JP7114926B2 - Machine tool with swivel table and processing method using the machine tool - Google Patents

Description

TECHNICAL FIELD The present invention relates to a machine tool having a swivel table and a machining method using the machine tool.

Patent Documents 1 and 2 describe a cylindrical grinder as a machine tool provided with a swivel table. Such a cylindrical grinder can grind not only a cylindrical workpiece but also a workpiece having a tapered portion at the end of the cylindrical portion by rotating the rotary table.

JP 2015-217481 A JP 2015-217482 A

In a cylindrical grinder equipped with a swivel table, reproducibility due to deflection and thermal displacement that occur when grinding a workpiece, and setup movement of the headstock and tailstock when both ends of the workpiece are supported by the headstock and tailstock. For these reasons, there is a risk that the accuracy of the outer diameter of the workpiece and the taper angle will decrease. 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 perform centering of the workpiece. There is a problem that the

An object of the present invention is to provide a machine tool equipped with a turning table capable of automating highly accurate centering of a workpiece, and a machining method using the machine tool.

One aspect of the present invention provides a bed,
a grinding wheel stand provided on the upper surface of the bed for supporting a grinding wheel capable of grinding the outer circumference of a workpiece so as to be rotatable about the central axis of the grinding wheel;
a table or the wheelhead provided on the upper surface of the bed and movable along a guide rail;
a turning table provided on the top surface of the table and capable of turning around a turning axis perpendicular to the top surface;
a headstock and a tailstock provided on the upper surface of the turning table, supporting both ends of the workpiece and rotating the workpiece around a rotation axis passing through both support points;
a position detection device provided movably toward the outer circumference of the workpiece and having two detection probes capable of detecting the outer circumference position of the workpiece;
a control device that controls each operation of the table or the wheelhead, the swivel table, the headstock, and the position detection device to machine the outer circumference of the workpiece;
with
The two detection probes are arranged on free end sides of two arms that are rotatable within a range of a predetermined angle about a rotation axis parallel to the guide rail, and the arms are rotated at one side of the predetermined angle. When the arm rotates, it is positioned at a position where the outer peripheral position of the workpiece can be detected, and when the arm rotates to an angle on the other side of the predetermined angle, it is positioned at a position retracted from the workpiece,
The control device is
a central axis calculation unit that obtains a central axis of the workpiece based on the outer peripheral position of the workpiece detected by the two detection probes;
a turning table turning part for turning the turning table so that the central axis of the workpiece is parallel to the guide rail;
In a machine tool with a swivel table, comprising:

Another aspect of the present invention is a bed, and a grinding wheel provided on the upper surface of the bed and capable of grinding the outer periphery of a workpiece whose final shape has a cylindrical portion and a tapered portion. a whetstone base that is rotatably supported; a table or the whetstone base that is provided on the upper surface of the bed and is movable along a guide rail; a turning table that can turn around a turning axis perpendicular to the upper surface; and a turning table that is provided on the upper surface of the turning table, supports both ends of the workpiece, and rotates the workpiece around a rotation axis that passes through both support points. and a position detection device provided movably toward the outer periphery of the workpiece and having a detection probe capable of detecting the outer peripheral position of the workpiece. and
a central axis calculation step of obtaining a central axis of the workpiece based on the outer peripheral position of the workpiece detected by the detection probe;
a first turning table turning step of turning the turning table so that the central axis of the workpiece is parallel to the guide rail;
a processing step of grinding the outer circumference of the cylindrical portion of the workpiece;
By repeating the central axis calculating step, the first rotating table rotating step, and the machining step, when the outer diameter of the cylindrical portion reaches the target diameter, the rotating table is rotated to the target taper angle of the tapered portion. a second turning table turning process;
a tapering step of grinding the tapered portion of the workpiece;
a third turning table turning step of turning the turning table to a state before performing the second turning table turning step after the machining of the taper portion is completed;
a taper angle calculation step of obtaining a taper angle of the tapered portion based on the outer peripheral position of the tapered portion detected by the detection probe;
with
A machine comprising a turning table, 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 reaches the target taper angle. It is in the processing method by machine.

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 the turntable can be automatically executed with high accuracy in the machine tool. As a result, the machine tool can perform high-precision centering when the workpiece is loaded or processed. Then, the machine tool processes the outer circumference of the cylindrical workpiece by moving the table or the wheelhead along the guide rails. Therefore, the accuracy of the outer diameter and taper angle of the machined workpiece 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 direction. FIG. 2B is a view of the position detection device of FIG. 2A viewed from the X-axis direction; 2B is a diagram for explaining the operating state of the position detection device of FIG. 2A; FIG. FIG. 2B is a diagram showing an operation state when detecting a small-diameter workpiece with the position detection device of FIG. 2A , in which the detection probe is positioned at the retracted position; FIG. 2B is a diagram showing an operation state when detecting a small-diameter workpiece with the position detection device of FIG. 2A, in which the detection probe is positioned at the detection start position; FIG. 2B is a diagram showing an operation state when detecting a small-diameter workpiece with the position detection device of FIG. 2A, in which the detection probe is positioned at the first detection position; FIG. 2B is a diagram showing an operation state when detecting a small-diameter workpiece with the position detection device of FIG. 2A, in which the detection probe is positioned at the second detection position; FIG. 2B is a diagram showing an operation state when detecting a small-diameter workpiece with the position detection device of FIG. 2A, in which the detection probe is returned to the retracted position and positioned. FIG. 2B is a diagram showing an operation state when detecting a large-diameter workpiece with the position detection device of FIG. 2A, in which the detection probe is positioned at the retracted position; FIG. 2B is a diagram showing an operation state when detecting a large-diameter workpiece with the position detection device of FIG. 2A, in which the first detection probe is positioned at the detection start position; FIG. 2B is a diagram showing an operation state when detecting a large-diameter workpiece with the position detection device of FIG. 2A, in which the first detection probe is positioned at the first detection position; FIG. 2B is a diagram showing an operation state when detecting a large-diameter workpiece with the position detection device of FIG. 2A, in which the first detection probe is returned to the retracted position and positioned. FIG. 2B is a diagram showing an operation state when detecting a large-diameter workpiece with the position detection device of FIG. 2A, in which the second detection probe is positioned at the detection start position; FIG. 2B is a diagram showing an operation state when detecting a large-diameter workpiece with the position detection device of FIG. 2A, in which the second detection probe is positioned at the second detection position; FIG. 2B is a diagram showing an operation state when detecting a large-diameter workpiece with the position detection device of FIG. 2A , in which the second detection probe is returned to the retracted position and positioned. FIG. 2 is a view of a cover that constitutes the machine tool of FIG. 1 as seen from the Y-axis direction; It is the figure which looked at the cover of FIG. 6A from the Z-axis direction. 6B illustrates the operating state of the cover of FIG. 6A when the swivel table is swiveled counterclockwise; FIG. 6B illustrates the operating state of the cover of FIG. 6A when the swivel table is rotated clockwise; FIG. 2 is a cross-sectional view showing the internal structure of a headstock that constitutes the machine tool of FIG. 1; FIG. FIG. 8B is a cross-sectional view taken along line VIIIB-VIIIB in FIG. 8A; FIG. 8B is a cross-sectional view taken along line VIIIC-VIIIC of FIG. 8A. 4 is a flow chart for explaining a position detection operation in a grinding method for a cylindrical workpiece; 4 is a flow chart for explaining a turning motion and a grinding motion of a turning table in a grinding method for a cylindrical workpiece; FIG. 2 is a plan view showing a state in which a workpiece is loaded into the machine tool of FIG. 1; FIG. 11 is a plan view for explaining position detection of a workpiece carried into the machine tool of FIG. 10; FIG. 12 is a plan view for explaining the turning of the workpiece in FIG. 11; FIG. 13 is a plan view showing the state of the workpiece of FIG. 12 after grinding; 4 is a flow chart for explaining the turning motion and grinding motion of the turning table in the method for grinding a cylindrical workpiece having a tapered portion; 4 is a flowchart for explaining a position detection operation in a grinding method for a cylindrical workpiece having a tapered portion; 4 is a flow chart for explaining a verification operation of a tapered portion in a grinding method for a cylindrical workpiece having a tapered portion; FIG. 14 is a plan view showing a tapered portion attached to the workpiece after grinding of FIG. 13; FIG. 16 is a plan view for explaining the turning of the workpiece in FIG. 15; FIG. 17 is a plan view for explaining position detection of the workpiece in FIG. 16; FIG. 18 is a plan view for explaining corrective turning of the workpiece in FIG. 17; FIG. 19 is a plan view showing the state of the workpiece of FIG. 18 after grinding;

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

As shown in FIG. 1, a cylindrical grinder 10 includes a bed 11 placed on the floor, 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. A table 14 , a grinding wheel 15 provided on the upper surface of the bed 11 and having a grinding wheel 16 , a position detection device 50 provided on the grinding wheel 15 , and a control device 17 provided on the side 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 for turning the turning table 30 on the upper surface of the traverse table 20 .

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

The swivel table 30 is formed in a flat hexagonal shape when viewed from above. The turning table 30 is supported so as to be able to turn about the Y-axis around a turning shaft 30a while sliding on the upper surface of the traverse table 20. As shown in FIG. FIG. 1 shows a state in which the turning table 30 has a turning angle θ with respect to the Z-axis. Like the upper surface of the traverse table 20, the lower surface of the turning table 30 is subjected to a scraping process 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 of the 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 side 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 side of the turning table 30. Prepare.

The actuator 40 rotates the swivel table 30 by rotating the ball screw 42 by driving the motor 41 and moving the position of the ball screw nut 43 on the XZ plane. In order to fix the turning table 30 to the traverse table 20 when the turning table 30 is turned, clamp devices 31a and 31b are provided at both ends of the turning table 30 in the longitudinal direction.

Here, when the turn table 30 is turned, a triangular surface is exposed on the upper surface of the traverse table 20. If coolant, cutting oil, grinding dust, abrasive grains, etc. adhere to this exposed surface, the turning table 30 may not turn. Occasionally, wear and tear occur, which may reduce the accuracy of the turning angle. Therefore, a cover 60 is arranged between the traverse table 20 and the turning table 30 to protect the upper surface of the traverse table 20, as shown in FIGS. 6A and 6B. Details of the cover 60 will be described later.

The headstock 13 and the tailstock 14 have a center 13 a and a center 14 a , respectively, and are fixed to the upper surface of the table unit 12 . A center 13a of the headstock 13 and a center 14a of the tailstock 14 support both ends of the cylindrical workpiece W, respectively. The headstock 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, the headstock 13 incorporates a bearing 13c for supporting the center 13a. When the workpiece W rotates, the temperature of the headstock 13 becomes high due to the 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 due to an emergency stop or the like, the internal pressure of the headstock 13 decreases as the inside of the headstock 13 cools, and the coolant, cutting oil, etc. adhering to the exterior of the headstock 13 is sucked. There is a risk that it will be lost.

Therefore, high-pressure air is supplied from the outside of the headstock 13 to the inside of the headstock 13 in order to prevent coolant, cutting oil, or the like from entering the bearing 13c that supports the center 13a through the clearance of the headstock 13. An air purge path 130 (13d, 13e, 13f, 13g) is provided for the purpose. Details of the air purge path 130 (13d, 13e, 13f, 13g) will be described later.

The grinding wheel 15 holds a tool (grinding wheel 16) used for grinding, and is driven by an unillustrated actuator (linear motor or the like) along a guide rail 15a laid on the bed 11 in the X-axis direction. can be moved. The grinding wheel 15 supports the grinding wheel 16 rotatably about the center axis 16a so that the center axis 16a of the grinding wheel 16 capable of grinding the outer circumference of the workpiece W faces the Z-axis direction. A guide rail may be laid in the Z-axis direction so that the wheelhead 15 can move on the bed 11 in the Z-axis direction.

The position detection device 50 is provided on the wheelhead 15 and detects the outer peripheral position and end surface position of the workpiece W with two independently operable first and second detection probes 51 and 52 . If one detection probe is used for detection, the detection range is limited to the stroke of the wheelhead 15 in the X-axis direction. , the detection range is less likely to be restricted by the stroke of the wheelhead 15 in the X-axis direction.

Further, when grinding a cylindrical work W with the cylindrical grinder 10, even if the work W is shaken or the turning angle of the turning table 30 is set to 0 degrees, the center axis of the work W is When the traverse table 20 is tilted with respect to the guide rails 21, it is necessary to detect the outer peripheral positions of both ends of the workpiece W and center the workpiece W based on the detected outer peripheral positions. When two detection probes having a fixed arrangement interval are used for detection, the detection operation time for a 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 controls relative movement between the workpiece W and the grinding wheel 16 (movement in the Z-axis direction and the X-axis direction among the three orthogonal axes). The outer periphery of the workpiece W is ground by controlling. In addition, the control device 17 controls the operation of the position detection device 50, calculates the center axis line and outer diameter of the workpiece W based on the detected outer peripheral position of the workpiece W, and calculates the workpiece W having a tapered portion. Calculate the taper angle of W.

(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 wheelhead 15 and is movable on the bed 11 together with the wheelhead 15 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 respectively detect the outer peripheral position of the workpiece W, and a first arm 53 and a second arm 53 to which the first and second detection probes 51 and 52 are attached, respectively. It comprises an arm 54, and a first hydraulic cylinder 55 and a second hydraulic cylinder 56 for rotating the first and second arms 53, 54, respectively.

The first detection probe 51 and the first arm 53 are supported by a first hydraulic cylinder 55 on the front side of the upper surface of the wheelhead 15 (on the workpiece W side) so as to be rotatable about the rotation axis 50a around the Z axis. The detection probe 52 and the second arm 54 are supported on the front side of the upper surface of the wheelhead 15 by a second hydraulic cylinder 56 so as to be rotatable around the Z-axis around the rotary shaft 50a. 2A to 2C show the state in which the first and second detection probes 51 and 52 are positioned above the wheelhead 15 at the retracted position.

The first and second detection probes 51 and 52 are general contact-type probes, and detect the positions of contact with the contactors 51a and 52a at the tips, respectively. The first and second detection probes 51 and 52 may be non-contact probes such as light or laser.
The first and second arms 53 and 54 are each formed in an L shape, and in FIGS. arranged side by side. Here, the 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 the portions lower than the bent portions 53a and 54a are referred to as base portions 53b and 54b.

The lower end sides of the bases 53b and 54b of the first and second arms 53 and 54 are respectively supported on the front side of the upper surface of the wheelhead 15 so as to be freely rotatable around the Z axis around the same rotary shaft 50a. On the free end side of the bent portions 53a and 54a of the first and second arms 53 and 54, the contactors 51a and 52a of the first and second detection probes 51 and 52 face 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.

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

The bent portions 53a and 54a of the first and second arms 53 and 54 are long enough that the first and second detection probes 51 and 52 attached to the free end sides of the bent portions 53a and 54a are parallel on the same XY plane. is formed Thereby, the first and second detection probes 51 and 52 can detect the outer peripheral position of the workpiece W on the same outer circumference.

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 at the contactors 51a and 52a of the first and second detection probes 51 and 52 (Fig. 2C A point Q) is formed at a matching length. As a result, the contactors 51a and 52a are fixed at the same position in the direction of the central axis C of the workpiece W, so that even if the first and second arms 53 and 54 perform different operations, In the positioning of the contactors 51a and 52a, the effects of errors due to the shape of the workpiece W and the support of the workpiece W can be suppressed, and accurate measurement can be performed. In addition, by adjusting the lengths of the bent portions 53a and 54a of the first and second arms 53 and 54, it is possible to avoid interference with the driving portion that rotates the first and second arms 53 and 54, and close to the processing portion. can be measured in position.

Further, the base portion 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 grinder 10 on the side opposite to the grinding wheel 16 (on the operator side). It is formed in a length that does not interfere with the first detection probe 51 . Although the rotating shafts 50a of the first and second arms 53 and 54 are the same rotating shaft, the rotating shafts 50a may be different. Also, although the first hydraulic cylinder 55 and the second hydraulic cylinder 56 are hydraulic cylinders, they may be motors or other drive actuators.

(3. Operation of position detection device)
As shown in FIG. 3, the first and second arms 53 and 54 are moved together with the first and second detection probes 51 and 52 by extending and contracting the rods 55a and 56a of the first and second hydraulic cylinders 55 and 56. It rotates about the Z-axis around the rotating shaft 50a within the range of a predetermined angle φ. That is, as shown by the solid line in FIG. 3, the extension of the rods 55a and 56a of the first and second hydraulic cylinders 55 and 56 causes the first and second arms 53 and 54 to move to one side (work piece W) at a predetermined angle φ. side), the first and second detection probes 51 and 52 are positioned at the 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 located at outer peripheral positions 180 degrees apart across the central axis C of the workpiece W, that is, the outer peripheral circle CC of the workpiece W, the central axis C of the workpiece W, and the grinding wheel. The XZ coordinate values of the positions of two intersections P1 and P2 (hereinafter referred to as "first and second detection positions P1 and P2") with a straight line S parallel to the X-axis passing through the center axis 16a of 16 are detected.

Also, as shown by the dashed line in FIG. 3, contraction of the rods 55a and 56a of the first and second hydraulic cylinders 55 and 56 moves the first and second arms 53 and 54 to the other side of the predetermined angle φ. When rotated, the first and second detection probes 51 and 52 are positioned at retracted positions retracted upward (in the Y-axis direction) from the detection start positions described above. In this manner, the first and second detection probes 51 and 52 can independently move between the detection start position and the retracted position, so that when one detection probe detects the workpiece, the other detection probe detects 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 of detecting P1 and P2 will be described. It should be noted that the position detection device 50 is positioned so that 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 contactors 51a and 52a 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 head 15) is moved away from the workpiece W in the X-axis direction, and the contactor 51a of the first detection probe 51 is moved to the outer circumference of the workpiece W. to detect the first detection position P1. Next, as shown in FIG. 4D, the position detection device 50 (grindstone head 15) is moved in the X-axis direction toward the workpiece W, and the contactor 52a of the second detection probe 52 is moved to the outer circumference of the workpiece W. to detect the second detection position P2.

After that, the position detection device 50 (grindstone head 15) is moved in the direction 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 positions. Then, as shown in FIG. 4E, the rods 55a and 56a of the first and second hydraulic cylinders 55 and 56 are contracted to simultaneously rotate the first and second arms 53 and 54, and the first and second detection probes 51 are rotated. , 52 are positioned at the retracted position above the detection start position. As described above, the detection of the first and second detection positions P1 and P2 of the workpiece W is completed.

Further, for example, as shown in FIG. 5A, the first and second detection probes 51 and 52 of the first and second detection probes 51 and 52 have a larger diameter D (>H) than the radial arrangement interval H of the workpiece W. A case of detecting two detection positions P1 and P2 will be described. It is assumed that the position detection device 50 is 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 to position the first detection probe 51 at the detection start position. At this time, the contactor 51a of the first detection probe 51 is separated from the outer periphery of the workpiece W. As shown in FIG.

Next, as shown in FIG. 5C, the position detection device 50 (grindstone head 15) is moved away from the workpiece W in the X-axis direction, and the contactor 51a of the first detection probe 51 is moved to the outer circumference of the workpiece W. to detect the first detection position P1. After that, the position detection device 50 (grindstone head 15) is moved in the direction of 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 at the retracted position above the detection start 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, thereby positioning the second detection probe 52 at the detection start position. At this time, the contactor 52a of the second detection probe 52 is separated from the outer circumference of the workpiece W. As shown in FIG.

Next, as shown in FIG. 5F, the position detection device 50 (grindstone head 15) is moved in a direction approaching the workpiece W in the X-axis direction, and the contactor 52a of the second detection probe 52 is moved to the outer circumference of the workpiece W. to detect the second detection position P2. After that, the position detection device 50 (grindstone head 15) is moved in the direction 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, thereby positioning the second detection probe 52 at the retracted position above the detection start position. As described above, the detection of the first and second detection positions P1 and P2 of the workpiece W is completed.

(4. Configuration of cover)
Conventional cylindrical grinders are equipped with covers on both sides of the grindstone table to prevent the adhesion of coolant, cutting oil, grinding dust, abrasive grains, etc. to the top surface of the table (see Japanese Patent No. 3923769 and Japanese Patent No. 3065536). However, there is a problem that the size of the cylindrical grinder increases.

In the cylindrical grinder 10 of this embodiment, as shown in FIGS. 6A and 6B, the cover 60 is made of a plastic sheet or the like and has substantially the same length as the revolving table 30 in the longitudinal direction and extends in the lateral direction of the revolving table 30 . It is formed into a structure that becomes a bellows. The central portion of the cover 60 in the longitudinal direction when the bellows are closed is attached to an attachment portion 32 that protrudes from the center of the longitudinal side surface of the swivel table 30 on the upper side in FIG.

The central portion of the cover 60 in the longitudinal direction when the bellows are closed is attached to the attachment portion 32 so that coolant, cutting oil, etc. do not enter from the attachment portion. 6A of the cover 60 (on the side of the wheelhead 15) is in close contact with the longitudinal side of the guide member 33, and the longitudinal side of the lower side of the cover 60 in FIG. 6A (on the side opposite to the wheelhead 15) is brought into close contact with the longitudinal side surface of the upper side (the wheelhead 15 side) of the swivel table 30 in FIG. 6A.

The attachment portion 32 is rotatably supported by a rotating shaft 33 a provided at the center of a long rectangular parallelepiped guide member 33 . The guide member 33 is arranged slidably in the Z-axis direction with play in a groove 22 provided on the longitudinal side surface of the traverse table 20 on the upper side (on the wheelhead 15 side) in FIG. 6A.

(5. Operation of the cover)
As shown in FIG. 7A, when the swivel table 30 swivels about the Y-axis counterclockwise around the swivel shaft 30a, the guide member 33 slides in the groove 22 in the Z-axis direction (to the left in the drawing). Further, as shown in FIG. 7B, when the turning table 30 turns clockwise about the Y-axis around the turning shaft 30a, the guide member 33 slides in the groove 22 in the Z-axis direction (to the right in the drawing).

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

In addition, since the cover 60 prevents coolant, cutting oil, grinding dust, abrasive grains, etc. from adhering to the swivel surface (upper surface) of the traverse table 20, the flatness of the swivel surface can be maintained for a long period of time. It is possible to improve machining accuracy by accurate positioning. In addition, since the cover 60 is structured so as not to protrude from the bed 11 when the revolving table 30 revolves, the cost of the apparatus can be reduced by making the cylindrical grinder 10 more compact, and the workability is improved and the workpiece can be processed more efficiently. Reliability can be improved.

(6. Configuration of Air Purge Route)
Some conventional cylindrical grinders supply high-pressure air from the outside to the inside of the headstock to prevent coolant, cutting oil, etc. from entering (see Japanese Patent No. 4867277 and Japanese Patent No. 5931103). However, if coolant, cutting oil, etc., which is accelerated by the rotation of the grinding wheel during grinding and overcomes the pressure of the air is produced, there is a problem that the coolant, cutting oil, etc., enter through the gaps in the headstock.

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

Air is jetted toward the workpiece W side from the front air purge chamber 13d, as indicated by the illustrated arrow. At the same time, the air is supplied toward the atmospheric pressure chamber 13f and also supplied from the rear air purge chamber 13e toward the atmospheric pressure chamber 13f. Air supplied to the atmospheric pressure chamber 13f is exhausted to the outside through the exhaust hole 13g. Since the inside of the atmospheric pressure chamber 13f is connected to the outside pressure, it is constantly maintained at the atmospheric pressure. Therefore, the air pressure in the rear air purge chamber 13e is constantly higher than that in the atmospheric pressure chamber 13f.

As described above, when the inside of the headstock 13 is cooled due to an emergency stop or the like, external air is supplied to the inside of the headstock 13 through the air discharge hole 13g and the atmospheric pressure chamber 13f. Since the atmospheric pressure chamber 13f is usually not a place where coolant, cutting oil, or the like is directly supplied, the possibility of coolant, cutting oil, or the like entering the headstock 13 is low. Further, since the atmospheric pressure is the same between the atmospheric pressure chamber 13f and the workpiece W side, no movement of air due to cooling occurs.

Also, as described above, even if coolant, cutting oil, etc., which overcomes the air pressure is generated and penetrates into the atmospheric pressure chamber 13f, the pressure of the coolant, cutting oil, etc. drops in the atmospheric pressure chamber 13f. Therefore, there is a low possibility that it will penetrate to the bearing 13c further behind.

Also, even if coolant, cutting oil, etc. mixed with air enters the atmospheric pressure chamber 13f, the coolant, cutting oil, etc. are naturally discharged to the outside from the discharge hole 13g at the bottom of the atmospheric pressure chamber 13f. Since the discharge hole 13g is provided at the bottom of the atmospheric pressure chamber 13f, coolant, cutting oil, etc. are prevented from entering from the outside.

(7. Operation of control device)
7-1. Grinding Operation of Cylindrical Workpiece The grinding operation (processing method) of the cylindrical work piece W in the control device 17 will be described with reference to FIGS. 9A, 9B, and 10 to 13. FIG. In addition, 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 between the first and second detection probes 51 and 52 (d<H). and However, the same applies when the outer diameter d of the workpiece W before grinding is larger than the radial arrangement interval H of the workpiece W between the first and second detection probes 51 and 52 (d>H).

Also, as shown in FIG. 10, the workpiece W is to be ground into a cylindrical shape with a target diameter dd indicated by a dashed line. In addition, normal grinding includes steps of empty grinding, rough grinding, fine grinding, fine grinding, and spark-out.

The control device 17 moves the wheelhead 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 of the workpiece W on the one end side (headstock 13 side) (Fig. Step S1 of 9A). It is assumed that the first and second detection probes 51 and 52 are positioned at the retracted positions.

The control device 17 is configured so that the position detection device 50 can detect first and second detection positions P1f and P2f on the first outer circumference circle CC1 on one end side (headstock 13 side) of the workpiece W shown in FIG. 2, the wheel head 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 wheel head 15 and the outer diameter of the workpiece W, etc., which have been input in advance (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 (Fig. 9A step S3). Then, the wheel head 15 is moved away from the outer circumference 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. store the XZ coordinate values (X1f, Z1f) of the first detection position P1f (step S4 in FIG. 9A, see FIG. 11).

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

The control device 17 can detect the first and second detection positions P1b and P2b on the second outer circle CC2 on the other end side (tailstock 14 side) of the workpiece W shown in FIG. 10 by the position detection device 50. As described above, the wheel head 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 wheel head 15 and the outer diameter of the workpiece W, etc., which are input in advance (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 (Fig. 9A step S8). Then, the wheel head 15 is moved away from the outer circumference of the workpiece W, the first detection probe 51 is brought into contact with the first detection position P1b on the second outer circumference circle CC2 of the workpiece W, and the detected workpiece W is detected. store the XZ coordinate values (X1b, Z1b) of the first detection position P1b (step S9 in FIG. 9A, see FIG. 11).

Next, the control device 17 moves the wheelhead 15 in a direction approaching the outer circumference of the workpiece W, and brings the second detection probe 52 into contact with the second detection position P2b on the second outer circumference circle CC2 of the workpiece W. , the XZ coordinate values (X2b, Z2b) of the detected second detection position P2b of the workpiece W are 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, and the first and second detection probes 51 and 52 are positioned at the retracted positions (step in FIG. 9A). S11). Then, it is determined whether or not the grinding of the workpiece W is completed (step S12 in FIG. 9A).

When the grinding of the workpiece W is not completed, the control device 17 sets the stored XZ coordinate values (X1f, Z1f), (X2f, Z2f) and the XZ coordinate values (X1b, Z1b), (X2b, Z2b) of the first and second detection positions P1b, P2b on the second peripheral circle CC2, the first and second peripheral circles of the workpiece W Calculate XZ coordinate values (Xcf, Zcf) and (Xcp, Zcp) of center positions Cpf and Cpb (one end side center position, other end side center position) of CC1 and CC2 (see step S13 in FIG. 9B and 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 circle CC1 and the X-coordinate value Xcf of the center position Cpf of the first outer circle CC1 is , the distance a in the X-axis direction between the X-coordinate value X2f of the second detection position P2f on the first outer circle CC1 and the X-coordinate value Xcf of the center position Cpf of the first outer circle CC1. Therefore, the distance a is represented by Formula (1), and the X-coordinate value Xcf of the center position Cpf is represented by Formula (2). Note that the Z coordinate value is similarly represented. Also, the second outer circumference circle CC2 is similarly represented. From the above, the equations (3) and (4) are obtained, so the XZ of the center positions Cpf and Cpb (one end side center position, other end side center position) of the first and second outer circumference circles CC1 and CC2 of the workpiece W Coordinate values (Xcf, Zcf) and (Xcp, Zcp) can be calculated.

Then, a straight line passing through the center positions Cpf and Cpb of the first and second outer circles CC1 and CC2 of the workpiece W is calculated as the center axis line C of the workpiece W (see step S14 in FIG. 9B and FIG. 11). As a result, the central axis C of the workpiece W can be easily obtained automatically. It should be noted that steps S1 to S14 correspond to the "center axis line calculation section" and the "center axis line calculation step" of the present invention.

The control device 17 determines whether the X-coordinate value Xcf of the center position Cpf of the first outer circle CC1 and the X-coordinate value Xcb of the center position Cpb of the second outer circle CC2 are the same (step S15 in FIG. 9B). ). When the X-coordinate value Xcf of the center position Cpf of the first outer circle CC1 and the X-coordinate value Xcb of the center position Cpb of the second outer circle CC2 are not the same, the center axis C of the workpiece W is aligned with the first outer circle CC1. from the center position Cpf of the second outer circle CC2 toward the center position Cpb of the second outer circle CC2 (upward to the right in FIG. 10) or not (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 circle CC1 toward the center position Cpb of the second outer circle CC2 (in this example), the controller 17 The turning table 30 is turned clockwise in FIG. 21, the workpiece W is centered, and the process proceeds to step S19.

On the other hand, the control device 17 causes the center axis C of the workpiece W to be negatively 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 (up left shoulder in FIG. 10). 10 counterclockwise in FIG. 21, the workpiece W is centered, and the process proceeds to step S19. Steps S15 to S18 correspond to the "swivel table turning section", the "swivel table turning process", and the "first turning table turning process" of the present invention.

The control device 17 rotates the centered workpiece W and also the grinding wheel 16 (step S19 in FIG. 9B) so that the grinding wheel 16 is positioned on the outer periphery of the workpiece W on one end side (headstock 13 side). The wheel head 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 grinding wheel 15 toward the workpiece W, and stops the movement of the grinding wheel 15 when the grinding wheel 16 contacts the outer periphery of the workpiece W and cuts to the depth of cut for rough grinding. do. Then, the traverse table 20 is moved with respect to the grinding wheel 16 from one end side (headstock 13 side) of the workpiece W toward the other end side (tailstock 14 side), and the grinding wheel 16 roughens the workpiece W. Grind (step S21 in FIG. 9B).

The control device 17 determines whether or not the rough grinding has been completed (step S22 in FIG. 9B), and when the rough grinding has not been completed, the process returns to step S20 and repeats the above-described processing. On the other hand, when the rough grinding is completed, the grinding wheel 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 workpiece W on one end side (headstock 13 side). Move (step S23 in FIG. 9B).

The control device 17 moves the grinding wheel 15 toward the workpiece W, and stops the movement of the grinding wheel 15 when the grinding wheel 16 contacts the outer periphery of the workpiece W and cuts to the depth of cut for fine grinding. do. Then, the traverse table 20 is moved with respect to the grinding wheel 16 from one end side (headstock 13 side) of the workpiece W toward the other end side (tailstock 14 side), and the grinding wheel 16 moves the workpiece W precisely. Grind (step S24 in FIG. 9B). Then, it is determined whether or not fine grinding has been completed (step S25 in FIG. 9B), and if fine grinding has not been completed, the process returns to step S23 and the above-described processing is repeated. Note that steps S19 to S25 correspond to the "processing steps" of the present invention.

On the other hand, when the fine grinding is completed in step S25, the control device 17 returns to step S1 and performs the processing by the position detection device 50 (step S1-11 in FIG. 9A). Then, in step S12, it is determined whether or not the grinding of the workpiece W has been completed. , X-coordinate values X1f and X2f of the second detection positions P1f and P2f and X-coordinate values X1b and X2b of the first and second detection positions P1b and P2b on the second outer circumference circle CC2 are expressed by the formulas (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 circles CC1 and CC2 are the same as the target diameter dd (step S27 in FIG. 9B). 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 repeats the above processing. On the other hand, if the outer diameters d1 and d2 of the first and second outer circles CC1 and CC2 are the same as the target diameter dd in step S27, the control device 17 ends all processing. 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. 14A to 14C for grinding the tapered portion on the other end side (tailstock 14 side) of the cylindrical portion of the workpiece W that has been ground. and FIGS. 15-19. In addition, as shown in FIG. 15, the workpiece W has two grooves on the part between the end surface of the other end side (tailstock 14 side) of the workpiece W and a position spaced apart by L in the direction of the central axis line C. It is assumed that a taper portion T having a target taper angle Ψ indicated by a dashed line is provided. However, the same can be applied to the case where the tapered portion T is attached to one end side of the workpiece W (headstock 13 side). For the sake of convenience, this example also describes a case where rough grinding and fine grinding are performed.

The control device 17 turns the turning table 30 counterclockwise in FIG. 15 by a turning angle Ψ/2 (see step S31 in FIG. 14A and FIG. 16, which corresponds to the “second turning table turning step” of the present invention). Then, while rotating the workpiece W, rotate the grinding wheel 16 (step S32 in FIG. 14A), and move the grinding wheel 15 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 the position where the tapered portion T of the workpiece W is machined, and stops the movement of the wheelhead 15 . Then, the traverse table 20 is moved with respect to the grinding wheel 16 from the large diameter side toward the small diameter side of the tapered portion T of the workpiece W, and the workpiece W is roughly ground by the grinding wheel 16 (step S34 in FIG. 14A). .

The control device 17 determines whether or not the rough grinding is completed (step S35 in FIG. 14A), and when the rough grinding is not completed, returns to step S33 and repeats the above-described processing. On the other hand, when the rough grinding is completed, the wheel head 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 large diameter side of the tapered portion T of the workpiece W. (step S36 in FIG. 14A).

The control device 17 moves to the position where the tapered portion T of the workpiece W is machined, and stops the movement of the wheelhead 15 . Then, the traverse table 20 is moved with respect to the grinding wheel 16 from the large diameter side toward the small diameter side of the tapered portion T of the workpiece W, and the grinding wheel 16 precisely grinds the workpiece W (step S37 in FIG. 14A). . Then, it is determined whether or not fine grinding has been completed (step S38 in FIG. 14A), and if fine grinding has not been completed, the process returns to step S36 and the above-described processing is repeated. Note that steps S32 to S38 correspond to the "tapering process" of the present invention.

On the other hand, when the fine grinding is completed, the control device 17 turns the turning table 30 clockwise in FIG. 16 by turning angle Ψ/2 (see step S39 in FIG. 14A and FIG. Equivalent to “swivel table swivel process”). Then, the wheel head 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 circumference 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 positions.

The control device 17 uses the position detection device 50 to detect the first and second detection positions P1l on the large diameter side outer circumference (hereinafter referred to as "large diameter outer circumference") CL of the tapered portion T of the workpiece W shown in FIG. , P2l, the grindstone Position the platform 15 and the traverse table 20 (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 (Fig. 14B step S42). Then, the wheelhead 15 is moved away from the outer periphery of the workpiece W, and the first detection probe 51 is brought into contact with the first detection position P1l on the large-diameter outer circumference CL of the workpiece W, thereby detecting the workpiece W. store the XZ coordinate values (X1l, Z1l) of the first detection position P1l (step S43 in FIG. 14B, see FIG. 17).

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

The control device 17 actuates 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 (Fig. 14B step S45). Then, the wheel head 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 small diameter side (step S46 in FIG. 14B). .

The control device 17 uses the position detection device 50 to detect first and second detection positions P1s and P2s on the small diameter side outer circumference (hereinafter referred to as "small diameter outer circumference") CS of the tapered portion T of the workpiece W shown in FIG. can be detected, the wheel head 15 and the traverse 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 (Fig. 14B step S48). Then, the wheel head 15 is moved away from the outer periphery of the workpiece W, and the first detection probe 51 is brought into contact with the first detection position P1s on the small-diameter outer circle CS of the workpiece W. The XZ coordinate values (X1s, Z1s) of the first detection position P1s are stored (step S49 in FIG. 14B, see FIG. 17).

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

As shown in FIG. 17, the control device 17 calculates XZ coordinate values (X1l, Z1l) and (X2l, Z2l) of the first and second detection positions P1l and P2l on the stored large-diameter outer circle CL using the formula (9). ) to calculate the taper angle σ of the taper portion T (step S52 in FIG. 14C, see FIG. 17). As a result, the taper angle σ can be easily obtained automatically. Note that 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 (step S53 in FIG. 14C, see FIG. 17). Then, when the taper angle σ and the target taper angle Ψ are not the same, the 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 precision grinding of the workpiece W and position detection of the tapered portion T are performed again (steps S36-S52).

When the taper angle .sigma. σ)/2 is added to calculate the corrected turning angle ψ+(ψ−σ)/2. On the other hand, when the taper angle σ is larger than the target taper angle Ψ, the control device 17 subtracts from the target taper angle an angle (σ−Ψ)/2 that is half the difference between the taper angle σ and the target taper angle Ψ. Then, the modified turning angle Ψ-(σ-Ψ)/2 is calculated.

Then, in step S53, when the taper angle σ and the target taper angle Ψ are the same, the control device 17 ends all processing. As a result, the final shape of the workpiece W is, as shown in FIG. Then, it is ground into a cylindrical shape having a highly accurate taper portion T with a taper angle 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 rotation of the rotation table 30 are automatically performed by the cylindrical grinder 10. It is executable with precision. As a result, the cylindrical grinder 10 can perform highly accurate centering of the workpiece W while it is being loaded and processed. The cylindrical grinder 10 processes the outer periphery of the cylindrical workpiece W by moving the traverse table 20 along the guide rails 21 . Therefore, the accuracy of the outer diameter and taper angle of the workpiece W after machining can be improved.

In other words, when machining a workpiece W having a tapered portion T, it is necessary to machine the tapered portion T with high accuracy with respect to the cylindrical portion. (the diameter of the cylindrical portion is not uniform), and the tilt (turning) of the turning table 30 may not be adjusted. In addition, in order to machine the tapered portion T after machining the cylindrical portion with high accuracy, it is also necessary to adjust the inclination (rotation) of the rotary table 30 and the amount of movement of the wheelhead 15 toward the workpiece W, and the like.

Therefore, by measuring the outer position of the workpiece W in the Z-axis direction (2 points in the Z-axis direction and 2 points in the X-axis direction) when the workpiece W is carried in, the shape, inclination, etc. of the workpiece W can be accurately determined. can be measured, and the tilt (turning) of the turning table 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 of the tapered portion T (taper angle, etc.) can be grasped, resulting in even more accurate measurement. can be processed into Furthermore, by automatically performing these measurements and machining by the control device 17, the machining can be performed without the need for human measurement and adjustment, and machining efficiency can be improved, enabling high-precision machining.

(8. Others)
In the above embodiment, the position detecting device 50 detects the outer peripheral position of the workpiece W after rough grinding and fine grinding are completed. may Thereby, the machining accuracy of the workpiece W can be further improved.
Further, the position detection device 50 is provided movably together with the wheelhead 15, but may be provided so as to be independently movable by a dedicated moving device for the position detection device 50. FIG.

Further, since the position detection device 50 is provided on the upper surface of the grinding wheel 15 , the rotation axes of the first and second arms 53 and 54 are positioned at different positions from the rotation axis of the grinding wheel 16 . However, the first and second arms 53 and 54 may be provided so that the axis of rotation of the first and second arms 53 and 54 and the axis of rotation of the grinding wheel 16 are coaxial. As a result, the position detection device 50 can detect the position with reference to the rotation axis of the grinding wheel 16, that is, the center of the grinding wheel 16, so that it is less likely to be affected by thermal displacement and can maintain highly accurate position detection.

In addition, although a table traverse type cylindrical grinder is taken as an example of a machine tool, the present invention can be applied to a wheelhead traverse type cylindrical grinder. Moreover, the present invention is applicable not only to cylindrical grinders but also 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 during the turning operation of the turning table 30 .

10: Cylindrical Grinding Machine, 11: Bed, 13: Headstock, 14: Tailstock, 17: Control Device, 20: Traverse Table, 30: Turning Table, 50: Position Detector, 51: First Detection Probe, 52 : second detection probe 53: first arm 54: second arm W: workpiece T: tapered portion

Claims (6)

bed and
a grinding wheel stand provided on the upper surface of the bed for supporting a grinding wheel capable of grinding the outer circumference of a workpiece so as to be rotatable about the central axis of the grinding wheel;
a table or the wheelhead provided on the upper surface of the bed and movable along a guide rail;
a turning table provided on the top surface of the table and capable of turning around a turning axis perpendicular to the top surface;
a headstock and a tailstock provided on the upper surface of the turning table, supporting both ends of the workpiece and rotating the workpiece around a rotation axis passing through both support points;
a position detection device provided movably toward the outer circumference of the workpiece and having two detection probes capable of detecting the outer circumference position of the workpiece;
a control device that controls each operation of the table or the wheelhead, the swivel table, the headstock, and the position detection device to machine the outer circumference of the workpiece;
with
The two detection probes are arranged on free end sides of two arms that are rotatable within a range of a predetermined angle about a rotation axis parallel to the guide rail, and the arms are rotated at one side of the predetermined angle. When the arm rotates, it is positioned at a position where the outer peripheral position of the workpiece can be detected, and when the arm rotates to an angle on the other side of the predetermined angle, it is positioned at a position retracted from the workpiece,
The control device is
a central axis calculating unit that obtains a central axis of the workpiece based on the outer peripheral position of the workpiece detected by the two detection probes;
a turning table turning part for turning the turning table so that the center axis of the workpiece is parallel to the guide rail;
A machine tool with a swivel table. The free ends of the two arms are each bent in the same direction parallel to the guide rail so that the two detection probes are positioned on the same outer circumference of the workpiece. A machine tool with a swivel table. 3. A machine tool comprising a swivel table according to claim 1, wherein said position detection device is provided on said wheelhead. A bed and a grinding wheel that supports a grinding wheel that is provided on the upper surface of the bed and that can grind the outer periphery of a workpiece whose final shape has a cylindrical portion and a tapered portion so as to be rotatable around the central axis of the grinding wheel. a table, which is provided on the upper surface of the bed and which is movable along a guide rail; a swivel table that can swivel around; 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 about a rotation axis passing through both support points; and a position detection device provided movably toward the outer periphery of the workpiece and having a detection probe capable of detecting the outer peripheral position of the workpiece, wherein
a central axis calculation step of obtaining a central axis of the workpiece based on the outer peripheral position of the workpiece detected by the detection probe;
a first turning table turning step of turning the turning table so that the central axis of the workpiece is parallel to the guide rail;
a processing step of grinding the outer circumference of the cylindrical portion of the workpiece;
By repeating the central axis calculating step, the first rotating table rotating step, and the machining step, when the outer diameter of the cylindrical portion reaches the target diameter, the rotating table is rotated to the target taper angle of the tapered portion. a second turning table turning process;
a tapering step of grinding the tapered portion of the workpiece;
a third turning table turning step of turning the turning table to a state before performing the second turning table turning step after the machining of the taper portion is completed;
a taper angle calculation step of obtaining a taper angle of the tapered portion based on the outer peripheral position of the tapered portion detected by the detection probe;
with
A machine comprising a turning table, 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 reaches the target taper angle. Machining method. In the taper angle calculation step, two outer circumference positions on the same outer circumference circle on the large diameter side of the taper portion detected by the detection probe and the same angle on the small diameter side of the taper portion detected by the detection probe. 5. The machining method using a machine tool having a turning table according to claim 4 , wherein the taper angle of said taper portion is obtained based on two outer peripheral positions on the outer peripheral circle. In the central axis calculation step, a center position on one end side of the outer circumference circle is obtained from two outer circumference positions on the same outer circumference circle on one end side of the workpiece detected by the detection probe, and the center position is detected by the detection probe. The other end side center position of the outer circumference circle is obtained from two outer circumference positions on the same outer circumference circle on the other end side of the workpiece to be processed, and a straight line passing through the one end side center position and the other end side center position 6. A processing method using a machine tool provided with a swivel table according to claim 4 or 5 , wherein the center axis of said workpiece is obtained.

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