JP7277693B2 - Roundness measuring device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a work centering device and a roundness measuring device, and more particularly, a work centering device for matching the center axis of a work with the rotating shaft of a measurement table of the roundness measuring device, and the work centering device. It relates to a roundness measuring device with

2. Description of the Related Art Conventionally, there is known a roundness measuring device for measuring the roundness of a circular workpiece such as a cylindrical object or columnar object (see Patent Document 1, etc.). A roundness measuring device, for example, places a workpiece on a rotatable measurement table, brings a probe into contact with the surface of the workpiece, and measures the displacement of the probe as the workpiece rotates to measure the trueness of the workpiece. Measure circularity.

In such a roundness measuring machine, it is necessary to align the center axis of the workpiece with the rotation center of the measuring table before measuring the workpiece. For this reason, it is known that a work centering device is mounted on a measurement table. As a work centering device, for example, a chuck disclosed in Patent Document 2 (hereinafter referred to as a scroll chuck) or a centering device having aperture blades disclosed in Patent Document 3 (hereinafter referred to as an iris chuck) is used. )It has been known. These centering devices have a plurality of chuck members. The scroll chuck has chuck claws as chuck members, and the iris chuck has aperture blades.

A scroll chuck (similar to an iris chuck) includes a chuck body on which a workpiece is placed, and a plurality of chuck claws (aperture blades in the case of an iris chuck) provided around the center of the chuck body. By simultaneously interlocking multiple chuck claws toward the center of the chuck body, which corresponds to the center of rotation of the table, the workpiece is moved on the chuck body to align the center axis of the workpiece with the center of rotation of the measurement table. there is

JP 2012-145492 A Japanese Patent No. 5587460 JP 2012-64585 A

However, a roundness measuring device equipped with a work centering device measures the roundness of the work in a state in which the chuck member of the work centering device is in contact with the work, that is, in a state in which the chuck member holds the centering. Since it is used for measurement, there is a problem that the probe cannot be brought into contact with the portion where the chuck member is in contact, and the measurement cannot be performed at that portion.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances. An object of the present invention is to provide a roundness measuring device.

In order to achieve the object of the present invention, the work centering apparatus of the present invention comprises a chuck table on which a magnetic work is placed, and a plurality of chuck members provided around the center of the chuck table. By moving from the standby position toward the center of the chuck table, the workpiece placed on the surface of the chuck table is moved toward the center of the chuck table to align the center axis of the workpiece with the center of the chuck table. magnets arranged on the rear surface of the chuck table for fixing to the surface of the chuck table the workpiece whose central axis is aligned with the center of the chuck table by the plurality of chuck members; Prepare.

According to the work centering apparatus of the present invention, first, a plurality of chuck members are kept on standby at a position separated from the center of the chuck table, and in this state, a magnetic work is placed at an arbitrary position on the surface of the chuck table. Place. Next, when the plurality of chuck members are interlocked toward the center of the chuck table, the work placed on the surface of the chuck table is pushed by the plurality of chuck members and moved toward the center of the chuck table. go. When the work is completely sandwiched between the chuck members, the interlocking of the chuck members is stopped, and the work is centered at that point. That is, the central axis of the work coincides with the center of the chuck table.

Next, when measuring the location where the chuck member abuts, the plurality of chuck members are returned to the retracted position away from the center of the chuck table, and then the location is measured. At this time, since the workpiece is fixed to the surface of the chuck table by magnetic force, it is measured in a state of being centered with respect to the chuck table. Therefore, by using the work centering device of the present invention, it is possible to perform measurement even at a position where the chuck member of the work centering device abuts.

In one aspect of the present invention, it is preferable that a plurality of magnets be arranged along the radial direction from the center of the chuck table.

In one aspect of the present invention, it is preferable that a plurality of magnets be arranged along concentric circles around the center of the chuck table.

According to one aspect of the present invention, works having different diameters or inner diameters can be fixed using the same chuck table.

In one aspect of the present invention, the magnet is preferably a permanent magnet.

In one aspect of the present invention, the magnet is preferably an electromagnet.

According to one aspect of the present invention, the configuration of the work centering device can be simplified by using a permanent magnet as the magnet. Moreover, by using an electromagnet as the magnet, it is possible to generate a magnetic force when necessary, or to generate a magnetic force having a magnitude corresponding to the size or material of the workpiece.

In order to achieve the object of the present invention, the roundness measuring apparatus of the present invention comprises a base, a measuring table provided on the base, a workpiece centering device of the present invention mounted on the measuring table, A detector that has a probe that contacts the work placed on the chuck table of the work centering device, and that detects the displacement of the probe when the work and the work centering device are rotated relative to each other. And prepare.

According to the roundness measuring apparatus of the present invention, since it is equipped with the work centering device of the present invention, even if the chuck member of the work centering device abuts, it is possible to measure that portion. It can be carried out.

According to the present invention, it is possible to perform the measurement of a portion where the chuck member of the workpiece centering device abuts.

Overall perspective view of the roundness measuring device of the embodiment Block showing the configuration of the roundness measuring device of the embodiment Plan view of centering device with aperture blades in open position Plan view of the centering device with the aperture blades positioned at the aperture position A plan view of the centering device in which the workpiece is centered by the centering device Longitudinal cross-sectional view of the centering device along line AA in FIG. A plan view of a centering device showing an example of the arrangement of magnets. Explanatory diagram showing work centering procedure and roundness measurement A plan view of a centering device showing another example of the arrangement of magnets.

BEST MODE FOR CARRYING OUT THE INVENTION A workpiece centering device and a roundness measuring device according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view showing the appearance of a roundness measuring device 12 provided with a work centering device (hereinafter referred to as a centering device) 10 according to an embodiment. FIG. 2 is a block diagram showing the configuration of the roundness measuring device 12. As shown in FIG.

As shown in FIGS. 1 and 2, the roundness measuring device 12 is composed of a measuring machine main body 14 and an arithmetic processing section 16 .

The measuring instrument main body 14 includes a base 17 and a measuring table (hereinafter referred to as a table) 18 rotatably provided on the base 17 as shown in FIG. The centering device 10 of the embodiment is mounted on this table 18 . The centering device 10 will be described later.

The table 18 has an X-direction fine movement knob 20 and a Y-direction fine movement knob 22 on its side surface. The X-direction fine movement knob 20 and the Y-direction fine movement knob 22 are connected to table movement shafts (not shown), respectively. It is possible to micro-feed in the direction. As a result, the horizontal position of the table 18 is finely adjusted.

The table 18 also has an X-direction tilting knob 24 and a Y-direction tilting knob 26 on its side surface. By operating the X-direction tilt knob 24 and the Y-direction tilt knob 26, the tilt angles of the table 18 in the X and Y directions are finely adjusted.

A rotation mechanism 28 is provided inside the base 17 and below the table 18 . The rotation mechanism 28 rotates the work W centered by the centering device 10 together with the centering device 10 by rotating the table 18 . In the following description, the term "centering" means that the central axis a of the workpiece W is aligned with the rotation center b of the table 18 by the centering device 10. FIG. The configuration and operation of the centering device 10 will be described later.

As shown in FIG. 1, a column 30 is erected on the base 17 along the Z direction (vertical direction), and a slider 32 is attached to the column 30 so as to be movable in the Z direction. A horizontal arm 34 is attached to the slider 32 so as to be horizontally movable. A detector 36 is provided at the tip of the horizontal arm 34 , and the detector 36 is provided with a stylus 38 .

When the work W is measured by the roundness measuring device 12, the work W is placed on the centering device 10, and after centering by the centering device 10, the probe 38 is brought into contact with the outer peripheral surface of the work W, and then The work W is rotated by the table 18 . As a result, the displacement of the stylus 38 is detected by the detector 36, and the displacement signal from the detector 36 is transmitted to the arithmetic processor 16 in FIG.

In addition, although the roundness measuring device 12 of the embodiment is a device that rotates the table 18 with respect to the detector 36 , it may be a device that rotates the detector 36 with respect to the table 18 . An electric micrometer using a differential transformer is used as the detector 36, and the displacement of the stylus 38 is detected by this electric micrometer.

As shown in FIG. 2, the rotation mechanism 28 of the table 18 includes a bearing 39, an encoder 40, a motor 42, and the like. The table 18 is rotatably supported by the base 17 (see FIG. 1) via bearings 39 and is rotated by the power of the motor 42 . As the bearing 39, for example, an ultra-high-precision hydrostatic air bearing is used, whereby the table 18 is rotated with high rotational accuracy. The encoder 40 is attached to the rotating shaft 43 of the motor 42, and the rotation angle of the rotating shaft 43 is read by the encoder 40 with high accuracy.

The arithmetic processing section 16 includes an amplifier 44 , an A/D converter 46 and arithmetic/processing means 48 . Further, the arithmetic processing unit 16 includes a program 50 for controlling the arithmetic processing unit 16 and display means 52 for displaying the processing result.

The arithmetic processing unit 16 amplifies the detection signal (analog voltage value) from the detector 36 by the amplifier 44 and then converts it into a digital signal by the A/D converter 46 . Then, the calculation/processing means 48 calculates the roundness of the outer peripheral surface of the work W based on the rotation angle data input from the encoder 40 and the digital signal converted by the A/D converter 46, The calculation result is displayed on the display means 52 .

Next, the centering device 10 of the embodiment will be described.

FIG. 3 is a plan view of the centering device 10 of the embodiment, and is a plan view of the centering device 10 in which three diaphragm blades (chuck members) 54, 54, 54 are positioned at the open position. Also, FIG. 4 is a plan view of the centering device 10 in which the three diaphragm blades 54, 54, 54 are positioned at the diaphragm position. FIG. 5 is a plan view of the centering device 10 in which the workpiece W is centered by the centering device 10. FIG. FIG. 6 is a vertical cross-sectional view of the centering device 10 taken along line AA of FIG.

The centering device 10 of the embodiment shown in FIGS. 3 to 6 has a structure called a so-called iris chuck, and includes three aperture blades 54 formed in a substantially crescent shape, a base plate 56, and a chuck. It comprises a table 58 , a plurality of magnets 60 , a retaining ring 62 , an operating ring 64 and a magnetic shield plate 66 .

The base plate 56 is circular in plan view. As shown in the cross-sectional view of FIG. 6, the base plate 56 has a recess 68 which is circular in plan view on its back side, and this recess 68 is fitted to the upper part of the table 18 indicated by the chain double-dashed line in FIG. . As a result, the centering device 10 is mounted on the table 18 with the center c of the base plate 56 aligned with the rotation center b of the table 18 .

A circular pedestal portion 70 in a plan view is formed in the central portion of the surface side of the base plate 56 so as to protrude from the surface 56</b>A of the base plate 56 . A chuck table 58 is provided integrally with the pedestal portion 70 at the central portion of the pedestal portion 70 . The chuck table 58 is a table on which a workpiece W (see FIG. 5) is placed, and is circular in plan view.

As will be described later, the magnetic workpiece W, which is the object to be measured, is fixed to the surface of the chuck table 58 by the magnetic force of the magnet 60 . For this reason, the chuck table 58 is made of, for example, austenitic stainless steel, which is a non-magnetic material, but is not limited to this. The chuck table 58 may be made of resin as long as the material can fix the workpiece W to the surface of the chuck table 58 by the magnetic force of the magnet 60 .

As shown in FIG. 6, a plurality of cylindrical magnets 60 are arranged on the rear surface of the chuck table 58 . This magnet 60 is a permanent magnet.

FIG. 7 is a plan view of the centering device 10 showing an example of the arrangement form of the magnets 60 with respect to the chuck table 58. As shown in FIG. In FIG. 7, three aperture blades 54 are omitted in order to make the arrangement of the magnets 60 easier to understand. According to FIG. 7, a plurality of magnets 60 are arranged radially from the center c of the chuck table 58 . Specifically, a plurality of magnets 60 are arranged in close contact along six radial rows extending radially from the center c of the chuck table 58 .

By arranging the magnets 60 in this manner, the magnetic force of the magnets 60 can be applied to the entire surface of the chuck table 58 substantially uniformly. Therefore, even if the workpieces W have different diameters or inner diameters, the workpieces W can be fixed by the same chuck table 58 .

On the other hand, the retaining ring 62 shown in FIG. 6 is fitted and fixed to the pedestal portion 70 . Three pins 72 (see FIGS. 3 and 4) are provided on the surface of the retaining ring 62 at equal intervals along the inner periphery of the retaining ring 62 . One end of the aperture blade 54 is rotatably connected to the pin 72 .

The three aperture blades 54 are provided around the center c of the chuck table 58 . The three aperture blades 54 are arranged above the chuck table 58 so as to intersect each other, and a cam groove 74 is formed at the other end. A pin 76 provided on the back surface of the operation ring 64 is fitted into the cam groove 74 .

As shown in FIG. 6, the operation ring 64 has an outer peripheral flange portion 64A in sliding contact with the outer peripheral flange portion 62A of the retaining ring 62, and is rotatable with the outer peripheral flange portion 62A of the retaining ring 62 as a guide. A knob 78 is provided on the outer peripheral flange portion 64A of the operation ring 64, as shown in FIG.

When the operating ring 64 is rotated in the direction of arrow B from the open position in FIG. 3, the pin 76 provided on the operating ring 64 also moves in the same direction. As a result, the diaphragm blades 54 connected to the pin 76 via the cam groove 74 are interlocked toward the center c of the chuck table 58 and positioned at the diaphragm position shown in FIG. Further, when the operating ring 64 is rotated in the direction of arrow C from the throttle position in FIG. 4, the pin 76 provided on the operating ring 64 also moves in the same direction. As a result, the diaphragm blades 54 connected to the pins 76 via the cam grooves 74 are interlocked in the direction away from the center c of the chuck table 58 and positioned at the open position shown in FIG.

As shown in FIG. 6, the magnetic shield plate 66 is provided on the back side of the chuck table 58 so as to hold the magnet 60 between itself and the chuck table 58 . The magnetic shield plate 66 protects the equipment of the roundness measuring device 12 , such as the encoder 40 , from the magnetic field noise caused by the magnet 60 .

Next, a method for centering the workpiece W using the centering device 10 of the embodiment will be described. FIGS. 8A, 8B, and 8C are explanatory diagrams showing the centering procedure of the work W using the centering device 10 and the roundness measurement performed thereafter.

First, prior to centering the work W, the centering device 10 is mounted on the table 18 . As a result, the rotation center b of the table 18 and the center c of the chuck table 58 of the centering device 10 are aligned.

Next, as shown in FIGS. 3 and 8A, the three aperture blades 54 are kept waiting at the open position spaced apart from the center c of the chuck table 58, and in this state, any position on the surface of the chuck table 58 is moved. Work W is placed on the . Thereby, the work W is fixed to the surface of the chuck table 58 by the magnetic force of the magnet 60 .

Next, the operation ring 64 is rotated in the direction of arrow B from the open position in FIG. As a result, the work W fixed to the surface of the chuck table 58 is pushed by the three aperture blades 54 and moves toward the center c of the chuck table 58 .

5 and 8B, when the work W is completely sandwiched between the three aperture blades 54, the interlocking of the three aperture blades 54 stops, and at this point the work W is centered. be. That is, the central axis a of the work coincides with the center c of the chuck table 58 and also coincides with the rotation center b of the table 18 .

Next, when measuring the point d by bringing the probe 38 into contact with the point d where the aperture blade 54 abuts, the operation ring 64 in FIG. 3, that is, the position away from the center c of the chuck table 58 as shown in FIG. 8(C). After that, the probe 38 is brought into contact with the point d to measure the point d.

During measurement, the work W is fixed to the surface of the chuck table 58 by magnetic force, so that the work W is measured in a state of being centered with respect to the chuck table 58 without being displaced.

Therefore, according to the roundness measuring device 12 of the embodiment, by using the centering device 10 of the embodiment, even the point d where the diaphragm blade 54 abuts is constrained by the diaphragm blade 54. Measurement of the point d can be performed without

Modifications of the centering device 10 will be described below.

Regarding the array form of the magnets 60, in one example of FIG. Instead of this arrangement, a plurality of magnets 60 are arranged along a plurality of (three in FIG. 9) concentric circles centered on the center c of the chuck table 58, as shown in the plan view of the centering device 10 in FIG. may

Even if the magnets 60 are arranged as shown in FIG. 9, the magnetic force of the magnets 60 can be applied to the entire surface of the chuck table 58 substantially uniformly. Therefore, even if the workpieces W have different diameters or inner diameters, the workpieces W can be fixed by the same chuck table 58 .

Also, as the magnet 60, a permanent magnet is exemplified in the embodiment, but an electromagnet can be used instead. Similarly, in the case of electromagnets, a plurality of electromagnets may be arranged radially from the center c of the chuck table 58, or may be arranged along a plurality of concentric circles centered on the center c of the chuck table 58. .

Further, in the case of an electromagnet, since the magnetic force can be varied, the fixing strength of the workpiece W to the chuck table 58 can be varied. For example, in the case of a workpiece that is placed on the chuck table 58 in an unstable manner (for example, a cylindrical workpiece with a small diameter and a thin wall thickness), it is preferable to increase the magnetic force.

In the case of electromagnets, it is also possible to drive only a part of the electromagnets required for centering the workpiece without driving all the electromagnets.

10 Work centering device 12 Roundness measuring device 14 Measuring machine body 16 Arithmetic processing unit 17 Base 18 Table 20 X direction fine movement knob 22 Y direction fine movement knob 24...X-direction tilt knob, 26...Y-direction tilt knob, 28...Rotating mechanism, 30...Column, 32...Slider, 34...Horizontal arm, 36...Detector, 38...Probe, 39...Bearing, 40...Encoder , 42... Motor, 43... Rotating shaft, 44... Amplifier, 46... A/D converter, 48... Calculation/processing means, 50... Program, 52... Display means, 54... Diaphragm blade, 56... Base plate, 58... Chuck table 60 Magnet 62 Retaining ring 64 Operation ring 66 Magnetic shield plate 68 Recess 70 Base 72 Pin 74 Cam groove 76 Pin 78 Knob

Claims (3)

A roundness measuring device for measuring the roundness of a magnetic workpiece,
a chuck table on which the workpiece is placed;
A plurality of chuck members are provided around the center of the chuck table, and are interlocked from a standby position toward the center of the chuck table to move the workpiece placed on the surface of the chuck table to the chuck. a plurality of chuck members that are moved toward the center of the table so that the central axis of the work is aligned with the center of the chuck table;
a magnet arranged on the back surface of the chuck table, the magnet fixing the work, whose central axis is aligned with the center of the chuck table by the plurality of chuck members, to the surface of the chuck table;
has
returning the plurality of chuck members to the standby position to enable measurement of locations of the workpiece contacted by the plurality of chuck members ;
a plurality of the magnets are arranged along a plurality of concentric circles centered on the center of the chuck table;
Roundness measuring device. The roundness measuring device according to claim 1 , wherein the magnet is a permanent magnet. The roundness measuring device according to claim 1 , wherein the magnet is an electromagnet.

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