JP2020075307A - Turn table device and machine tool - Google Patents

Abstract

To provide a turn table device capable of detecting a turning angle of a turn table with a high degree of accuracy, and a machine tool.SOLUTION: A turn table device includes: a table 20; a turn table 30 that is loaded on the table 20 and that can be turned with respect to the table 20; and a turning angle detector 50 that has arc-linear motion conversion mechanisms 51, 52, 53 and 57 for converting an arc motion associated with turning of the turn table 30 to a linear motion and that detects a turning angle of the turn table 30 by making a sensor device 54 measure the linear motion of a scale, converted by the arc-linear motion conversion mechanisms 51, 52, 53 and 57.SELECTED DRAWING: Figure 2A

Description

  The present invention relates to a turning table device and a machine tool.

  Patent Documents 1-3 describe a cylindrical grinder as a machine tool including a turning table device. With such a cylindrical grinder, not only grinding of a cylindrical work piece but also grinding of a work piece having a taper portion at the end of the cylindrical portion is possible by turning the turning table with respect to the traverse table. .. In the swivel table device described in Patent Document 3, the nut is fixed to the swivel table, and the screw shaft meshed with the nut is fixed to the traverse table. The operator turns the turning table by driving a motor connected to the screw shaft.

  In the turning table device described in Patent Document 3, a protrusion is provided on the traverse table and designated as a reference point. Then, the turning angle of the turning table is detected based on the distance from the turning center of the turning table in the X-axis direction to the reference point, the distance in the Z-axis direction, and the distance from the rotation center of the workpiece to the reference point.

JP, 2005-217481, A Japanese Patent No. 3666204 Japanese Patent No. 2578041

  In the turning table device described in Patent Document 3, since the turning angle of the turning table is indirectly detected, a detection error may occur. Therefore, there is a turning table device in which an R surface is formed on the end surface of the turning table, a scale is attached, and the sensor reads the scale to directly detect the turning angle of the turning table.

  However, if a processing error of the R surface formed on the end surface of the turning table or an attachment error of the scale occurs, the positioning work of the sensor that cancels the error becomes difficult, and a reading error of the sensor may occur. Further, since the distance between the scale attached to the R surface and the fixed sensor changes as the turning table turns, the sensor may not be read.

  It is an object of the present invention to provide a turning table device and a machine tool capable of detecting a turning angle of a turning table with high accuracy.

  A swivel table device according to the present invention is a table, a swivel table mounted on the table and capable of swiveling with respect to the table, and an arc-to-linear motion conversion mechanism for converting an arc motion accompanying the swivel of the swivel table into a linear motion. And a turning angle detecting device for detecting a turning angle of the turning table by measuring a linear movement of the scale converted by the circular arc linear movement converting mechanism by a sensor device.

  According to the present invention, since the turning angle detection device includes the circular arc linear motion conversion mechanism that converts the circular arc motion associated with the swiveling of the swivel table into the linear motion, the scale is attached to a flat surface to eliminate the attachment error. It can be reduced. Therefore, since the positioning of the sensor device only needs to be adjusted in the direction of the gap with the scale, the positioning work of the sensor device is facilitated and the occurrence of a reading error of the sensor device can be suppressed. Further, since the distance between the scale and the sensor device does not change, the sensor device can always read with high accuracy.

  A machine tool according to the present invention includes a bed, a grindstone base that is provided on an upper surface of the bed, and that rotatably supports a grinding wheel capable of grinding the outer periphery of a workpiece around a central axis of the grinding wheel, and the turning. A table device, the table or the grindstone that is provided on the upper surface of the bed and can move along a guide rail, and the table that is provided on the upper surface of the table and that can swivel about a swivel axis perpendicular to the upper surface. A turning table, and a headstock and a tailstock, which are provided on the upper surface of the turning table, respectively support both ends of the workpiece, and rotate the workpiece about a rotation axis passing through both support points, are provided.

  According to the present invention, since the turning angle of the turning table can be detected with high accuracy by the turning angle detection device, the machining accuracy of the workpiece can be maintained with high accuracy.

It is the figure which looked at the machine tool of this embodiment from the direction of the Y-axis. It is the figure which looked at the turning angle detection device which comprises the machine tool of FIG. 1 from the Y-axis direction. It is the figure which looked at the turning angle detection device of Drawing 2A from the direction of the Z-axis. It is a figure which shows the positional relationship between the turning axis and the turning angle detection device before turning the turning table. It is a figure which shows the positional relationship of the turning axis and the turning angle detection apparatus after turning the turning table. It is a figure which shows the positional relationship of the turning axis and turning angle detection apparatus before turning the turning table of another example. It is a figure which shows the positional relationship of the turning axis | shaft after turning the turning table of another example, and a turning angle detection apparatus. 3 is a flowchart for explaining the operation of the machine tool of FIG. 1.

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

  As shown in FIG. 1, a cylindrical grinder 10 includes a bed 11 placed on a floor surface, a turning table device 12 provided on the upper surface of the bed 11, a headstock 13 provided on the upper surface of the turning table device 12, and The tailstock 14, a grindstone base 15 provided on the upper surface of the bed 11 and having a grinding wheel 16, and a control device 17 and the like provided on the side surface of the bed 11 are provided.

  The turning table device 12 includes a traverse table 20 provided on the upper surface of the bed 11, and a turning table 30 provided on the upper surface of the traverse table 20. Furthermore, a turning mechanism 40 that turns the turning table 30 on the upper surface of the traverse table 20, a turning angle detection device 50 that detects a turning angle of the turning table 30, and the like are provided.

  The traverse table 20 is formed in a long rectangular shape in a top view. The traverse table 20 can be moved along a guide rail 20a laid on the bed 11 in the Z-axis direction by driving an actuator (not shown) such as a linear motor. 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 when the turning table 30 is placed.

  The revolving table 30 is formed in a flat hexagonal shape in a top view. The swivel table 30 is supported so as to swivel around the Y-axis around the swivel shaft 30a 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. Like the upper surface of the traverse table 20, the lower surface of the turning table 30 is subjected to scraping and the like.

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

  The turning mechanism 40 causes the turning table 30 to turn by rotating the screw shaft of the ball screw mechanism 41 by the rotation of the handle 42 by the operator and moving the position of the nut of the ball screw mechanism 41 on the XZ plane. Then, in order to fix the turning table 30 to the traverse table 20 when the turning table 30 is turned, clamp devices 33a and 33b are provided on both longitudinal ends of the turning table 30.

  The turning angle detection device 50 detects the turning angle θ of the turning table 30. The turning angle detection device 50 is provided on one end side of the upper surface of the traverse table 20, measures the amount of movement of the position on the one end side of the turning table 30 with respect to the traverse table 20, and detects the turning angle θ of the turning table 30. The details of the turning angle detection device 50 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 turning table device 12. The center 13a of the headstock 13 and the center 14a of the tailstock 14 support both ends of the cylindrical workpiece W, respectively. The headstock 13 has a built-in spindle motor 13b for rotating the workpiece W around a central axis passing through both support points of the centers 13a and 14a.

  The grindstone base 15 holds a tool (grinding wheel 16) used for grinding, and is driven along with a guide rail 15a laid on the bed 11 in the X-axis direction by driving an actuator (a linear motor or the like) not shown. Can be moved. The grinding wheel base 15 rotatably supports the grinding wheel 16 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 whetstone base 15 can be moved in the Z-axis direction on the bed 11.

  The control device 17 controls the rotation of the workpiece W and the rotation of the grinding wheel 16, and also controls the relative movement between the workpiece W and the grinding wheel 16 (movement in the Z-axis direction and the X-axis direction of the three orthogonal axes). The outer periphery of the workpiece W is ground by controlling.

(2. Configuration of turning angle detection device)
Next, the configuration of the turning angle detection device 50 will be described with reference to the drawings. As shown in FIGS. 1, 2A, and 2B, the turning angle detection device 50 includes a slider 51, a linear guide 52, an arm 53, and a sensor device 54. The slider 51 is formed in a rectangular parallelepiped shape, and the scale 55 is attached to the side surface thereof. A cam follower 56 is provided on the upper surface of the slider 51. A bearing may be used instead of the cam follower 56.

  The linear guide 52 is formed in a rail shape, and is provided on one end side of the upper surface of the traverse table 20 so as to extend in the X axis direction. A slider 51 is slidably mounted on the linear guide 52 in the X-axis direction to guide the movement of the slider 51. The arm 53 is provided on one end side of the revolving table 30 so as to extend in the Z-axis direction. One end of a tension spring 57 is connected to the arm 53. The other end of the tension spring 57 is connected to the slider 51, so that the arm 53 is in constant contact with the cam follower 56. The slider 51, the linear guide 52, the arm 53, and the tension spring 57 form an arc-linear motion conversion mechanism that converts the arc motion associated with the turning of the turning table 30 into a linear motion.

  The sensor device 54 includes, for example, a magnetic sensor, and is provided near the scale 55 of the slider 51 on one end side of the upper surface of the traverse table 20. The sensor device 54 reads the scale 55 of the slider 51 that moves along with the turning of the turning table 30, measures the amount of movement of the slider 51, and determines the turning angle θ of the turning table 30 based on the measured amount of movement of the slider 51. To detect.

  According to the above-described turning angle detection device 50, since the scale 55 is attached to the flat side surface of the slider 51, the processing error on the side surface of the slider 51 can be reduced and the attachment error of the scale 55 can be reduced. Therefore, since the positioning of the sensor device 54 only needs to be adjusted in the gap direction with the scale 55, the positioning work of the sensor device 54 is facilitated and the occurrence of a reading error of the sensor device 54 can be suppressed. Further, even if the turning table 30 turns, the scale 55 attached to the slider 51 moves linearly, so that the distance from the fixed sensor device 54 does not change. Therefore, it is possible to always read the sensor device 54 with high accuracy.

(3. Detection processing of the turning angle detection device)
The turning angle detection processing by the turning angle detection device 50 having the above configuration will be described. First, as shown in FIG. 3A, a case where the center of the revolving shaft 30a of the revolving table 30 and the center of the cam follower 56 are aligned with each other will be described. In this case, as shown in FIG. 3A, the center-to-center distance Za in the Z-axis direction between the center of the turning shaft 30a of the turning table 30 and the center of the cam follower 56 is measured and stored in advance.

  Then, as shown in FIG. 3B, the sensor device 54 measures the amount of movement of the slider 51 by reading the scale 55 of the slider 51 that moves along with the turning of the turning table 30. Then, the turning angle θa of the turning table 30 is calculated by substituting the measured movement amount Xda of the slider 51 and the stored center-to-center distance Za in the Z-axis direction into the equation (1).

  Next, as shown in FIG. 4A, a case will be described in which the center of the revolving shaft 30a of the revolving table 30 and the center of the cam follower 56 are displaced by a distance Xb in the X-axis direction. In this case, as shown in FIG. 4A, the center-to-center distance Zb in the Z-axis direction and the center-to-center distance Xb in the X-axis direction between the center of the turning shaft 30a of the turning table 30 and the center of the cam follower 56 are measured and stored in advance. deep. In the following description, a straight line extending in the Z-axis direction passing through the center of the turning shaft 30a of the turning table 30 is referred to as a reference line B.

  Then, as shown in FIG. 4B, the sensor device 54 reads the scale 55 of the slider 51 that moves along with the turning of the turning table 30, and measures the amount of movement of the slider 51. Then, by substituting the measured movement amount Xdb of the slider 51 and the stored center-to-center distance Xb in the X-axis direction into the equation (2), the center of the turning axis 30a of the turning table 30 and the turning table 30 after turning. The center-to-center distance Xc in the X-axis direction of the center of the cam follower 56 is calculated.

  Then, the sensor device 54 substitutes the calculated center-to-center distance Xc in the X-axis direction and the stored center-to-center distance Zb in the Z-axis direction into the equation (3), whereby the turning table 30 after turning is turned. A first angle α formed by a reference line B and a straight line C passing through the center of the turning shaft 30a of 30 and the center of the cam follower 56 is calculated. Then, by substituting the measured movement amount Xdb of the slider 51, the stored center-to-center distance Zb in the Z-axis direction and the center-to-center distance Xb in the X-axis direction into the formula (4), the turning table 30 turns after turning. The center-to-center distance L between the center of the turning shaft 30a of the table 30 and the center of the cam follower 56 is calculated.

  Then, the sensor device 54 substitutes the stored center-to-center distance Xb in the X-axis direction and the calculated center-to-center distance L into the equation (5) to obtain the straight line C and the reference after turning of the turning table 30. The second angle β formed by the line B is calculated. Then, the turning angle θb of the turning table 30 is calculated by substituting the calculated first angle α and second angle β into the equation (6).

(4. Operation of machine tool equipped with turning table device)
Next, a description will be given of a case where a tapered surface having a taper angle θw is machined on one end side of the cylindrical workpiece W in the operation of the cylindrical grinder 10 provided with the turning table device 12 by the operator. The operator holds both ends of the cylindrical work W between the center 13a of the headstock 13 and the center 14a of the tailstock 14 (step S1 in FIG. 5).

  Then, the worker turns the turning table 30 by turning the handle 42 while looking at the display monitor of the control device 17 in which the turning detection angle from the sensor device 54 is displayed (step S2 in FIG. 5). The turning angle of the turning table 30 can be detected with high accuracy by the turning angle detection device 50 described above.

  The operator confirms whether the turning detection angle displayed on the display monitor has reached the target taper angle θw of the tapered surface (step S3 in FIG. 5), and the turning detection angle displayed on the display monitor is When the target taper angle θw of the taper surface is reached, taper rough machining is commanded from the controller 17 (step S4 in FIG. 5).

  Then, the operator confirms whether or not the taper rough machining has been completed (step S5 in FIG. 5), and when the taper rough machining is completed, the taper angle θd of the machined taper surface and the target taper angle of the taper surface. An error Δθ from θw is displayed on the monitor (step S6 in FIG. 5). The taper angle θd of the processed tapered surface can be calculated based on the detected position of two positions and the trigonometric function by detecting the position coordinates of, for example, two positions of the tapered surface, which is a known method.

  While looking at the display monitor, the operator turns the handle 42 to turn the turning table 30 so that the error Δθ becomes zero (step S7 in FIG. 5). Then, it is confirmed whether or not the error Δθ reaches zero (step S8 in FIG. 5), and when the error Δθ reaches zero, the controller 17 instructs the taper finishing process (step S9 in FIG. 5). Then, it is confirmed whether or not the taper finishing process is completed (step S10 in FIG. 5), and when the taper finishing process is completed, all the operations are completed.

(5. Other)
In the above-described embodiment, the turning of the turning table 30 is configured such that the ball screw mechanism 41 is operated by the handle 42, but the ball screw mechanism 41 may be operated by a motor. This makes it possible to automate the adjustment of the turning angle of the turning table 30.

  Further, the taper angle θd of the processed tapered surface is calculated each time the processing is performed, and the error Δθ is obtained and adjusted. However, the correction coefficient is obtained in advance from the relationship between the taper angle calculated by processing the test piece and detected by the position detection device and the turning detection angle detected by the sensor device 54. Then, at the time of actually machining the workpiece, the turning detection angle detected by the sensor device 54 may be corrected to a measured value by a correction coefficient.

  Further, although a table traverse type cylindrical grinder is given as an example of the machine tool, it can be applied to a wheel head traverse type cylindrical grinder. Further, the present invention is applicable not only to the cylindrical grinder but also to other machine tools.

10: Cylindrical grinder, 11: Bed, 12: Turning table device, 13: Headstock, 14: Tailstock, 20: Traverse table, 30: Turning table, 40: Turning mechanism, 41: Ball screw mechanism, 42: Handle , 50: turning angle detection device, 51: slider, 52: linear guide, 53: arm, 54: sensor device, 55: scale, 56: cam follower, 57: tension spring, W: workpiece

Claims (3)

A table,
A turning table placed on the table and capable of turning with respect to the table;
The rotary table has a circular arc linear motion conversion mechanism for converting the circular arc motion associated with the swivel of the swivel table into a linear motion, and the linear motion of the scale converted by the circular arc linear motion conversion mechanism is measured by a sensor device to swivel the swivel table. A turning angle detection device that detects an angle,
And a turning table device. The circular arc translation conversion mechanism,
A linear rail disposed on one end side of the turning table and extending in the turning direction of the turning table,
A slider movable along the rail,
A linear arm extending from one end side of the turning table in a direction perpendicular to the turning direction,
An abutting member arranged on the slider and capable of abutting on the arm;
The turning table device according to claim 1, further comprising: a biasing member that is connected between the arm and the slider and that biases the arm and the abutting member in a direction of abutting the arm and the abutting member. Bed and
A grindstone that is provided on the upper surface of the bed and that rotatably supports a grinding wheel capable of grinding the outer periphery of a workpiece around the central axis of the grinding wheel.
A swivel table device according to claim 1 or 2,
Provided on the upper surface of the bed, the table or the grindstone that is movable along a guide rail,
The turning table provided on the upper surface of the table and capable of turning around a turning axis perpendicular to the upper surface,
A headstock and a tailstock that are provided on the upper surface of the revolving table, respectively support both ends of the workpiece, and rotate the workpiece around a rotation axis passing through both support points;
A machine tool including a turning table device.

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