JPH02145241A - Centering device - Google Patents

Abstract

PURPOSE:To facilitate centering work by equipping a rocking shaft rockably supported on a main body, the conical body fixed to one end thereof and rocking the rocking shaft and a detecting means detecting the rocking of the rocking shaft. CONSTITUTION:A main body 20 having the shank 21 attached/detached to a main shaft and a sensor bracket 30 are possessed, a rocking shaft 41 is provided at the lower part thereof and press-fitted to a spherical face bearing 42. The bearing 42 is rotatably supported on the support member 45 of the bracket 30 lower end. A centering tool 49 (conical body) having a tapered face 49a at the lower end of the shaft 41 is energized to the lower part by the compression spring 48 outer-inserted rockably. Four touch sensors 54 are screwed by a nut 55 on the upper face of the bracket 30. When the main shaft is approached to a work WK along the shaft thereof and the tapered face 49a of the conical body 49 is abutted to the peripheral edge of the hole HL of the work WK, the shaft 41 is rocked in case of the shaft 41 and hole HL being not co-axial and this is detected by the sensor 54, so the main shaft is driven so that the shaft 41 becomes in the state of not rocking.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a centering device used in machine tools such as machining centers and three-dimensional measuring devices.

B. Prior Art Conventionally, there has been known a centering device for centering, for example, the main shaft of a machining center with respect to a circular hole formed in a workpiece. This type of conventional centering device includes a main shaft movable in three axes (x, y, and z) that are orthogonal to each other and a touch sensor that is coaxially attached, and performs centering work as follows.

First, the main shaft on which the touch sensor is attached is moved along the axis in two directions toward the workpiece, and the probe, which is the detection part of the touch sensor, is inserted into the hole in the workpiece.

Next, the probe is moved along the horizontal X-axis perpendicular to the Z-axis, brought into contact with the wall of the hole, and its coordinates are read. Next, the probe is moved in the opposite direction along the y-axis to come into contact with the wall surface, its coordinates are read, and the center coordinates of xli[ are calculated and determined from the two read X coordinates. Similarly, for the y-axis, the probe is brought into contact with two points on the inner peripheral surface of the hole of the workpiece, and the coordinates are read, thereby calculating and determining the center coordinates of the y-axis. X obtained in this way
.

The y-coordinate is the center of the hole.

C0 Problems to be Solved by the Invention However, in the above-mentioned centering method, it is necessary to bring the probe into contact with the wall surface of the hole multiple times, so the operation is complicated and the probe is easily damaged. In addition, calculation processing to find the center is essential.

A technical object of the present invention is to enable centering work to be performed without using a sensor that is easily damaged, such as a probe, and without performing the complicated operations described above.

00 Means for Solving the Problems The present invention will be explained with reference to FIG. 1 showing an embodiment of the invention. 12, and is applied to a centering device that centers the main shaft 12 with respect to a hole HL formed in a workpiece WK. The main body 20 includes a mounting portion 21 for the main shaft 12, a swing shaft 41 that is swingably supported by the main shaft 20 and coaxially with the main shaft 12 at all times, and one end of the swing shaft 41. It has a tapered surface 49a that comes into contact with the periphery of the hole HL when the main shaft 12 is brought close to the workpiece WK along the axis, and when the swing shaft 41 and the hole HL are not coaxial, the swing shaft The above technical problem is solved by providing a cone 49 for swinging the swing shaft 41 and detection means 54a to 54d for detecting the swing of the swing shaft 41.

86 action When the main shaft 12 is brought close to the workpiece WK along its axes (two axes) by the driving means 65z, the tapered surface 49 of the cone 49
a comes into contact with the periphery of the hole HL of the workpiece WK. At this time,
If the swing shaft 41 and the hole HL are not coaxial, the swing shaft 41
oscillates, and this is detected by the detection means 54a to 54d. Therefore.

If the main shaft 12 is driven by the drive means 65x, 65y so that the swing shaft 41 does not swing.

The main shaft 12 is centered with respect to the hole HL.

In the above-mentioned sections and section E, which describe the present invention in detail, figures of embodiments are used to make the present invention easier to understand, but the present invention is not limited to the embodiments.

F. Embodiment An embodiment in which the present invention is applied to a centering device for a machining center will be described with reference to FIGS. 1 to 5.

FIG. 2 shows a schematic configuration of the machining center 10. The machining center 10 has a table 11 on which a workpiece WK is placed and held, and a main shaft 12 provided above the table 11 and rotated by a motor (not shown).The main shaft 12 is equipped with various cutting tools CT. Along with performing machining work on the workpiece WK.

A measurement tool (not shown) is attached to perform measurement work. That is, the main shaft 12 is connected to the motors 65x to 65z shown in FIG.
This allows the tool CT to move in three axes directions of the +yHZ axes that are orthogonal to each other, and thereby moves the tool CT to a predetermined position to process the workpiece WK.

In addition, prior to the machining operation, a centering device 100 as shown in FIG.
This tool CT and centering device 100, which perform centering on the workpiece WK, are held in a tool magazine 13,
The automatic tool changer 14 grasps tools from the tool magazine 13 according to the work, mounts them on the spindle 12, removes the tools from the spindle 12, and transports them to the tool magazine 13.

Centering device [1!100 is the main body 20 as shown in FIG.
and a sensor bracket 30 screwed onto the main body 20 via a bolt 71. The main body 20 is formed with a shank (mounting part) 21 that is attached to and detached from the main shaft 12 of the machining center 1o described above, and a gripped part 22 that is gripped by the automatic tool change bag @14. A swing shaft 41 extending downward is provided inside the sensor bracket 30 , and this shaft 41 is press-fitted into a spherical bearing 42 . A bracket 44 is screwed onto one lower end of the sensor bracket 30 via a five-bolt 43.
A spherical bearing 42 is rotatably supported by a support member 45 held at the support member 45 . Therefore, the shaft 41 has a spherical bearing 42
The rotation of the main shaft 12 makes it possible to swing around the axis X, and when the main shaft 12 is not swinging, it is held coaxially with the main shaft 12.

A dog 47 having a spherical surface 47a is screwed onto the upper end of the shaft 41 with a bolt 46, and a centering tool 49 (cone) having a tapered surface 49a is slidably fitted onto the lower end of the shaft 41. is urged downward by the compression spring 48, and the shaft 41
It is held on the swing shaft 41 by a nut 50 screwed into the pivot shaft 41 . Further, a spring receiver 51 is screwed onto the bracket 44 with a bolt 52, and a conical spring 53 is provided between the spring receiver 51 and the spherical bearing 42. This conical spring 5
3 holds the weight of the centering tool 49 so that the swing shaft 41 does not swing due to the weight of the centering tool 49 when the centering device 100 is mounted on a machining center whose main axis extends in the horizontal direction.

As shown in Figure 3, which is a sectional view taken along the line ■-■ in Figure 1,
Four touch sensors 54a, 54b, 5, 4c, and 54d are screwed onto the upper surface of the sensor bracket 30 with nuts 55, and when the swing shaft 41 is not swinging, the tip portion PR of each sensor 54a to 54d is is the spherical surface 47 of the dog 47
They are in contact with the a-ends, respectively. Each sensor 54a to 54
d outputs a contact signal when it is in contact with the spherical surface 47a, and when the shaft 41 swings and the tip PR of one of the sensors leaves the spherical surface 47a, the contact signal from that sensor is cut off. It will be done. That is, the main shaft 12 and the swing shaft 41 are coaxial only when contact signals are output from all four sensors.

Further, transmission couplers 56a to 56d are attached to the surface of the main body 20 in correspondence with the sensors 54a to 54d, and the presence or absence of a contact signal from each sensor 54a to 54d is determined via the transmission couplers 56a to 56d to a proximity switch 61a. ~61
d (Fig. 4). That is, transmission coupler 56
a to 56d and the proximity switches 61a to 61d are connected electromagnetically, although in a non-contact manner, and the proximity switches 61a to 61d are turned on due to changes in the magnetic field within the transmission couplers 56a to 56d due to the output of the contact signal. outputs an on signal. Here, FIG. 4 is a block diagram of the drive system on the side of the machining center 10, and ON signals from the proximity switches 61a to 61d are once input to the interface circuit 62 and then input to the controller 63.

The controller 63 includes X*Y+Z axis motors 65x
, 65y, and 65z are connected, and this motor drive circuit 64 drives each motor according to a command from the controller 53 to move the main shaft 12 in the x-, y-, and z-axis directions, respectively. Further, 66x to 66z are encoders that detect the position coordinates of the main shaft 12 from the state of each motor 65x to 65y, and the output thereof is sent to the controller 63.
is input. Note that 30a in FIG. 1 is a window for confirming the contact state between the touch sensors 54a to 54d and the spherical surface 47a, and is provided at four locations as shown in FIG.

In the configuration of the above embodiment, the motor 65x.

65y and 65z are driving means, touch sensors 54a to 5
4d constitute the detection means.

Next, the operation of the embodiment will be explained based on the flowchart of FIG.

Prior to machining work using the cutting tool CT, the automatic tool changer 14 moves the centering device @100 to the machining center 10.
Then, the controller 63 executes the centering procedure as shown in FIG.

First, in step S1, the centering device 100 is lowered toward the workpiece WK along two axes (FIG. 1) by the motor 65z via the motor drive circuit 64, and the tapered surface 49a of the centering tool 49 is aligned with the hole HL. contact the periphery of the Next, in step S2, it is determined whether an on signal is output from the proximity switch 61a, that is, whether a contact signal is output from the touch sensor 54a. here,
For example, as shown in FIG. 1, the center of the swing shaft 41 is located at the hole HL.
If the centering tool 49 is deviated from the center of the X-axis in the direction of a ten-sided dot, the centering tool 49 is lowered and the swing shaft 41 swings clockwise. As a result, the spherical surface 47a of the dog 47 is connected to the touch sensor 5.
4a moves away from the tip PR, the contact signal from the touch sensor 54a is cut off, and the proximity switch 61a is turned off. Therefore, if step S2 is negative, the main shaft 12 is moved in one direction along the X-axis by the motor 65x via the motor drive circuit 64 in step S7. Next, in step S8, it is determined whether the proximity switch 61a is on or not, and if the result is negative, the process remains in step S8 until the result is positive, and if the result is positive, the main shaft 12 is stopped in step S9, and the process proceeds to step S4.

Here, since the touch sensors 54a and 54b are respectively provided on the line x1 extending in the X-axis direction as shown in FIG. 3, both of them will not be in a signal non-output state at the same time. Similarly, the touch sensors 54c and 54d are also connected to the axis y.
1, so they are never in a non-signal output state at the same time.

If step S2 is affirmative, the process proceeds to step S3, where it is determined whether the nearby switch 61b is on, that is, whether a contact signal is output from the touch sensor 54b. If step S3 is affirmed, the process proceeds to step S4, and if negative, the process proceeds to step S10. Step SIO
Now, the main shaft 12 is moved in the child direction along the X-axis by the motor 65x via the motor drive circuit 64. Next, in step Sll, it is determined whether the proximity switch 61b is on or not. If the determination is negative, the process remains in step Sll until the determination is affirmative. If the determination is affirmative, the main shaft is stopped in step S12, and the process proceeds to step S4.

In step S4, it is determined whether the proximity switch 61c is on or not.
That is, it is determined whether a contact signal is output from the touch sensor 54c. If step S4 is affirmed, the process proceeds to step S5, and if negative, the process proceeds to step S13. In step S13, the motor 65y causes the main shaft 12 to
is moved in one direction along y@ (Figure 3). Next, in step 814, the process waits until the proximity switch 64c is turned on, and then, in step S15, the main spindle 12 is stopped, and the process proceeds to step S5.

In step S5, whether the proximity switch 61d is on or not,
That is, it is determined whether or not a contact signal is output from the touch sensor 54d, and if the determination is affirmative, the process is terminated, and if the determination is negative, the process proceeds to step 816. In step 816, the main shaft 12 is moved in the child direction along the y-axis by the motor 65y, and then in step S17, the proximity switch 61
Wait until d is turned on, and then, in step 318, the main shaft 12 is stopped and the process is ended.

According to the above procedure, the tapered surface 49a of the centering tool 49 can be brought into contact with the periphery of the hole HL while the swing shaft 41 is not swinging. Since the tapered surface 49a is symmetrical with respect to the swing axis 41, the main axis 12 is adjusted coaxially with the hole HL. As a result, subsequent machining and measurement operations can be performed with high accuracy without performing centering operations using a touch sensor as in the prior art.

Note that, depending on the diameter of the workpiece to be centered, the centering tool 80 can be replaced with another centering tool 80, such as the one shown by the two-dot chain line in FIG. 1, for example.

Further, the means for detecting whether or not the swing shaft 41 is swinging is not limited to the above-mentioned method, and various types of sensors such as magnetic, capacitive, and optical are used. It is possible. Furthermore, in the above, machining center 10
Although we have shown an example in which it is applied to a three-dimensional shape measuring device, it can also be applied to a three-dimensional shape measuring device. can also be used.

G0 Effect of the Invention According to the present invention, when the tapered surface of the cone provided at the tip of the swing shaft is brought into contact with the periphery of the hole in the workpiece, if the swing shaft and the hole are not coaxial, the swing will not occur. The shaft is configured to swing, and it is also possible to detect whether or not the swing shaft is swinging, so the cone can swing while keeping the tapered surface of the cone in contact with the periphery of the hole in the workpiece. Set the main shaft in an X position so that the shaft does not swing.

By driving in two axes (y), the main spindle can be centered with respect to the hole in the workpiece without performing complicated operations or arithmetic processing as in the conventional case. In addition, since the swing axis and the cone can be made stronger than conventional probes, the conventional problem of damaging the probe can be eliminated.

[Brief explanation of the drawing]

1 to 5 show one embodiment of the present invention, FIG. 1 is a sectional view of a centering device according to the present invention, FIG. 2 is an overall configuration diagram of a machining center, and FIG. 3 is a diagram similar to that of FIG. ■-■ line sectional view,
FIG. 4 is a block diagram showing the drive control system of the machining center, and FIG. 5 is a flowchart showing the processing procedure. 12: Main shaft 20: Main body 21: Shank 41: Swing shaft 49: Centering member 49a: Tapered surface 54a to 54d
: Touch sensor 65x~65z: Motor

Claims (1)

[Scope of Claims] A centering device that is removably attached to a main shaft movable in three axes (x, y, and z) directions orthogonal to each other by a driving means, and that centers the main shaft with respect to a hole formed in a workpiece, comprising: a main body in which a mounting portion for the main shaft is formed; a swing shaft that is swingably supported by the main body and always coaxial with the main shaft; and a swing shaft that is fixed to one end of the swing shaft and that supports the main shaft. a cone that has a tapered surface that comes into contact with the circumferential edge of the hole when brought close to the work along its axis, and that swings the swing shaft when the swing shaft and the hole are not coaxial; What is claimed is: 1. A centering device comprising: a detection means for detecting rocking of a moving shaft.