JP2019076961A - Grinding machine and grinding method - Google Patents

Abstract

To provide a grinding machine and a grinding method which can improve grinding processing accuracy.SOLUTION: A control device 31 of a grinding machine 1 determines an eccentricity amount d of a shaft line of a work-piece W to be grinding-processed corresponding to deformation force F applied in a radial direction of the inputted work-piece W to be grinding-processed while referring to a correlation between the predetermined deformation force F applied in the radial direction of the work-piece W and the eccentricity amount d of the shaft line of the work-piece W, and controls feed motion of feeding devices 24 and 25 while adding the eccentricity amount d, so that the work-piece W to be grinding-processed is grinding-processed with a grinding wheel 28.SELECTED DRAWING: Figure 12

Description

  The present invention relates to a grinding machine and a grinding method.

  Patent documents 1 and 2 describe a grinder which clamps a work and performs grinding. This grinding machine measures the eccentricity etc. of the rotation axis of the workpiece, and performs the grinding process of the workpiece based on this eccentricity etc.

Patent No. 4637106 Patent No. 3559924 gazette

  In the above-mentioned grinder, a workpiece is clamped and grinding processing is performed. That is, both ends of the workpiece are pressurized and supported by the center of the spindle stock and the center of the tailstock, and one end of the workpiece is held by a chuck to perform grinding. However, when the workpiece is gripped by the chuck in an inclined state, the workpiece is bent and deformed when it is pressure-supported at the center, and the rotation axis of the workpiece is eccentric.

  Then, if the workpiece is ground while the rotational axis of the workpiece is eccentric, the deformation stress is released when the pressure support of the center is released after the grinding, even if grinding is performed with high accuracy. Since the eccentricity of the rotation axis of the object is returned, the grinding processing accuracy is deteriorated.

  This invention is made in view of such a situation, and an object of this invention is to provide the grinder and grinding method which can improve grinding processing precision.

(Grinder)
The grinding machine of the present invention rotatably supports a grinding wheel, holds a grinding wheel head having a grinding wheel drive motor for rotating the grinding wheel, and holds one end of a workpiece by a chuck and rotatably supports it. A headstock having a workpiece drive motor for rotationally driving a workpiece, a tailstock for pressing and supporting the other end of the workpiece at a center, and the workpiece in a direction intersecting the rotational axis of the workpiece The grinding apparatus further includes: a feeding device relatively moving the grinding wheel closer to and away from each other; and a control device configured to grind the workpiece with the grinding wheel by controlling a feeding operation of the feeding device.

  The control device includes a storage device, an input device for inputting the shape of the workpiece and storing the shape in the storage device, and the pressure direction of the workpiece by pressure support of the center based on the shape of the workpiece. A first computing device for determining the amount of eccentricity of the axis of the workpiece due to the deformation force applied to the surface and the deformation force, and storing the correlation between the deformation force and the amount of eccentricity in the storage device; Based on the measurement value from the measuring device, the deformation force applied in the radial direction of the workpiece to be ground by the pressure support of the center is determined by pressure support of the center and stored in the storage device. A second calculation device for determining the radial movement amount of the workpiece to be ground by the pressure support of the center based on the measurement value from the measurement device provided on the object and storing the movement amount in the storage device; The deformation force and the front With reference to the correlation with the amount of eccentricity, the amount of eccentricity of the axis line of the workpiece for the current grinding process corresponding to the input deformation force applied in the radial direction of the workpiece for the current grinding processing is obtained, or And a third computing device for obtaining the movement amount as an eccentricity of the axis of the workpiece to be ground and to store it in the storage device, and adding the eccentricity of the axis of the workpiece to be ground. By controlling the feed operation of the feed device, the grinding wheel is used to grind the workpiece to be ground.

(Grinding method)
The grinding method for grinding a workpiece with the grinder according to the present invention includes the step of inputting the shape of the workpiece and the diameter of the workpiece by the pressure support of the center based on the shape of the workpiece. The first calculation process of determining the amount of eccentricity of the axis of the workpiece due to the deformation force applied in the direction and the deformation force, and determining the correlation between the deformation force and the amount of eccentricity, and the measuring device provided at the center Based on the measured value, the deformation force applied to the radial direction of the workpiece to be ground by the pressure support of the center is determined by the pressure support of the center, or to the measurement value from the measuring device provided on the workpiece to be ground by the current grinding Based on the second operation process for determining the radial movement amount of the workpiece to be ground by the pressure support of the center based on the center, and the correlation between the deformation force and the eccentricity, the second calculation step is input. Subject to grinding A third operation step of determining the eccentricity of the axis of the workpiece to be ground corresponding to the deformation force applied in the radial direction of the workpiece, or determining the movement as the eccentricity of the axis of the workpiece; A processing step of grinding the workpiece to be subjected to the current grinding process by the grinding wheel by controlling the feed operation of the feed device in consideration of the eccentricity of the axis line of the workpiece to be subjected to the current grinding process; Equipped with

  According to the grinding machine and the grinding method of the present invention, the feed operation of the grinding wheel is controlled based on the eccentricity of the axis of the workpiece obtained from the deformation force applied in the radial direction of the workpiece. It is possible to perform accurate grinding on the machined workpiece and to improve the grinding accuracy.

It is a top view of a grinding machine in an embodiment of the present invention. It is the figure which looked at the crankshaft of grinding object from the radial direction. It is a figure which shows the structure of the control apparatus of the grinding machine of FIG. It is a flowchart for demonstrating the operation | movement of the control apparatus of FIG. It is a flowchart for demonstrating the grinding method of a crankshaft. It is the figure which looked at the state which pressed and held the crankshaft by the center from the radial direction. It is the figure which looked at the state which hold | gripped and deformed the crankshaft with the chuck | zipper from the radial direction. It is the figure which looked at the eccentric state of the crank pin when holding and deforming a crankshaft with a chuck | zipper from the axial direction of a crankshaft. It is a figure which shows the table which matched the eccentricity amount of each grinding process site | part when changing the deformation force with respect to a crankshaft, and a phase. It is a figure which shows the graph which took the deformation | transformation force on the horizontal axis, and took the eccentricity on the vertical axis | shaft and represented the table of FIG. 8 by the spline curve. It is a figure which shows the deformation force concerning the crankshaft of grinding object calculated | required from distortion of a center, and the phase of the said deformation force. It is the figure seen from the axial direction of the crankshaft. When the phase of a crank journal is 0 degree, it is a figure which shows the positional relationship of the rotation center of a crank journal, the center of a crank pin, and the rotation center of a grinding wheel. When the phase of a crank journal is 90 degrees, it is a figure which shows the positional relationship of the rotation center of a crank journal, the center of a crank pin, and the rotation center of a grinding wheel. When the phase of a crank journal is 180 degrees, it is a figure which shows the positional relationship of the rotation center of a crank journal, the center of a crank pin, and the rotation center of a grinding wheel. When the phase of a crank journal is 270 degrees, it is a figure which shows the positional relationship of the rotation center of a crank journal, the center of a crank pin, and the rotation center of a grinding wheel. In order to explain the method of calculating the feed position of the grinding wheel during grinding, it is a diagram showing the positional relationship between the rotation center of the crank journal, the center of the crank pin, and the rotation center of the grinding wheel. FIG. 5 is a layout diagram of an eddy current distance sensor that measures the amount of movement of the crank pin in the X-axis direction and the amount of movement in the Y-axis direction of the crankshaft currently subjected to grinding processing.

(1. Configuration of grinding machine)
A twin head grinder will be described as an example of the grinder according to the present embodiment with reference to the drawings. In the following description, as shown in FIG. 2, a workpiece to be ground by the grinding machine 1 is exemplified by a single plane crankshaft W of four cylinders in series, and the ground portion is a crank pin P1- P4 and crank journal J1-J5.

The crank pins P1 to P4 are formed in a cylindrical shape having a central axis Lp radially offset from the central axis Lj of the cylindrical crank journal J1 to J5.
As shown in FIG. 1, in the grinding machine 1, a bed 11 is fixed on the floor, and a headstock 12 and a tailstock 13 supporting both ends of a crankshaft W rotatably are attached to the bed 11.

  A master spindle Cm (C-axis) is rotatably supported on the spindle stock 12, and a center 14 for supporting one end of the crankshaft W and a chuck 15 with three claws are attached to the tip of the master spindle Cm. The master spindle Cm is advanced and retracted in an axial direction parallel to the Z axis by an advancing and retracting drive device 16, and is rotationally driven about an axis parallel to the Z axis by a master servomotor 17 (workpiece driving motor) having an encoder 17a. .

  On the tailstock 13 a slave main shaft Cs (C axis) is rotatably supported coaxially with the master main shaft Cm, and a center 18 supporting the other end of the crankshaft W is attached to the tip of the slave main shaft Cs. A strain gauge SG (see FIG. 3, a measuring device) for measuring strain (measurement value) in the X-axis direction and the Y-axis direction is attached to the center 18.

  The slave spindle Cs is advanced and retracted in the axial direction parallel to the Z axis by the center pressing device 19, and is rotationally driven about an axis parallel to the Z axis in synchronization with the master spindle Cm by the slave servomotor 20 having the encoder 20a. Be done.

  The advancing and retracting drive device 16 includes a master moving motor 16a, a feed screw 16b, a guide 16c, a slider 16d, and a floating joint 16e. A feed screw 16b is connected to the motor shaft of the master movement motor 16a. The guide 16c is disposed parallel to and in parallel with the feed screw 16b.

  The feed screw 16b is screwed into the slider 16d, and the guide 16c is penetrated. Furthermore, the master main axis Cm is connected to the slider 16d via the floating joint 16e. The master main spindle Cm is advanced and retracted in the axial direction parallel to the Z-axis by the movement of the slider 16d along the guide 16c by the rotation of the feed screw 16b by the driving of the master moving motor 16a.

  The center pressure device 19 includes a slave movement motor 19a, a feed screw 19b, a guide 19c, a slider 19d, and a spring 19e. A feed screw 19 b is connected to the motor shaft of the slave movement motor 19 a. The guide 19c is disposed parallel to and in parallel with the feed screw 19b.

  The feed screw 19b is screwed into the slider 19d, and the guide 19c is penetrated. Further, the slider 19d presses the slave main spindle Cs toward the workpiece W via the spring 19e, and movably connects the slave main spindle Cs to the opposite side of the workpiece W via the stopper rod (not shown).

  The slave main shaft Cs is advanced and retracted in the axial direction parallel to the Z-axis by the movement of the slider 19d along the guide 19c by the rotation of the feed screw 19b by the drive of the slave movement motor 19a. Both ends of the crankshaft W are gripped by the chuck 15 and are moved at the centers 14 and 18 by axial movement parallel to the Z axis of the master main spindle Cm and the slave main spindle Cs by the forward / backward driving device 16 and the center pressing device 19. It is sandwiched and supported.

  Then, since the master main shaft Cm is fixed by the floating joint 16e so as not to move in the axial direction parallel to the Z axis with respect to the slider 16d, the slave main shaft Cs is Z by the center pressure device 19 so as to compress the spring 19e. By moving in the axial direction parallel to the axis, it is possible to apply a pressing force to the crankshaft W in accordance with the amount of compression of the spring 19 e.

  Further, in the bed 11, two tables 23 movable in the Z-axis direction by the Z-axis servomotor 21 having the encoder 21a and the feed screw 22 are provided side by side in the axial direction parallel to the Z-axis.

  Then, in each of the tables 23, an X-axis servomotor 24 (feed device) having an encoder 24 a and a feed screw 25 (feed device) in an axial direction parallel to the X-axis (a direction intersecting the rotation axis of the crankshaft W) Two movable grinding heads 26 capable of moving (approaching and moving away from the crankshaft W) are provided side by side in the axial direction parallel to the Z axis.

  A grinding wheel drive motor 27 rotatably supports the grinding wheel 28 on an axis parallel to the Z axis on each grinding wheel head 26, and a coolant nozzle 29 (FIG. 11A) for supplying coolant toward the grinding point Is provided). Further, the bed 11 is provided with a sizing device 30 that measures the diameter of the crankshaft W (crank pins P1-P4 and crank journals J1-J5).

  Furthermore, the grinding machine 1 is provided with a control device 31 that rotates the master main spindle Cm, the slave main spindle Cs and the grinding wheel 28 and controls the feeding operation of the grinding wheel 28 relative to the crankshaft W. The configuration of the control device 31 will be described in detail in the outline of the grinding method described below.

(2. Outline of grinding method)
As described in the background art, in the grinding machine 1, the crankshaft W is clamped for grinding. That is, both ends of the crankshaft W are pressure-supported by the center 14 of the headstock 12 and the center 18 of the tailstock 13, and one end of the crankshaft W is gripped by the chuck 15 for grinding.

  However, when the crankshaft W is held by the chuck 15 in a tilted state, the crankshaft W bends and is deformed when it is pressure-supported by the centers 14 and 18, and the central axis of the crank pins P1-P4 and the crank journal The rotation axis of J1-J5 is decentered. Then, if grinding is performed with this eccentricity occurring, even if grinding is performed with high accuracy, the deformation stress is released when the pressure support of the centers 14 and 18 is released after grinding, and the above-mentioned eccentricity returns Therefore, the grinding process accuracy is deteriorated.

  Therefore, in the control device 31 of the grinding machine 1 of the present embodiment, the deformation force applied to the crankshaft W to be ground and the center axis of the crank pin P1-P4 and the crank journal J1-J5 according to the phase of the deformation force. The amount of eccentricity of the rotation axis (hereinafter simply referred to as "the amount of eccentricity") and the phase of the amount of eccentricity (equivalent to the phase of the deformation force) are obtained, and the obtained amounts of eccentricity of the ground parts P1-P4 and J1-J5 are added. And grinding processing of each grinding process site | part P1-P4, J1-J5 is performed.

(3. Configuration and operation of control device)
Next, the configuration and operation of the control device 31 will be described in detail with reference to the drawings. As shown in FIG. 3, the control device 31 includes an input device 32, a first arithmetic device 33, a second arithmetic device 34, a third arithmetic device 35, and a storage device 36.

  The input device 32 inputs the shape of the crankshaft W and stores it in the storage device 36 (step S1 in FIG. 4, input step). The shape of the crankshaft W includes, for example, the axial length of the crankshaft W, the axial length of the crankpins P1 to P4, the shaft diameter, the eccentricity, the axial length of the crank journals J1 to J5, and the like.

  The first arithmetic unit 33 is based on the shape of the crankshaft W input from the input device 32 and the pressure applied to the center 18 input from the center pressure device 19, the deformation force applied to the crankshaft W and the deformation force Phase (step S2 in FIG. 4, first operation step), and the amount of eccentricity of each ground portion P1-P4, J1-J5 according to the determined deformation force and phase is determined by known three-dimensional analysis (FIG. Step S3 of 4, first operation step).

  Specifically, as shown in FIG. 6A, the crankshaft W is supported by the centers 14 and 18, and as shown in FIG. 6B, when held by the chuck 15, the crankshaft W intersects with the rotational axis Lw of the crankshaft W. It bends in the direction and deforms. The crank pins P1 to P4 are not shown.

  Then, as shown in FIG. 7, the eccentricity d of the center Opa1 of the crank pin Pa1 shown by the solid line after the deformation is applied to the center 18 with respect to the center Opb1 of the crank pin Pb1 shown by the two dotted chain line before the deformation. According to the deformation force F applied to the crankshaft W obtained based on the pressure and the phase φ of the deformation force F, it can be obtained by three-dimensional analysis. The amount of eccentricity of the other crank pins P2-P4 and the amount of eccentricity of the crank journals J1-J5 can be determined in the same manner.

  Then, the first computing device 33 creates a table of deformation force and eccentricity (step S4 in FIG. 4, first computing step), and creates a relational expression (correlation) consisting of spline curves based on the table. It memorize | stores in the memory | storage device 36 (FIG. 4 S5, 1st calculation process).

  Specifically, as shown in FIG. 8, a table (correlation) is created in which the amounts of eccentricity of the ground parts P1-P4 and J1-J5 are made to correspond when the deformation force F and the phase φ are changed. . Then, as shown in FIG. 9, a graph is created with the horizontal axis representing the deformation force F and the vertical axis representing the eccentricity d, and the relational expression (correlation) consisting of spline curves is calculated for each grinding site P1-P4, J1-. Lead about J5.

  The second arithmetic unit 34 obtains the deformation force applied to the crankshaft W to be ground and the phase of the deformation force based on the strain of the center 18 input from the strain gauge SG and stores it in the storage device 36 (see FIG. Step S6 of 4, second operation step).

  Specifically, as shown in FIG. 10, the deformation force Fx in the X axis direction and the deformation force Fy in the Y axis direction are determined from the strain in the X axis direction of the center 18 and the strain in the Y axis direction and the rigidity of the center 18 The deformation force F applied to the crankshaft W to be ground and the phase φ of the deformation force F are determined by combining the deformation force Fx in the X-axis direction and the deformation force Fy in the Y-axis direction.

  The third arithmetic unit 35 calculates ground portions P1-P4 and J1-J5 based on the relational expression of the deforming force and the eccentricity calculated by the first arithmetic unit 33 and the deforming force calculated by the second arithmetic unit 34. The amount of eccentricity is calculated and stored in the storage unit 36 (step S7 in FIG. 4, third operation step).

  Specifically, the deformation force F applied to the crankshaft W to be ground, which is obtained by the second calculation device 34, is read from the storage device 36, and the deformation force F is stored in the storage device 36. The eccentricity d of each of the ground parts P1-P4 and J1-J5 is determined by substituting the relationship between the deformation force F and the eccentricity d of the ground parts P1-P4 and J1-J5 obtained in the above.

  The control device 31 controls the feed operation of the grinding wheel 28 in consideration of the amount of eccentricity of each of the ground parts P1-P4 and J1-J5 obtained from the storage device 36 by the third arithmetic unit 35, thereby the grinding wheel 28 The grinding process is performed on each of the ground parts P1-P4 and J1-J5 (step S8 in FIG. 4).

  Here, the positions of the crank pin P1 and the grinding wheel 28 in the grinding process of the crankshaft W will be described with reference to FIGS. 11A to 11D. However, in FIGS. 11A to 11D, the crankshaft W is illustrated as being not deformed. Further, in FIGS. 11A to 11D, the crank journal J3 is not shown.

  In the following description, the illustrated left direction is referred to as the forward feed direction of the grinding wheel 28, and the illustrated right direction is referred to as the backward feed direction of the grinding wheel 28. The rotation phase α of the crank journal J3 (hereinafter referred to as the phase α of the crank journal J3) is the rotation of the crank journal J3 relative to a straight line connecting the rotation center Oj3 of the crank journal J3 and the rotation center Og of the grinding wheel 28. The angle formed by the straight line connecting the center Oj3 and the center Op1 of the crankpin P1.

  As shown in FIG. 11A, when the phase α of the crank journal J3 is 0 °, the center Op1 of the crankpin P1 is at a position on a straight line connecting the rotation center Oj3 of the crank journal J3 and the rotation center Og of the grinding wheel 28. The rotation center Og of the grinding wheel 28 is at the most retracted position in the reverse feed direction.

  That is, the grinding point Q of the crank pin P1 and the grinding wheel 28 is located on a straight line connecting the center Op1 of the crank pin P1, the rotation center Oj3 of the crank journal J3 and the rotation center Og of the grinding wheel 28. The coolant supplied from the coolant nozzle 29 is supplied from the upper side of the grinding wheel 28 toward the grinding point Q.

  As shown in FIG. 11B, when the phase α of the crank journal J3 is 90 °, the center Op1 of the crank pin P1 is eccentrically positioned uppermost with respect to the rotation center Oj3 of the crank journal J3. The rotation center Og of the crank journal J3 is a position advanced in the forward feed direction from the position when the phase α of the crank journal J3 is 0 °.

  As shown in FIG. 11C, when the phase α of the crank journal J3 is 180 °, the center Op1 of the crankpin P1 is on the extension of a straight line connecting the rotation center Oj2 of the crank journal J3 and the rotation center Og of the grinding wheel 28. In the position, the rotation center Og of the grinding wheel 28 is at the most advanced position in the forward feed direction from the position when the phase α of the crank journal J3 is 90 °.

  As shown in FIG. 11D, when the phase α of the crank journal J3 is 270 °, the center Op1 of the crank pin P1 is at the lowermost eccentric position with respect to the rotation center Oj3 of the crank journal J3. The rotation center Og of the crank journal J3 is located at a position retracted in the reverse feed direction from the position when the phase α of the crank journal J3 is 180 °. In the grinding process of the crank pin P1, the operations of FIGS. 6A to 6D are repeated. The other crank pins P2-P4 are similar.

  However, in the grinding machine 1 of the present embodiment, since the crankshaft W is deformed, it is necessary to control the feed operation of the grinding wheel 28 in consideration of the eccentricity of the crankpin P1 in the grinding process of the crankpin P1. . The other crank pins P2-P4 and crank journals J1-J5 can be similarly ground and machined.

(4. Grinding wheel feed operation)
Next, control of the feed operation of the grinding wheel 28 will be described with reference to the drawings. As shown in FIG. 12, in this grinding processing control, according to the phase α of the crank journal J3, the feed position of the grinding wheel 28, ie, the distance X between the rotation center Oj3 of the crank journal J3 and the rotation center Og of the grinding wheel 28. Needs to fluctuate.

  The radius of the grinding wheel 28 is R, and the radius of the crank pin Pa1 before grinding shown by the solid line is r. A distance S between a rotation center Oj3 of the crank journal J3 and a center Op1 of the crank pin P1 after grinding shown by a dashed dotted line in the figure is a rotation center Oj3 of the crank journal J3 and a center Opa1 of the crank pin Pa1 before grinding. The distance of is S1.

  Further, a straight line M2 connecting the rotation center Oj3 of the crank journal J3 and the center Opa1 of the crank pin Pa1 before grinding is formed on the straight line M1 connecting the rotation center Oj3 of the crank journal J3 and the rotation center Og of the grinding wheel 28. Let the angle be α1. Further, an angle formed by a straight line M3 connecting the rotation center Og of the grinding wheel 28 and the center Opa1 of the crank pin Pa1 before grinding is defined as β1 relative to the straight line M1.

  The center Opa1 of the crank pin Pa1 before grinding is offset by an eccentricity d with respect to the center Op1 of the crank pin P1 after grinding, and the rotation center Oj3 of the crank journal J3 and the crank pin P1 after grinding It is assumed that a phase φ is deviated with respect to a straight line M4 connecting the center Op1.

  When set as described above, the relationship of the following equation (1) is derived. Since S, d, α, and φ are known values in the equation (1), S1 · sin α1 represented by the equation (2) can be obtained. Therefore, since S1 · sin α1, r and R are known values, X can be obtained by the following equation (3). Then, a table indicating the relationship between α and X is created, and the feed operation of the grinding wheel 28 is controlled in accordance with this table.

(5. Detailed operation of grinding process)
Next, the detailed operation of the grinding process (machining process) will be described with reference to the drawings. Here, the grinding machine 1 first performs cutting of the crankshaft W with the two grinding wheels 28, first the crank pin P1 and the crank journal J3, then the crank pin P2 and the crank journal J4, and then the crank pin P3. And the crank journal J5, and then, with one grinding wheel 28, the crank pin P4, then the crank journal J2, and finally the crank journal J1.

  The controller 31 advances the master main shaft Cm (center 14) and the slave main shaft Cs (center 18) in the direction in which they approach each other to pressure-support the crankshaft W (step S11 in FIG. 5). Then, the control device 31 grips the crankshaft W with the chuck 15 and controls the operations of the master servo motor 17, the slave servo motor 20 and the grinding wheel drive motor 27 to start rotating the crankshaft W and the grinding wheel 28. (Step S12 of FIG. 5).

  The controller 31 controls the operation of the X-axis servomotor 25 to forward-feed the grinding wheel 28 in the X-axis direction with respect to the crankshaft W at the rough grinding feed speed to start the air-grinding (step in FIG. 5) S13). During this time, the control device 31 reads a table indicating the relationship between the phase α of the crank journal J3 corresponding to the crankshaft W to be ground and the feed position X of the grinding wheel 28 (step S14 in FIG. 5).

  The control device 31 detects an AE wave generated by the grinding wheel 28 with a contact detection sensor (AE sensor) (not shown) and determines whether or not the contact with the crank pin Pa1 (step S15 in FIG. 5). Then, when the control device 31 determines that the grinding wheel 28 contacts the crank pin Pa1, the control device 31 controls the feed operation of the grinding wheel 28 according to the read table to perform rough grinding (step S16 in FIG. 5). The finish grinding process is performed (step S17 in FIG. 5), and the spark out is further performed (step S18 in FIG. 5).

  When the spark out is completed, the control device 31 controls the operation of the X-axis servomotor 25 to start backward feeding of the grinding wheel 28 in the X-axis direction with respect to the crankshaft W (step S19 in FIG. 5). Then, the control device 31 controls the operations of the master servomotor 17, the slave servomotor 20, and the grinding wheel drive motor 27 to stop the rotation of the crankshaft W and the grinding wheel 28 (step S20 in FIG. 5).

  Then, the control device 31 releases the gripping of the chuck 15 and retracts the master main shaft Cm (center 14) and the slave main shaft Cs (center 18) in the direction away from each other to remove the crankshaft W (step S21 in FIG. 5). . Then, the presence or absence of a crankshaft W to be ground next is checked (step S22 in FIG. 5), and if there is a crankshaft W to be ground next, the process returns to step S11 to repeat the above processing. If there is no crankshaft W to be ground for grinding, all processing ends.

  According to the grinding machine 1 of the present embodiment, the feeding operation of the grinding wheel 28 is performed by the crank pin P1-P4 and the crank journal J1- obtained from the deformation force F in the radial direction applied to the crankshaft W and the phase φ of the deformation force F. Since control is performed based on the eccentricity d of the axis of J5, accurate grinding can be performed on the crank pins P1-P4 of the crankshaft W deformed by the deformation force F and the crank journals J1-J5. Accuracy can be improved.

(6. Configuration and operation of another control device)
Next, although the control device of another example has the same configuration as the control device 31 shown in FIG. 3, the functions of the second arithmetic device 34 and the third arithmetic device 35 are different. That is, instead of the strain gauges SG attached to the sensor 18, an eddy current distance sensor DS (measuring device) shown in FIG. 13 and a hydraulic cylinder OS (measuring device) for moving the distance sensor DS It is disposed on the crankshaft W.

  The distance sensor DS is disposed on one crank pin or crankshaft selected as an object to be measured among the crank pins P1-P4 and crankshafts J1-J5 of the crankshaft W currently to be ground, and the distance X The amount of movement in the axial direction (measurement value) and the amount of movement in the Y axis direction (measurement value) are measured. The second arithmetic unit 34 obtains the amount of eccentricity of the measurement object based on the movement amount of the measurement object in the X-axis direction and the movement amount of the Y-axis direction input from the distance sensor DS, and stores it in the storage device 36.

  Specifically, as shown in FIG. 13, with the position of the crank pin Pb1 in the X-axis direction and the position in the Y-axis direction of the crankshaft W before deformation shown by the one-dot chain line in the figure as zero, The amount of movement x2 in the X-axis direction and the amount of movement y2 in the Y-axis direction of the crankpin Pa1 after deformation are measured. Then, the amount of movement x1 in the X-axis direction and the amount of movement y1 in the Y-axis direction of the crankpin P1 after grinding shown in solid line are measured, and the eccentricity d and phase φ of the crankpin P1 are expressed by It asks by (5).

  The third arithmetic unit 35 is a crankpin P1 other than the measurement target based on the table of the deformation force and the eccentricity calculated by the first arithmetic unit 33 and the eccentricity of the measurement target calculated by the second arithmetic unit 34. The eccentricity amounts of P4 and crankshafts J1-J5 are determined and stored in the storage unit 36.

  Specifically, the eccentricity d and the phase φ of the crankpin P1 determined by the second arithmetic unit 34 are applied to the table of the deformation force F and the eccentricity d determined by the first arithmetic unit 33, whereby the crankpin is obtained. The amount of eccentricity d of crank pins P2-P4 other than P1 and journal pins J1-J5 is determined. The subsequent processing is the same as that of the control device 31 described above.

(7. Other)
In the embodiment described above, the crankshaft W of a single plane in series 4 cylinders is described as an example of a workpiece, but a double plane crankshaft, a crankshaft in series 6 cylinders, etc., or a cylindrical shaft other than the crankshaft W The invention is also applicable to a cam shaft and the like.

  Further, although the grinding machine 1 is configured to include the chuck 15 on the master main spindle Cm, it may be a grinding machine including the chuck on the slave main spindle Cs. Further, although the chuck 15 having three claws is provided, it may be a grinding machine provided with a floating chuck. In addition, although the master spindle Cm and the slave spindle Cs are configured to be rotationally driven, a grinding machine may be used in which only the master spindle Cm is rotationally driven. In addition, a single head grinding machine may be used.

1: Grinding machine, 12: Headstock, 13: Endstock, 14, 18: Center, 15: Chuck, 17: Master servomotor (workpiece drive motor), 19: Center pressure device, 24: X axis servo Motor (feeder), 25: Feed screw (feeder), 26: Wheel head, 27: Wheel drive motor, 28: Wheel, 31: Controller, 32: Input device, 33: First arithmetic unit, 34 : Second computing device 35: Third computing device 36: Storage device W: Crankshaft P1-P4: Crank pin J1-J5: Crank journal SG: Strain gauge (measuring device) DS: Distance sensor (Measurement device)

Claims (5)

A grinding wheel head rotatably supporting a grinding wheel and having a grinding wheel drive motor for rotationally driving the grinding wheel;
A headstock having a workpiece drive motor that holds one end of a workpiece by a chuck and rotatably supports it, and rotationally drives the workpiece;
A tailstock for pressing and supporting the other end of the workpiece at a center;
A feeding device for relatively moving the grinding wheel closer to or away from the workpiece in a direction intersecting the rotation axis of the workpiece;
A control device for grinding the workpiece with the grinding wheel by controlling the feeding operation of the feeding device;
A grinding machine comprising
The controller is
Storage device,
An input device for inputting the shape of the workpiece and storing it in the storage device;
Based on the shape of the workpiece, the deformation force applied in the radial direction of the workpiece by the pressure support of the center and the eccentricity of the axis of the workpiece due to the deformation force are determined, and the deformation force and the eccentricity A first computing device that stores the correlation with the above in the storage device;
Based on the measurement value from the measuring device provided in the center, the deformation force applied in the radial direction of the workpiece to be ground by the pressure support of the center is determined by the pressure support of the center and stored in the storage device or The radial movement amount of the workpiece to be ground processed by the pressure support of the center is determined based on the measurement value from the measuring device provided on the workpiece to be ground and stored in the storage device. Two arithmetic units,
An offset amount of the axis line of the workpiece of the current grinding object corresponding to the deformation force applied in the radial direction of the workpiece of the current grinding object input with reference to the correlation between the deformation force and the eccentricity amount And a third arithmetic unit for storing the movement amount as an eccentricity amount of the axis line of the workpiece to be ground and to store the movement amount in the storage device,
A grinding machine which grinds the workpiece of the current grinding object by the grinding wheel by controlling the feed operation of the feeding device in consideration of the eccentricity of the axis line of the workpiece of the current grinding object. .   The grinding machine according to claim 1, wherein the measurement device provided at the center is a sensor that measures distortion of two orthogonal axes in the radial direction of the workpiece.   The grinding machine according to claim 1 or 2, wherein the control device is a grinding target of a crankshaft having a crank journal and a crank pin having a central axis offset from the rotation axis of the crank journal in the radial direction.   The control device determines the distance between the rotation axis of the crank journal and the rotation axis of the grinding wheel based on the distance between the central axis of the crank pin before grinding and the rotation axis of the grinding wheel, and feeds the feed A grinding machine according to claim 3, which controls the feed operation of the device. A grinding method for grinding a workpiece with a grinder
The grinder is
A grinding wheel head rotatably supporting a grinding wheel and having a grinding wheel drive motor for rotationally driving the grinding wheel;
A headstock having a workpiece drive motor that holds one end of a workpiece by a chuck and rotatably supports it, and rotationally drives the workpiece;
A tailstock for pressing and supporting the other end of the workpiece at a center;
A feeding device for relatively moving the grinding wheel closer to or away from the workpiece in a direction intersecting the rotation axis of the workpiece;
A control device for grinding the workpiece with the grinding wheel by controlling the feeding operation of the feeding device;
Equipped with
The grinding method is
An input step of inputting the shape of the workpiece;
Based on the shape of the workpiece, the deformation force applied in the radial direction of the workpiece by the pressure support of the center and the eccentricity of the axis of the workpiece due to the deformation force are determined, and the deformation force and the eccentricity The first operation process for determining the correlation with
Based on the measurement value from the measuring device provided in the center, the deformation force applied in the radial direction of the workpiece to be ground by the pressure support of the center is determined by the pressure support of the center, or to the workpiece to be ground by grinding A second operation step of obtaining a radial movement amount of the workpiece to be ground by the pressure support of the center based on the measurement value from the provided measuring device;
An offset amount of the axis line of the workpiece of the current grinding object corresponding to the deformation force applied in the radial direction of the workpiece of the current grinding object input with reference to the correlation between the deformation force and the eccentricity amount A third operation step of determining the movement amount as an eccentricity amount of the axial line of the workpiece, or
A processing step of grinding the workpiece to be ground by the grinding wheel by controlling the feed operation of the feed device in consideration of the eccentricity of the axis line of the workpiece to be ground by grinding; ,
Grinding method comprising:

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