when one of them reaches a fixed size, the grinding process is temporarily interrupted at the same time on the left and right grindstone heads, and the remaining grinding is performed again. Therefore, more accurate grinding can be performed.

  Next, a fourth embodiment of a crankpin grinding 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 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 temporarily stops the grinding process (186), and waits until the other crank pin CP (c) reaches the target dimension for finishing the rough grinding.

  When the measured value of the other crank pin CP (c) reaches the rough grinding end target dimension (187), one of the grinding wheel bases 8 for which grinding has been temporarily suspended is advanced (188), and the left and right grinding wheel bases are moved forward. 8 and 9 are fed forward with fine grinding to perform fine grinding of the crank pins CP (A) and CP (C) (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.

  In the above-described embodiment, when the grinding process is temporarily interrupted, the example in which the grindstone table is retracted by a predetermined amount in a state in which the headstock and the grindstone table are synchronously controlled has been described. However, the present invention is not limited thereto. It is not something. That is, when the grinding process is temporarily interrupted, the longitudinal movement of the grinding wheel head in the X-axis direction may be stopped without synchronously controlling the headstock and the grinding wheel base.

  Moreover, although the above-mentioned Example demonstrated the twin head crankpin grinder with two whetstone stands, this invention is applicable also to the grinder provided with two or more whetstone stands.

  Moreover, although the above-mentioned Example demonstrated the case where the last process was a spark-out with the cutting amount of zero, it is not limited to it. That is, the present invention is also applied to the grinding process in which the final process gives the cut amount. And in that case, as a method of temporarily interrupting the grinding process, in addition to the above-described method of retracting the grindstone table by a predetermined amount, synchronous control is performed so as not to give a cutting amount without retreating the grindstone table by a predetermined amount, After all the grinding wheel heads have finished the grinding process of the process one stage before the final process, the grinding process of the final process may be performed by giving a cutting amount at the same time.

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 control apparatus of the twin head crankpin grinding machine of this invention. The flowchart of the twin head crankpin grinding machine of this invention. The cycle diagram of the twin head crankpin grinding machine of this invention. The flowchart of the grinding method of the crankpin in 2nd Embodiment. The flowchart of the grinding method of the crankpin in 3rd Embodiment. The flowchart of the grinding method of the crankpin 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 (2)

A headstock for rotationally driving the crankshaft around the journal center as a rotation axis, and each of at least two or more grinding wheels provided with a grinding wheel and moving back and forth independently in a direction orthogonal to the rotation axis of the crankshaft. A method of synchronously controlling and grinding a plurality of crankpins of the crankshaft at the same time,
First, the grinding process of the final stage of the grinding wheel head that has completed the grinding process of one stage before the final process is suspended until all grinding wheel bases finish the grinding process of the first stage of the final process, and then the final grinding step is to end at the same time, grinding method of the crank pin, characterized in that to subsequently retract each wheel head of simultaneously by starting each the grinding by that final step in the wheel head simultaneously. A headstock for rotationally driving the crankshaft around the journal center as a rotation axis, and each of at least two or more grinding wheels provided with a grinding wheel and moving back and forth independently in a direction orthogonal to the rotation axis of the crankshaft. A plurality of crankshafts are controlled according to the sequence of at least a rough grinding process, a fine grinding process performed after the rough grinding process, and a final spark-out process performed after the fine grinding process by synchronous control. A method of grinding a crankpin at the same time,
Previous all wheel head spark-out of fine grinding step of grinding is finished wheel head in the final step is suspended until the grinding fine grinding step is terminated, subsequently that by the respective wheel head in the final step A crankpin grinding method, characterized in that the spark-out of the final step is completed simultaneously by starting the spark-out simultaneously, and then the respective grindstone heads are simultaneously retracted .

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