JPH0765884B2 - Non-contact type dimension measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type size measuring device which measures the size of an object to be measured in a non-contact manner by utilizing a discharge phenomenon in a dark current region.

[0002]

2. Description of the Related Art Conventionally, a measuring device using a touch sensor has been known as a device capable of measuring the dimension of an object to be measured with high accuracy. That is, when the measurement electrode, which is a touch sensor, is gradually brought closer to the object to be measured and they come into contact with each other, an electric current is allowed to flow between them, and by detecting this electric current, it is detected that the both have come into contact with each other. Alternatively, it is known that the contact pressure generated between the two at the time of contact is detected to measure the dimension of the object to be measured from the amount of movement of the measuring electrode up to that time. However, in the case of the above-mentioned measuring devices, all of them are of the type in which the sensor is brought into contact with the surface of the object to be measured, and therefore there is a drawback that the object to be measured is damaged.

On the other hand, as a non-contact type dimension measuring device, a measuring device using an optical sensor is known and a device capable of highly accurate measurement has been developed, but it is very expensive and the device is complicated. Therefore, it was not possible to use it easily at the production site because it requires special handling.

In addition, as a non-contact type dimension measuring device,
A device using a magnetic or electrostatic sensor is also known, but none of them can measure accurately.

[0005]

As described above, the conventional non-contact method has the same accuracy as the dimension measuring device using the touch sensor, and the structure is simple and inexpensive, and the handling is easy. However, there is no dimension measuring device that can be easily used on the production site.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object thereof is to provide a gap between two objects even when they approach each other. Oite the spark discharge is generated by applying a constant DC voltage of about does not reach the (50~300V), is gradually moved to the object of the two Tsu is the interval approaches, both
The current does not flow between the two while the distance between them is large, but when they approach each other by 1 to 2 μ, a minute current that is neither a current due to a spark discharge nor a current due to a tunnel phenomenon suddenly enters the gap between them, that is, Focusing on the fact that a current flows due to field emission, and applying this phenomenon to the measuring electrode and the object to be measured, which are two objects, the measuring electrode is prevented from contacting the object to be measured. An object of the present invention is to provide a dimension measuring device adapted to measure dimensions.

That is, according to the present invention, in order to achieve the above-mentioned object, a measuring electrode and an object to be measured which are arranged apart from each other are provided.
By moving one side back and forth with respect to the other, both
It is installed so that a person relatively approaches or separates, and a constant DC voltage is applied between the measuring electrode and the object to be measured to measure the measuring electrode or the object to be measured. One of the objects is the other
Then, when both are brought close to the point of contact,
So that a current due to field emission flows between them.
And when the measurement electrode and the object to be measured comes close, when Ru is provided a current detector for detecting an electric field discharge morphism current <br/> are flow therebetween co
When the current detector detects field emission current,
Stop the movement of the moved measurement electrode or DUT
Means and, in which the forward movement is provided means for calculating the dimensions of the measurement point of the movement amount or found to be measured <br/> Jobutsu up when stopped.

[0008]

With the above structure, the measuring electrode, for example , is measured so that the measuring electrode and the object to be measured are relatively close to each other.
When gradually moving forward toward the regular item, the gap between the two
While it is large, no current flows between the two, but the contact size
When approaching the previous distance (1 to 2 μ), a current due to field emission suddenly flows between the two. Then since it was <br/> current flow is detected by the current detector, the forward movement of the measuring electrodes is stopped. Ie in this case the measurement
The electrode gradually approaches the DUT, and between the two
When the gap reaches the specified distance, the field emission current flows between them.
This current flows, and the measurement
Since the forward movement of the electrode is stopped, the measuring electrode is
A certain distance in front of the surface of the measurement point of
Position) and the measuring electrode is stopped.
The distance moved forward in the
It will correspond to the position (dimension). Therefore the measuring electrode
Calculate the dimension of the measurement point of the measured object from the amount of forward movement
As a result, it is possible to measure the dimensions of the location without touching the object to be measured.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an outer diameter measuring device for a round tip saw will be described below with reference to FIG. Reference numeral 1 denotes a driving device fixed to a machine base (not shown) of the measuring device, which uses a pulse motor. Reference numeral 2 denotes a moving mechanism composed of a ball screw, which includes a screw shaft 3 having a spiral groove formed on the outer periphery thereof, and a ball (not shown) formed on the outer periphery of the screw shaft 3.
It is formed by the nut body 4 screwed through. One end of the screw shaft 3 is connected to the rotary shaft of the pulse motor 1 which is a driving device via the coupling 5. When the screw shaft 3 is rotated by the rotation of the pulse motor 1, the nut body 4 is screwed. It is moved along the shaft 3, but in that case the nut body 4 itself is moved without turning. 6 arm protruding from the nut body 4, 7 A
A support rod is provided along the screw shaft 3 so as to be parallel to the screw shaft 3 by fixing the base end portion to the front end of the arm 6 , and the measurement electrode 9 is attached to the front end portion via an insulator 8. The nut body 4 is attached and is moved back and forth with respect to an object 11 to be measured, which will be described later, by moving the nut body 4 along the screw shaft 3.

Reference numeral 10 is a round tip saw 11 which is an object to be measured.
Is a supporting shaft for mounting the measuring device, and is provided on the machine base of the measuring device so as to be located in the moving direction of the measuring electrode 9.
In addition, the rotation mechanism (not shown) is configured to rotate by a predetermined angle.

Reference numeral 12 is a DC power source whose output voltage can be adjusted in the range of 50 to 300 V. The cathode is connected to the measuring electrode 9 via the current limiting resistor 13, and the anode is connected to the measuring electrode 9 via the current detecting resistor 14 to form a round tip saw. It is connected to the 11 side. Reference numeral 15 is a current detector connected to both ends of the current detection resistor 14, 16 is a rotation stop instruction means for instructing the pulse motor 1 to stop its rotation when the current detector 15 detects a current, and 17 is This is a calculation means for calculating the outer diameter dimension of the round tip saw 11 at that location from the amount of forward movement of the measurement electrode 9 by stopping the forward movement.

Next, the case where the radius of the tooth portion of the round tip saw is measured using the above measuring device will be described below. After the round tip saw 11 to be measured is attached to the support shaft 10, the pulse motor 1 is rotated in the positive direction to rotate the screw shaft 3. Then, the nut body 4 moves along the screw shaft 3, and the measurement electrode 9 gradually moves forward in the direction of the tip saw 11. In that case, at the beginning, since the tip of the measuring electrode 9 and the outer periphery of the tip saw 11 are considerably separated from each other, no current flows between the measuring electrode 9 and the tip saw 11, but when the width gradually narrows and approaches 1 to 2 μ. A current due to field emission flows in the gap between the two. That is, from the anode of the DC power supply 12, the current detection resistor 14, the tip saw 11,
Since a current due to field emission flows through the measurement electrode 9 and the current limiting resistor 13 to the cathode of the DC power source 12, a voltage drop occurs across the current detecting resistor 14, and the fact that the current has flowed indicates that the current detector 15 Detected by.

When it is detected that a current has flowed, the rotation stop command means 16 commands the pulse motor 1 to stop its rotation, so that the rotation of the pulse motor 1 is stopped, and measurement is performed. The forward movement of the electrode 9 is stopped immediately before it contacts the tip saw 11. When the forward movement of the measurement electrode 9 is stopped, the radius of the tooth portion of the tip saw 11 at that location is calculated by the calculating means 17 from the forward movement amount up to that point. That is, the position of the tip of the first measurement electrode 9 and the support shaft 10 to which the tip saw 11 is attached
Assuming that the distance from the center of A is A and the distance that the measurement electrode 9 has moved before the rotation of the pulse motor 1 is stopped is B, the radius X of the tooth portion of the tip saw 11 is X = A -B
-C (where C is the gap between the tip of the measuring electrode 9 and the outer periphery of the tooth portion of the tip saw 11 when the forward movement is stopped). The calculation result thus obtained may be recorded in a recording device or the like prepared separately. The distance A may be set in advance, and the distance B may be calculated from the number of pulses supplied to the pulse motor 1.

After measuring the radius X of one tooth portion of the tip saw 11 in this way, the pulse motor 1 is rotated in the opposite direction to move the measuring electrode 9 backward to the original position and the support shaft 10 is moved. The tooth portion of the tip saw 11 is rotated by one pitch. Then, after that, the above operation is repeated to measure the radius X of the entire tooth portion.

The relationship between the voltage of the DC power supply 12 and the gap at which a current due to field emission starts to flow is shown in FIG .
Apply between the measuring electrode 9 and the tip saw 11 of the object to be measured.
Depending on the height of DC voltage
But, for example, when the voltage of the DC power supply 12 was set to 300 V, approaching the current limiting resistor 13 300Emuomega, when the current detecting resistor 14 is set to 100 K.OMEGA, between the outer periphery of the tip and the chip saw 11 of the measuring electrode 9 until 2μ Then, a current due to field emission flows in the gap between the two. By the way, when the voltage of the DC power supply 12 is set to 350 V or more, as is clear from Paschen's law shown in FIG. 3, spark discharge is generated in the gap of about 10 μ, and the discharge start gap is very unstable. Become.

In the above description, the case of implementing the outer diameter measuring device for the round tip saw 11 has been described. Therefore, the round tip saw 11 to be measured is mounted on the support shaft 10 for measurement. The structure of the attachment part for mounting the measurement object may be formed by implementing an appropriate structure according to the shape of the measurement object.

[0017]

As described above, the present invention is separated from each other.
One of the measurement electrodes and
By moving forward and backward, both approaches relatively
The measurement voltage should be
Apply a constant DC voltage between the pole and the DUT, and
Or one of the DUTs moves forward with respect to the other.
When both are close to the point of contact, the electric field between them
Provided so that a current due to radiation flows, and the measuring electrode
And the DUT come close to each other, the field emission
The current detector that detects the current
When the detector detects field emission current,
Means to stop the movement of the pole or the object to be measured and its advance
When the movement is stopped, the measured amount of forward movement is measured.
Since a means for calculating the size of the measurement point of the object is provided,
The measuring electrode or the DUT to the other
Even if they are moved forward, one of them will move a certain distance before the other.
It is always stopped at a position (1 to 2 μ apart) and
The distance moved forward until the one is stopped is
It corresponds to the position (dimension) of the surface of the measurement point.
Therefore, the size of the measurement point of
By calculating the method, it is possible to
Since it is possible to measure the size of a place, it is possible to provide a size measuring device that can measure with the same degree of accuracy as a size measuring device using a touch sensor, although it is a non-contact type.

Moreover, when the measuring electrode and the object to be measured come close to each other
The electric field discharge morphism current flowing between both, because it is very small current, measured without I measured at a point coupled with a non-contact type, to generate "missing" or "scratches" the object to be measured Therefore, it is possible to provide a dimension measuring device that can be used for dimension measurement and angle measurement of saw teeth and cemented carbide tools, and can also be used for dimension measurement of materials such as cermet having large specific resistance and semiconductors.

Since it can be implemented with a relatively simple structure, it can be manufactured at low cost and can be used without special care in handling, so that it is possible to provide a size measuring device that can be easily used at the production site.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a part of a case of being applied to an outer diameter measuring device for a round tip saw as an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between an applied voltage between a measurement electrode and an object to be measured and a gap in which a current due to a radiation electric field starts to flow.

FIG. 3 is a diagram showing Paschen's law.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive device 2 Moving mechanism 9 Measurement electrode 11 Object to be measured 12 DC power supply 15 Current detector 16 Rotation stop command means 17 Calculation means

Claims (1)

[Claims] 1. A measuring electrode and an object to be measured which are arranged apart from each other.
By moving one of them back and forth with respect to the other
Te, set as both are or separated or relatively close
With kicking, by applying a constant DC voltage between the measuring electrode and the object to be measured, one of the measuring electrode or the object to be measured and other
Moved forward with respect to each other, and both came close to the point of contact
In this case, the electric field emission current should flow between them.
Only, also when said measuring electrode and the object to be measured it comes close, both
Keru set a current detector for detecting an electric field discharge morphism current flowing between
When this current detector detects the field emission current,
Stop moving the measurement electrode or the DUT that has been moved forward.
Means for moving amount or these until the forward movement is stopped
A non-contact type dimension measuring device provided with means for calculating the dimension of a measurement point of an object to be measured.