JPS601365Y2 - Contact detection head - Google Patents

Description

[Detailed description of the invention] This invention is installed on the spindle of a numerically controlled machine tool that has a contact detection function, and the contact surface formed at the tip is brought into contact with the surface to be measured, such as a hole formed in a workpiece, etc. This is related to a contact detection head that performs centering of a hole or measurement of a hole diameter by rotating the contact detection head. A surface and a contact surface for dimension measurement, which is brought into contact with the surface to be measured with the contact detection head stopped, are provided separately, and hole centering and dimension measurement can be performed over a long period of time regardless of the hole diameter. The goal is to be able to do it accurately across the board.

Another object of the present invention is to enable dimension measurement without positioning the spindle of a machine tool in a particular phase.

In recent years, a contact detection head is attached to the spindle of a numerically controlled machine tool that has a contact detection function, and this contact detection head is moved in a predetermined direction, so that the contact surface formed at the tip of the contact detection head is attached to the spindle of a numerically controlled machine tool that has a contact detection function. The center position of the hole is detected from the amount of movement of the hole formed in the hole until it comes into contact with the surface to be measured, thereby centering the spindle and measuring the hole diameter.

Figure 1 shows the movement locus of the contact detection head when centering is performed by positioning the spindle at the center of the hole. The spindle S is indexed to the center position 00 by moving the contact detection head TS from the center position XO in the Y-axis direction and indexing it to the center position in the Y-axis direction.
can be divided into

However, if there is a misalignment between the rotation center O3 of the spindle S and the center OP of the contact surface of the contact detection head TS, even if the above operation is performed, the spindle S cannot be accurately centered at the center position of the hole. Therefore, when performing centering, it is preferable to perform contact detection with the contact detection head rotated to eliminate positioning errors due to misalignment.

On the other hand, Fig. 2 shows the movement locus of the contact detection head when measuring the hole diameter, and shows the contact detection head TS at the center of the hole.
0 in the X-axis direction, and detects the amount of movement from when the contact detection head TS starts moving from one end until it contacts the other end. The hole diameter is measured by adding the outer diameter dimension d.

Therefore, when measuring the hole diameter, a measurement error occurs if the outer diameter dimension d of the contact surface changes.

Therefore, in order to accurately measure the hole diameter, it is necessary to prevent wear of the contact surface, and it is preferable to avoid rotating the contact surface detection head to detect contact.

However, in the past, one contact surface was formed at the tip of the contact detection head, and this contact surface was used for both centering and hole diameter measurement. If contact detection is performed by rotating the detection head, the contact surface will wear out, making it impossible to accurately measure dimensions over a long period of time.In order to avoid contact surface wear, the contact detection head must be stopped and the center When centering is performed, there is a problem in that accurate centering cannot be performed due to misalignment of the contact surface.

The present invention has been made in view of the above points.The present invention has been made in view of the above points.The present invention has been made in view of the above points.The present invention has been made in view of the above points. The present invention is characterized in that two contact surfaces of the shape are formed, one of these contact surfaces is used as a contact surface for centering, and the other is used as a contact surface for dimension measurement.

Embodiments of the present invention will be described below based on the drawings.

FIG. 3 is an overall diagram showing the configuration of a numerically controlled machine tool that has the function of automatically centering a hole formed in a workpiece W and measuring the diameter of the hole. It is constituted by a numerical control device 3.

Reference numeral 10 denotes a bed of the machine body 1, on which a table 11 on which a workpiece W is placed is guided so as to be movable in a direction perpendicular to the plane of the paper (X-axis direction).
Column 1 that guides the unit so that it can move in the vertical direction (Y-axis direction)
3 is guided so as to be movable in the left-right direction (Z-axis direction).

The table 11 is moved in the X-axis direction by a servo motor 14 fixed to the bed 10, and the spindle head 12 is moved by a servo motor 15 attached to the rear end of the bed 10.
and a servo motor 16 attached to the top of the column 13.
It is adapted to be moved in the Y-axis direction and the Z-axis direction by.

As a result, the relative position between the workpiece W and the spindle head 12 is changed, and the workpiece W is machined and the hole machined in the workpiece W is centered.

A spindle 17 is mounted on the spindle head 12, and the spindle 17 is rotatably driven by a spindle motor 18 attached to the rear end of the spindle head 12.

When machining a workpiece W, a machining tool is attached to this spindle 17, and when centering a hole machined in the workpiece W or measuring the hole diameter, the contact detection head shown in the figure is centered. It will be installed.

FIG. 4 shows the structure of the contact detection head TS, which is attached to the spindle 17 and has two protrusions 21 and 22 protruding from the tip of the head main body 20 in the axial direction. A member 23 is mounted so that its axial position can be adjusted and fixed by a nut 24.

Among the protrusions 21 and 22 of this shaft member 23, the outer peripheral surface of the protrusion 21 on the tip side has a spherical contact surface 2 with an outer diameter of Dl.
1a is formed, and the outer peripheral surface of the protrusion 22 has an outer diameter D.
A spherical contact surface 22a that is larger than l by a predetermined amount 2
is formed.

In this embodiment, since the contact surface 21a of the tip surface is used as the contact surface for hole diameter measurement, the outer diameter dimension d1 of this contact surface 21a is
is accurately measured in advance and stored as a constant in the numerical control device 3, and this constant is used when calculating the hole diameter.

Further, a contact surface 21b for measuring the depth of the hole, etc. is also formed at the tip of the protrusion 21 on the tip side, so that the depth of the hole, etc. can also be measured.

Reference numeral 19 in FIG. 1 denotes a contact detection coil disposed around the spindle head 12. This coil 19 is excited by an alternating current voltage applied from the contact detection device 2 1 and surrounds the spindle 17. It generates magnetic flux like this.

Therefore, when the contact detection head TS comes into contact with the workpiece W, an induced current as shown by the broken line in FIG. 3 flows, and the coil 1
9's impedance changes.

The contact detection device 2 detects contact between the contact detection head TS and the workpiece W by changing the impedance of the coil 19, and when contact is detected, sends a contact detection signal to the numerical control device 3. Send TDS.

The numerical control device 3 processes the workpiece W by distributing command pulses to the servo motors 14, 15, and 16 according to numerical command data given by a paper tape or the like. Performs control for centering or measuring hole diameter.

When centering a hole or measuring the diameter of a hole, a contact detection head center is attached to the spindle 17 instead of a tool using a tool changer in the enclosure, and the tip of the contact detection head center is machined. It is inserted into a hole shaped like object W.

When centering the hole, as shown in FIG. 5, the contact detection head TS is moved in the Z-axis 1''-) direction until the protrusion 22 enters the hole, and the hole diameter is measured. If you do,
As shown in FIG. 6, the contact detection head TS is moved in the two-axis direction so that only the protrusion 21 on the tip side enters the hole.

When centering the hole, the main shaft motor 18 is then energized, and the contact detection head embryo is rotated and moved along the route shown in FIG. 1 to center the hole. be exposed.

Further, when measuring the hole diameter, the main shaft motor 18 is deenergized, and the contact detection head TS is moved along the route shown in FIG. 2 in a stopped state to measure the hole diameter.

In this way, since centering is performed while the contact detection head TS is rotated, it is possible to accurately center the hole regardless of the roundness of the contact surface or the deflection of the contact detection head TS. However, since the contact surface for centering and the contact surface for dimension measurement are formed separately, even if contact detection is performed by rotating the contact detection head TS during centering, the contact surface for dimension measurement will not be detected. The surface will not wear out and the hole diameter can be measured accurately over a long period of time.

In the above embodiment, the contact surface 21a formed on the protrusion 21 on the tip side is used as a contact surface for dimension measurement, and the contact surface 22a formed on the waist protrusion 22 is used as a contact surface for centering. However, the contact surface 21a may be used as a contact surface for centering, and the contact surface 22a may be used as a contact surface for dimension measurement.

In addition, the above embodiment was an example in which the centering of the hole machined in the workpiece W and the measurement of the hole diameter were performed, but the contact detection head of the present invention is capable of detecting the centering of the hole machined in the workpiece W. It can also be used to measure the center position and groove width.

As described above, in the contact detection head of the present invention, two contact surfaces are formed on the outer periphery of the tip of the shaft portion of the contact detection head, and one of these contact surfaces is used as a contact surface for centering. Since the other side is used for dimension measurement, even if the contact detection head is rotated and centering operation is performed for contact detection, the contact surface for dimension measurement will not wear out at all, and the centering will be maintained. Detection of the center position and measurement of dimensions such as hole diameter by the drawing operation can be performed accurately over a long period of time.

In addition, since the pair of protrusions are coaxially arranged, different contact surfaces can be used for centering and dimension measurement even when performing centering operation and dimension measurement for small diameter holes. This has the advantage of allowing highly accurate centering and dimension measurement.

Furthermore, in the contact detection head of the present invention, since the shape of the pair of contact surfaces is a continuous spherical surface in the circumferential direction surrounding the shaft, contact detection is possible no matter what the angular phase of the spindle is. By relatively moving the head along the X-axis or Y-axis, it is possible to measure dimensions by bringing the contact surface into contact with the surface to be measured, making it possible to measure dimensions without indexing the spindle to a fixed angular position. There are advantages to doing so.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the movement trajectory of the contact detection head when centering a hole, Figure 2 is a diagram showing the movement trajectory of the contact detection head when measuring the hole diameter, and Figure 3 is a diagram showing the movement trajectory of the contact detection head when performing hole diameter measurement. A diagram showing an example of a numerically controlled machine tool equipped with a contact detection head according to the present invention, FIG. 4 is an enlarged partial cross-sectional view of the contact detection head, and FIG. 5 shows the position of the protrusion when performing centering. The figure shown in FIG. 6 is a diagram showing the position of the protrusion when measuring dimensions. 1...Machine body, 2...Contact detection device, 3...Numerical control device, 12...Spindle head, 17...Spindle , 18... Motor, 19... Contact detection coil, 20...
...Head body, 21.22...Protrusion, 2
1a, 22a...Contact surface, 23...Shaft member, TS...Touch detection head, W...
...workpiece.

Claims (1)

[Scope of utility model registration request] It is attached to a rotating spindle of a numerically controlled machine tool having a contact detection function, and the contact surface formed at the tip is brought into contact with a surface to be measured such as a hole formed in a workpiece while the spindle is rotating. A contact detection head for centering a hole and measuring dimensions such as hole diameter by stopping the spindle, the head for contact detection having a protrusion for centering and a projection for dimension measurement at the tip of the shaft of the head for contact detection. The protrusions are spaced apart from each other in the axial direction, and a spherical contact surface that surrounds the shaft and continues in the circumferential direction is formed on the outer peripheral surface of the pair of protrusions. A contact detection head characterized in that the distance from the contact surface is shorter than that of the other contact surface.