JP2019147210A - Machine tool having rotatable table, and processing method by machine tool - Google Patents

Abstract

To provide a machine tool having a rotatable table which can automate accurate centering of a workpiece, and a processing method by the machine tool.SOLUTION: A machine tool 10 having a rotatable table 30, includes: a table 20 or a wheel spindle stock 15 that is movable along a guide rail 21; a position detection device 50 having detection probes 51 and 52 which are provided so as to be movable toward the outer periphery of a workpiece and can each detect an outer peripheral position of the workpiece W; and a control device 17 which controls each operation of the table 20 or the wheel spindle stock 15, and the rotatable table 30, a spindle head 13 and a position detection device 50, and processes the outer periphery of the workpiece W. The control device 17 includes: a center axis calculation part which determines a center axis C of the workpiece W based on the outer peripheral position of the workpiece W detected by detection probes 51 and 52; and a rotatable table rotating part which rotates the rotatable table 30 so that the center axis C of the workpiece W is parallel to the guide rail 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a machine tool including a turning table and a processing method using the machine tool.

  Patent Documents 1 and 2 describe a cylindrical grinder as a machine tool including a turning table. In such a cylindrical grinding machine, not only grinding of a cylindrical workpiece but also a workpiece having a tapered portion at the end of the cylindrical portion can be ground by turning a turning table.

Japanese Patent Laying-Open No. 2015-217481 JP2015-217482A

  In a cylindrical grinding machine equipped with a swivel table, deflection and thermal displacement that occur during grinding of the workpiece, reproducibility due to setup movement of the headstock and tailstock when supporting both ends of the workpiece with the headstock and tailstock For example, the accuracy of the outer diameter and taper angle of the workpiece may be reduced. In order to ensure the accuracy of the outer diameter and taper angle of the workpiece, it is necessary for the operator to detect the outer peripheral position of the workpiece and center the workpiece. There is a problem that it takes.

  An object of this invention is to provide the machine tool provided with the turning table which can automate the highly accurate centering of a workpiece, and the processing method by the said machine tool.

  A machine tool including a swivel table according to the present invention includes a bed and a grindstone stand that is provided on the upper surface of the bed and supports a grindstone capable of grinding the outer periphery of the workpiece so as to be rotatable about the central axis of the grindstone. And a table or grindstone table provided on the upper surface of the bed and movable along a guide rail, and a turning table provided on the upper surface of the table and capable of turning about a turning axis perpendicular to the upper surface, A headstock and a tailstock that are provided on the upper surface of the swivel table, support both ends of the workpiece, rotate the workpiece around a rotation axis passing through both support points, and toward the outer periphery of the workpiece. A position detection device having a detection probe that is movably provided and capable of detecting the outer peripheral position of the workpiece, the table or the grindstone table, the turning table, the headstock, and the By controlling the respective operations of 置検 detection device, and a control device for machining of the outer periphery of the workpiece.

  The control device includes a center axis calculation unit that obtains a center axis of the workpiece based on an outer peripheral position of the workpiece detected by the detection probe, and a center axis of the workpiece is parallel to the guide rail. Thus, a turning table turning unit for turning the turning table is provided.

  A processing method by a machine tool according to the present invention includes a bed, and a grinding wheel base that is provided on the upper surface of the bed and supports a grinding wheel capable of grinding the outer periphery of the workpiece so as to be rotatable around the central axis of the grinding wheel. Provided on the upper surface of the bed, provided on the upper surface of the bed, movable along a guide rail, or the grindstone table, and provided on the upper surface of the traverse table, around a turning axis perpendicular to the upper surface. A swivel table capable of swiveling, a spindle table and a tailstock that are provided on an upper surface of the swivel table, support both ends of the workpiece, and rotate the workpiece around a rotation axis passing through both support points; A position detection device having a detection probe that is movably provided toward the outer periphery of the workpiece and capable of detecting the outer periphery position of the workpiece; A center axis calculation step for obtaining a center axis of the workpiece based on an outer peripheral position of the workpiece detected by the detection probe, and the turning so that the center axis of the workpiece is parallel to the guide rail. A first turning table turning step for turning the table, and a machining step for grinding the outer periphery of the workpiece, the center axis calculating step, turning the first turning table until the outer diameter of the workpiece reaches a target diameter The process and the processing process are repeated.

  According to the present invention, the detection of the outer peripheral position of the workpiece, the calculation of the center axis of the workpiece, and the centering of the workpiece by turning of the turning table can be automatically performed with high accuracy in the machine tool. As a result, the machine tool can perform high-precision centering in the loaded state and the processed state of the workpiece. And a machine tool processes the outer periphery of a cylindrical workpiece by the movement along the guide rail of a table or a grindstone base. Therefore, the accuracy of the outer diameter and taper angle of the workpiece after processing can be improved.

It is the figure which looked at the machine tool of this embodiment from the Y-axis direction. It is the figure which looked at the position detection apparatus which comprises the machine tool of FIG. 1 from the Y-axis direction. It is the figure which looked at the position detection apparatus of FIG. 2A from the Z-axis line direction. It is the figure which looked at the position detection apparatus of FIG. 2A from the X-axis direction. It is a figure for demonstrating the operation state of the position detection apparatus of FIG. 2A. It is a figure which shows the operation state at the time of detecting a small diameter workpiece with the position detection apparatus of FIG. 2A, and is a state in which the detection probe is positioned at the retracted position. It is a figure which shows the operation state at the time of detecting a small diameter workpiece with the position detection apparatus of FIG. 2A, and is a state in which the detection probe is positioned at the detection start position. It is a figure which shows the operation state at the time of detecting a small diameter workpiece with the position detection apparatus of FIG. 2A, and is a state in which the detection probe is positioned at the first detection position. It is a figure which shows the operation state at the time of detecting a small diameter workpiece with the position detection apparatus of FIG. 2A, and is a state in which the detection probe is positioned at the second detection position. It is a figure which shows the operation state at the time of detecting a small diameter workpiece with the position detection apparatus of FIG. 2A, and is a state in which the detection probe is returned and positioned. It is a figure which shows the operation state at the time of detecting a large diameter workpiece with the position detection apparatus of FIG. 2A, and is a state in which the detection probe is positioned at the retracted position. It is a figure which shows the operation state at the time of detecting a large diameter workpiece with the position detection apparatus of FIG. 2A, and is a state in which the first detection probe is positioned at the detection start position. It is a figure which shows the operation state at the time of detecting a large diameter workpiece with the position detection apparatus of FIG. 2A, and is a state in which the first detection probe is positioned at the first detection position. It is a figure which shows the operation state at the time of detecting a large diameter workpiece with the position detection apparatus of FIG. 2A, and is a state in which the first detection probe is returned to the retracted position. It is a figure which shows the operation state at the time of detecting a large diameter workpiece with the position detection apparatus of FIG. 2A, and is a state in which the second detection probe is positioned at the detection start position. It is a figure which shows the operation state at the time of detecting a large diameter workpiece with the position detection apparatus of FIG. 2A, and is a state in which the second detection probe is positioned at the second detection position. It is a figure which shows the operation state at the time of detecting a large diameter workpiece with the position detection apparatus of FIG. 2A, and is a state in which the second detection probe is returned to the retracted position and positioned. It is the figure which looked at the cover which comprises the machine tool of FIG. 1 from the Y-axis direction. It is the figure which looked at the cover of Drawing 6A from the Z-axis direction. It is a figure which shows the operation state of the cover of FIG. 6A when turning a turning table counterclockwise. It is a figure which shows the operation state of the cover of FIG. 6A when turning a turning table clockwise. It is sectional drawing which shows the internal structure of the head stock which comprises the machine tool of FIG. It is a VIIIB-VIIIB arrow sectional view of Drawing 8A. It is a VIIIC-VIIIC arrow sectional view of Drawing 8A. It is a flowchart for demonstrating the position detection operation | movement in the grinding method of a cylindrical workpiece. It is a flowchart for demonstrating the turning operation | movement and grinding operation | movement of a turning table in the grinding method of a cylindrical workpiece. It is a top view which shows the state which carried in the workpiece into the machine tool of FIG. It is a top view for demonstrating the position detection of the workpiece carried in to the machine tool of FIG. It is a top view for demonstrating turning of the workpiece of FIG. It is a top view which shows the state after grinding of the workpiece of FIG. It is a flowchart for demonstrating the turning operation | movement and grinding operation | movement of a turning table in the grinding method of the cylindrical workpiece which has a taper part. It is a flowchart for demonstrating the position detection operation | movement in the grinding method of the cylindrical workpiece which has a taper part. It is a flowchart for demonstrating the verification operation | movement of the taper part in the grinding method of the cylindrical workpiece which has a taper part. It is a top view which shows the taper part attached to the workpiece after grinding of FIG. FIG. 16 is a plan view for explaining the turning of the workpiece in FIG. 15. It is a top view for demonstrating the position detection of the workpiece of FIG. It is a top view for demonstrating the correction | amendment turning of the workpiece of FIG. It is a top view which shows the state after grinding of the workpiece of FIG.

(1. Configuration of cylindrical grinding machine)
A table traverse type cylindrical grinder will be described as an example of a machine tool including a turning table according to the present embodiment with reference to FIG. In FIG. 1, the moving direction of a traverse table 20 to be described later is the Z-axis direction of the three orthogonal axes, the moving direction of the grindstone table 15 is the X-axis direction of the three orthogonal axes, the Z-axis direction and the X-axis direction. A direction perpendicular to the axial direction is defined as a Y-axis direction of three orthogonal axes.

  As shown in FIG. 1, the cylindrical grinding machine 10 includes a bed 11 placed on a floor surface, a table unit 12 provided on the upper surface of the bed 11, a headstock 13 and a tailstock provided on the upper surface of the table unit 12. The base 14 includes a grinding wheel base 15 having a grinding wheel 16 provided on the upper surface of the bed 11, a position detection device 50 provided on the grinding wheel base 15, and a control device 17 provided on a side surface of the bed 11.

  The table unit 12 includes a traverse table 20 provided on the upper surface of the bed 11, a turning table 30 provided on the upper surface of the traverse table 20, and an actuator 40 that turns the turning table 30 on the upper surface of the traverse table 20.

  The traverse table 20 is formed in a rectangular shape that is long when viewed from above. The traverse table 20 is movable along a guide rail 21 laid in the Z-axis direction on the bed 11 by driving an actuator (not shown) such as a linear motor. The upper surface of the traverse table 20 is subjected to scuffing or the like so that the lower surface of the swivel table 30 can slide.

  The turntable 30 is formed in a hexagonal shape that is flat when viewed from above. The swivel table 30 is supported so as to be able to swivel around the swivel axis 30a around the Y axis while sliding on the upper surface of the traverse table 20. FIG. 1 shows a state in which the turning table 30 has a turning angle θ with respect to the Z axis. Similar to the upper surface of the traverse table 20, the lower surface of the turning table 30 is subjected to scuffing or the like.

  The actuator 40 adjusts the turning angle θ of the turning table 30. The actuator 40 is provided on one end side of the upper surface of the traverse table 20, and moves the position on one end side of the turning table 30 with respect to the traverse table 20. More specifically, the actuator 40 includes a motor 41 provided on one end of the upper surface of the traverse table 20, a ball screw 42 connected to the motor 41, and a ball screw nut 43 provided on one end of the turning table 30. Prepare.

  In the actuator 40, the ball screw 42 is rotated by the drive of the motor 41, and the position of the ball screw nut 43 moves on the XZ plane, so that the turning table 30 is turned. In order to fix the turning table 30 to the traverse table 20 in a state where the turning table 30 is turned, clamp devices 31 a and 31 b are provided on both ends in the longitudinal direction of the turning table 30.

  Here, when the swivel table 30 is swung, a triangular surface is exposed on the upper surface of the traverse table 20, but when coolant, cutting oil, grinding scraps, abrasive grains, or the like adhere to the exposed surface, the swivel table 30 swivels. Sometimes wear and twisting occur, and the accuracy of the turning angle may be reduced. Therefore, a cover 60 that protects the upper surface of the traverse table 20 is disposed between the traverse table 20 and the turning table 30, as shown in FIGS. 6A and 6B. Details of the cover 60 will be described later.

  The headstock 13 and the tailstock 14 include a center 13a and a center 14a, respectively, and are fixed to the upper surface of the table unit 12. The center 13a of the head stock 13 and the center 14a of the tailstock 14 respectively support both ends of the cylindrical workpiece W. The spindle stock 13 incorporates a spindle motor 13b for rotating the workpiece W around a central axis passing through both support points of the centers 13a and 14a.

  Here, as shown in FIG. 8, a bearing 13c for supporting the center 13a is built in the headstock 13. When the workpiece W is rotated, the headstock 13 becomes hot due to heat generated by the spindle motor 13b and the bearing 13c. In this state, for example, when the drive of the spindle motor 13b is stopped by an emergency stop or the like, the internal pressure decreases as the inside of the spindle base 13 cools down, and the coolant or cutting oil adhering to the exterior of the spindle base 13 is sucked in. There is a risk of it.

  Therefore, high-pressure air is supplied to the head stock 13 from the outside of the head stock 13 in order to prevent coolant, cutting oil, and the like from entering the bearing 13 c that supports the center 13 a from the clearance of the head stock 13. Air purge path 130 (13d, 13e, 13f, 13g) is provided. The details of the air purge path 130 (13d, 13e, 13f, 13g) will be described later.

  The grindstone table 15 holds a tool (grinding wheel 16) used for grinding and is driven along a guide rail 15a laid on the bed 11 in the X-axis direction by driving an actuator (not shown) such as a linear motor. Can be moved. The grinding wheel base 15 supports the grinding wheel 16 rotatably around the central axis 16a so that the central axis 16a of the grinding wheel 16 capable of grinding the outer periphery of the workpiece W faces the Z-axis direction. A guide rail may be laid in the Z-axis direction so that the grindstone table 15 can be moved in the Z-axis direction on the bed 11.

  The position detection device 50 is provided on the grindstone table 15 and detects the outer peripheral position and the end face position of the workpiece W with the first and second detection probes 51 and 52 that can be independently operated. When detecting with one detection probe, the detection range is limited to the stroke in the X-axis direction of the grindstone table 15, but the position detection device 50 has two first and second detection probes 51 and 52 that can operate independently. Therefore, it is difficult for the detection range to be restricted by the stroke of the grinding wheel base 15 in the X-axis direction.

  In addition, when grinding a cylindrical workpiece W with the cylindrical grinding machine 10, the center axis of the workpiece W is maintained even when the workpiece W is shaken or the turning angle of the turning table 30 is set to 0 degree. When the traverse table 20 is tilted with respect to the guide rail 21, it is necessary to detect the outer peripheral positions on both ends of the workpiece W and to center the workpiece W based on the detected outer peripheral positions. In the case of detection with two detection probes with fixed arrangement intervals, the detection operation time of the small-diameter workpiece W tends to be long. Since detection is performed by the detection probes 51 and 52, the detection operation time can be shortened. Details of the position detection device 50 will be described later.

  The control device 17 controls the rotation of the workpiece W and the grinding wheel 16, and the relative movement between the workpiece W and the grinding wheel 16 (movement in the Z-axis direction and the X-axis direction among three orthogonal axes). The outer periphery of the workpiece W is ground by controlling. Further, the control device 17 controls the operation of the position detection device 50, calculates the center axis, outer diameter, and the like of the workpiece W based on the detected outer peripheral position of the workpiece W, and also has a tapered portion. The taper angle of W is calculated.

(2. Configuration of position detection device)
As shown in FIGS. 2A to 2C, the position detection device 50 is provided on the upper surface of the grindstone table 15 and can move along the grindstone table 15 on the bed 11 in the X-axis direction. This eliminates the need for a moving device dedicated to the position detection device 50, thereby reducing costs. The position detection device 50 includes a first detection probe 51 and a second detection probe 52 that detect the outer peripheral position of the workpiece W, respectively, and a first arm 53 and a second arm to which the first and second detection probes 51 and 52 are respectively attached. The arm 54 includes a first hydraulic cylinder 55 and a second hydraulic cylinder 56 that rotate the first and second arms 53 and 54, respectively.

  The first detection probe 51 and the first arm 53 are supported by the first hydraulic cylinder 55 so as to be rotatable around the rotation axis 50a around the Z axis on the upper front side (workpiece W side) of the grindstone base 15, The detection probe 52 and the second arm 54 are supported by the second hydraulic cylinder 56 so as to be rotatable about the rotation axis 50a around the Z axis on the front upper surface side of the grindstone base 15. 2A to 2C, the first and second detection probes 51 and 52 are positioned at the upper retreat position with respect to the grindstone table 15.

The first and second detection probes 51 and 52 are general contact-type probes, and detect the positions touched by the contact members 51a and 52a at the tips. The first and second detection probes 51 and 52 may be non-contact probes such as light and laser.
The first and second arms 53 and 54 are each formed in an L shape. In FIGS. 2A to 2C, the Z axis line is formed so as to be reverse L shapes facing the same direction when viewed in the X axis direction. Arranged side by side. Here, upper portions of the first and second arms 53 and 54 extending in the Z-axis direction are referred to as bent portions 53a and 54a, and lower portions of the bent portions 53a and 54a are referred to as base portions 53b and 54b.

  The lower ends of the bases 53b and 54b of the first and second arms 53 and 54 are supported on the front side of the upper surface of the grindstone base 15 so as to be freely rotatable around the same rotation axis 50a around the Z axis. On the free end side of the bent portions 53a and 54a of the first and second arms 53 and 54, the contacts 51a and 52a of the first and second detection probes 51 and 52 are directed to the workpiece W side, The first and second detection probes 51 and 52 are attached so as to protrude from the free ends of the bent portions 53a and 54a, respectively.

  The front end of the rod 55a of the first hydraulic cylinder 55 is attached to a substantially central portion of the base 53b of the first arm 53 so as to be freely rotatable, and the rear end of the first hydraulic cylinder 55 is the rear side of the upper surface of the grinding wheel base 15 ( It is attached so as to be freely rotatable on the side opposite to the workpiece W). The tip of the rod 56a of the second hydraulic cylinder 56 is attached to the upper part of the base 54b of the second arm 54 so as to be freely rotatable. The rear end of the second hydraulic cylinder 56 is mounted on the rear side of the upper surface of the grinding wheel base 15 so as to be freely rotatable.

  The bent portions 53a and 54a of the first and second arms 53 and 54 are long so that the first and second detection probes 51 and 52 attached to the free ends of the bent portions 53a and 54a are parallel on the same XY plane. Formed. Thereby, the 1st, 2nd detection probes 51 and 52 can detect the outer periphery position on the same outer periphery of the workpiece W, respectively.

  Further, the bent portions 53a and 54a of the first and second arms 53 and 54 are positioned in the direction of the center axis C of the workpiece W in the contacts 51a and 52a of the first and second detection probes 51 and 52 (see FIG. 2C). The points Q) are formed to coincide with each other. As a result, the contacts 51a and 52a are fixed so that the positions of the workpiece W in the direction of the central axis C coincide with each other, so that the first and second arms 53 and 54 perform different operations. In the positioning of the contacts 51a and 52a, the influence of errors due to the shape of the workpiece W and the support of the workpiece W can be suppressed, and measurement can be performed with high accuracy. Further, by adjusting the lengths of the bent portions 53a and 54a of the first and second arms 53 and 54, the first and second arms 53 and 54 are close to the processing portion without interfering with the drive unit that rotates the first and second arms 53 and 54. Can be measured in position.

  Further, when the base 53b of the first arm 53 detects the outer peripheral position of the workpiece W having the maximum diameter that can be machined by the cylindrical grinding machine 10 on the side opposite to the grinding wheel 16 (operator side), The first detection probe 51 is formed to a length that does not interfere with it. In addition, although the rotating shaft 50a of the first and second arms 53 and 54 is the same rotating shaft, the rotating shaft 50a may be different. The first hydraulic cylinder 55 and the second hydraulic cylinder 56 are hydraulic cylinders, but may be motors or other drive actuators.

(3. Operation of position detection device)
As shown in FIG. 3, the rods 55 a and 56 a of the first and second hydraulic cylinders 55 and 56 expand and contract, so that the first and second arms 53 and 54 together with the first and second detection probes 51 and 52. It rotates around the Z axis around the rotation axis 50a within a range of a predetermined angle φ. That is, as shown by the solid line in FIG. 3, the first and second arms 53 and 54 are moved to one side of the predetermined angle φ (workpiece W by the extension of the rods 55a and 56a of the first and second hydraulic cylinders 55 and 56). The first and second detection probes 51 and 52 are positioned at a detection start position where the outer peripheral position of the workpiece W can be detected.

  The first and second detection probes 51 and 52 are positioned at an outer peripheral position 180 degrees apart from the center axis C of the workpiece W, that is, the outer circumference CC of the workpiece W, the center axis C of the workpiece W, and the grinding wheel. XZ coordinate values of the positions of two intersections P1, P2 (hereinafter referred to as “first and second detection positions P1, P2”) with a straight line S parallel to the X axis passing through the 16 central axis 16a are detected.

  Also, as shown by the one-dot chain line in FIG. 3, the first and second arms 53 and 54 are brought to the other angle of the predetermined angle φ by reducing the rods 55a and 56a of the first and second hydraulic cylinders 55 and 56. When rotated, the first and second detection probes 51 and 52 are positioned at the retracted position retracted upward (Y-axis direction) from the above-described detection start position. In this way, the first and second detection probes 51 and 52 can move independently between the detection start position and the retracted position, so that when one detection probe is detected, the other detection probe is moved to the workpiece. When interfering with W or the like, the other detection probe can be retracted to avoid the interference.

  For example, as shown in FIG. 4A, the first and second detection positions of the workpiece W having a smaller diameter d (<H) than the radial arrangement interval H of the workpiece W in the first and second detection probes 51 and 52. A case where P1 and P2 are detected will be described. The position detection device 50 is positioned at a position where the first and second detection probes 51 and 52 do not interfere with the workpiece W when the first and second arms 53 and 54 are rotated. .

  First, as shown in FIG. 4B, the rods 55a and 56a of the first and second hydraulic cylinders 55 and 56 (not shown) are extended to rotate the first and second arms 53 and 54 at the same time. The detection probes 51 and 52 are positioned at the detection start position. At this time, the contacts 51 a and 52 a of the first and second detection probes 51 and 52 are separated from the outer periphery of the workpiece W, respectively.

  Next, as shown in FIG. 4C, the position detection device 50 (grindstone base 15) is moved away from the workpiece W in the X-axis direction, and the contact 51 a of the first detection probe 51 is moved to the outer periphery of the workpiece W. And the first detection position P1 is detected. Next, as shown in FIG. 4D, the position detection device 50 (grindstone base 15) is moved in a direction approaching the workpiece W in the X-axis direction, and the contact 52 a of the second detection probe 52 is moved to the outer periphery of the workpiece W. To detect the second detection position P2.

  Thereafter, the position detection device 50 (grinding wheel base 15) is moved away from the workpiece W in the X-axis direction, and the first and second detection probes 51 and 52 are returned to the detection start position. Then, as shown in FIG. 4E, the rods 55a and 56a of the first and second hydraulic cylinders 55 and 56 are contracted to rotate the first and second arms 53 and 54 at the same time. , 52 are positioned at the retracted position above the detection start position. Thus, the detection of the first and second detection positions P1, P2 of the workpiece W is completed.

  For example, as shown in FIG. 5A, the first and second workpieces W having a diameter D (> H) larger than the radial arrangement interval H of the workpieces W in the first and second detection probes 51 and 52. A case where the two detection positions P1 and P2 are detected will be described. The position detection device 50 is assumed to be positioned at a position where the first detection probe 51 does not interfere with the workpiece W when the first arm 53 is rotated.

  First, as shown in FIG. 5B, the rod 55a of the first hydraulic cylinder 55 (not shown) is extended to rotate the first arm 53, and the first detection probe 51 is positioned at the detection start position. At this time, the contact 51 a of the first detection probe 51 is separated from the outer periphery of the workpiece W.

  Next, as shown in FIG. 5C, the position detection device 50 (grindstone base 15) is moved away from the workpiece W in the X-axis direction, and the contact 51 a of the first detection probe 51 is moved to the outer periphery of the workpiece W. And the first detection position P1 is detected. Thereafter, the position detection device 50 (grinding wheel base 15) is moved in a direction approaching the workpiece W in the X-axis direction, and the first detection probe 51 is returned to the detection start position.

  Then, as shown in FIG. 5D, the rod 55a of the first hydraulic cylinder 55 is contracted to rotate the first arm 53, and the first detection probe 51 is positioned from the detection start position to the upper retracted position.

  Next, as shown in FIG. 5E, the rod 56a of the second hydraulic cylinder 56 (not shown) is extended to rotate the second arm 54, and the second detection probe 52 is positioned at the detection start position. At this time, the contact 52 a of the second detection probe 52 is separated from the outer periphery of the workpiece W.

  Next, as shown in FIG. 5F, the position detection device 50 (grindstone base 15) is moved in a direction approaching the workpiece W in the X-axis direction, and the contact 52 a of the second detection probe 52 is moved to the outer periphery of the workpiece W. To detect the second detection position P2. Thereafter, the position detection device 50 (grinding wheel base 15) is moved away from the workpiece W in the X-axis direction, and the second detection probe 52 is returned to the detection start position.

  Then, as shown in FIG. 5G, the rod 56a of the second hydraulic cylinder 56 is contracted to rotate the second arm 54, and the second detection probe 52 is positioned from the detection start position to the upper retracted position. Thus, the detection of the first and second detection positions P1, P2 of the workpiece W is completed.

(4. Cover configuration)
Conventional cylindrical grinders are provided with covers on both sides of a grindstone head to prevent adhesion of coolant, cutting oil, grinding scraps, abrasive grains, etc. on the upper surface of the table (see Japanese Patent Nos. 3923769 and 3065536). However, there is a problem that the cylindrical grinder becomes larger.

  In the cylindrical grinding machine 10 of the present embodiment, as shown in FIGS. 6A and 6B, the cover 60 is made of a plastic sheet or the like and is substantially the same as the length of the turning table 30 in the longitudinal direction. It is formed in a structure that becomes bellows. The central portion in the longitudinal direction of the cover 60 when the bellows is closed is attached to a mounting portion 32 provided to project from the center of the longitudinal side surface on the upper side (grinding wheel base 15 side) of FIG.

  The longitudinal center portion of the cover 60 when the bellows is closed is attached to the attachment portion 32 so that coolant, cutting oil or the like does not enter from the attachment portion. 6A of the cover 60 in FIG. 6A (the grinding wheel base 15 side) is in close contact with the long side surface of the guide member 33, and the long side surface of the cover 60 in the lower side (opposite side of the grinding wheel base 15) in FIG. Is closely attached to the longitudinal side surface of the turning table 30 on the upper side (grinding wheel base 15 side) in FIG. 6A.

  The attachment portion 32 is supported by a rotary shaft 33a provided at the center of a long rectangular parallelepiped guide member 33 so as to be freely rotatable. The guide member 33 is slidably disposed in the Z-axis direction with a backlash in a groove portion 22 provided on the longitudinal side surface of the traverse table 20 on the upper side (the grinding wheel base 15 side) in FIG. 6A.

(5. Operation of the cover)
As shown in FIG. 7A, when the turning table 30 turns counterclockwise about the Y axis about the turning axis 30a, the guide member 33 slides in the Z axis direction (left direction in the drawing) within the groove portion 22. As shown in FIG. 7B, when the turning table 30 turns clockwise about the turning axis 30a about the Y axis, the guide member 33 slides in the Z axis direction (right direction in the drawing) within the groove portion 22.

  In this state, since the turning shaft 30a of the turning table 30 and the longitudinal center portion of the cover 60 are offset, as the turning angle increases, an internal load in the sliding direction is generated on the cover 60 and the cover 60 is damaged. There is a risk. However, since the guide member 33 has a backlash in the groove portion 22, an internal load in the sliding direction is not generated in the cover 60 or is small even if generated. Therefore, damage to the cover 60 can be suppressed.

  Moreover, since the turning surface (upper surface) of the traverse table 20 can prevent adhesion of coolant, cutting oil, grinding scraps, abrasive grains, and the like by the cover 60, the flatness of the turning surface can be maintained for a long period of time, and the turning table 30 has a high height. Processing accuracy can be improved by accurate positioning. Further, since the cover 60 has a structure that does not jump out of the bed 11 when the turning table 30 is turned, the cylindrical grinding machine 10 can be made compact, and the cost of the apparatus can be reduced. Reliability can be improved.

(6. Configuration of air purge path)
Some conventional cylindrical grinding machines supply high-pressure air from the outside of the headstock to the inside to prevent intrusion of coolant, cutting oil, and the like (see Japanese Patent Nos. 4867277 and 5931103). However, when coolant, cutting oil, or the like that is accelerated by the rotation of the grinding wheel during grinding and overcomes the air pressure is generated, there is a problem that the coolant, cutting oil, or the like enters from the gap of the headstock.

  In the cylindrical grinding machine 10 of the present embodiment, as shown in FIGS. 8A to 8C, the air purge path 130 (13d, 13e, 13f, 13g, 13h, 13i) is a front side provided on the workpiece W side with respect to the bearing 13c. The air purge chamber 13d, the rear air purge chamber 13e provided on the spindle motor 13b side with respect to the bearing 13c, the atmospheric pressure chamber 13f provided between the front air purge chamber 13d and the rear air purge chamber 13e, and the bottom of the atmospheric pressure chamber 13f And a discharge hole 13g communicating with the outside. The discharge hole 13g is led to a position away from the headstock 13 by a pipe (not shown).

  As indicated by the arrows in the figure, air is ejected from the front air purge chamber 13d toward the workpiece W. At the same time, the air is supplied toward the atmospheric pressure chamber 13f and is supplied from the rear air purge chamber 13e toward the atmospheric pressure chamber 13f. The air supplied to the atmospheric pressure chamber 13f is exhausted to the outside through the discharge hole 13g. Since the atmospheric pressure chamber 13f is connected to the external atmospheric pressure, the atmospheric pressure chamber 13f is constantly maintained at the atmospheric pressure. For this reason, the rear air purge chamber 13e is constantly at a higher pressure than the atmospheric pressure chamber 13f.

  As described above, when the inside of the head stock 13 is cooled due to an emergency stop or the like, external air is supplied from the discharge hole 13g to the inside of the head stock 13 through the atmospheric pressure chamber 13f. Since the atmospheric pressure chamber 13f is not usually a location to which coolant, cutting oil, or the like is directly supplied, there is a low possibility that coolant, cutting oil, or the like enters the spindle stock 13. Further, since the atmospheric pressure chamber 13f and the workpiece W side have the same atmospheric pressure, the movement of air due to cooling does not occur.

  Further, as described above, even if coolant or cutting oil that overcomes the air pressure is generated and coolant or cutting oil enters the atmospheric pressure chamber 13f, the pressure of the coolant or cutting oil decreases in the atmospheric pressure chamber 13f. Therefore, there is a low possibility that the bearing 13c will enter further.

  Further, even if coolant, cutting oil, or the like mixed with air enters the atmospheric pressure chamber 13f, the coolant, cutting oil, or the like together with air is naturally discharged to the outside from the discharge hole 13g at the bottom of the atmospheric pressure chamber 13f. In addition, since the discharge hole 13g is provided in the bottom part of the atmospheric pressure chamber 13f, intrusion of coolant, cutting oil, or the like from the outside is prevented.

(7. Operation of control device)
7-1. Grinding Operation of Cylindrical Workpiece The grinding operation (processing method) of the cylindrical workpiece W in the control device 17 will be described with reference to FIGS. 9A, 9B, and 10 to 13. As shown in FIG. 4A, the outer diameter d of the workpiece W before grinding is smaller than the radial arrangement interval H of the workpiece W in the first and second detection probes 51 and 52 (d <H). And However, the case where the outer diameter d of the workpiece W before grinding is larger than the arrangement interval H in the radial direction of the workpiece W in the first and second detection probes 51 and 52 (d> H) can be similarly applied.

  Further, as shown in FIG. 10, the workpiece W is ground into a cylindrical shape having a target diameter dd indicated by a one-dot chain line. In addition, normal grinding is performed by idle grinding, rough grinding, fine grinding, fine grinding, and spark-out processes. In the following description, the case of rough grinding and fine grinding will be described for convenience.

  The control device 17 moves the grindstone table 15 and the traverse table 20 in the X-axis direction and the Z-axis direction so that the position detection device 50 approaches the outer periphery on one end side (the headstock 13 side) of the workpiece W (see FIG. 9A, step S1). It is assumed that the first and second detection probes 51 and 52 are positioned at the retracted position.

  The control device 17 can detect the first and second detection positions P1f and P2f on the first outer circumference circle CC1 on one end side (the headstock 13 side) of the workpiece W shown in FIG. 10 with the position detection device 50. In addition, the grinding wheel base 15 and the traverse table 20 are positioned based on the position coordinates of the first and second detection probes 51 and 52 with respect to the grinding wheel base 15 inputted in advance, the outer diameter of the workpiece W, and the like (FIG. 9A). Step S2).

  The control device 17 operates the first and second hydraulic cylinders 55 and 56 to rotate the first and second arms 53 and 54 to position the first and second detection probes 51 and 52 at the detection positions (see FIG. 9A, step S3). Then, the grindstone table 15 is moved away from the outer periphery of the workpiece W, the first detection probe 51 is brought into contact with the first detection position P1f on the first outer circumference circle CC1 of the workpiece W, and the detected workpiece W is detected. The XZ coordinate value (X1f, Z1f) of the first detection position P1f is stored (see step S4 in FIG. 9A and FIG. 11).

  Next, the control device 17 moves the grindstone table 15 in a direction approaching the outer periphery of the workpiece W, and brings the second detection probe 52 into contact with the second detection position P2f on the first outer periphery circle CC1 of the workpiece W. Then, the XZ coordinate value (X2f, Z2f) of the second detection position P2f of the detected workpiece W is stored (see step S5 in FIG. 9A and FIG. 11). Then, the first and second hydraulic cylinders 55 and 56 are operated to rotate the first and second arms 53 and 54 to position the first and second detection probes 51 and 52 at the retracted positions (step of FIG. 9A). S6).

  The control device 17 can detect the first and second detection positions P1b and P2b on the second outer circumference circle CC2 on the other end side (the tailstock 14 side) of the workpiece W shown in FIG. As described above, the grinding wheel base 15 and the traverse table 20 are positioned based on the position coordinates of the first and second detection probes 51 and 52 with respect to the grinding wheel base 15 inputted in advance and the outer diameter of the workpiece W (see FIG. 9A, step S7).

  The control device 17 operates the first and second hydraulic cylinders 55 and 56 to rotate the first and second arms 53 and 54 to position the first and second detection probes 51 and 52 at the detection positions (see FIG. Step S8 of 9A). Then, the grindstone table 15 is moved away from the outer periphery of the workpiece W, the first detection probe 51 is brought into contact with the first detection position P1b on the second outer periphery circle CC2 of the workpiece W, and the detected workpiece W is detected. The XZ coordinate value (X1b, Z1b) of the first detection position P1b is stored (see step S9 in FIG. 9A and FIG. 11).

  Next, the control device 17 moves the grinding wheel base 15 in a direction approaching the outer periphery of the workpiece W, and brings the second detection probe 52 into contact with the second detection position P2b on the second outer periphery circle CC2 of the workpiece W. The XZ coordinate value (X2b, Z2b) of the detected second detection position P2b of the workpiece W is stored (see step S10 in FIG. 9A and FIG. 11). Then, the first and second hydraulic cylinders 55 and 56 are operated to rotate the first and second arms 53 and 54 to position the first and second detection probes 51 and 52 at the retracted positions (step of FIG. 9A). S11). Then, it is determined whether grinding of the workpiece W has been completed (step S12 in FIG. 9A).

  When the grinding of the workpiece W has not been completed, the control device 17 determines the XZ coordinate values (X1f, Z1f), (X2f, X2) of the first and second detection positions P1f, P2f on the stored first outer circumference circle CC1. Z2f) and the first and second outer circles of the workpiece W based on the XZ coordinate values (X1b, Z1b) and (X2b, Z2b) of the first and second detection positions P1b and P2b on the second outer circle CC2. XZ coordinate values (Xcf, Zcf), (Xcp, Zcp) of the center positions Cpf, Cpb (one end side center position, the other end side center position) of CC1, CC2 are calculated (see step S13 in FIG. 9B, FIG. 11). .

  That is, as shown in FIG. 11, the distance a in the X-axis direction between the X coordinate value X1f of the first detection position P1f on the first outer circumference circle CC1 and the X coordinate value Xcf of the center position Cpf of the first outer circumference circle CC1 is The X coordinate value X2f of the second detection position P2f on the first outer circumference circle CC1 and the X coordinate value Xcf of the center position Cpf of the first outer circumference circle CC1 are equal to the distance a in the X axis direction. Therefore, the distance a is expressed by Expression (1), and the X coordinate value Xcf of the center position Cpf is expressed by Expression (2). The Z coordinate value is similarly expressed. The second outer circumference circle CC2 is also expressed in the same manner. From the above, since Expressions (3) and (4) are obtained, XZ of the center positions Cpf, Cpb (one end side center position, the other end side center position) of the first and second outer circumference circles CC1, CC2 of the workpiece W. Coordinate values (Xcf, Zcf), (Xcp, Zcp) can be calculated.

  Then, a straight line passing through the center positions Cpf and Cpb of the first and second outer circumference circles CC1 and CC2 of the workpiece W is calculated as the center axis C of the workpiece W (see step S14 in FIG. 9B and FIG. 11). As a result, the center axis C of the workpiece W can be easily obtained automatically. Steps S1-S14 correspond to the “center axis calculation unit” and “center axis calculation step” of the present invention.

  The control device 17 determines whether or not the X coordinate value Xcf of the center position Cpf of the first outer circumference circle CC1 is the same as the X coordinate value Xcb of the center position Cpb of the second outer circumference circle CC2 (step S15 in FIG. 9B). ). When the X coordinate value Xcf of the center position Cpf of the first outer circumference circle CC1 and the X coordinate value Xcb of the center position Cpb of the second outer circumference circle CC2 are not the same, the center axis C of the workpiece W is the first outer circumference circle CC1. It is determined whether or not the center position Cpf is inclined positively toward the center position Cpb of the second outer circumference circle CC2 (step S16 in FIG. 9B).

  When the center axis C of the workpiece W is positively inclined from the center position Cpf of the first outer circumference circle CC1 toward the center position Cpb of the second outer circumference circle CC2 (in this example), the control device 17 The turning table 30 is turned clockwise in FIG. 10 by the turning angle θc represented by the equation (5) (see step S17 in FIG. 9B, FIG. 12), and the center axis C of the workpiece W is guided to the guide rail of the traverse table 20. The workpiece W is centered by being parallel to 21 and the process proceeds to step S19.

  On the other hand, in the control device 17, the center axis C of the workpiece W is negatively inclined (ascending to the left in FIG. 10) from the center position Cpf of the first outer circumference circle CC1 toward the center position Cpb of the second outer circumference circle CC2. At this time, the turning table 30 is turned counterclockwise in FIG. 10 by the turning angle θu represented by the equation (6) (step S18 in FIG. 9B), and the center axis C of the workpiece W is guided to the guide rail of the traverse table 20. The workpiece W is centered by being parallel to 21 and the process proceeds to step S19. Steps S15 to S18 correspond to the “turning table turning portion”, the “turning table turning step”, and the “first turning table turning step” of the present invention.

  The control device 17 rotates the workpiece W that has been centered and rotates the grinding wheel 16 (step S19 in FIG. 9B), and the grinding wheel 16 is placed on the outer periphery on one end side (the headstock 13 side) of the workpiece W. The grindstone table 15 and the traverse table 20 are moved in the X axis direction and the Z axis direction so as to approach each other (step S20 in FIG. 9B).

  The control device 17 moves the grindstone table 15 toward the workpiece W, and stops the movement of the grindstone table 15 after the grinding wheel 16 has been cut to the depth of cutting during rough grinding after contacting the outer periphery of the workpiece W. To do. Then, the traverse table 20 is moved relative to the grinding wheel 16 so as to go from one end side (the headstock 13 side) of the workpiece W to the other end side (the tailstock 14 side). Grinding is performed (step S21 in FIG. 9B).

  The control device 17 determines whether or not the rough grinding has been completed (step S22 in FIG. 9B). If the rough grinding has not been completed, the control device 17 returns to step S20 and repeats the above processing. On the other hand, when the rough grinding is completed, the grinding wheel base 15 and the traverse table 20 are moved in the X-axis direction and the Z-axis direction so that the grinding wheel 16 approaches the outer periphery on one end side (the headstock 13 side) of the workpiece W. Move (step S23 in FIG. 9B).

  The control device 17 moves the grinding wheel base 15 toward the workpiece W, and stops the movement of the grinding wheel base 15 when the grinding wheel 16 cuts to the cutting amount at the time of fine grinding after contacting the outer periphery of the workpiece W. To do. Then, the traverse table 20 is moved with respect to the grinding wheel 16 so as to go from one end side (the headstock 13 side) of the workpiece W to the other end side (the tailstock 14 side). Grinding is performed (step S24 in FIG. 9B). Then, it is determined whether or not fine grinding has been completed (step S25 in FIG. 9B). If fine grinding has not been completed, the process returns to step S23 and the above processing is repeated. Steps S19 to S25 correspond to the “machining process” of the present invention.

  On the other hand, when the precise grinding is completed in step S25, the control device 17 returns to step S1 and performs the processing by the position detection device 50 described above (step S1-11 in FIG. 9A). In step S12, it is determined whether or not the grinding of the workpiece W is completed. In this case, since the grinding of the workpiece W is completed, the process proceeds to step S26 and the first on the first outer circumference CC1. The X coordinate values X1f, X2f of the second detection positions P1f, P2f and the X coordinate values X1b, X2b of the first, second detection positions P1b, P2b on the second outer circumference circle CC2 are expressed by Equations (7) and (8). And the outer diameters d1 and d2 of the first and second outer circles CC1 and CC2 are calculated (step S26 in FIG. 9B).

  Then, the control device 17 determines whether or not the outer diameters d1 and d2 of the first and second outer circumferences CC1 and CC2 are the same as the target diameter dd (step S27 in FIG. 9B), and the first and second When the outer diameters d1 and d2 of the outer circumference circles CC1 and CC2 are not the same as the target diameter dd, the process returns to step S23 and the above-described processing is repeated. On the other hand, when the outer diameters d1 and d2 of the first and second outer circumferences CC1 and CC2 are the same as the target diameter dd in step S27, the control device 17 ends all the processes. As described above, the final shape of the workpiece W is ground into a highly accurate cylindrical shape having an outer diameter of the target diameter dd, as shown in FIG.

7-2. Grinding Operation of Workpiece Having Tapered Part Next, FIGS. 14A to 14C show operations when the tapered part is ground to the other end side (the tailstock 14 side) of the cylindrical part of the workpiece W after the above-described grinding is completed. The description will be made with reference to FIGS. As shown in FIG. 15, the workpiece W includes two parts between the end surface on the other end side (the tailstock 14 side) of the workpiece W and a position separated by L in the central axis C direction. It is assumed that a taper portion T having a target taper angle Ψ shown by a dotted line is attached. However, the present invention can be similarly applied to the case where the tapered portion T is provided on one end side (the head stock 13 side) of the workpiece W. In this example as well, a case where rough grinding and fine grinding are performed will be described for convenience.

  The control device 17 turns the turning table 30 counterclockwise in FIG. 15 by the turning angle Ψ / 2 (refer to step S31 in FIG. 14A, FIG. 16, corresponding to the “second turning table turning step” of the present invention). Then, the workpiece W is rotated and the grinding wheel 16 is rotated (step S32 in FIG. 14A), so that the grinding wheel 16 approaches the outer circumference on the large diameter side of the tapered portion T of the workpiece W and The traverse table 20 is moved in the X axis direction and the Z axis direction (step S33 in FIG. 14A).

  The control device 17 moves to a position where the tapered portion T of the workpiece W is processed, and stops the movement of the grindstone table 15. Then, the traverse table 20 is moved with respect to the grinding wheel 16 from the large diameter side of the tapered portion T of the workpiece W toward the small diameter side, and the grinding wheel 16 is roughly ground (step S34 in FIG. 14A). .

  The control device 17 determines whether or not the rough grinding has been completed (step S35 in FIG. 14A). If the rough grinding has not been completed, the control device 17 returns to step S33 and repeats the above processing. On the other hand, when the rough grinding is completed, the grinding wheel base 15 and the traverse table 20 are moved in the X-axis direction and the Z-axis direction so that the grinding wheel 16 approaches the outer circumference of the tapered portion T of the workpiece W. (Step S36 in FIG. 14A).

  The control device 17 moves to a position where the tapered portion T of the workpiece W is processed, and stops the movement of the grindstone table 15. Then, the traverse table 20 is moved with respect to the grinding wheel 16 from the large diameter side of the tapered portion T of the workpiece W toward the small diameter side, and the workpiece W is precisely ground by the grinding wheel 16 (step S37 in FIG. 14A). . Then, it is determined whether or not fine grinding has been completed (step S38 in FIG. 14A). If fine grinding has not been completed, the process returns to step S36 and the above processing is repeated. Steps S32 to S38 correspond to the “taper processing step” of the present invention.

  On the other hand, when the precise grinding is completed, the control device 17 turns the turning table 30 clockwise by the turning angle Ψ / 2 in FIG. 16 (see step S39 in FIG. 14A, FIG. 17, “third” in the present invention). Corresponds to “swivel table turning process”). Then, the grindstone table 15 and the traverse table 20 are moved in the X axis direction and the Z axis direction so that the position detection device 50 approaches the outer periphery of the tapered portion T of the workpiece W on the large diameter side (step S40 in FIG. 14B). ). It is assumed that the first and second detection probes 51 and 52 are positioned at the retracted position.

  The control device 17 uses the position detection device 50 to detect first and second detection positions P1l on the outer diameter circle (hereinafter referred to as “large diameter outer circle”) CL of the tapered portion T of the workpiece W shown in FIG. , P2l based on the pre-input position coordinates of the first and second detection probes 51, 52 with respect to the grindstone table 15, the large diameter dd of the tapered portion T of the workpiece W, and the like. The platform 15 and the traverse table 20 are positioned (step S41 in FIG. 14B).

  The control device 17 operates the first and second hydraulic cylinders 55 and 56 to rotate the first and second arms 53 and 54 to position the first and second detection probes 51 and 52 at the detection positions (see FIG. 14B, step S42). Then, the grindstone table 15 is moved away from the outer periphery of the workpiece W, the first detection probe 51 is brought into contact with the first detection position P11 on the large-diameter outer circumference CL of the workpiece W, and the detected workpiece W is detected. The XZ coordinate value (X1l, Z1l) of the first detection position P1l is stored (see step S43 in FIG. 14B, FIG. 17).

  Next, the control device 17 moves the grindstone table 15 in a direction approaching the outer periphery of the workpiece W, and brings the second detection probe 52 into contact with the second detection position P2l on the large-diameter outer circle CL of the workpiece W. Then, the XZ coordinate value (X2l, Z2l) of the detected second detection position P2l of the workpiece W is stored (see step S44 in FIG. 14B, FIG. 17).

  The control device 17 operates the first and second hydraulic cylinders 55 and 56 to rotate the first and second arms 53 and 54 to position the first and second detection probes 51 and 52 at the retracted positions (see FIG. Step S45 of 14B). Then, the grindstone table 15 and the traverse table 20 are moved in the X-axis direction and the Z-axis direction so that the position detection device 50 approaches the outer periphery on the small diameter side of the tapered portion T of the workpiece W (step S46 in FIG. 14B). .

  The control device 17 uses the position detection device 50 to detect the first and second detection positions P1s and P2s on the outer diameter circle (hereinafter referred to as “small diameter outer circle”) CS of the tapered portion T of the workpiece W shown in FIG. Can be detected, based on the position coordinates of the first and second detection probes 51 and 52 with respect to the grinding wheel table 15 inputted in advance and the small diameter of the tapered portion T of the workpiece W, etc. The table 20 is positioned (step S47 in FIG. 14B).

  The control device 17 operates the first and second hydraulic cylinders 55 and 56 to rotate the first and second arms 53 and 54 to position the first and second detection probes 51 and 52 at the detection positions (see FIG. 14B, step S48). Then, the grindstone platform 15 is moved away from the outer periphery of the workpiece W, the first detection probe 51 is brought into contact with the first detection position P1s on the small-diameter outer circumference circle CS of the workpiece W, and the detected workpiece W is detected. The XZ coordinate value (X1s, Z1s) of the first detection position P1s is stored (see step S49 in FIG. 14B and FIG. 17).

  Next, the control device 17 moves the grindstone table 15 in a direction approaching the outer periphery of the workpiece W, and brings the second detection probe 52 into contact with the second detection position P2s on the small-diameter outer circle CS of the workpiece W, The XZ coordinate value (X2s, Z2s) of the second detection position P2s of the detected workpiece W is stored (see step S50 in FIG. 14B and FIG. 17). Then, the first and second hydraulic cylinders 55 and 56 are operated to rotate the first and second arms 53 and 54 to position the first and second detection probes 51 and 52 at the retracted positions (step in FIG. 14B). S51).

  As shown in FIG. 17, the control device 17 calculates the XZ coordinate values (X1l, Z1l), (X2l, Z2l) of the first and second detection positions P1l, P2l on the stored large-diameter outer circumference circle CL by the equation (9). ) And the taper angle σ of the taper portion T is calculated (see step S52 in FIG. 14C and FIG. 17). Thereby, the taper angle σ can be easily obtained automatically. Steps S40 to S52 correspond to the “taper angle calculation step” of the present invention.

  The control device 17 determines whether or not the taper angle σ and the target taper angle ψ are the same (see step S53 in FIG. 14C and FIG. 17). When the taper angle σ and the target taper angle ψ are not the same, a corrected turning angle is calculated (step S54 in FIG. 14C), and the turning table 30 is turned counterclockwise in FIG. 18 by the corrected turning angle (FIG. 14A). Step S55), the process returns to Step S36, and the precise grinding of the workpiece W and the position detection of the tapered portion T are performed again (Steps S36 to S52).

  When the taper angle σ is smaller than the target taper angle ψ (in this example), the control device 17 adds the target taper angle ψ to a half angle (Ψ−) of the difference between the target taper angle Ψ and the taper angle σ. A corrected turning angle Ψ + (Ψ−σ) / 2 obtained by adding σ) / 2 is calculated. On the other hand, when the taper angle σ is larger than the target taper angle Ψ, the control device 17 subtracts an angle (σ−Ψ) / 2 that is a half of the difference between the taper angle σ and the target taper angle Ψ from the target taper angle. The corrected turning angle Ψ− (σ−Ψ) / 2 is calculated.

  And the control apparatus 17 complete | finishes all the processes, when taper angle (sigma) and target taper angle (PSI) are the same in step S53. As described above, the final shape of the workpiece W is a portion between the end surface on the other end side (the tailstock 14 side) of the workpiece W and a position separated by L in the central axis C direction as shown in FIG. Then, it is ground into a cylindrical shape having a highly accurate taper portion T having a taper angle of Ψ.

  According to this embodiment, the detection of the outer peripheral position of the workpiece W, the calculation of the center axis C of the workpiece W, and the centering of the workpiece W by the turning of the turning table 30 are automatically performed in the cylindrical grinding machine 10. It is feasible with accuracy. Thereby, the cylindrical grinding machine 10 can perform high-precision centering in the loaded state and the processed state of the workpiece W. The cylindrical grinding machine 10 processes the outer periphery of the cylindrical workpiece W by moving along the guide rail 21 of the traverse table 20. Therefore, the accuracy of the outer diameter and taper angle of the workpiece W after processing can be improved.

  That is, when processing the workpiece W having the tapered portion T, it is necessary to process the tapered portion T with high accuracy with respect to the cylindrical portion. However, when the workpiece W is loaded, the shape of the workpiece W is prepared. It is not possible (the diameter of the cylindrical portion is not uniform), and the tilt (turning) of the turning table 30 may not be adjusted, and the tilt (turning) of the turning table 30 needs to be adjusted. And in order to process the taper part T after a process of a cylindrical part with high precision, it is also necessary to adjust the inclination (turning) of the turning table 30 and the amount of movement of the grindstone table 15 to the workpiece W.

  Therefore, by measuring the outer position of the workpiece W in the Z-axis direction (two points in the Z-axis direction and two points in the X-axis direction) when the workpiece W is loaded, the shape, inclination, etc. of the workpiece W can be accurately determined. The inclination (turning) of the turntable 30 can be adjusted. Furthermore, by measuring the outer position of the workpiece W in the Z-axis direction (two points in the Z-axis direction and two points in the X-axis direction) during machining, the shape (taper angle, etc.) of the taper portion T can be grasped and more accurately Can be processed. Furthermore, by automatically performing these measurements and processing by the control device 17, processing that does not require measurement and adjustment by humans is performed, processing efficiency is improved, and high-precision processing is possible.

(8. Others)
In the above-described embodiment, the detection of the outer peripheral position of the workpiece W by the position detection device 50 is performed after the completion of the rough grinding and the fine grinding. May be. Thereby, the processing accuracy of the workpiece W can be further improved.
Further, the position detection device 50 is provided so as to be movable together with the grindstone table 15, but it may be configured to be provided so as to be able to move independently by a dedicated movement device of the position detection device 50.

  Further, since the position detection device 50 is provided on the upper surface of the grinding wheel base 15, the rotation axes of the first and second arms 53 and 54 are at positions different from the rotation axis of the grinding wheel 16. However, the first and second arms 53 and 54 may be provided so that the rotation axis of the first and second arms 53 and 54 and the rotation axis of the grinding wheel 16 are coaxial. Thereby, since the position detection apparatus 50 can detect a position on the basis of the rotation axis of the grinding wheel 16, that is, the center, the position detection apparatus 50 is hardly affected by the thermal displacement and can maintain a highly accurate position detection.

  Further, although a table traverse type cylindrical grinder has been exemplified as a machine tool, the present invention can be applied to a grindstone traverse type cylindrical grinder. Moreover, this invention is applicable not only to a cylindrical grinding machine but to other machine tools. Further, the detection of the outer peripheral position of the workpiece W by the position detection device 50 may be performed in the turning operation of the turning table 30.

10: Cylindrical grinding machine, 11: Bed, 13: Spindle head, 14: Tailstock, 17: Control device, 20: Traverse table, 30: Turning table, 50: Position detection device, 51: First detection probe, 52 : Second detection probe, 53: first arm, 54: second arm, W: workpiece, T: taper part

Claims (8)

Bed and
A grinding wheel base that is provided on the upper surface of the bed and supports a grinding wheel capable of grinding the outer periphery of the workpiece so as to be rotatable around the central axis of the grinding wheel;
A table provided on the upper surface of the bed and movable along a guide rail or the grinding wheel base;
A turning table provided on the upper surface of the table and capable of turning about a turning axis perpendicular to the upper surface;
A headstock and a tailstock that are provided on the upper surface of the swivel table, support both ends of the workpiece, and rotate the workpiece around a rotation axis passing through both support points;
A position detection device provided with a detection probe capable of moving toward the outer periphery of the workpiece and capable of detecting the outer peripheral position of the workpiece;
A control device for processing the outer periphery of the workpiece by controlling the operations of the table or the grindstone table, the turning table, the headstock and the position detection device;
With
The control device includes:
Based on the outer peripheral position of the workpiece detected by the detection probe, a center axis calculation unit for obtaining a center axis of the workpiece;
A turning table turning unit for turning the turning table so that a center axis of the workpiece is parallel to the guide rail;
A machine tool comprising a swivel table. The position detection device includes two detection probes,
The two detection probes are respectively arranged on the free end sides of two arms that can rotate within a predetermined angle range around a rotation axis parallel to the guide rail, and the arm is set to one angle of the predetermined angle. 2. When rotated, the workpiece is positioned at a position where the outer peripheral position of the workpiece can be detected, and when the arm rotates to the other side of the predetermined angle, the workpiece is positioned at a position retracted from the workpiece. A machine tool comprising the turning table according to 1.   The free ends of the two arms are respectively bent in the same direction parallel to the guide rail so that the two detection probes are located on the same outer circumference of the workpiece. A machine tool with a swivel table.   The said position detection apparatus is a machine tool provided with the turning table as described in any one of Claims 1-3 provided in the said grindstone stand. A bed, a grinding wheel base that is provided on the upper surface of the bed and supports a grinding wheel capable of grinding the outer periphery of the workpiece so as to be rotatable about a central axis of the grinding wheel, and is provided on the upper surface of the bed. A table or a grindstone table that is movable along a guide rail, a swivel table that is provided on the top surface of the table and is capable of swiveling around a swivel axis perpendicular to the top surface, and the swivel table Provided on the upper surface, respectively supporting the both ends of the workpiece and rotating the workpiece about a rotation axis passing through both support points, and a tailstock and movable toward the outer periphery of the workpiece A position detection device having a detection probe capable of detecting the outer peripheral position of the workpiece, and a processing method by a machine tool comprising:
Based on the outer peripheral position of the workpiece detected by the detection probe, a center axis calculation step for obtaining a center axis of the workpiece;
A first turning table turning step for turning the turning table so that a center axis of the workpiece is parallel to the guide rail;
A processing step of grinding an outer periphery of the workpiece;
With
A machining method using a machine tool including a turning table, wherein the center axis calculation step, the first turning table turning step, and the machining step are repeated until an outer diameter of the workpiece reaches a target diameter. When the final shape of the workpiece has a cylindrical portion and a tapered portion,
By repeating the center axis calculation step, the first turning table turning step, and the machining step, the turning table is turned to the target taper angle of the tapered portion when the outer diameter of the cylindrical portion becomes the target diameter. A second turning table turning step,
A taper processing step of processing the tapered portion of the workpiece;
A third turning table turning step for turning the turning table to a state before completion of the second turning table turning step after completion of processing of the tapered portion;
A taper angle calculation step for obtaining a taper angle of the taper portion based on an outer peripheral position of the taper portion detected by the detection probe;
With
6. The turning according to claim 5, wherein the second turning table turning step, the taper processing step, the taper angle calculating step, and the third turning table turning step are repeated until the taper angle of the taper portion becomes the target taper angle. A processing method using a machine tool including a table.   The taper angle calculation step includes two outer peripheral positions on the same outer circumference circle on the large diameter side of the taper portion detected by the detection probe, and the same on the small diameter side of the taper portion detected by the detection probe. The processing method by a machine tool provided with the turning table of Claim 6 which calculates | requires the taper angle of the said taper part based on the outer periphery position of two places on an outer periphery circle | round | yen.   The center axis calculation step obtains one end side center position of the outer circumference circle from two outer circumference positions on the same outer circumference circle on the one end side of the workpiece detected by the detection probe, and detects by the detection probe. The other end side center position of the outer periphery circle is obtained from two outer periphery positions on the same outer periphery circle on the other end side of the workpiece to be obtained, and a straight line passing through the one end side center position and the other end side center position is obtained. The processing method by the machine tool as described in any one of Claims 5-7 calculated | required as a center axis line of the said workpiece.

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