JPS5952707A - Touch sensor - Google Patents

Abstract

PURPOSE:To obtain a touch sensor which detects the tip position of a tool highly precisely without reference to the material of the tool and causes damage to neither the tool tip and the sensor itself without paying much attention to its handling, by detecting the contacting of a valve plate with a body to be measured from variation in the pressure in air-sealed container. CONSTITUTION:When pressurized air is introduced into the container 2 from an intake 5, the valve plate 4 seals an opening part (U-shaped inflection part) at one end of the container under the pressure in the container. The valve plate 4 abuts to the inside end 3a of a lid body 3 even when the pressurized air is not sealed in the container, so the valve plate 4 never falls on the bottom part of the container 2 easily and the air intake 5 is opened in the space between the valve plate 4 and lid body 3 all the time. If the tool 1 moves to contact with the valve plate 4 when the valve plate 4 seals the container 2, the valve plate 4 is pressed in the container 2 by the contacting pressure to form a gap between the valve plate 4 and the U-shaped inflection part 2a of the container 2. Consequently, the pressurized air in the container 2 leaks and the pressure drops. This pressure drop is detected by the detector 6 of a flowmeter or differential pressure gauge, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a touch sensor. In particular, the present invention relates to a touch sensor that detects the position of a tool tip in order to detect, for example, the wear state of a tool of a numerically controlled machine tool or to correct the length dimension of the tool.

Numeric value 11ilJ? 1llll machine tools require highly accurate tool positioning and centering when setting tools in the machine. In addition, for example, in a numerically controlled machine tool with an automatic tool changer, it is possible to detect whether the tool tip is damaged during machining or whether the tool tip position has changed due to wear. It is necessary to correct the position and take measures such as making an emergency stop depending on the situation.

To detect the position of such a tool tip, conventionally, a sensor that detects by electrical conduction caused by contact with the tool tip or a sensor that detects by a change in magnetic flux due to mechanical displacement has been mainly used. However, these sensors can only be applied to conductive tools, and have drawbacks such as poor repeatability of position detection due to temperature changes and high hysteresis. The problem was that it caused damage to both.

゛The present invention was made in view of these problems, and it is possible to detect the position of the tool tip with high precision regardless of the tool material, and the tool tip position and sensor itself can be detected without much care in handling. An object of the present invention is to provide a touch sensor that does not cause 4'R scratches on the touch sensor.

For this purpose, the touch sensor according to the present invention includes a gas-filled container, a valve plate attached to the container, and a detector for detecting a pressure change in the container, and the touch sensor includes a gas-filled container, a valve plate attached to the container, and a detector for detecting pressure changes in the container. When the object comes into contact with the valve plate, the gas inside the container leaks through the valve plate, and the contact between the object to be measured and the valve plate is detected from the pressure change inside the container at this time. It is something.

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are longitudinal sectional views showing a gas-filled container portion of a touch sensor according to an embodiment of the present invention. In addition,
FIG. 1 shows a state in which the tool 1, which is an object to be measured, is not in contact with the sensor, and FIG. 2 shows a state in which it is in contact with the sensor. The gas-filled container 2 has a threaded portion on the inner peripheral surface of one end, and the lid 3 is screwed onto this threaded portion in an airtight manner. The other end of the container 2 is open as a whole, but the periphery of the one end is bent in the shape of an opening 111 as shown in the figure, and a lid screwed onto this opening-shaped bent portion 2a and the bottom of the container. A valve plate 4 is attached to the inner end 3a of the body 3 and closes the mouth-shaped bent portion. A gas inlet 5 is inserted through the periphery of the container 2 and the lid 3.
is formed. As shown in FIG. 3, the gas inlet 5 communicates with a detector 6 such as an instantaneous flow meter or a differential pressure gauge. In FIG. 3, reference numeral 7 is a gas source that sends pressurized gas into the gas container 2 through the detector 6, and 8 is a display unit, such as a lamp, connected to the detector 6.

When pressurized gas is introduced into the container 2 through the inlet 5, the valve plate 4 seals the opening (mouth-shaped bent portion) at one end of the container by the pressure inside the container. Note that even when pressurized gas is not sealed in the container, the valve plate 4 is in contact with the inner end 3a of the lid 3, so the valve plate 4 does not fall to the bottom of the container 2, and therefore the gas inlet 5 is closed. It is designed to always open into the space between the valve plate 4 and the lid 3. When pressurized gas is introduced into the container 2 and the valve plate 4 is sealing the container 2, when the tool 1 moves and contacts the valve plate 4, the contact pressure at that time causes the valve plate 4 to close the container 2. The valve plate 4 is pushed inward, and a gap is created between the valve plate 4 and the mouth-shaped bent portion 2a of the container 2. As a result, the pressurized gas inside the container 2 leaks as shown in FIG. 2, and the pressure inside the container 2 decreases. This pressure drop is detected by a detector 6 such as a flow meter or a differential pressure gauge, and contact between the tool 1 and the valve plate, ie, the touch sensor, is detected by lighting the lamp on the display unit 8 and other operations.

FIG. 4 is a vertical new view of a tool contacting part of a touch sensor, that is, a gas enclosure, showing another embodiment of the present invention. In this case, a compression spring (
A valve plate return spring 9 is disposed, and the spring force of the spring 9 and the gas pressure within the container bring the valve plate 4 into close contact with the upper end opening of the container 2.

In this embodiment, even if the pressure of the pressurized gas is low, or even if the pressurized gas is not sealed in the container, the valve of the container can be kept closed, and the lower limit of the pressure of the gas used can be maintained. It is advantageous because there is no If the valve bends due to gas pressure, it is possible that the position detection accuracy will deteriorate, but this will not happen if the working pressure is low, and the ability to use low pressure gas means that detection can be performed with even higher accuracy. . When the tool 1 contacts the valve plate 4, the force applied to the tip of the tool is determined by the gas pressure and the force of the spring, and does not depend on how the tool 1 is applied. The pressure of the gas is the force applied to the tool 1
Although there is an α-tangent relationship, tool contact is detected by gas leakage, so there is no deterioration in accuracy due to pressure.

As mentioned above, the touch sensor according to the present invention has a buffering effect r+U due to gas pressure, which prevents damage to the tool tip and the sensor. In addition, there is no deterioration of the 411 degree curve due to changes in pressure, and the 'I'f & construction is simple and can be manufactured at low cost.

[Brief explanation of drawings]

1 shows an embodiment of the present invention, FIG. 1 is a vertical cross-sectional view of a gas-filled container of a touch sensor that is in a state where the tool is not in contact, and No. 21g1 is a vertical cross-sectional view of the container in a state where the tool is in contact. Figure 3 is a diagram schematically showing the overall configuration of the touch sensor, and the width 34 diagram is the i! 44: Cross-sectional view. 1... Tool (object to be measured), 2... Gas enclosure, 3
Lid body, 4...Valve plate, 5...Gas inlet, 6...Detector, 7...Gas source, 8...Display i+, l(, 9...Valve plate return spring. Figure 3 Figure 4 35-

Claims (1)

[Claims] It has a gas-filled container, a valve plate housed in the container, and a detector that detects a pressure change in the container, and when an object to be measured comes into contact with the valve plate of the container, A touch sensor characterized in that gas leaks through the valve plate, and contact between the object to be measured and the valve plate is detected from a pressure change in the container at this time.