JPS5866801A - Contact type sensor - Google Patents

Abstract

PURPOSE:To prevent the deformation and failure of a sensor and an object to be measured and to permit always accurate setting of a reference position for measurement by sensing the pressures in directions X, Y, Z by means of an elastic member and a piezoelectric transducer. CONSTITUTION:When an object 22 to be measured is fixed to a working table 21 and the reference plane of the object 22 is brought into contact with the measuring contactor 26 of a contact type sensor 20 by moving the table 21, the contactor 26 moves like a chain line and tilts a measuring base plate 26c with a contact part 28a as a fulcrum. When the plate 26c tilts, said plate compresses or deforms a coil spring 27 which presses the contactor 26, thus producing a change in the pressing force in the disposing direction of the spring 27. This change is transmitted to a pieozelectric transducer part 25, and produces a voltage change in its output. If the part 25 is connected to a digital counter 33, the voltage change is discriminated by a prescribed threshold voltage and a reset signal is formed, by which the count value of a counter 33 is cleared or preset and the reference position of the object 22 is set.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a touch sensor, and particularly to a contact sensor that detects contact with an object to be measured using a piezoelectric transducer and detects its position.

Generally, in machine tools, it is extremely important to accurately set a reference position for measuring one machining position when machining the machine tools, and various measuring devices are well known. These measuring devices were equipped with contact sensors that were brought into contact with the measurement reference surface of the object to be measured to detect electrical continuity. When setting the reference position using this contact sensor, the measurement reference surface and the contact sensor often come into strong contact, and the impact may cause the measurement reference surface to move. In order to overcome these drawbacks, the applicant has proposed a structure as shown in FIG. (Utility Model Publication No. 55-98541).

That is, a workpiece 2 made of a metal material is fixed on a table 1 of a processing machine such as a milling machine.

A contact sensor 4 is attached to the processing table 1 through a tool chuck 3 of a spindle (not shown) provided at an upper position. This contact sensor 4 has a large-diameter chuck part 5 as a mounting part that is mounted on the tool chuck 3, and this chuck part 5 has a cylindrical shape and has a lid 6 screwed onto its upper end. A flange portion 7 is formed on the outer periphery of the lower end. A detection rod 9 is fitted inside the chuck portion 5 via an insulator 8 made of ceramic or plastic, and this detection rod 9 has a fitting portion 9a with the chuck portion 5 and a contact portion at the tip. 9b and an intermediate portion 9c between the contact portion 9b and the fitting portion 9a. This intermediate part 9c has X, Y, and 2 of the detection rod 9.
An elastic buffer portion 10 having an elastic structure in the axial direction is formed. This elastic shock absorber has a hollow section 10 m provided in a part of the intermediate section 9c, and the hollow section 10 m is provided from the outer peripheral surface of the hollow section 10 m.
It is constructed by forming 1 obt spiral incision that reaches a. A connector 11 is attached to the intermediate portion 9c of the detection rod 9, and is connected to an operating circuit (not shown) of the digital counter 3 via a conductive wire 12.

On the other hand, the end of the bereavement conductor 14 connected to the operating circuit is
The workpiece 1 is electrically connected to the workpiece 1 via a fixture 16 on the processing table 1 using a connector 15 such as a clip.

In order to set the reference position in the contact type sensor 4 having the above configuration, it is necessary to set the reference position on the processing table 1 on which the workpiece 2 is placed.
When the reference surface of the workpiece 20 is brought into contact with the contact portion 9b of the detection rod 9, the workpiece 2 and the detection rod 9 are electrically connected due to this contact, and the workpiece 20 is detected. The display on the digital counter 13 is cleared to zero, and the display blinks or a buzzer (not shown) or the like is activated to notify the operator that the reference position has been set.

In this case, since the detection rod 9 has an elastic buffer lO, even if the detection rod 9 strongly contacts the workpiece 2, the x, y, z
It is possible to absorb external force from three axial directions.

-2 However, in the detection device with the structure shown in Fig. 1, if the workpiece 2 is not made of wood or is made of a material with no electrical conduction in the synthetic resin ring, it may not be used or detected with strong force. There was a problem in that when the rod 9 came into contact with the workpiece 2, the elastic part 1O was deformed.

The problem also occurred that the reference surfaces of the dragon 1 and the workpiece 2 were coated with oil or dust, causing electrical contact with the detection rod 9.

Therefore, the present invention has been made in consideration of the above-mentioned nine circumstances, and focuses on the fact that a piezoelectric transducer generates a changing voltage when it is pressed by an external force from all directions such as x, y, and z. By transmitting the movement of the probe to the piezoelectric transducer via the elastic member, it is possible to absorb the amount of movement caused by external forces from all directions and transmit only that pressure.
Moreover, even materials without electrical conductivity such as insulating materials can be measured to
It is an object of the present invention to provide a contact type sensor that can always accurately set a reference position for measurement without causing deformation of the contact type sensor or the measured object due to movement of the workpiece. It is.

The present invention will be described in detail below based on an illustrated embodiment, in which the present invention is applied to a machine tool.

Let me explain the case.

FIG. 2 is a longitudinal sectional view showing an embodiment of the contact type sensor according to the present invention. Reference numeral 21 denotes a processing machine body such as a milling machine, and a /3 processing table. A workpiece n such as a metal material or synthetic resin is fixed on the processing table 21 by a fixture 32. This processing table 2
A spindle (not shown) is provided at the upper position of the tool 1, and a contact sensor is attached to the spindle via a tool chuck collar. This contact type sensor addition is for the sensor case and this sensor case 24.
A piezoelectric transducer section fixed therein, a measuring element 26 disposed movably in either direction, and an elastic member such as a coil spring that transmits the pressure generated by the movement of the measuring element 26 to the piezoelectric transducing element section 25. n and between the stopper members of the probe 26. The sensor case 24 is
It has a cylindrical shape, has a flange portion 24m formed on its outer periphery, and is formed so as to be attached to the tool chuck n above the flange portion 24m. A lid 9 is provided at the upper end of the sensor case. Screw threads are cut into the outer part of the lid body and near the upper end of the sensor case 24, and the lid body 29 is formed to be screwed into the sensor case so that its position can be adjusted.

A piezoelectric transducer element section is fixed to the inside of the lid, which is a part of the sensor case. Therefore, by rotating the lid body 29 and adjusting the fixing position, it is possible to adjust the electrical output level of the piezoelectric transducer element. A pressing plate made of an insulating material is fixed to the tip of a coil spring n arranged to press the piezoelectric transducer part, and the piezoelectric transducer part 25 is pressed through the suppressing plate (9). There is.

A measuring element 26 is disposed at the lower end of the coil spring γ so as to be swingable and movable in any of the x, y, and z directions. The probe 26 includes a contact portion 26 a that comes into contact with the object to be measured;
Measuring rod portion 26 b following contact portion 26 m and measuring rod portion 26
A probe board 26e is fixed near the base of the sailing rod 26b in a direction perpendicular to the sailing rod 26b. Measurement head board 26
C is disk-shaped, and its outer periphery is formed into a curved shape, and is arranged so as to be in contact with the inner periphery of the sensor case.
6 does not move in the horizontal direction. Further, a spring fixing member 26d formed to fit into the inner diameter of the coil spring n is disposed on the upper surface of the measuring element board 26c. Further, the measuring element 26 is placed on the stopper member path by being pressed by the coil spring n, thereby x
, y, and z directions so that they change color when rocking or moving. This stopper member path has a contact portion 28 a with the measuring element 26 so that the measuring element 26 can easily move.
It is formed in the shape of a Vi edge. The contact portion 28m may have a spherical shape as well as a drilled or solid shape, and the contact area is small and the same effect can be achieved. In addition, strike sono (between some parts,
In order to penetrate the measuring rod 26b near the center,
A space is formed so that the measuring rod 26b can move in two directions: A dustproof cover 31 is provided.The dustproof cover 31 is made of a flexible material that provides less resistance to the movement of the probe 26.

Since the contact sensor application of the present invention is configured as described above, in order to set the reference position of the workpiece n, the workpiece 22 is placed on the processing table 21 of the processing machine using the fixture 32. The machining table 21 is fixed, and the processing table 21 is moved, and the measuring element 26% of the contact type sensor is attached.
The reference surface of the workpiece 22 is brought into contact with the contact portion 26 a of the workpiece 22 . Then, the probe 26 moves as shown by the chain line and tilts with the probe substrate 26c as the fulcrum of the contact portion 28at. When the measuring head board 26 c is tilted, the measuring head 26
The coil spring γ that was pressing on is compressed and deformed,
The pressing force changes in the direction in which the coil spring n is arranged. This change in pressing force is applied to the piezoelectric transducer section 2 through the suppression plate (9).
5, and a voltage change occurs in the output of the piezoelectric transducer 8S25.

By connecting the piezoelectric transducer element and the digital counter blade with a conductive wire, this voltage change can be discriminated by a predetermined threshold voltage to form a reset signal and clear or preset the count value of the digital counter blade. The reference position of the object to be measured 22 can be set.

In addition, since there is a relationship between the pressing force and the output voltage, the piezoelectric transducer part δ can also measure the amount of deviation of the probe 26. It can also be used as a contact sensor.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications, such as being applicable to various measuring instruments, without changing the gist thereof.

As described above, according to the contact type sensor according to the present invention, X is applied to the contact portion of the probe.

The elastic member and piezoelectric transducer act on external forces from all directions (Y, Z), so the contact sensor can be easily contacted from any direction without damaging the contact sensor or damaging the object to be measured. It can also be measured, and the functional effects are extremely large.

Furthermore, since the object to be measured is not used as part of the detection circuit, it has the advantage that it can be used even if the object to be measured is an insulator. Furthermore, even if the surface of the object to be measured is contaminated with oil or dust, there is no contact failure as in the conventional method, and the practical effects obtained are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the main part of a conventional contact type sensor, and FIG. 2 is a longitudinal sectional view showing an embodiment of the contact type sensor according to the present invention. Add...Contact sensor U...Sensor case 25.
...Piezoelectric conversion element part 26...Measuring element 261...Contact part 26b...Measurement preliminary 26c...Measurement element board...Coil spring collar...Stopper part Container...Lid member 31...Dust-proof cover patent applicant Futaba Electronics Co., Ltd. Figure 2

Claims (7)

[Claims] (1) A piezoelectric transducer section fixed within the sensor case,
an elastic member disposed such that one end contacts and presses the piezoelectric transducer portion, and the other end of the elastic member includes x,
It has a configuration that includes nine probes that are movable in either the y or z directions, and a stopper member that is placed in contact with the probes, allowing for the swing or movement of the probe. A contact portion sensor characterized in that an output electric signal of a piezoelectric transducer is extracted as an output electric signal. (2) The piezoelectric transducer part is fixed to the lid member of the sensor case, and an adjustment screw is formed on the outer periphery of the lid member, and the contact according to claim 1 can adjust the amount of electricity of the piezoelectric transducer part. formula sensor. (3) The contact type sensor according to claim 1 or 2, wherein the elastic member is a coiled spring. (4) The probe has a configuration including a contact portion that comes into contact with the object to be measured, a measurement rod portion following the contact portion, and a probe substrate fixed near the base of the measurement rod portion. The contact type sensor according to item 1, item 2, or item 3. (5) The measuring board of the measuring head is in the shape of a disk with a spherical outer periphery, and the outer periphery of the measuring board is arranged so as to be in contact with the inner periphery of the sensor case. 1. The contact type sensor according to item 4. (6) The stopper member according to claim 1, 2, 3, 4, or 5, wherein the portion that contacts the probe is formed into an edge shape or a spherical shape. Contact sensor. (7) The sensor case has a structure in which a dustproof cover covering the space with the outer periphery of the probe is attached below the sensor case. Contact type sensor according to item 6.