JPH0156363B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a touch sensor used to detect contact between objects in numerically controlled machine tools and the like.

Conventionally, in machine tools, especially numerically controlled machine tools, in order to know the length of a tool, trial cutting has been performed or the tool length has been measured using various sensors. However, although it is certain to perform trial cutting, it requires a great deal of time, which is particularly undesirable for highly efficient machines such as numerically controlled machine tools. In addition, many conventional sensors use so-called binary discrimination, which only determines whether the detected value is above or below a certain value.In order to accurately determine the tool position, the tool or sensor must be moved slowly enough. It is necessary to stop the machine accurately at the position where the sensor's detection output changes, and it requires skill to operate the machine.
It took time. In addition, three-value discrimination (predetermined first
(and determining which of the three regions it falls into, intermediate between the second threshold, below the first threshold, and above the second threshold), or a type of sensor whose position can be read with a dial, meter, etc., based on magnetism. There are proximity sensors, position sensors using differential transformers, etc., but the accuracy of these sensors tends to depend on the shape of the tip of the tool, the sensing length changes each time the measurement is repeated, and the so-called repeatability is low.
There were drawbacks such as sensors and tools being easily damaged. As described above, the tool length (i.e., tool tip position) sensor used in conventional machine tools takes a long time to measure, requires skill,
Measurement accuracy was poor and the cost was high. These drawbacks can be solved if there is a contact sensor that can accurately sense the contact of the tool tip, is easy to operate, and is inexpensive.

An object of the present invention is to provide a contact sensor that has good sensing accuracy, is easy to handle, and is inexpensive.

The structure of the contact sensor according to the present invention is such that a fluid is passed through an elastic tube whose cross section is deformed in accordance with the displacement of a contacted part due to contact with a contact body, and the contact is sensed from a change in the flow rate or pressure of the fluid. a type contact sensing means, an electrical contact sensing means for sensing the contact from a change in insulation resistance between the contact body and the touched part, and a logic circuit receiving outputs of both the contact sensing means, When the fluid contact sensing means senses the contact, the displacement is a first threshold, and the electrical contact sensing means senses the contact, the displacement is a second threshold. Second
is larger than a threshold value, and the logic circuit outputs a logic signal according to a comparison between the displacement and the first and second threshold values.

The contact body will be described in detail below with reference to the drawings.

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, and 1 is a fluid supply device that supplies fluid such as air. Reference numeral 2 denotes a regulator that keeps the pressure or flow rate of the fluid sent from the supply device 1 constant and sends it throughout the system through piping 3. Reference numeral 10 denotes a sensor section whose cross-sectional view is shown in FIG. Pipe 1 is fitted to the top so that it can move up and down.
1 and a contact piece 113 that deforms the contact piece 113.
4 is a fluid type sensor that detects a decrease in the flow rate of fluid in the pipe 3 or an increase in pressure loss that occurs when the tool 7 presses the contact piece 13. Further, the detection terminal of the electric sensor 5 is connected to the contact piece 13 and the tool 7 in order to electrically detect the contact between the tool 7 and the contact piece 13. The outputs of the two electrical and fluid sensors 4 and 5 are connected to a display 6 with a built-in logic circuit.

Here, if we consider a case where the tool 7 gradually approaches the sensor section 10 from a distance, first, the insulation between the tool 7 and the contact piece 13 is broken and the electric sensor 10
is activated, and then the contact piece 13 is pushed and the pipe 11
is deformed, which causes the fluid sensor 4 to operate. By adjusting the setting sensitivity of the fluid type sensor 4, the two sensors 4,
5 can be activated. Then, the outputs of these two sensors 4 and 5 are added to the logic circuit shown in FIG.
Lamps 61, 62, and 63 are lit according to the area, and three states of the tool length are displayed: "short,""appropriate," and "too long" (three-value discrimination). The logic circuit shown in FIG. 4 consists of an inverting input AND circuit 64, an exclusive logic circuit 65, and an AND circuit 66. In general machine tools, there is an electrical connection between the tool and the machine, so one of the detection terminals of the electric sensor 5 is connected to the contact piece 13 and the other to an appropriate position on the machine. In addition, the contact piece 1 in the normal state (when the tool 7 is not in contact with the contact piece 13)
Insulating plate 14 to avoid electrical contact between 3 and the machine.
is attached to the bottom of the case 12.

The lower surface of the sensor section 10 is fixed to the reference surface of the machine tool, and the distance between this lower surface and the upper surface of the contact piece 13 is measured in advance. Therefore, the distance between the lower end of the tool 7 and the reference surface when the lower end of the tool 7 contacts the contact piece 13 and is located in area B in FIG. 3 (when the lamp 62 is lit) is known in advance. From this, it is possible to determine the distance between the lower end of the tool 7 and the reference surface, and the suitability of the length of the tool 7, from the lighting states of the lamps 61 to 63. That is, the lamps 61, 62
The lighting of and 63 indicates that the tool length is short (or the tool length compensation amount is insufficient), the tool length is appropriate (or the tool length compensation amount is appropriate), and the tool length is long (or the tool length compensation amount is excessive). Was.

As explained above, the contact sensor according to the present invention uses a three-value discriminant, so it has good sensing accuracy, quick sensing, and easy handling. Furthermore, it does not require expensive parts and has a simple configuration. It is inexpensive and has high impact resistance. Therefore, this contact sensor can be used not only for the machine tool mentioned in the embodiment but also for contact sensing and position sensing in various devices.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention, and FIG. 2 is a horizontal cross-sectional view of the sensor section in this embodiment.
FIG. 3 is a diagram showing the relationship between the tool position and sensor operation in the embodiment shown in FIG. 1, and FIG. 4 is a circuit diagram of a display for three-value discrimination in this embodiment. DESCRIPTION OF SYMBOLS 1...Fluid supply device, 2...Adjuster, 3...Piping, 4...Fluid type sensor, 5...Electric sensor, 6...Tool position indicator, 7...Tool, 10...
...Sensor part, 11...Thin pipe, 12...Case, 13...Contact part, 14...Insulating plate.

Claims (1)

[Claims] 1. Fluid type contact sensing means for detecting the contact from changes in the flow rate or pressure of the fluid by flowing a fluid through an elastic tube whose cross section is deformed in accordance with the displacement of the contacted part due to the contact of the contact body, and the contact body electrical contact sensing means for sensing the contact based on a change in insulation resistance between the contact portion and the contact portion; and a logic circuit receiving outputs from both of the contact sensing means, the fluidic contact sensing means detecting the contact. When the displacement at which the electrical contact sensing means senses the contact is set as a first threshold and the displacement at which the electrical contact sensing means senses the contact is set as a second threshold, the first threshold is larger than the second threshold, and the logic circuit The contact sensor is characterized in that it outputs a logic signal according to a comparison between the displacement and the first and second threshold values.