JPH023442B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a three-dimensional position detection device, and particularly to an improvement in a holding mechanism for a stylus having an electrode contact at one end thereof.

As is well known, in machine tools such as milling machines,
There is a growing trend for a processing machine to have a function of measuring three-dimensional dimensions of a workpiece after processing. For this reason, conventionally, position detection devices such as those shown in Figures 1 and 2 have been used to detect the position of the reference plane and end face of the workpiece, and to detect the machining position from the reference plane and end face. .

In FIGS. 1 and 2, reference numeral 11 denotes an electrode contact made of a conductive sphere, which is provided at one end of the filler 12, and this holding mechanism is constructed as follows.

That is, within the housing 1, the filler 12
is fixed to the disk 4, and receiving members 6, 7, and 8 are held and fixed to the disk 4 via an insulating plate 5.

At the bottom of the housing 1, set screws 3 having spherical bodies 2 are arranged at approximately three equal parts. This spherical body is adapted to be in contact with the receiving members 6, 7, and 8, and a pressing force is applied by the spring 10 through the insulating member 9, so that they are pressed into contact with each other.

14 is a lock screw for locking the set screw 3. The position detecting device having the above-mentioned configuration is connected to the machine tool 1 by the shank 13 as shown in FIG.
When the electrode contactor 11 comes into contact with the workpiece 14 placed on the table 15, it is electrically detected by the detection circuit 16, and the position and the like are detected.

However, in the configuration of the conventional device described above, as is clear from FIG. It is designed to ensure the only stable position.

The present invention has been made to solve the problems of the prior art, and includes holding an electrode contactor made of a conductive sphere via a stylus by first and second holding members that are in pressure contact within a housing; 1st
The holding member has a concentric spherical surface with the electrode contactor, and the second holding member is configured to be in line contact with the concentric spherical surface.

The present invention will be described below with reference to the embodiments shown in the drawings. In FIGS. 4a, b and 5, the electrode contactor 21 is attached to one end of the stylus 22,
a first retaining member within the housing 26, e.g. disc 2;
The other end of the stylus 22 is fixed to 3.
The circumferential portion of the disk 23 is formed to form a rotating curved surface body 24 .

A second holding member 25 is disposed at the bottom of the housing 26, and the rotating curved surface body 24 and the second holding member are pressed together by a spring 28, and the contact surface of the holding member 25 is as shown in the figure. It has a spherical shape concentric with the electrode contactor 21.

Further, a relay plate 27 is provided at the upper part of the housing 26, and a shank 29 is provided on this relay plate 27.
is attached, and as mentioned above, the position detecting device of the present invention described above is connected to the fifth position detecting device via the shank.
As shown in the figure, it is attached to machine tools, etc.

Now, in the apparatus of the present invention described above, if the contact surface of the second holding member 25 for positioning the electrode contactor 21 is attached to the contact surface of the first holding member 25, as shown in FIG.
3 are in contact at three points A, B, and C, they are on a spherical surface with a radius R relative to the center Q of the electrode contactor 21.

As mentioned above, the center of the electrode contactor 21 and the center of the contact surface (spherical surface) of the second holding member 25 coincide, so if one point among the three points A, B, and C on the spherical surface is P, then = In R, even if the positions of A, B, ie P change, the position of Q remains unchanged.

Next, if an error of =R+ΔR, that is, ΔR occurs, and P is shifted by Δd, Q will shift to the position of Q', and the error'=ε will be as follows.

ε=△d△R/R Therefore, even if there is an error of △d in the setting position of the holding member of the electrode contactor, the error of the electrode contactor can be reduced to △R/R. In this case, the rotating curved surface body 24 of the first holding member 23 has the axis of the stylus 22 as its central axis, and is pressed against the concentric spherical surface of the second holding member 25 so as to be in circular line contact, and the rotating curved surface body 24 The surrounding area is housing 2
Since it is statically fitted with 6, △d in the stationary state
≒0, and the error ε becomes extremely small.
Further, the electrode contactor can operate smoothly even if force is applied in any three-dimensional direction to the electrode contactor. The rotating curved surface body 24 is made of an insulating material, for example, and the moment the electrode contactor 21 comes into contact with the object to be measured (conductor), the lead wires a and a' are turned on and position detection is performed.

FIG. 6 shows an example of a contact position detection circuit used in the present invention, in which a lead wire 31 from a connector 30,
32 and a lead 36 from a table 35 on which a workpiece 33 is placed is connected to an input of an amplifier 37. The output of the amplifier 37 is connected to an excitation winding 38' of a relay 38, and a power source 39 is connected via the relay 38 to a notification device 40 such as a lamp or a buzzer, and to a counter.

Now, when the table 35 of the machine tool moves its main shaft 41 vertically and horizontally in the direction of the arrow, and the electrode contactor 21 approaches and contacts the end surface of the workpiece 33, the input of the amplifier 37 becomes a closed circuit. The output activates the relay 38. The annunciation device 40 is therefore activated and the point of contact is quickly and accurately detected. Also, since an input is given to the counter 41 at the same time, the input causes the counter 4
By resetting 1 to zero and starting counting from this point, the distance traveled by the table or spindle can be determined.

In addition, in the above embodiment, the stylus 22 is
Although the configuration is such that it can operate in the dimensional direction, the second holding member 25 is made of a cylindrical surface member as shown in FIG. A curved surface body 24' having a generatrix parallel to the generatrix of
It is also possible to have a structure that does not rotate around the second axis to restrict movement in the Y direction and operate in two directions, X and Z.

Furthermore, the housing 26 may not have a cylindrical shape, but may have a structure in which the contact piece returns to its position before operation when it is in a stationary state.

In addition, in FIG. 4, substantially the same function can be obtained even if the contact surface between the rotating curved surface body 24 and the second holding member is approximated by a curved surface close to a spherical surface or a straight line.

As is clear from the above explanation, according to the present invention, both holding members of the electrode contactor are in line contact, so the contact area is large, and no matter what direction the stylus moves in the horizontal direction, the amount of movement of the stylus is limited. constant. Therefore, it has good reproducibility, high precision, good durability, and has a relatively simple structure, which is advantageous in manufacturing.

[Brief explanation of drawings]

Figures 1a and b are schematic diagrams showing an example of a conventional position detection device, Figures 2a and b are views taken along lines A-A and B-B in Figure 1a, and Figure 3 is a schematic diagram showing an example of a conventional position detection device. A block diagram showing an example of a position detection circuit using the device, FIGS. 4a, b and 5 are schematic diagrams showing an embodiment of the present invention, and FIG. 6 is a block diagram showing an example of a position detection circuit using the embodiment. FIGS. 7a and 7b are block diagrams illustrating the operation of the above embodiment, and FIGS. 8 and 9 are block diagrams showing main parts of other embodiments of the present invention, respectively. 21... Electrode contact, 22... Stylus, 23
... Disk, 24 ... Rotating curved body, 26 ... Housing.

Claims (1)

[Claims] 1. An electrode contact made of a conductive sphere is held by first and second holding members that are in pressure contact within a housing via a stylus, and the first holding member is attached to the electrode contact. A position detection device characterized in that the second holding member has a concentric spherical surface and is configured to be in line contact with the concentric spherical surface. 2. The position detection device according to claim 1, wherein the first holding member includes a rotating curved body provided on the circumference of a disk. 3. The second holding member has a cylindrical shape,
2. The position detection device according to claim 1, wherein the first holding member is configured to be two-dimensionally movable on a cylindrical surface of the second holding member.